WEBVTT 00:00.520 --> 00:02.670 align:start position:0% In<00:00:00.680> the<00:00:00.760> late<00:00:00.960> 1980s,<00:00:01.840> there<00:00:01.920> was<00:00:02.000> only<00:00:02.240> one 00:02.670 --> 00:02.680 align:start position:0% In the late 1980s, there was only one 00:02.680 --> 00:04.950 align:start position:0% In the late 1980s, there was only one thing<00:00:03.160> everyone<00:00:03.680> was<00:00:03.880> talking<00:00:04.280> about.<00:00:04.840> It 00:04.950 --> 00:04.960 align:start position:0% thing everyone was talking about. It 00:04.960 --> 00:06.950 align:start position:0% thing everyone was talking about. It wasn't<00:00:05.240> Madonna's<00:00:05.640> latest<00:00:05.960> single,<00:00:06.600> leg 00:06.950 --> 00:06.960 align:start position:0% wasn't Madonna's latest single, leg 00:06.960 --> 00:09.470 align:start position:0% wasn't Madonna's latest single, leg warmers,<00:00:07.520> shoulder<00:00:07.920> pads,<00:00:08.240> or<00:00:08.400> even<00:00:09.200> big 00:09.470 --> 00:09.480 align:start position:0% warmers, shoulder pads, or even big 00:09.480 --> 00:12.310 align:start position:0% warmers, shoulder pads, or even big hair.<00:00:10.400> It<00:00:10.600> was<00:00:10.920> ozone. 00:12.310 --> 00:12.320 align:start position:0% hair. It was ozone. 00:12.320 --> 00:15.590 align:start position:0% hair. It was ozone. Or<00:00:12.480> more<00:00:12.680> precisely,<00:00:13.600> a<00:00:13.800> vast,<00:00:14.480> hulking<00:00:15.120> great 00:15.590 --> 00:15.600 align:start position:0% Or more precisely, a vast, hulking great 00:15.600 --> 00:18.270 align:start position:0% Or more precisely, a vast, hulking great hole<00:00:16.480> that<00:00:16.600> had<00:00:16.800> opened<00:00:17.200> up<00:00:17.400> in<00:00:17.560> our<00:00:17.720> planet's 00:18.270 --> 00:18.280 align:start position:0% hole that had opened up in our planet's 00:18.280 --> 00:20.950 align:start position:0% hole that had opened up in our planet's life<00:00:18.600> support<00:00:19.120> system,<00:00:19.520> the<00:00:19.720> ozone<00:00:20.320> layer. 00:20.950 --> 00:20.960 align:start position:0% life support system, the ozone layer. 00:20.960 --> 00:21.310 align:start position:0% life support system, the ozone layer. >> [music] 00:21.310 --> 00:21.320 align:start position:0% >> [music] 00:21.320 --> 00:23.430 align:start position:0% >> [music] >> And<00:00:21.480> the<00:00:21.560> culprit,<00:00:22.200> supervillain<00:00:22.920> gases 00:23.430 --> 00:23.440 align:start position:0% >> And the culprit, supervillain gases 00:23.440 --> 00:26.150 align:start position:0% >> And the culprit, supervillain gases known<00:00:23.760> as<00:00:24.040> chlorofluorocarbons, 00:26.150 --> 00:26.160 align:start position:0% known as chlorofluorocarbons, 00:26.160 --> 00:28.750 align:start position:0% known as chlorofluorocarbons, or<00:00:26.400> CFCs,<00:00:27.640> found<00:00:28.000> in<00:00:28.120> everything<00:00:28.480> from 00:28.750 --> 00:28.760 align:start position:0% or CFCs, found in everything from 00:28.760 --> 00:30.470 align:start position:0% or CFCs, found in everything from fridges<00:00:29.280> to<00:00:29.520> deodorants,<00:00:30.160> and<00:00:30.320> they<00:00:30.400> were 00:30.470 --> 00:30.480 align:start position:0% fridges to deodorants, and they were 00:30.480 --> 00:32.830 align:start position:0% fridges to deodorants, and they were destroying<00:00:31.080> the<00:00:31.200> precious<00:00:31.760> ozone<00:00:32.680> in<00:00:32.750> [music] 00:32.830 --> 00:32.840 align:start position:0% destroying the precious ozone in [music] 00:32.840 --> 00:35.270 align:start position:0% destroying the precious ozone in [music] the<00:00:32.920> stratosphere.<00:00:34.160> By<00:00:34.360> the<00:00:34.480> late<00:00:34.800> '80s,<00:00:35.160> the 00:35.270 --> 00:35.280 align:start position:0% the stratosphere. By the late '80s, the 00:35.280 --> 00:37.670 align:start position:0% the stratosphere. By the late '80s, the hole<00:00:35.520> was<00:00:35.680> reaching<00:00:36.080> sizes<00:00:36.520> of<00:00:36.600> around<00:00:36.920> 22 00:37.670 --> 00:37.680 align:start position:0% hole was reaching sizes of around 22 00:37.680 --> 00:40.950 align:start position:0% hole was reaching sizes of around 22 million<00:00:38.360> square<00:00:38.880> kilometers.<00:00:39.800> By<00:00:39.960> 2040,<00:00:40.840> the 00:40.950 --> 00:40.960 align:start position:0% million square kilometers. By 2040, the 00:40.960 --> 00:44.110 align:start position:0% million square kilometers. By 2040, the hole<00:00:41.200> would<00:00:41.320> have<00:00:41.480> gone<00:00:41.920> global.<00:00:42.400> By<00:00:42.560> 2050, 00:44.110 --> 00:44.120 align:start position:0% hole would have gone global. By 2050, 00:44.120 --> 00:45.870 align:start position:0% hole would have gone global. By 2050, the<00:00:44.320> ozone<00:00:44.760> layer<00:00:44.960> could<00:00:45.120> have<00:00:45.240> collapsed 00:45.870 --> 00:45.880 align:start position:0% the ozone layer could have collapsed 00:45.880 --> 00:49.070 align:start position:0% the ozone layer could have collapsed entirely.<00:00:47.280> Harmful<00:00:47.920> UV<00:00:48.360> radiation<00:00:48.960> would 00:49.070 --> 00:49.080 align:start position:0% entirely. Harmful UV radiation would 00:49.080 --> 00:51.190 align:start position:0% entirely. Harmful UV radiation would come<00:00:49.440> flooding<00:00:50.040> through,<00:00:50.720> causing<00:00:51.120> huge 00:51.190 --> 00:51.200 align:start position:0% come flooding through, causing huge 00:51.200 --> 00:54.030 align:start position:0% come flooding through, causing huge increases<00:00:52.160> in<00:00:52.320> skin<00:00:52.760> cancer,<00:00:53.200> cataracts,<00:00:53.840> and 00:54.030 --> 00:54.040 align:start position:0% increases in skin cancer, cataracts, and 00:54.040 --> 00:56.630 align:start position:0% increases in skin cancer, cataracts, and compromised<00:00:54.760> immune<00:00:55.160> systems.<00:00:56.160> Plants<00:00:56.520> and 00:56.630 --> 00:56.640 align:start position:0% compromised immune systems. Plants and 00:56.640 --> 00:58.270 align:start position:0% compromised immune systems. Plants and crops<00:00:57.040> would<00:00:57.240> be<00:00:57.440> failing.<00:00:57.840> The<00:00:57.960> word 00:58.270 --> 00:58.280 align:start position:0% crops would be failing. The word 00:58.280 --> 01:00.710 align:start position:0% crops would be failing. The word "uninhabitable"<00:00:59.680> was<00:00:59.880> being<00:01:00.200> used<00:01:00.520> by 01:00.710 --> 01:00.720 align:start position:0% "uninhabitable" was being used by 01:00.720 --> 01:03.110 align:start position:0% "uninhabitable" was being used by leading<00:01:00.915> [music]<00:01:01.120> scientists. 01:03.110 --> 01:03.120 align:start position:0% leading [music] scientists. 01:03.120 --> 01:04.869 align:start position:0% leading [music] scientists. Before<00:01:03.520> climate<00:01:03.880> change,<00:01:04.160> this<00:01:04.480> was<00:01:04.720> the 01:04.869 --> 01:04.879 align:start position:0% Before climate change, this was the 01:04.879 --> 01:07.350 align:start position:0% Before climate change, this was the greatest<00:01:05.440> environmental<00:01:06.040> apocalypse<00:01:06.600> of<00:01:07.000> our 01:07.350 --> 01:07.360 align:start position:0% greatest environmental apocalypse of our 01:07.360 --> 01:09.150 align:start position:0% greatest environmental apocalypse of our age.<00:01:07.640> And<00:01:08.000> yet, 01:09.150 --> 01:09.160 align:start position:0% age. And yet, 01:09.160 --> 01:11.430 align:start position:0% age. And yet, we<00:01:09.320> don't<00:01:09.520> seem<00:01:09.680> to<00:01:09.760> talk<00:01:09.960> about<00:01:10.200> it<00:01:10.280> anymore. 01:11.430 --> 01:11.440 align:start position:0% we don't seem to talk about it anymore. 01:11.440 --> 01:17.350 align:start position:0% we don't seem to talk about it anymore. Is<00:01:11.640> it<00:01:11.840> because<00:01:13.240> we<00:01:13.480> actually<00:01:14.080> fixed<00:01:14.600> it? 01:17.350 --> 01:17.360 align:start position:0% 01:17.360 --> 01:18.750 align:start position:0% I'm<00:01:17.480> James<00:01:17.760> Shaw,<00:01:17.880> and<00:01:18.120> you're<00:01:18.280> watching 01:18.750 --> 01:18.760 align:start position:0% I'm James Shaw, and you're watching 01:18.760 --> 01:21.310 align:start position:0% I'm James Shaw, and you're watching Astro<00:01:19.400> Earth.<00:01:19.960> Join<00:01:20.240> me<00:01:20.400> in<00:01:20.560> this<00:01:20.800> video<00:01:21.120> as<00:01:21.240> we 01:21.310 --> 01:21.320 align:start position:0% Astro Earth. Join me in this video as we 01:21.320 --> 01:23.350 align:start position:0% Astro Earth. Join me in this video as we discover<00:01:21.640> the<00:01:21.720> truth<00:01:22.280> about<00:01:22.560> the<00:01:22.640> hole<00:01:23.040> in<00:01:23.200> the 01:23.350 --> 01:23.360 align:start position:0% discover the truth about the hole in the 01:23.360 --> 01:25.070 align:start position:0% discover the truth about the hole in the ozone<00:01:23.760> layer.<00:01:24.240> We'll<00:01:24.320> get<00:01:24.480> to<00:01:24.560> the<00:01:24.640> bottom<00:01:24.880> of 01:25.070 --> 01:25.080 align:start position:0% ozone layer. We'll get to the bottom of 01:25.080 --> 01:27.710 align:start position:0% ozone layer. We'll get to the bottom of what<00:01:25.320> it<00:01:25.520> is,<00:01:25.760> why<00:01:26.320> it's<00:01:26.600> there,<00:01:26.800> and<00:01:26.960> how 01:27.710 --> 01:27.720 align:start position:0% what it is, why it's there, and how 01:27.720 --> 01:29.670 align:start position:0% what it is, why it's there, and how humanity<00:01:28.400> managed<00:01:28.840> to<00:01:29.000> fix<00:01:29.360> it.<00:01:29.440> And<00:01:29.560> I'll 01:29.670 --> 01:29.680 align:start position:0% humanity managed to fix it. And I'll 01:29.680 --> 01:31.630 align:start position:0% humanity managed to fix it. And I'll explain<00:01:30.160> why<00:01:30.360> we<00:01:30.520> might<00:01:30.880> not<00:01:31.120> be<00:01:31.280> out<00:01:31.440> of<00:01:31.520> the 01:31.630 --> 01:31.640 align:start position:0% explain why we might not be out of the 01:31.640 --> 01:34.710 align:start position:0% explain why we might not be out of the woods<00:01:32.840> just<00:01:33.160> yet.<00:01:34.080> For<00:01:34.200> those<00:01:34.440> of<00:01:34.520> you<00:01:34.600> that 01:34.710 --> 01:34.720 align:start position:0% woods just yet. For those of you that 01:34.720 --> 01:37.030 align:start position:0% woods just yet. For those of you that might<00:01:34.880> be<00:01:35.000> late<00:01:35.320> to<00:01:35.440> this<00:01:35.840> ozone<00:01:36.400> party,<00:01:36.840> and 01:37.030 --> 01:37.040 align:start position:0% might be late to this ozone party, and 01:37.040 --> 01:38.470 align:start position:0% might be late to this ozone party, and even<00:01:37.240> for<00:01:37.320> those<00:01:37.480> of<00:01:37.560> you<00:01:37.600> that<00:01:37.800> aren't,<00:01:38.160> it's 01:38.470 --> 01:38.480 align:start position:0% even for those of you that aren't, it's 01:38.480 --> 01:40.070 align:start position:0% even for those of you that aren't, it's worth<00:01:38.760> going<00:01:38.960> back<00:01:39.160> to<00:01:39.200> the<00:01:39.280> basics<00:01:39.720> to<00:01:39.840> start 01:40.070 --> 01:40.080 align:start position:0% worth going back to the basics to start 01:40.080 --> 01:43.350 align:start position:0% worth going back to the basics to start things<00:01:40.400> off.<00:01:41.200> What<00:01:41.560> actually<00:01:42.040> is<00:01:42.600> the<00:01:42.800> ozone 01:43.350 --> 01:43.360 align:start position:0% things off. What actually is the ozone 01:43.360 --> 01:45.150 align:start position:0% things off. What actually is the ozone layer?<00:01:43.920> Well,<00:01:44.160> Earth's<00:01:44.400> atmosphere<00:01:44.880> is<00:01:44.960> like 01:45.150 --> 01:45.160 align:start position:0% layer? Well, Earth's atmosphere is like 01:45.160 --> 01:47.790 align:start position:0% layer? Well, Earth's atmosphere is like a<00:01:45.280> jacket,<00:01:46.160> or<00:01:46.480> several<00:01:46.960> jackets<00:01:47.440> for<00:01:47.640> our 01:47.790 --> 01:47.800 align:start position:0% a jacket, or several jackets for our 01:47.800 --> 01:50.190 align:start position:0% a jacket, or several jackets for our planet.<00:01:48.480> There<00:01:48.680> are<00:01:48.840> five<00:01:49.440> main<00:01:49.760> layers.<00:01:50.120> The 01:50.190 --> 01:50.200 align:start position:0% planet. There are five main layers. The 01:50.200 --> 01:51.670 align:start position:0% planet. There are five main layers. The bit<00:01:50.360> we're<00:01:50.480> most<00:01:50.720> familiar<00:01:51.000> with<00:01:51.280> is<00:01:51.520> the 01:51.670 --> 01:51.680 align:start position:0% bit we're most familiar with is the 01:51.680 --> 01:54.230 align:start position:0% bit we're most familiar with is the troposphere.<00:01:52.800> This<00:01:53.120> is<00:01:53.320> where<00:01:53.520> we<00:01:53.680> live.<00:01:54.160> The 01:54.230 --> 01:54.240 align:start position:0% troposphere. This is where we live. The 01:54.240 --> 01:56.390 align:start position:0% troposphere. This is where we live. The troposphere<00:01:54.760> starts<00:01:55.280> on<00:01:55.520> Earth's<00:01:55.960> surface 01:56.390 --> 01:56.400 align:start position:0% troposphere starts on Earth's surface 01:56.400 --> 01:59.070 align:start position:0% troposphere starts on Earth's surface and<00:01:56.480> extends<00:01:56.920> up<00:01:57.160> to<00:01:57.240> around<00:01:57.600> 20<00:01:58.120> km.<00:01:59.000> Now, 01:59.070 --> 01:59.080 align:start position:0% and extends up to around 20 km. Now, 01:59.080 --> 02:00.950 align:start position:0% and extends up to around 20 km. Now, this<00:01:59.280> actually<00:01:59.560> varies<00:01:59.920> depending<00:02:00.200> on<00:02:00.440> where 02:00.950 --> 02:00.960 align:start position:0% this actually varies depending on where 02:00.960 --> 02:02.670 align:start position:0% this actually varies depending on where you're<00:02:01.160> standing.<00:02:01.920> And<00:02:02.120> no,<00:02:02.320> I<00:02:02.360> don't<00:02:02.560> mean 02:02.670 --> 02:02.680 align:start position:0% you're standing. And no, I don't mean 02:02.680 --> 02:05.510 align:start position:0% you're standing. And no, I don't mean like<00:02:02.920> on<00:02:03.080> a<00:02:03.120> mountain.<00:02:04.080> It's<00:02:04.280> around<00:02:04.600> 18<00:02:05.080> to<00:02:05.200> 20 02:05.510 --> 02:05.520 align:start position:0% like on a mountain. It's around 18 to 20 02:05.520 --> 02:08.550 align:start position:0% like on a mountain. It's around 18 to 20 km<00:02:05.840> at<00:02:05.920> the<00:02:06.000> equator,<00:02:06.880> but<00:02:07.000> only<00:02:07.160> 6<00:02:07.600> km<00:02:08.160> at<00:02:08.440> the 02:08.550 --> 02:08.560 align:start position:0% km at the equator, but only 6 km at the 02:08.560 --> 02:11.830 align:start position:0% km at the equator, but only 6 km at the poles.<00:02:09.520> The<00:02:09.600> troposphere<00:02:10.160> is<00:02:10.360> a<00:02:10.520> hard-working 02:11.830 --> 02:11.840 align:start position:0% poles. The troposphere is a hard-working 02:11.840 --> 02:13.990 align:start position:0% poles. The troposphere is a hard-working layer.<00:02:12.480> It<00:02:12.600> provides<00:02:13.000> the<00:02:13.120> air<00:02:13.240> we<00:02:13.400> breathe, 02:13.990 --> 02:14.000 align:start position:0% layer. It provides the air we breathe, 02:14.000 --> 02:16.630 align:start position:0% layer. It provides the air we breathe, contains<00:02:14.480> 99%<00:02:15.160> of<00:02:15.240> the<00:02:15.320> atmosphere's<00:02:15.800> water, 02:16.630 --> 02:16.640 align:start position:0% contains 99% of the atmosphere's water, 02:16.640 --> 02:18.510 align:start position:0% contains 99% of the atmosphere's water, and<00:02:16.760> is<00:02:16.959> where<00:02:17.200> you'll<00:02:17.400> find<00:02:17.720> pretty<00:02:17.959> much<00:02:18.320> all 02:18.510 --> 02:18.520 align:start position:0% and is where you'll find pretty much all 02:18.520 --> 02:20.710 align:start position:0% and is where you'll find pretty much all of<00:02:18.640> our<00:02:18.800> weather.<00:02:19.480> As<00:02:19.720> you<00:02:19.840> climb,<00:02:20.320> the<00:02:20.520> air 02:20.710 --> 02:20.720 align:start position:0% of our weather. As you climb, the air 02:20.720 --> 02:23.110 align:start position:0% of our weather. As you climb, the air gets<00:02:21.000> thinner<00:02:21.360> and<00:02:21.760> colder. 02:23.110 --> 02:23.120 align:start position:0% gets thinner and colder. 02:23.120 --> 02:24.750 align:start position:0% gets thinner and colder. Next<00:02:23.400> up<00:02:23.520> is<00:02:23.640> the<00:02:23.800> stratosphere,<00:02:24.600> which 02:24.750 --> 02:24.760 align:start position:0% Next up is the stratosphere, which 02:24.760 --> 02:27.790 align:start position:0% Next up is the stratosphere, which extends<00:02:25.160> from<00:02:25.280> around<00:02:25.600> 6<00:02:26.000> to<00:02:26.240> 50<00:02:26.720> km<00:02:27.200> above<00:02:27.600> the 02:27.790 --> 02:27.800 align:start position:0% extends from around 6 to 50 km above the 02:27.800 --> 02:30.150 align:start position:0% extends from around 6 to 50 km above the Earth's<00:02:28.280> surface.<00:02:29.280> The<00:02:29.400> only<00:02:29.600> clouds<00:02:30.000> that 02:30.150 --> 02:30.160 align:start position:0% Earth's surface. The only clouds that 02:30.160 --> 02:31.630 align:start position:0% Earth's surface. The only clouds that usually<00:02:30.440> venture<00:02:30.800> this<00:02:31.160> high<00:02:31.440> are 02:31.630 --> 02:31.640 align:start position:0% usually venture this high are 02:31.640 --> 02:34.510 align:start position:0% usually venture this high are cumulonimbus<00:02:32.640> thunderclouds,<00:02:33.760> whose<00:02:34.080> tops 02:34.510 --> 02:34.520 align:start position:0% cumulonimbus thunderclouds, whose tops 02:34.520 --> 02:36.430 align:start position:0% cumulonimbus thunderclouds, whose tops just<00:02:34.920> scrape<00:02:35.280> the<00:02:35.400> lowest<00:02:35.760> part<00:02:36.200> of<00:02:36.360> the 02:36.430 --> 02:36.440 align:start position:0% just scrape the lowest part of the 02:36.440 --> 02:38.070 align:start position:0% just scrape the lowest part of the stratosphere,<00:02:37.440> which<00:02:37.560> is<00:02:37.680> why<00:02:37.800> they've<00:02:37.959> got 02:38.070 --> 02:38.080 align:start position:0% stratosphere, which is why they've got 02:38.080 --> 02:40.710 align:start position:0% stratosphere, which is why they've got their<00:02:38.160> distinctive<00:02:38.720> anvil-shaped<00:02:39.840> caps. 02:40.710 --> 02:40.720 align:start position:0% their distinctive anvil-shaped caps. 02:40.720 --> 02:42.390 align:start position:0% their distinctive anvil-shaped caps. They're<00:02:40.840> sort<00:02:40.959> of<00:02:41.080> squashed<00:02:42.080> against<00:02:42.320> the 02:42.390 --> 02:42.400 align:start position:0% They're sort of squashed against the 02:42.400 --> 02:44.910 align:start position:0% They're sort of squashed against the ceiling<00:02:42.800> of<00:02:42.880> the<00:02:43.160> atmospheric<00:02:43.680> boundary. 02:44.910 --> 02:44.920 align:start position:0% ceiling of the atmospheric boundary. 02:44.920 --> 02:46.870 align:start position:0% ceiling of the atmospheric boundary. Commercial<00:02:45.400> passenger<00:02:45.800> jets<00:02:46.160> fly<00:02:46.560> in<00:02:46.680> the 02:46.870 --> 02:46.880 align:start position:0% Commercial passenger jets fly in the 02:46.880 --> 02:48.830 align:start position:0% Commercial passenger jets fly in the lower<00:02:47.280> stratosphere,<00:02:47.880> trying<00:02:48.040> to<00:02:48.160> stay<00:02:48.360> above 02:48.830 --> 02:48.840 align:start position:0% lower stratosphere, trying to stay above 02:48.840 --> 02:51.550 align:start position:0% lower stratosphere, trying to stay above the<00:02:49.000> weather<00:02:49.760> for<00:02:49.920> a<00:02:49.959> smoother<00:02:50.440> ride.<00:02:51.320> In<00:02:51.480> the 02:51.550 --> 02:51.560 align:start position:0% the weather for a smoother ride. In the 02:51.560 --> 02:54.030 align:start position:0% the weather for a smoother ride. In the troposphere,<00:02:52.200> temperatures<00:02:52.880> fall<00:02:53.480> as<00:02:53.800> you 02:54.030 --> 02:54.040 align:start position:0% troposphere, temperatures fall as you 02:54.040 --> 02:55.910 align:start position:0% troposphere, temperatures fall as you climb,<00:02:54.959> but<00:02:55.080> in<00:02:55.120> the<00:02:55.200> stratosphere,<00:02:55.800> they 02:55.910 --> 02:55.920 align:start position:0% climb, but in the stratosphere, they 02:55.920 --> 02:58.910 align:start position:0% climb, but in the stratosphere, they actually<00:02:56.320> increase<00:02:57.400> with<00:02:57.760> altitude.<00:02:58.840> And 02:58.910 --> 02:58.920 align:start position:0% actually increase with altitude. And 02:58.920 --> 03:00.030 align:start position:0% actually increase with altitude. And there's<00:02:59.080> a<00:02:59.160> reason<00:02:59.480> for<00:02:59.600> this,<00:02:59.840> and<00:02:59.920> it's 03:00.030 --> 03:00.040 align:start position:0% there's a reason for this, and it's 03:00.040 --> 03:01.670 align:start position:0% there's a reason for this, and it's actually<00:03:00.280> the<00:03:00.360> reason<00:03:00.720> you're<00:03:00.920> watching<00:03:01.400> this 03:01.670 --> 03:01.680 align:start position:0% actually the reason you're watching this 03:01.680 --> 03:07.390 align:start position:0% actually the reason you're watching this video.<00:03:02.440> This<00:03:03.360> is<00:03:03.560> where<00:03:03.760> the<00:03:03.959> ozone<00:03:04.480> layer<00:03:04.760> is. 03:07.390 --> 03:07.400 align:start position:0% 03:07.400 --> 03:09.190 align:start position:0% Beyond<00:03:07.680> that<00:03:08.000> is<00:03:08.120> the<00:03:08.280> mesosphere,<00:03:09.080> the 03:09.190 --> 03:09.200 align:start position:0% Beyond that is the mesosphere, the 03:09.200 --> 03:11.670 align:start position:0% Beyond that is the mesosphere, the thermosphere,<00:03:10.120> and<00:03:10.239> the<00:03:10.360> exosphere.<00:03:11.320> And 03:11.670 --> 03:11.680 align:start position:0% thermosphere, and the exosphere. And 03:11.680 --> 03:14.150 align:start position:0% thermosphere, and the exosphere. And past<00:03:12.080> that,<00:03:12.480> well,<00:03:12.600> that's<00:03:12.920> space.<00:03:13.800> And<00:03:14.000> we've 03:14.150 --> 03:14.160 align:start position:0% past that, well, that's space. And we've 03:14.160 --> 03:15.990 align:start position:0% past that, well, that's space. And we've actually<00:03:14.400> got<00:03:14.519> a<00:03:14.560> whole<00:03:14.880> other<00:03:15.239> channel<00:03:15.720> for 03:15.990 --> 03:16.000 align:start position:0% actually got a whole other channel for 03:16.000 --> 03:18.070 align:start position:0% actually got a whole other channel for space.<00:03:16.480> So,<00:03:16.640> if<00:03:16.760> that's<00:03:17.040> your<00:03:17.120> thing,<00:03:17.760> why<00:03:17.880> not 03:18.070 --> 03:18.080 align:start position:0% space. So, if that's your thing, why not 03:18.080 --> 03:20.310 align:start position:0% space. So, if that's your thing, why not check<00:03:18.239> it<00:03:18.400> out<00:03:18.560> after<00:03:18.800> this<00:03:18.959> video? 03:20.310 --> 03:20.320 align:start position:0% check it out after this video? 03:20.320 --> 03:22.270 align:start position:0% check it out after this video? Anyway,<00:03:20.560> back<00:03:20.800> to<00:03:20.920> ozone.<00:03:21.360> Every<00:03:21.880> layer<00:03:22.160> of 03:22.270 --> 03:22.280 align:start position:0% Anyway, back to ozone. Every layer of 03:22.280 --> 03:24.430 align:start position:0% Anyway, back to ozone. Every layer of the<00:03:22.400> atmosphere<00:03:22.880> has<00:03:23.120> a<00:03:23.200> specific<00:03:23.760> job<00:03:24.040> to<00:03:24.160> do. 03:24.430 --> 03:24.440 align:start position:0% the atmosphere has a specific job to do. 03:24.440 --> 03:27.030 align:start position:0% the atmosphere has a specific job to do. And<00:03:24.600> the<00:03:24.840> ozone<00:03:25.440> layer<00:03:25.640> is<00:03:25.920> possibly<00:03:26.600> the<00:03:26.760> most 03:27.030 --> 03:27.040 align:start position:0% And the ozone layer is possibly the most 03:27.040 --> 03:29.110 align:start position:0% And the ozone layer is possibly the most important<00:03:27.680> of<00:03:27.840> them<00:03:28.040> all. 03:29.110 --> 03:29.120 align:start position:0% important of them all. 03:29.120 --> 03:30.670 align:start position:0% important of them all. But<00:03:29.239> to<00:03:29.320> understand<00:03:29.840> why<00:03:30.040> that<00:03:30.320> is,<00:03:30.480> we<00:03:30.560> need 03:30.670 --> 03:30.680 align:start position:0% But to understand why that is, we need 03:30.680 --> 03:32.470 align:start position:0% But to understand why that is, we need to<00:03:30.760> understand<00:03:31.080> a<00:03:31.120> bit<00:03:31.280> more<00:03:31.440> about<00:03:31.800> what<00:03:32.200> this 03:32.470 --> 03:32.480 align:start position:0% to understand a bit more about what this 03:32.480 --> 03:35.350 align:start position:0% to understand a bit more about what this vital<00:03:32.880> layer<00:03:33.200> is<00:03:33.440> actually<00:03:33.920> made<00:03:34.440> of. 03:35.350 --> 03:35.360 align:start position:0% vital layer is actually made of. 03:35.360 --> 03:37.390 align:start position:0% vital layer is actually made of. We're<00:03:35.519> all<00:03:35.640> familiar<00:03:35.959> with<00:03:36.200> oxygen,<00:03:36.760> O2.<00:03:37.200> It's 03:37.390 --> 03:37.400 align:start position:0% We're all familiar with oxygen, O2. It's 03:37.400 --> 03:39.070 align:start position:0% We're all familiar with oxygen, O2. It's what<00:03:37.560> we're<00:03:37.720> all<00:03:37.840> breathing<00:03:38.160> in<00:03:38.360> right<00:03:38.560> now. 03:39.070 --> 03:39.080 align:start position:0% what we're all breathing in right now. 03:39.080 --> 03:42.229 align:start position:0% what we're all breathing in right now. Well,<00:03:39.320> ozone<00:03:39.760> is<00:03:40.040> O3.<00:03:41.120> That's<00:03:41.440> three<00:03:41.840> oxygen 03:42.229 --> 03:42.239 align:start position:0% Well, ozone is O3. That's three oxygen 03:42.239 --> 03:46.030 align:start position:0% Well, ozone is O3. That's three oxygen atoms<00:03:42.680> combined<00:03:43.440> to<00:03:43.640> form<00:03:43.959> a<00:03:44.080> pale<00:03:44.519> blue<00:03:44.920> gas. 03:46.030 --> 03:46.040 align:start position:0% atoms combined to form a pale blue gas. 03:46.040 --> 03:47.590 align:start position:0% atoms combined to form a pale blue gas. You<00:03:46.080> know<00:03:46.200> that<00:03:46.320> sort<00:03:46.440> of<00:03:46.560> sharp,<00:03:47.080> fresh<00:03:47.360> smell 03:47.590 --> 03:47.600 align:start position:0% You know that sort of sharp, fresh smell 03:47.600 --> 03:49.229 align:start position:0% You know that sort of sharp, fresh smell you<00:03:47.680> often<00:03:47.920> get<00:03:48.120> just<00:03:48.360> after<00:03:48.600> a<00:03:48.640> thunderstorm? 03:49.229 --> 03:49.239 align:start position:0% you often get just after a thunderstorm? 03:49.239 --> 03:52.270 align:start position:0% you often get just after a thunderstorm? Well,<00:03:49.400> that,<00:03:50.320> that<00:03:50.600> is<00:03:50.760> ozone. 03:52.270 --> 03:52.280 align:start position:0% Well, that, that is ozone. 03:52.280 --> 03:54.750 align:start position:0% Well, that, that is ozone. Ozone<00:03:52.680> can<00:03:52.800> be<00:03:52.920> both<00:03:53.200> a<00:03:53.240> hero<00:03:53.760> and<00:03:54.160> a<00:03:54.240> villain, 03:54.750 --> 03:54.760 align:start position:0% Ozone can be both a hero and a villain, 03:54.760 --> 03:57.390 align:start position:0% Ozone can be both a hero and a villain, and<00:03:55.000> whether<00:03:55.240> it's<00:03:55.440> good<00:03:55.840> or<00:03:56.040> bad<00:03:56.600> depends<00:03:57.080> on 03:57.390 --> 03:57.400 align:start position:0% and whether it's good or bad depends on 03:57.400 --> 03:59.310 align:start position:0% and whether it's good or bad depends on where<00:03:57.800> it<00:03:58.200> is. 03:59.310 --> 03:59.320 align:start position:0% where it is. 03:59.320 --> 04:02.430 align:start position:0% where it is. Bad<00:03:59.880> ozone<00:04:00.400> is<00:04:00.640> tropospheric<00:04:01.680> or<00:04:01.880> ground 04:02.430 --> 04:02.440 align:start position:0% Bad ozone is tropospheric or ground 04:02.440 --> 04:04.470 align:start position:0% Bad ozone is tropospheric or ground level.<00:04:02.840> It's<00:04:03.000> a<00:04:03.120> harmful<00:04:03.720> air<00:04:03.920> pollutant<00:04:04.400> and 04:04.470 --> 04:04.480 align:start position:0% level. It's a harmful air pollutant and 04:04.480 --> 04:06.990 align:start position:0% level. It's a harmful air pollutant and often<00:04:04.680> the<00:04:04.720> main<00:04:05.000> ingredient<00:04:05.560> in<00:04:05.800> smog.<00:04:06.680> But 04:06.990 --> 04:07.000 align:start position:0% often the main ingredient in smog. But 04:07.000 --> 04:09.510 align:start position:0% often the main ingredient in smog. But good<00:04:07.440> ozone<00:04:07.920> is<00:04:08.080> stratospheric.<00:04:09.000> It<00:04:09.200> hangs 04:09.510 --> 04:09.520 align:start position:0% good ozone is stratospheric. It hangs 04:09.520 --> 04:11.630 align:start position:0% good ozone is stratospheric. It hangs out<00:04:09.640> around<00:04:09.920> 15<00:04:10.240> to<00:04:10.360> 35<00:04:10.800> km<00:04:11.080> above<00:04:11.280> the<00:04:11.400> Earth's 04:11.630 --> 04:11.640 align:start position:0% out around 15 to 35 km above the Earth's 04:11.640 --> 04:13.750 align:start position:0% out around 15 to 35 km above the Earth's surface<00:04:12.440> and<00:04:12.760> basically<00:04:13.240> acts<00:04:13.480> like<00:04:13.640> a 04:13.750 --> 04:13.760 align:start position:0% surface and basically acts like a 04:13.760 --> 04:16.630 align:start position:0% surface and basically acts like a sunscreen<00:04:14.600> for<00:04:14.840> the<00:04:14.959> planet.<00:04:16.000> This<00:04:16.359> is<00:04:16.519> the 04:16.630 --> 04:16.640 align:start position:0% sunscreen for the planet. This is the 04:16.640 --> 04:18.030 align:start position:0% sunscreen for the planet. This is the ozone<00:04:16.920> layer<00:04:17.160> we've<00:04:17.400> all<00:04:17.560> heard<00:04:17.760> of<00:04:17.840> and<00:04:17.959> it 04:18.030 --> 04:18.040 align:start position:0% ozone layer we've all heard of and it 04:18.040 --> 04:21.710 align:start position:0% ozone layer we've all heard of and it blocks<00:04:18.320> an<00:04:18.400> incredible<00:04:18.880> 98%<00:04:20.160> of<00:04:20.440> all<00:04:21.079> harmful 04:21.710 --> 04:21.720 align:start position:0% blocks an incredible 98% of all harmful 04:21.720 --> 04:24.990 align:start position:0% blocks an incredible 98% of all harmful UV<00:04:22.080> radiation.<00:04:22.720> Yeah,<00:04:23.280> 98%.<00:04:24.320> It<00:04:24.600> It<00:04:24.720> works 04:24.990 --> 04:25.000 align:start position:0% UV radiation. Yeah, 98%. It It works 04:25.000 --> 04:27.510 align:start position:0% UV radiation. Yeah, 98%. It It works hard.<00:04:25.919> The<00:04:26.040> vast<00:04:26.280> majority<00:04:26.760> of<00:04:26.960> sunlight<00:04:27.360> is 04:27.510 --> 04:27.520 align:start position:0% hard. The vast majority of sunlight is 04:27.520 --> 04:29.510 align:start position:0% hard. The vast majority of sunlight is what's<00:04:27.760> known<00:04:28.000> as<00:04:28.320> visible<00:04:28.880> light,<00:04:29.240> the<00:04:29.320> light 04:29.510 --> 04:29.520 align:start position:0% what's known as visible light, the light 04:29.520 --> 04:31.630 align:start position:0% what's known as visible light, the light we<00:04:29.640> can<00:04:29.840> see,<00:04:30.080> with<00:04:30.320> wavelengths<00:04:30.720> of<00:04:30.880> 400<00:04:31.440> to 04:31.630 --> 04:31.640 align:start position:0% we can see, with wavelengths of 400 to 04:31.640 --> 04:35.030 align:start position:0% we can see, with wavelengths of 400 to 700<00:04:32.520> nm.<00:04:33.840> Ultraviolet<00:04:34.560> radiation<00:04:34.919> is 04:35.030 --> 04:35.040 align:start position:0% 700 nm. Ultraviolet radiation is 04:35.040 --> 04:37.470 align:start position:0% 700 nm. Ultraviolet radiation is actually<00:04:35.360> only<00:04:35.520> 8%<00:04:36.200> of<00:04:36.560> all<00:04:36.919> light<00:04:37.200> and<00:04:37.320> it's 04:37.470 --> 04:37.480 align:start position:0% actually only 8% of all light and it's 04:37.480 --> 04:40.230 align:start position:0% actually only 8% of all light and it's invisible<00:04:38.120> to<00:04:38.360> the<00:04:38.520> human<00:04:39.200> eye,<00:04:39.600> though<00:04:39.840> some 04:40.230 --> 04:40.240 align:start position:0% invisible to the human eye, though some 04:40.240 --> 04:43.590 align:start position:0% invisible to the human eye, though some insects,<00:04:40.880> like<00:04:41.080> bumblebees,<00:04:42.080> can<00:04:42.400> see<00:04:42.640> it. 04:43.590 --> 04:43.600 align:start position:0% insects, like bumblebees, can see it. 04:43.600 --> 04:45.470 align:start position:0% insects, like bumblebees, can see it. Visible<00:04:44.040> light<00:04:44.320> consists<00:04:44.880> of<00:04:45.080> different 04:45.470 --> 04:45.480 align:start position:0% Visible light consists of different 04:45.480 --> 04:47.630 align:start position:0% Visible light consists of different colors<00:04:45.800> that<00:04:45.919> you<00:04:46.040> can<00:04:46.240> see<00:04:46.560> in<00:04:46.720> a<00:04:46.760> rainbow<00:04:47.400> and 04:47.630 --> 04:47.640 align:start position:0% colors that you can see in a rainbow and 04:47.640 --> 04:50.950 align:start position:0% colors that you can see in a rainbow and UV<00:04:48.240> is<00:04:48.600> no<00:04:48.880> different.<00:04:49.560> It<00:04:49.800> also<00:04:50.160> has<00:04:50.480> its<00:04:50.720> own 04:50.950 --> 04:50.960 align:start position:0% UV is no different. It also has its own 04:50.960 --> 04:55.190 align:start position:0% UV is no different. It also has its own spectrum,<00:04:51.800> UVA,<00:04:52.600> UVB,<00:04:53.360> and<00:04:53.680> UVC.<00:04:55.000> They're 04:55.190 --> 04:55.200 align:start position:0% spectrum, UVA, UVB, and UVC. They're 04:55.200 --> 04:57.950 align:start position:0% spectrum, UVA, UVB, and UVC. They're classified<00:04:55.800> by<00:04:56.040> wavelengths,<00:04:56.880> so<00:04:57.120> UVA<00:04:57.640> is<00:04:57.800> the 04:57.950 --> 04:57.960 align:start position:0% classified by wavelengths, so UVA is the 04:57.960 --> 05:01.350 align:start position:0% classified by wavelengths, so UVA is the longest<00:04:58.520> and<00:04:58.760> UVC<00:04:59.560> is<00:04:59.800> the<00:04:59.919> shortest.<00:05:01.160> You<00:05:01.280> may 05:01.350 --> 05:01.360 align:start position:0% longest and UVC is the shortest. You may 05:01.360 --> 05:03.790 align:start position:0% longest and UVC is the shortest. You may have<00:05:01.480> even<00:05:01.640> seen<00:05:01.960> UVA<00:05:02.360> and<00:05:02.560> UVB<00:05:02.960> on<00:05:03.200> sunscreen 05:03.790 --> 05:03.800 align:start position:0% have even seen UVA and UVB on sunscreen 05:03.800 --> 05:05.990 align:start position:0% have even seen UVA and UVB on sunscreen labels.<00:05:04.320> They're<00:05:04.520> what<00:05:04.720> causes<00:05:05.200> sunburn<00:05:05.760> and 05:05.990 --> 05:06.000 align:start position:0% labels. They're what causes sunburn and 05:06.000 --> 05:08.430 align:start position:0% labels. They're what causes sunburn and can<00:05:06.240> cause<00:05:06.680> skin<00:05:07.080> cancer. 05:08.430 --> 05:08.440 align:start position:0% can cause skin cancer. 05:08.440 --> 05:11.070 align:start position:0% can cause skin cancer. UVB<00:05:09.000> and<00:05:09.240> UVC<00:05:09.919> are<00:05:10.000> not<00:05:10.360> only<00:05:10.640> incredibly 05:11.070 --> 05:11.080 align:start position:0% UVB and UVC are not only incredibly 05:11.080 --> 05:12.830 align:start position:0% UVB and UVC are not only incredibly damaging<00:05:11.560> to<00:05:11.760> us,<00:05:12.080> but<00:05:12.240> they<00:05:12.360> mess<00:05:12.560> with<00:05:12.720> all 05:12.830 --> 05:12.840 align:start position:0% damaging to us, but they mess with all 05:12.840 --> 05:14.670 align:start position:0% damaging to us, but they mess with all sorts<00:05:13.040> of<00:05:13.120> stuff,<00:05:13.360> including<00:05:13.720> photosynthesis 05:14.670 --> 05:14.680 align:start position:0% sorts of stuff, including photosynthesis 05:14.680 --> 05:16.710 align:start position:0% sorts of stuff, including photosynthesis and<00:05:14.800> the<00:05:14.880> productivity<00:05:15.680> in<00:05:15.880> plants<00:05:16.480> and 05:16.710 --> 05:16.720 align:start position:0% and the productivity in plants and 05:16.720 --> 05:20.150 align:start position:0% and the productivity in plants and crops.<00:05:17.680> They<00:05:17.840> damage<00:05:18.440> DNA,<00:05:18.960> suppress<00:05:19.720> immune 05:20.150 --> 05:20.160 align:start position:0% crops. They damage DNA, suppress immune 05:20.160 --> 05:22.750 align:start position:0% crops. They damage DNA, suppress immune systems,<00:05:20.600> and<00:05:20.800> can<00:05:21.040> even<00:05:21.400> reduce<00:05:21.960> survival 05:22.750 --> 05:22.760 align:start position:0% systems, and can even reduce survival 05:22.760 --> 05:25.470 align:start position:0% systems, and can even reduce survival rates.<00:05:23.560> In<00:05:23.680> fact,<00:05:23.960> UVC<00:05:24.480> radiation<00:05:25.000> is<00:05:25.160> used<00:05:25.360> to 05:25.470 --> 05:25.480 align:start position:0% rates. In fact, UVC radiation is used to 05:25.480 --> 05:28.270 align:start position:0% rates. In fact, UVC radiation is used to disinfect<00:05:26.200> hospitals.<00:05:27.360> The<00:05:27.480> reason<00:05:27.800> being<00:05:28.080> is 05:28.270 --> 05:28.280 align:start position:0% disinfect hospitals. The reason being is 05:28.280 --> 05:30.070 align:start position:0% disinfect hospitals. The reason being is because<00:05:28.520> it<00:05:28.640> can<00:05:28.960> quite<00:05:29.160> literally<00:05:29.760> kill 05:30.070 --> 05:30.080 align:start position:0% because it can quite literally kill 05:30.080 --> 05:32.150 align:start position:0% because it can quite literally kill nearly<00:05:30.560> everything. 05:32.150 --> 05:32.160 align:start position:0% nearly everything. 05:32.160 --> 05:33.550 align:start position:0% nearly everything. And<00:05:32.280> here's<00:05:32.400> where<00:05:32.520> the<00:05:32.640> ozone<00:05:32.919> layer<00:05:33.120> comes 05:33.550 --> 05:33.560 align:start position:0% And here's where the ozone layer comes 05:33.560 --> 05:36.510 align:start position:0% And here's where the ozone layer comes in<00:05:33.680> because<00:05:33.840> it<00:05:34.000> screens<00:05:35.080> all<00:05:35.640> of<00:05:35.800> the<00:05:35.960> most 05:36.510 --> 05:36.520 align:start position:0% in because it screens all of the most 05:36.520 --> 05:39.030 align:start position:0% in because it screens all of the most harmful<00:05:37.200> UVC<00:05:37.919> radiation<00:05:38.480> and<00:05:38.600> the<00:05:38.720> vast 05:39.030 --> 05:39.040 align:start position:0% harmful UVC radiation and the vast 05:39.040 --> 05:42.230 align:start position:0% harmful UVC radiation and the vast majority<00:05:40.120> of<00:05:40.400> UVB.<00:05:41.258> [music]<00:05:41.640> Quite<00:05:41.919> simply, 05:42.230 --> 05:42.240 align:start position:0% majority of UVB. [music] Quite simply, 05:42.240 --> 05:43.790 align:start position:0% majority of UVB. [music] Quite simply, without<00:05:42.760> it,<00:05:42.840> the<00:05:42.919> radiation<00:05:43.440> would 05:43.790 --> 05:43.800 align:start position:0% without it, the radiation would 05:43.800 --> 05:46.750 align:start position:0% without it, the radiation would literally<00:05:44.320> sterilize<00:05:44.919> the<00:05:45.080> Earth's<00:05:45.360> surface. 05:46.750 --> 05:46.760 align:start position:0% literally sterilize the Earth's surface. 05:46.760 --> 05:48.750 align:start position:0% literally sterilize the Earth's surface. But<00:05:46.919> here's<00:05:47.200> the<00:05:47.360> thing.<00:05:47.880> Ozone<00:05:48.320> is<00:05:48.480> what's 05:48.750 --> 05:48.760 align:start position:0% But here's the thing. Ozone is what's 05:48.760 --> 05:51.310 align:start position:0% But here's the thing. Ozone is what's known<00:05:49.000> as<00:05:49.160> a<00:05:49.280> trace<00:05:50.040> gas.<00:05:50.680> That<00:05:50.880> means<00:05:51.120> there's 05:51.310 --> 05:51.320 align:start position:0% known as a trace gas. That means there's 05:51.320 --> 05:53.150 align:start position:0% known as a trace gas. That means there's not<00:05:51.680> a<00:05:51.760> lot<00:05:51.960> of<00:05:52.080> it,<00:05:52.280> basically.<00:05:52.720> In<00:05:52.840> fact, 05:53.150 --> 05:53.160 align:start position:0% not a lot of it, basically. In fact, 05:53.160 --> 05:54.870 align:start position:0% not a lot of it, basically. In fact, even<00:05:53.320> in<00:05:53.400> the<00:05:53.480> stratosphere,<00:05:54.440> ozone 05:54.870 --> 05:54.880 align:start position:0% even in the stratosphere, ozone 05:54.880 --> 05:57.510 align:start position:0% even in the stratosphere, ozone concentration<00:05:55.560> is<00:05:55.680> only<00:05:55.840> about<00:05:56.120> 15<00:05:56.840> parts<00:05:57.280> per 05:57.510 --> 05:57.520 align:start position:0% concentration is only about 15 parts per 05:57.520 --> 05:58.950 align:start position:0% concentration is only about 15 parts per million. 05:58.950 --> 05:58.960 align:start position:0% million. 05:58.960 --> 06:01.150 align:start position:0% million. If<00:05:59.040> you<00:05:59.160> took<00:05:59.440> all<00:05:59.680> the<00:05:59.840> ozone<00:06:00.200> in<00:06:00.400> the<00:06:00.640> world 06:01.150 --> 06:01.160 align:start position:0% If you took all the ozone in the world 06:01.160 --> 06:02.510 align:start position:0% If you took all the ozone in the world and<00:06:01.280> spread<00:06:01.520> it<00:06:01.560> across<00:06:01.840> the<00:06:02.000> Earth's<00:06:02.200> surface 06:02.510 --> 06:02.520 align:start position:0% and spread it across the Earth's surface 06:02.520 --> 06:05.710 align:start position:0% and spread it across the Earth's surface like<00:06:02.760> a<00:06:02.880> kind<00:06:03.120> of<00:06:03.360> ozoney<00:06:04.160> jam,<00:06:05.280> it<00:06:05.400> would<00:06:05.520> form 06:05.710 --> 06:05.720 align:start position:0% like a kind of ozoney jam, it would form 06:05.720 --> 06:08.910 align:start position:0% like a kind of ozoney jam, it would form a<00:06:05.760> layer<00:06:06.080> only<00:06:06.480> 3<00:06:07.160> mm<00:06:08.120> thick.<00:06:08.480> That's<00:06:08.640> the<00:06:08.720> same 06:08.910 --> 06:08.920 align:start position:0% a layer only 3 mm thick. That's the same 06:08.920 --> 06:11.710 align:start position:0% a layer only 3 mm thick. That's the same as<00:06:09.160> two<00:06:09.680> tiny<00:06:10.200> pennies. 06:11.710 --> 06:11.720 align:start position:0% as two tiny pennies. 06:11.720 --> 06:12.990 align:start position:0% as two tiny pennies. And<00:06:11.800> if<00:06:11.880> you<00:06:11.960> did<00:06:12.080> that<00:06:12.280> same<00:06:12.600> thing<00:06:12.760> with<00:06:12.880> the 06:12.990 --> 06:13.000 align:start position:0% And if you did that same thing with the 06:13.000 --> 06:15.510 align:start position:0% And if you did that same thing with the rest<00:06:13.280> of<00:06:13.360> the<00:06:13.520> atmosphere,<00:06:14.360> that<00:06:14.760> atmosphery 06:15.510 --> 06:15.520 align:start position:0% rest of the atmosphere, that atmosphery 06:15.520 --> 06:19.750 align:start position:0% rest of the atmosphere, that atmosphery jam<00:06:15.840> would<00:06:15.960> be<00:06:16.160> 8<00:06:16.560> km<00:06:17.440> high<00:06:18.160> and<00:06:18.520> very<00:06:18.720> sticky. 06:19.750 --> 06:19.760 align:start position:0% jam would be 8 km high and very sticky. 06:19.760 --> 06:21.870 align:start position:0% jam would be 8 km high and very sticky. So,<00:06:19.919> what<00:06:20.120> happens<00:06:20.480> when<00:06:20.640> you<00:06:20.760> discover<00:06:21.200> some 06:21.870 --> 06:21.880 align:start position:0% So, what happens when you discover some 06:21.880 --> 06:24.550 align:start position:0% So, what happens when you discover some of<00:06:22.040> that<00:06:22.280> precious<00:06:22.720> ozone<00:06:23.120> is<00:06:23.320> missing?<00:06:24.360> This 06:24.550 --> 06:24.560 align:start position:0% of that precious ozone is missing? This 06:24.560 --> 06:25.909 align:start position:0% of that precious ozone is missing? This animation<00:06:25.000> on<00:06:25.120> your<00:06:25.240> screen<00:06:25.560> shows<00:06:25.800> the 06:25.909 --> 06:25.919 align:start position:0% animation on your screen shows the 06:25.919 --> 06:28.830 align:start position:0% animation on your screen shows the actual<00:06:26.520> hole<00:06:27.120> in<00:06:27.480> our<00:06:27.760> ozone<00:06:28.120> layer<00:06:28.360> tracked 06:28.830 --> 06:28.840 align:start position:0% actual hole in our ozone layer tracked 06:28.840 --> 06:30.670 align:start position:0% actual hole in our ozone layer tracked over<00:06:29.040> two<00:06:29.320> decades. 06:30.670 --> 06:30.680 align:start position:0% over two decades. 06:30.680 --> 06:32.710 align:start position:0% over two decades. The<00:06:30.800> blue<00:06:31.120> and<00:06:31.320> purple<00:06:31.760> mark<00:06:32.080> the<00:06:32.280> area<00:06:32.560> with 06:32.710 --> 06:32.720 align:start position:0% The blue and purple mark the area with 06:32.720 --> 06:34.870 align:start position:0% The blue and purple mark the area with the<00:06:32.919> least<00:06:33.680> ozone.<00:06:34.160> Now,<00:06:34.320> technically,<00:06:34.720> this 06:34.870 --> 06:34.880 align:start position:0% the least ozone. Now, technically, this 06:34.880 --> 06:36.909 align:start position:0% the least ozone. Now, technically, this isn't<00:06:35.160> a<00:06:35.280> hole,<00:06:35.880> I<00:06:35.960> know,<00:06:36.240> in<00:06:36.400> shape.<00:06:36.720> It's<00:06:36.880> a 06:36.909 --> 06:36.919 align:start position:0% isn't a hole, I know, in shape. It's a 06:36.919 --> 06:39.870 align:start position:0% isn't a hole, I know, in shape. It's a region<00:06:37.440> of<00:06:37.600> exceptionally<00:06:38.360> depleted<00:06:39.000> ozone. 06:39.870 --> 06:39.880 align:start position:0% region of exceptionally depleted ozone. 06:39.880 --> 06:41.750 align:start position:0% region of exceptionally depleted ozone. But,<00:06:40.360> hole<00:06:40.720> was<00:06:40.960> snappier<00:06:41.480> and<00:06:41.640> more 06:41.750 --> 06:41.760 align:start position:0% But, hole was snappier and more 06:41.760 --> 06:43.710 align:start position:0% But, hole was snappier and more importantly,<00:06:42.760> more<00:06:43.000> concerning<00:06:43.520> to<00:06:43.640> the 06:43.710 --> 06:43.720 align:start position:0% importantly, more concerning to the 06:43.720 --> 06:46.870 align:start position:0% importantly, more concerning to the general<00:06:44.080> public.<00:06:45.200> Now,<00:06:45.360> in<00:06:45.480> 1979,<00:06:46.480> there<00:06:46.640> was 06:46.870 --> 06:46.880 align:start position:0% general public. Now, in 1979, there was 06:46.880 --> 06:49.390 align:start position:0% general public. Now, in 1979, there was no<00:06:47.160> significant<00:06:47.720> hole<00:06:48.080> at<00:06:48.440> all.<00:06:49.040> And<00:06:49.160> then<00:06:49.280> it 06:49.390 --> 06:49.400 align:start position:0% no significant hole at all. And then it 06:49.400 --> 06:51.230 align:start position:0% no significant hole at all. And then it just<00:06:49.720> grew<00:06:50.040> and<00:06:50.240> grew<00:06:50.440> and<00:06:50.600> grew<00:06:50.800> and<00:06:50.960> grew, 06:51.230 --> 06:51.240 align:start position:0% just grew and grew and grew and grew, 06:51.240 --> 06:53.110 align:start position:0% just grew and grew and grew and grew, covering<00:06:51.560> not<00:06:51.760> just<00:06:51.960> Antarctica,<00:06:52.960> but 06:53.110 --> 06:53.120 align:start position:0% covering not just Antarctica, but 06:53.120 --> 06:55.190 align:start position:0% covering not just Antarctica, but occasionally<00:06:53.840> stretching<00:06:54.240> as<00:06:54.400> far<00:06:54.680> as<00:06:54.880> South 06:55.190 --> 06:55.200 align:start position:0% occasionally stretching as far as South 06:55.200 --> 06:58.830 align:start position:0% occasionally stretching as far as South America<00:06:56.200> or<00:06:56.480> even<00:06:56.880> New<00:06:57.160> Zealand.<00:06:58.280> By<00:06:58.480> the<00:06:58.600> year 06:58.830 --> 06:58.840 align:start position:0% America or even New Zealand. By the year 06:58.840 --> 07:02.909 align:start position:0% America or even New Zealand. By the year 2000,<00:06:59.840> it<00:07:00.040> measured<00:07:00.360> 28.4<00:07:01.680> million<00:07:02.400> square 07:02.909 --> 07:02.919 align:start position:0% 2000, it measured 28.4 million square 07:02.919 --> 07:05.830 align:start position:0% 2000, it measured 28.4 million square kilometers,<00:07:04.080> almost<00:07:04.520> seven<00:07:04.880> times<00:07:05.360> the<00:07:05.440> size 07:05.830 --> 07:05.840 align:start position:0% kilometers, almost seven times the size 07:05.840 --> 07:09.190 align:start position:0% kilometers, almost seven times the size of<00:07:06.000> the<00:07:06.280> EU<00:07:06.960> or<00:07:07.200> three<00:07:07.680> times<00:07:08.080> the<00:07:08.160> size<00:07:08.919> of<00:07:09.080> the 07:09.190 --> 07:09.200 align:start position:0% of the EU or three times the size of the 07:09.200 --> 07:10.990 align:start position:0% of the EU or three times the size of the United<00:07:09.760> States. 07:10.990 --> 07:11.000 align:start position:0% United States. 07:11.000 --> 07:12.950 align:start position:0% United States. Looking<00:07:11.240> back<00:07:11.520> with<00:07:11.840> hindsight,<00:07:12.400> it<00:07:12.640> seems 07:12.950 --> 07:12.960 align:start position:0% Looking back with hindsight, it seems 07:12.960 --> 07:14.630 align:start position:0% Looking back with hindsight, it seems pretty<00:07:13.160> obvious<00:07:13.400> that<00:07:13.560> this<00:07:13.919> was<00:07:14.440> a 07:14.630 --> 07:14.640 align:start position:0% pretty obvious that this was a 07:14.640 --> 07:17.630 align:start position:0% pretty obvious that this was a planetary-scale<00:07:15.880> emergency.<00:07:17.120> But,<00:07:17.320> how<00:07:17.480> did 07:17.630 --> 07:17.640 align:start position:0% planetary-scale emergency. But, how did 07:17.640 --> 07:19.630 align:start position:0% planetary-scale emergency. But, how did we<00:07:17.760> even<00:07:18.000> realize<00:07:18.280> we<00:07:18.440> had<00:07:18.680> a<00:07:18.720> problem<00:07:19.200> in<00:07:19.520> the 07:19.630 --> 07:19.640 align:start position:0% we even realize we had a problem in the 07:19.640 --> 07:20.990 align:start position:0% we even realize we had a problem in the first<00:07:19.960> place? 07:20.990 --> 07:21.000 align:start position:0% first place? 07:21.000 --> 07:23.190 align:start position:0% first place? The<00:07:21.120> answer,<00:07:21.520> as<00:07:21.720> with<00:07:21.919> so<00:07:22.080> many<00:07:22.280> things,<00:07:22.800> is 07:23.190 --> 07:23.200 align:start position:0% The answer, as with so many things, is 07:23.200 --> 07:25.310 align:start position:0% The answer, as with so many things, is science. 07:25.310 --> 07:25.320 align:start position:0% science. 07:25.320 --> 07:27.470 align:start position:0% science. We<00:07:25.480> first<00:07:25.760> started<00:07:26.120> measuring<00:07:26.680> ozone<00:07:27.080> to<00:07:27.200> try 07:27.470 --> 07:27.480 align:start position:0% We first started measuring ozone to try 07:27.480 --> 07:29.430 align:start position:0% We first started measuring ozone to try and<00:07:27.600> understand<00:07:28.160> more<00:07:28.440> about<00:07:28.840> how<00:07:29.240> our 07:29.430 --> 07:29.440 align:start position:0% and understand more about how our 07:29.440 --> 07:32.190 align:start position:0% and understand more about how our atmosphere<00:07:30.160> worked.<00:07:31.000> By<00:07:31.120> the<00:07:31.200> late<00:07:31.440> 19th<00:07:32.000> and 07:32.190 --> 07:32.200 align:start position:0% atmosphere worked. By the late 19th and 07:32.200 --> 07:34.710 align:start position:0% atmosphere worked. By the late 19th and early<00:07:32.400> 20th<00:07:32.960> centuries,<00:07:33.919> scientists<00:07:34.480> had 07:34.710 --> 07:34.720 align:start position:0% early 20th centuries, scientists had 07:34.720 --> 07:36.750 align:start position:0% early 20th centuries, scientists had already<00:07:35.080> established<00:07:35.720> that<00:07:35.880> stratospheric 07:36.750 --> 07:36.760 align:start position:0% already established that stratospheric 07:36.760 --> 07:40.270 align:start position:0% already established that stratospheric ozone<00:07:37.520> acted<00:07:37.919> as<00:07:38.080> a<00:07:38.200> vital<00:07:38.800> shield<00:07:39.560> against 07:40.270 --> 07:40.280 align:start position:0% ozone acted as a vital shield against 07:40.280 --> 07:42.590 align:start position:0% ozone acted as a vital shield against harmful<00:07:40.840> radiation. 07:42.590 --> 07:42.600 align:start position:0% harmful radiation. 07:42.600 --> 07:45.310 align:start position:0% harmful radiation. In<00:07:42.760> the<00:07:42.840> mid-1920s,<00:07:44.280> Gordon<00:07:44.680> Dobson,<00:07:45.160> a 07:45.310 --> 07:45.320 align:start position:0% In the mid-1920s, Gordon Dobson, a 07:45.320 --> 07:48.470 align:start position:0% In the mid-1920s, Gordon Dobson, a British<00:07:46.040> scientist,<00:07:47.200> invented<00:07:47.760> a<00:07:47.840> new<00:07:48.160> type 07:48.470 --> 07:48.480 align:start position:0% British scientist, invented a new type 07:48.480 --> 07:50.310 align:start position:0% British scientist, invented a new type of<00:07:48.600> spectrophotometer, 07:50.310 --> 07:50.320 align:start position:0% of spectrophotometer, 07:50.320 --> 07:52.230 align:start position:0% of spectrophotometer, an<00:07:50.440> instrument<00:07:50.880> that<00:07:51.040> monitors<00:07:51.560> UV<00:07:51.880> levels 07:52.230 --> 07:52.240 align:start position:0% an instrument that monitors UV levels 07:52.240 --> 07:54.190 align:start position:0% an instrument that monitors UV levels from<00:07:52.360> the<00:07:52.480> ground<00:07:53.000> to<00:07:53.120> work<00:07:53.400> out<00:07:53.600> how<00:07:53.800> much 07:54.190 --> 07:54.200 align:start position:0% from the ground to work out how much 07:54.200 --> 07:56.710 align:start position:0% from the ground to work out how much ozone<00:07:54.600> there<00:07:54.760> is<00:07:55.000> in<00:07:55.160> the<00:07:55.280> stratosphere. 07:56.710 --> 07:56.720 align:start position:0% ozone there is in the stratosphere. 07:56.720 --> 07:58.390 align:start position:0% ozone there is in the stratosphere. More<00:07:56.920> than<00:07:57.080> a<00:07:57.120> century<00:07:57.640> later,<00:07:58.080> and<00:07:58.240> the 07:58.390 --> 07:58.400 align:start position:0% More than a century later, and the 07:58.400 --> 08:01.510 align:start position:0% More than a century later, and the Dobson<00:07:58.960> spectrophotometer<00:08:00.320> is<00:08:00.600> still<00:08:01.400> the 08:01.510 --> 08:01.520 align:start position:0% Dobson spectrophotometer is still the 08:01.520 --> 08:03.790 align:start position:0% Dobson spectrophotometer is still the foundation<00:08:02.240> of<00:08:02.360> the<00:08:02.560> global<00:08:03.040> network<00:08:03.600> for 08:03.790 --> 08:03.800 align:start position:0% foundation of the global network for 08:03.800 --> 08:07.150 align:start position:0% foundation of the global network for monitoring<00:08:04.360> atmospheric<00:08:05.080> ozone<00:08:05.520> even<00:08:05.920> today. 08:07.150 --> 08:07.160 align:start position:0% monitoring atmospheric ozone even today. 08:07.160 --> 08:10.270 align:start position:0% monitoring atmospheric ozone even today. In<00:08:07.280> fact,<00:08:07.720> what<00:08:07.960> are<00:08:08.080> known<00:08:08.440> as<00:08:08.720> Dobson<00:08:09.400> units 08:10.270 --> 08:10.280 align:start position:0% In fact, what are known as Dobson units 08:10.280 --> 08:13.230 align:start position:0% In fact, what are known as Dobson units are<00:08:10.480> now<00:08:10.760> the<00:08:11.000> gold<00:08:11.480> standard<00:08:12.120> for<00:08:12.360> monitoring 08:13.230 --> 08:13.240 align:start position:0% are now the gold standard for monitoring 08:13.240 --> 08:17.070 align:start position:0% are now the gold standard for monitoring the<00:08:13.520> ozone<00:08:14.120> hole.<00:08:15.000> So,<00:08:15.240> 300<00:08:16.200> Dobson<00:08:16.600> units<00:08:16.880> is 08:17.070 --> 08:17.080 align:start position:0% the ozone hole. So, 300 Dobson units is 08:17.080 --> 08:19.950 align:start position:0% the ozone hole. So, 300 Dobson units is the<00:08:17.320> ideal<00:08:18.080> amount<00:08:18.680> of<00:08:18.960> ozone.<00:08:19.640> It's<00:08:19.840> what 08:19.950 --> 08:19.960 align:start position:0% the ideal amount of ozone. It's what 08:19.960 --> 08:22.030 align:start position:0% the ideal amount of ozone. It's what gives<00:08:20.160> us<00:08:20.240> that<00:08:20.440> metaphorical<00:08:21.080> 3-mm<00:08:21.760> layer<00:08:22.000> I 08:22.030 --> 08:22.040 align:start position:0% gives us that metaphorical 3-mm layer I 08:22.040 --> 08:24.909 align:start position:0% gives us that metaphorical 3-mm layer I mentioned<00:08:22.440> before.<00:08:23.320> Less<00:08:23.600> than<00:08:23.840> that,<00:08:24.880> and 08:24.909 --> 08:24.919 align:start position:0% mentioned before. Less than that, and 08:24.919 --> 08:26.110 align:start position:0% mentioned before. Less than that, and you're<00:08:25.040> in<00:08:25.120> trouble. 08:26.110 --> 08:26.120 align:start position:0% you're in trouble. 08:26.120 --> 08:28.230 align:start position:0% you're in trouble. And<00:08:26.280> we<00:08:26.400> started<00:08:26.760> spotting<00:08:27.120> signs<00:08:27.400> of<00:08:27.480> exactly 08:28.230 --> 08:28.240 align:start position:0% And we started spotting signs of exactly 08:28.240 --> 08:30.470 align:start position:0% And we started spotting signs of exactly that<00:08:28.480> kind<00:08:28.680> of<00:08:28.760> trouble<00:08:29.120> in<00:08:29.240> the<00:08:29.320> 1970s<00:08:30.320> and 08:30.470 --> 08:30.480 align:start position:0% that kind of trouble in the 1970s and 08:30.480 --> 08:32.230 align:start position:0% that kind of trouble in the 1970s and the<00:08:30.520> 1980s. 08:32.230 --> 08:32.240 align:start position:0% the 1980s. 08:32.240 --> 08:34.750 align:start position:0% the 1980s. British<00:08:32.599> Antarctic<00:08:33.240> Survey<00:08:33.680> scientists<00:08:34.479> Joe 08:34.750 --> 08:34.760 align:start position:0% British Antarctic Survey scientists Joe 08:34.760 --> 08:37.550 align:start position:0% British Antarctic Survey scientists Joe Farman,<00:08:35.280> Brian<00:08:35.640> Gardiner,<00:08:36.200> and<00:08:36.440> Jon<00:08:36.719> Shanklin 08:37.550 --> 08:37.560 align:start position:0% Farman, Brian Gardiner, and Jon Shanklin 08:37.560 --> 08:39.430 align:start position:0% Farman, Brian Gardiner, and Jon Shanklin took<00:08:37.760> the<00:08:37.880> world<00:08:38.200> by<00:08:38.400> storm<00:08:39.039> when<00:08:39.200> their 08:39.430 --> 08:39.440 align:start position:0% took the world by storm when their 08:39.440 --> 08:42.149 align:start position:0% took the world by storm when their groundbreaking<00:08:40.240> paper,<00:08:41.120> "Large<00:08:41.599> Losses<00:08:41.960> of 08:42.149 --> 08:42.159 align:start position:0% groundbreaking paper, "Large Losses of 08:42.159 --> 08:44.430 align:start position:0% groundbreaking paper, "Large Losses of Total<00:08:42.560> Ozone<00:08:42.919> in<00:08:43.039> Antarctica",<00:08:43.800> published<00:08:44.280> in 08:44.430 --> 08:44.440 align:start position:0% Total Ozone in Antarctica", published in 08:44.440 --> 08:47.230 align:start position:0% Total Ozone in Antarctica", published in Nature<00:08:45.200> in<00:08:45.400> 1985. 08:47.230 --> 08:47.240 align:start position:0% Nature in 1985. 08:47.240 --> 08:49.430 align:start position:0% Nature in 1985. Working<00:08:47.600> through<00:08:47.760> a<00:08:47.839> backlog<00:08:48.480> of<00:08:48.640> data<00:08:49.040> from 08:49.430 --> 08:49.440 align:start position:0% Working through a backlog of data from 08:49.440 --> 08:51.710 align:start position:0% Working through a backlog of data from the<00:08:49.640> Dobson<00:08:50.160> spectrophotometer 08:51.710 --> 08:51.720 align:start position:0% the Dobson spectrophotometer 08:51.720 --> 08:54.070 align:start position:0% the Dobson spectrophotometer and<00:08:51.839> the<00:08:52.000> Halley<00:08:52.400> base<00:08:52.720> in<00:08:52.880> Antarctica, 08:54.070 --> 08:54.080 align:start position:0% and the Halley base in Antarctica, 08:54.080 --> 08:56.190 align:start position:0% and the Halley base in Antarctica, Shanklin<00:08:54.480> discovered<00:08:54.960> a<00:08:55.040> systematic<00:08:55.880> and 08:56.190 --> 08:56.200 align:start position:0% Shanklin discovered a systematic and 08:56.200 --> 08:58.350 align:start position:0% Shanklin discovered a systematic and rapid<00:08:56.560> decline<00:08:57.080> in<00:08:57.200> the<00:08:57.320> amount<00:08:58.160> of 08:58.350 --> 08:58.360 align:start position:0% rapid decline in the amount of 08:58.360 --> 09:01.829 align:start position:0% rapid decline in the amount of springtime<00:08:59.280> ozone.<00:09:00.400> In<00:09:00.560> 1979,<00:09:01.560> it<00:09:01.680> was 09:01.829 --> 09:01.839 align:start position:0% springtime ozone. In 1979, it was 09:01.839 --> 09:05.470 align:start position:0% springtime ozone. In 1979, it was relatively<00:09:02.680> fine,<00:09:03.440> but<00:09:03.640> by<00:09:03.839> 1984, 09:05.470 --> 09:05.480 align:start position:0% relatively fine, but by 1984, 09:05.480 --> 09:07.390 align:start position:0% relatively fine, but by 1984, the<00:09:05.560> stratospheric<00:09:06.320> ozone<00:09:06.720> layer<00:09:07.000> over<00:09:07.280> the 09:07.390 --> 09:07.400 align:start position:0% the stratospheric ozone layer over the 09:07.400 --> 09:10.829 align:start position:0% the stratospheric ozone layer over the Halley<00:09:07.760> base<00:09:08.120> was<00:09:08.440> only<00:09:08.720> around<00:09:09.160> 2/3<00:09:09.880> as<00:09:10.040> thick 09:10.829 --> 09:10.839 align:start position:0% Halley base was only around 2/3 as thick 09:10.839 --> 09:13.430 align:start position:0% Halley base was only around 2/3 as thick as<00:09:11.040> in<00:09:11.160> previous<00:09:11.839> decades. 09:13.430 --> 09:13.440 align:start position:0% as in previous decades. 09:13.440 --> 09:15.190 align:start position:0% as in previous decades. Something<00:09:13.800> was<00:09:13.960> happening<00:09:14.400> to<00:09:14.680> our<00:09:14.920> ozone, 09:15.190 --> 09:15.200 align:start position:0% Something was happening to our ozone, 09:15.200 --> 09:17.750 align:start position:0% Something was happening to our ozone, and<00:09:15.280> it<00:09:15.360> was<00:09:15.480> happening<00:09:16.520> fast. 09:17.750 --> 09:17.760 align:start position:0% and it was happening fast. 09:17.760 --> 09:21.390 align:start position:0% and it was happening fast. Between<00:09:18.080> 1986<00:09:18.960> and<00:09:19.160> 1987,<00:09:20.400> the<00:09:20.520> race<00:09:20.920> was<00:09:21.200> on 09:21.390 --> 09:21.400 align:start position:0% Between 1986 and 1987, the race was on 09:21.400 --> 09:23.829 align:start position:0% Between 1986 and 1987, the race was on to<00:09:21.560> find<00:09:21.960> out<00:09:22.160> what<00:09:22.400> exactly<00:09:23.000> was<00:09:23.200> causing<00:09:23.680> the 09:23.829 --> 09:23.839 align:start position:0% to find out what exactly was causing the 09:23.839 --> 09:26.030 align:start position:0% to find out what exactly was causing the loss.<00:09:24.640> Scientists<00:09:25.120> from<00:09:25.240> the<00:09:25.360> hunt<00:09:25.720> for 09:26.030 --> 09:26.040 align:start position:0% loss. Scientists from the hunt for 09:26.040 --> 09:29.870 align:start position:0% loss. Scientists from the hunt for ozone-depleting<00:09:27.200> substances,<00:09:28.080> or<00:09:28.360> ODS,<00:09:29.760> the 09:29.870 --> 09:29.880 align:start position:0% ozone-depleting substances, or ODS, the 09:29.880 --> 09:32.110 align:start position:0% ozone-depleting substances, or ODS, the BAS<00:09:30.400> team<00:09:30.640> had<00:09:30.839> theorized<00:09:31.280> that<00:09:31.520> possible 09:32.110 --> 09:32.120 align:start position:0% BAS team had theorized that possible 09:32.120 --> 09:35.190 align:start position:0% BAS team had theorized that possible chemical<00:09:32.680> causes<00:09:33.240> must<00:09:33.640> be<00:09:33.800> considered,<00:09:34.560> and 09:35.190 --> 09:35.200 align:start position:0% chemical causes must be considered, and 09:35.200 --> 09:36.750 align:start position:0% chemical causes must be considered, and they<00:09:35.360> weren't<00:09:35.560> the<00:09:35.640> first. 09:36.750 --> 09:36.760 align:start position:0% they weren't the first. 09:36.760 --> 09:38.230 align:start position:0% they weren't the first. If<00:09:36.880> you've<00:09:37.000> heard<00:09:37.200> of<00:09:37.360> the<00:09:37.560> ozone<00:09:37.920> hole,<00:09:38.120> then 09:38.230 --> 09:38.240 align:start position:0% If you've heard of the ozone hole, then 09:38.240 --> 09:39.350 align:start position:0% If you've heard of the ozone hole, then you<00:09:38.320> already<00:09:38.560> likely<00:09:38.880> know<00:09:39.080> that 09:39.350 --> 09:39.360 align:start position:0% you already likely know that 09:39.360 --> 09:40.870 align:start position:0% you already likely know that chlorofluorocarbons 09:40.870 --> 09:40.880 align:start position:0% chlorofluorocarbons 09:40.880 --> 09:43.670 align:start position:0% chlorofluorocarbons or<00:09:41.080> CFCs<00:09:41.760> were<00:09:41.880> eventually<00:09:42.280> found<00:09:42.640> out<00:09:42.840> to<00:09:43.040> be 09:43.670 --> 09:43.680 align:start position:0% or CFCs were eventually found out to be 09:43.680 --> 09:45.990 align:start position:0% or CFCs were eventually found out to be the<00:09:43.840> culprits,<00:09:44.440> but<00:09:45.040> they<00:09:45.240> simply<00:09:45.600> weren't<00:09:45.920> in 09:45.990 --> 09:46.000 align:start position:0% the culprits, but they simply weren't in 09:46.000 --> 09:48.030 align:start position:0% the culprits, but they simply weren't in the<00:09:46.120> public<00:09:46.520> consciousness<00:09:47.160> back<00:09:47.400> then.<00:09:47.880> They 09:48.030 --> 09:48.040 align:start position:0% the public consciousness back then. They 09:48.040 --> 09:49.670 align:start position:0% the public consciousness back then. They were<00:09:48.120> an<00:09:48.160> invisible<00:09:48.680> part<00:09:48.960> of<00:09:49.120> our<00:09:49.280> daily 09:49.670 --> 09:49.680 align:start position:0% were an invisible part of our daily 09:49.680 --> 09:52.670 align:start position:0% were an invisible part of our daily lives<00:09:50.120> using<00:09:50.560> aerosols<00:09:51.240> and<00:09:51.480> fridges,<00:09:52.440> a<00:09:52.480> sort 09:52.670 --> 09:52.680 align:start position:0% lives using aerosols and fridges, a sort 09:52.680 --> 09:56.910 align:start position:0% lives using aerosols and fridges, a sort of<00:09:52.800> killer<00:09:53.240> lying<00:09:53.640> in<00:09:53.960> darkness<00:09:54.640> waiting. 09:56.910 --> 09:56.920 align:start position:0% of killer lying in darkness waiting. 09:56.920 --> 09:59.550 align:start position:0% of killer lying in darkness waiting. But<00:09:57.120> way<00:09:57.240> back<00:09:57.440> in<00:09:57.560> 1974,<00:09:58.520> scientists<00:09:59.080> Mario 09:59.550 --> 09:59.560 align:start position:0% But way back in 1974, scientists Mario 09:59.560 --> 10:02.430 align:start position:0% But way back in 1974, scientists Mario Molina<00:10:00.160> and<00:10:00.400> F.<00:10:00.680> Sherwood<00:10:01.080> Rowland<00:10:01.960> published 10:02.430 --> 10:02.440 align:start position:0% Molina and F. Sherwood Rowland published 10:02.440 --> 10:04.070 align:start position:0% Molina and F. Sherwood Rowland published a<00:10:02.560> paper<00:10:03.040> theorizing<00:10:03.800> that 10:04.070 --> 10:04.080 align:start position:0% a paper theorizing that 10:04.080 --> 10:06.550 align:start position:0% a paper theorizing that chlorofluorocarbons<00:10:05.400> could<00:10:05.680> destroy<00:10:06.160> ozone 10:06.550 --> 10:06.560 align:start position:0% chlorofluorocarbons could destroy ozone 10:06.560 --> 10:08.270 align:start position:0% chlorofluorocarbons could destroy ozone in<00:10:06.720> the<00:10:06.800> stratosphere,<00:10:07.800> although<00:10:08.040> their 10:08.270 --> 10:08.280 align:start position:0% in the stratosphere, although their 10:08.280 --> 10:10.750 align:start position:0% in the stratosphere, although their paper<00:10:08.560> focused<00:10:08.880> on<00:10:09.080> chlorofluoromethanes 10:10.750 --> 10:10.760 align:start position:0% paper focused on chlorofluoromethanes 10:10.760 --> 10:12.950 align:start position:0% paper focused on chlorofluoromethanes only.<00:10:11.560> Now,<00:10:11.800> at<00:10:11.960> the<00:10:12.080> time<00:10:12.360> their<00:10:12.560> theories 10:12.950 --> 10:12.960 align:start position:0% only. Now, at the time their theories 10:12.960 --> 10:14.710 align:start position:0% only. Now, at the time their theories were<00:10:13.280> shot<00:10:13.640> down<00:10:13.920> by<00:10:14.040> the<00:10:14.120> industry<00:10:14.520> and<00:10:14.600> they 10:14.710 --> 10:14.720 align:start position:0% were shot down by the industry and they 10:14.720 --> 10:16.910 align:start position:0% were shot down by the industry and they were<00:10:14.840> denounced<00:10:15.440> as<00:10:15.680> scaremongers.<00:10:16.680> Their 10:16.910 --> 10:16.920 align:start position:0% were denounced as scaremongers. Their 10:16.920 --> 10:19.310 align:start position:0% were denounced as scaremongers. Their work<00:10:17.200> was<00:10:17.360> literally<00:10:17.680> called<00:10:18.440> pure<00:10:18.840> science 10:19.310 --> 10:19.320 align:start position:0% work was literally called pure science 10:19.320 --> 10:20.630 align:start position:0% work was literally called pure science fiction. 10:20.630 --> 10:20.640 align:start position:0% fiction. 10:20.640 --> 10:22.270 align:start position:0% fiction. As<00:10:20.880> a<00:10:20.960> side<00:10:21.320> note,<00:10:21.560> and<00:10:21.640> I<00:10:21.720> do<00:10:21.880> quite<00:10:22.040> enjoy 10:22.270 --> 10:22.280 align:start position:0% As a side note, and I do quite enjoy 10:22.280 --> 10:23.750 align:start position:0% As a side note, and I do quite enjoy this,<00:10:22.440> Molina<00:10:22.880> and<00:10:23.040> Rowland<00:10:23.360> were<00:10:23.480> later 10:23.750 --> 10:23.760 align:start position:0% this, Molina and Rowland were later 10:23.760 --> 10:27.070 align:start position:0% this, Molina and Rowland were later awarded<00:10:24.080> the<00:10:24.240> Nobel<00:10:24.720> Prize<00:10:25.560> in<00:10:25.720> 1995<00:10:26.840> for 10:27.070 --> 10:27.080 align:start position:0% awarded the Nobel Prize in 1995 for 10:27.080 --> 10:28.797 align:start position:0% awarded the Nobel Prize in 1995 for chemistry,<00:10:27.720> so<00:10:27.880> they<00:10:28.000> did<00:10:28.200> win 10:28.797 --> 10:28.807 align:start position:0% chemistry, so they did win 10:28.807 --> 10:28.870 align:start position:0% chemistry, so they did win >> [music] 10:28.870 --> 10:28.880 align:start position:0% >> [music] 10:28.880 --> 10:31.510 align:start position:0% >> [music] >> in<00:10:29.040> the<00:10:29.200> end.<00:10:29.840> Anyway,<00:10:30.120> in<00:10:30.200> 1986,<00:10:31.120> Susan 10:31.510 --> 10:31.520 align:start position:0% >> in the end. Anyway, in 1986, Susan 10:31.520 --> 10:33.910 align:start position:0% >> in the end. Anyway, in 1986, Susan Solomon,<00:10:31.920> a<00:10:32.040> researcher<00:10:32.640> at<00:10:32.960> NOAA,<00:10:33.400> led<00:10:33.760> a 10:33.910 --> 10:33.920 align:start position:0% Solomon, a researcher at NOAA, led a 10:33.920 --> 10:37.110 align:start position:0% Solomon, a researcher at NOAA, led a team<00:10:34.280> to<00:10:34.480> McMurdo<00:10:35.320> Base<00:10:35.680> to<00:10:35.800> find<00:10:36.160> out<00:10:36.320> exactly 10:37.110 --> 10:37.120 align:start position:0% team to McMurdo Base to find out exactly 10:37.120 --> 10:39.350 align:start position:0% team to McMurdo Base to find out exactly what<00:10:37.360> was<00:10:37.560> going<00:10:37.920> on.<00:10:38.440> See,<00:10:38.640> Solomon<00:10:39.120> had 10:39.350 --> 10:39.360 align:start position:0% what was going on. See, Solomon had 10:39.360 --> 10:41.829 align:start position:0% what was going on. See, Solomon had theorized<00:10:39.839> that<00:10:40.120> if<00:10:40.600> CFCs<00:10:41.280> were<00:10:41.400> responsible 10:41.829 --> 10:41.839 align:start position:0% theorized that if CFCs were responsible 10:41.839 --> 10:43.790 align:start position:0% theorized that if CFCs were responsible for<00:10:42.040> ozone<00:10:42.360> depletion,<00:10:43.320> then<00:10:43.440> there<00:10:43.560> would<00:10:43.640> be 10:43.790 --> 10:43.800 align:start position:0% for ozone depletion, then there would be 10:43.800 --> 10:46.270 align:start position:0% for ozone depletion, then there would be high<00:10:44.080> levels<00:10:44.440> of<00:10:44.680> chlorine<00:10:45.160> oxide<00:10:45.720> radicals 10:46.270 --> 10:46.280 align:start position:0% high levels of chlorine oxide radicals 10:46.280 --> 10:49.030 align:start position:0% high levels of chlorine oxide radicals in<00:10:46.440> the<00:10:46.560> stratosphere.<00:10:47.600> And<00:10:47.920> guess<00:10:48.240> what? 10:49.030 --> 10:49.040 align:start position:0% in the stratosphere. And guess what? 10:49.040 --> 10:51.150 align:start position:0% in the stratosphere. And guess what? There<00:10:49.320> were.<00:10:50.000> Molina<00:10:50.320> and<00:10:50.520> Rowland<00:10:50.760> had<00:10:50.960> been 10:51.150 --> 10:51.160 align:start position:0% There were. Molina and Rowland had been 10:51.160 --> 10:54.070 align:start position:0% There were. Molina and Rowland had been right<00:10:51.560> all<00:10:51.680> along.<00:10:52.640> So<00:10:52.880> yes,<00:10:53.160> there<00:10:53.360> was<00:10:53.920> a 10:54.070 --> 10:54.080 align:start position:0% right all along. So yes, there was a 10:54.080 --> 10:57.790 align:start position:0% right all along. So yes, there was a hole,<00:10:54.440> and<00:10:54.680> yes,<00:10:55.360> it<00:10:55.640> was<00:10:55.960> caused<00:10:56.520> by<00:10:56.800> humans. 10:57.790 --> 10:57.800 align:start position:0% hole, and yes, it was caused by humans. 10:57.800 --> 10:59.070 align:start position:0% hole, and yes, it was caused by humans. Shock. 10:59.070 --> 10:59.080 align:start position:0% Shock. 10:59.080 --> 11:01.150 align:start position:0% Shock. But<00:10:59.280> one<00:10:59.440> question<00:10:59.839> still<00:11:00.080> remained,<00:11:00.480> how 11:01.150 --> 11:01.160 align:start position:0% But one question still remained, how 11:01.160 --> 11:04.750 align:start position:0% But one question still remained, how exactly<00:11:01.800> did<00:11:02.080> CFCs<00:11:03.080> do<00:11:03.480> all<00:11:03.680> of<00:11:03.839> this?<00:11:04.520> Before 11:04.750 --> 11:04.760 align:start position:0% exactly did CFCs do all of this? Before 11:04.760 --> 11:06.790 align:start position:0% exactly did CFCs do all of this? Before we<00:11:04.839> get<00:11:05.000> into<00:11:05.160> the<00:11:05.200> chemistry,<00:11:05.680> if<00:11:06.160> like<00:11:06.520> me, 11:06.790 --> 11:06.800 align:start position:0% we get into the chemistry, if like me, 11:06.800 --> 11:08.310 align:start position:0% we get into the chemistry, if like me, you're<00:11:07.040> quite<00:11:07.320> enjoying<00:11:07.800> a<00:11:07.920> rather<00:11:08.160> more 11:08.310 --> 11:08.320 align:start position:0% you're quite enjoying a rather more 11:08.320 --> 11:10.829 align:start position:0% you're quite enjoying a rather more positive<00:11:09.000> climate<00:11:09.360> news<00:11:09.560> story<00:11:09.880> for<00:11:10.240> once<00:11:10.680> and 11:10.829 --> 11:10.839 align:start position:0% positive climate news story for once and 11:10.839 --> 11:13.110 align:start position:0% positive climate news story for once and you<00:11:10.920> fancy<00:11:11.240> some<00:11:11.480> more<00:11:11.720> like<00:11:12.000> this,<00:11:12.400> well<00:11:12.520> then 11:13.110 --> 11:13.120 align:start position:0% you fancy some more like this, well then 11:13.120 --> 11:14.630 align:start position:0% you fancy some more like this, well then I've<00:11:13.320> got<00:11:13.480> more<00:11:13.680> good<00:11:13.880> news.<00:11:14.360> I've<00:11:14.480> been<00:11:14.600> a 11:13.120 --> 11:15.750 align:start position:0% keep the good news going a little bit longer<00:12:27.760> and<00:12:27.960> head<00:12:28.200> back<00:12:28.560> to<00:12:28.800> Ozone? 11:14.954 --> 11:14.964 align:start position:0% longer and head back to Ozone? 11:14.964 --> 11:16.434 align:start position:0% longer and head back to Ozone? Let's<00:12:30.240> do<00:12:30.320> some<00:12:30.440> chemistry,<00:12:30.920> shall<00:12:31.120> we?<00:12:31.240> So, 11:16.434 --> 11:16.444 align:start position:0% Let's do some chemistry, shall we? So, 11:16.444 --> 11:18.874 align:start position:0% Let's do some chemistry, shall we? So, ozone<00:12:32.000> is<00:12:32.120> produced<00:12:32.600> when<00:12:32.800> oxygen<00:12:33.320> molecules 11:18.874 --> 11:18.884 align:start position:0% ozone is produced when oxygen molecules 11:18.884 --> 11:21.447 align:start position:0% ozone is produced when oxygen molecules absorb<00:12:34.520> UV<00:12:34.880> light<00:12:35.120> from<00:12:35.320> the<00:12:35.440> sun<00:12:36.000> and<00:12:36.280> split 11:21.447 --> 11:21.457 align:start position:0% absorb UV light from the sun and split 11:21.457 --> 11:24.994 align:start position:0% absorb UV light from the sun and split [music]<00:12:36.839> into<00:12:37.440> two<00:12:37.920> single<00:12:38.560> atoms.<00:12:39.560> One<00:12:39.880> then 11:24.994 --> 11:25.004 align:start position:0% [music] into two single atoms. One then 11:25.004 --> 11:26.753 align:start position:0% [music] into two single atoms. One then reacts<00:12:40.320> with<00:12:40.440> an<00:12:40.520> oxygen<00:12:40.839> molecule<00:12:41.240> to<00:12:41.320> become 11:26.753 --> 11:26.763 align:start position:0% reacts with an oxygen molecule to become 11:26.763 --> 11:29.954 align:start position:0% reacts with an oxygen molecule to become O3.<00:12:42.880> Now,<00:12:43.080> ozone<00:12:43.440> is<00:12:43.640> pretty<00:12:44.000> unstable.<00:12:44.920> If 11:29.954 --> 11:29.964 align:start position:0% O3. Now, ozone is pretty unstable. If 11:29.964 --> 11:31.514 align:start position:0% O3. Now, ozone is pretty unstable. If you<00:12:45.160> add<00:12:45.280> a<00:12:45.360> bit<00:12:45.640> more<00:12:45.800> sunshine,<00:12:46.320> it<00:12:46.440> can 11:31.514 --> 11:31.524 align:start position:0% you add a bit more sunshine, it can 11:31.524 --> 11:34.674 align:start position:0% you add a bit more sunshine, it can split<00:12:47.040> back<00:12:47.800> into<00:12:48.200> O2<00:12:48.760> with<00:12:49.080> one<00:12:49.400> lonely 11:34.674 --> 11:34.684 align:start position:0% split back into O2 with one lonely 11:34.684 --> 11:37.154 align:start position:0% split back into O2 with one lonely oxygen<00:12:50.080> atom<00:12:50.360> left<00:12:50.920> sort<00:12:51.080> of<00:12:51.200> spare,<00:12:51.920> allowing 11:37.154 --> 11:37.164 align:start position:0% oxygen atom left sort of spare, allowing 11:37.164 --> 11:39.394 align:start position:0% oxygen atom left sort of spare, allowing the<00:12:52.320> cycle<00:12:52.680> to<00:12:52.760> begin<00:12:53.280> all<00:12:53.480> over<00:12:53.680> again.<00:12:54.320> It's 11:39.394 --> 11:39.404 align:start position:0% the cycle to begin all over again. It's 11:39.404 --> 11:40.954 align:start position:0% the cycle to begin all over again. It's like<00:12:54.680> a<00:12:54.760> self-replicating<00:12:55.680> planetary 11:40.954 --> 11:40.964 align:start position:0% like a self-replicating planetary 11:40.964 --> 11:42.674 align:start position:0% like a self-replicating planetary sunscreen<00:12:56.600> whenever<00:12:57.000> you<00:12:57.240> need<00:12:57.493> [music]<00:12:57.560> it. 11:42.674 --> 11:42.684 align:start position:0% sunscreen whenever you need [music] it. 11:42.684 --> 11:46.074 align:start position:0% sunscreen whenever you need [music] it. Until<00:12:58.640> you<00:12:58.880> throw<00:12:59.240> some<00:12:59.560> chlorofluorocarbons 11:46.074 --> 11:46.084 align:start position:0% Until you throw some chlorofluorocarbons 11:46.084 --> 11:49.314 align:start position:0% Until you throw some chlorofluorocarbons into<00:13:01.520> the<00:13:01.600> mix.<00:13:02.240> Then<00:13:02.480> things<00:13:02.760> get<00:13:03.200> messy. 11:49.314 --> 11:49.324 align:start position:0% into the mix. Then things get messy. 11:49.324 --> 11:51.594 align:start position:0% into the mix. Then things get messy. CFCs<00:13:05.160> are<00:13:05.240> one<00:13:05.360> of<00:13:05.400> those<00:13:05.600> things<00:13:05.920> us<00:13:06.160> humans 11:51.594 --> 11:51.604 align:start position:0% CFCs are one of those things us humans 11:51.604 --> 11:53.594 align:start position:0% CFCs are one of those things us humans thought<00:13:07.160> we<00:13:07.280> were<00:13:07.400> inventing<00:13:07.920> to<00:13:08.040> make<00:13:08.360> life 11:53.594 --> 11:53.604 align:start position:0% thought we were inventing to make life 11:53.604 --> 11:56.714 align:start position:0% thought we were inventing to make life better,<00:13:09.320> easier,<00:13:09.839> and<00:13:10.280> cheaper.<00:13:11.320> They<00:13:11.440> first 11:56.714 --> 11:56.724 align:start position:0% better, easier, and cheaper. They first 11:56.724 --> 11:59.314 align:start position:0% better, easier, and cheaper. They first popped<00:13:12.080> up<00:13:12.280> in<00:13:12.360> the<00:13:12.520> 1890s<00:13:13.640> and<00:13:13.880> came<00:13:14.080> into 11:59.314 --> 11:59.324 align:start position:0% popped up in the 1890s and came into 11:59.324 --> 12:02.154 align:start position:0% popped up in the 1890s and came into widespread<00:13:15.000> use<00:13:15.360> in<00:13:15.480> the<00:13:15.560> 1930s. 12:02.154 --> 12:02.164 align:start position:0% widespread use in the 1930s. 12:02.164 --> 12:03.874 align:start position:0% widespread use in the 1930s. Primarily<00:13:17.760> used<00:13:18.040> as<00:13:18.320> coolants<00:13:18.800> in 12:03.874 --> 12:03.884 align:start position:0% Primarily used as coolants in 12:03.884 --> 12:06.274 align:start position:0% Primarily used as coolants in refrigerators<00:13:19.760> and<00:13:20.040> air<00:13:20.200> conditioners<00:13:21.280> to 12:06.274 --> 12:06.284 align:start position:0% refrigerators and air conditioners to 12:06.284 --> 12:08.794 align:start position:0% refrigerators and air conditioners to replace<00:13:21.800> toxic<00:13:22.240> gases<00:13:22.760> like<00:13:23.000> ammonia<00:13:23.600> and 12:08.794 --> 12:08.804 align:start position:0% replace toxic gases like ammonia and 12:08.804 --> 12:11.314 align:start position:0% replace toxic gases like ammonia and methyl<00:13:24.360> chloride.<00:13:25.640> They<00:13:25.800> were<00:13:25.920> also<00:13:26.200> pretty 12:11.314 --> 12:11.324 align:start position:0% methyl chloride. They were also pretty 12:11.324 --> 12:13.594 align:start position:0% methyl chloride. They were also pretty effective<00:13:26.840> in<00:13:27.000> aerosols<00:13:27.680> like<00:13:27.920> deodorant<00:13:28.440> and 12:13.594 --> 12:13.604 align:start position:0% effective in aerosols like deodorant and 12:13.604 --> 12:16.194 align:start position:0% effective in aerosols like deodorant and hairspray,<00:13:29.600> making<00:13:30.000> perfect<00:13:30.480> propellants<00:13:31.160> in 12:16.194 --> 12:16.204 align:start position:0% hairspray, making perfect propellants in 12:16.204 --> 12:18.754 align:start position:0% hairspray, making perfect propellants in the<00:13:31.400> pressurized<00:13:32.080> cans.<00:13:33.320> It's<00:13:33.440> important<00:13:33.760> to 12:18.754 --> 12:18.764 align:start position:0% the pressurized cans. It's important to 12:18.764 --> 12:19.794 align:start position:0% the pressurized cans. It's important to remember<00:13:34.080> when<00:13:34.200> we<00:13:34.280> look<00:13:34.440> back<00:13:34.640> at<00:13:34.720> these 12:19.794 --> 12:19.804 align:start position:0% remember when we look back at these 12:19.804 --> 12:20.834 align:start position:0% remember when we look back at these things<00:13:35.120> and<00:13:35.200> obviously<00:13:35.440> hindsight's<00:13:35.880> a 12:20.834 --> 12:20.844 align:start position:0% things and obviously hindsight's a 12:20.844 --> 12:22.914 align:start position:0% things and obviously hindsight's a beautiful<00:13:36.240> thing<00:13:36.440> that<00:13:36.520> at<00:13:36.640> the<00:13:36.800> time<00:13:37.520> CFCs 12:22.914 --> 12:22.924 align:start position:0% beautiful thing that at the time CFCs 12:22.924 --> 12:24.674 align:start position:0% beautiful thing that at the time CFCs were<00:13:38.120> considered<00:13:38.720> perfectly<00:13:39.280> safe.<00:13:39.640> They 12:24.674 --> 12:24.684 align:start position:0% were considered perfectly safe. They 12:24.684 --> 12:26.874 align:start position:0% were considered perfectly safe. They were<00:13:40.280> wonder<00:13:40.840> chemicals<00:13:41.480> to<00:13:41.640> some, 12:26.874 --> 12:26.884 align:start position:0% were wonder chemicals to some, 12:26.884 --> 12:30.114 align:start position:0% were wonder chemicals to some, non-toxic,<00:13:42.640> non-flammable<00:13:43.360> and<00:13:44.000> stable. 12:30.114 --> 12:30.124 align:start position:0% non-toxic, non-flammable and stable. 12:30.124 --> 12:32.834 align:start position:0% non-toxic, non-flammable and stable. CFCs<00:13:45.920> are<00:13:46.120> halogenoalkanes, 12:32.834 --> 12:32.844 align:start position:0% CFCs are halogenoalkanes, 12:32.844 --> 12:34.394 align:start position:0% CFCs are halogenoalkanes, which<00:13:48.120> are<00:13:48.200> molecules<00:13:48.800> consisting<00:13:49.320> of 12:34.394 --> 12:34.404 align:start position:0% which are molecules consisting of 12:34.404 --> 12:37.594 align:start position:0% which are molecules consisting of carbon,<00:13:50.160> fluorine<00:13:50.760> and<00:13:51.040> chlorine<00:13:51.680> atoms.<00:13:52.560> The 12:37.594 --> 12:37.604 align:start position:0% carbon, fluorine and chlorine atoms. The 12:37.604 --> 12:39.874 align:start position:0% carbon, fluorine and chlorine atoms. The carbon-chlorine<00:13:53.800> bond<00:13:54.120> is<00:13:54.360> long<00:13:54.720> and 12:39.874 --> 12:39.884 align:start position:0% carbon-chlorine bond is long and 12:39.884 --> 12:42.314 align:start position:0% carbon-chlorine bond is long and relatively<00:13:55.520> weak.<00:13:56.320> Now,<00:13:56.680> these<00:13:56.960> molecules 12:42.314 --> 12:42.324 align:start position:0% relatively weak. Now, these molecules 12:42.324 --> 12:44.514 align:start position:0% relatively weak. Now, these molecules can<00:13:57.560> float<00:13:57.920> up<00:13:58.120> into<00:13:58.320> the<00:13:58.400> stratosphere<00:13:59.400> where 12:44.514 --> 12:44.524 align:start position:0% can float up into the stratosphere where 12:44.524 --> 12:46.634 align:start position:0% can float up into the stratosphere where the<00:13:59.720> UV<00:14:00.080> rays<00:14:00.360> from<00:14:00.520> the<00:14:00.600> sun<00:14:01.000> provide<00:14:01.360> enough 12:46.634 --> 12:46.644 align:start position:0% the UV rays from the sun provide enough 12:46.644 --> 12:49.314 align:start position:0% the UV rays from the sun provide enough energy<00:14:02.120> to<00:14:02.360> break<00:14:02.840> that<00:14:03.160> carbon-chlorine 12:49.314 --> 12:49.324 align:start position:0% energy to break that carbon-chlorine 12:49.324 --> 12:50.514 align:start position:0% energy to break that carbon-chlorine bond. 12:50.514 --> 12:50.524 align:start position:0% bond. 12:50.524 --> 12:52.434 align:start position:0% bond. Bonds<00:14:05.920> like<00:14:06.120> the<00:14:06.200> one<00:14:06.400> between<00:14:06.800> carbon<00:14:07.280> and 12:52.434 --> 12:52.444 align:start position:0% Bonds like the one between carbon and 12:52.444 --> 12:55.154 align:start position:0% Bonds like the one between carbon and chlorine<00:14:08.120> are<00:14:08.320> called<00:14:08.640> covalent<00:14:09.480> bonds<00:14:10.120> and 12:55.154 --> 12:55.164 align:start position:0% chlorine are called covalent bonds and 12:55.164 --> 12:58.114 align:start position:0% chlorine are called covalent bonds and they<00:14:10.360> consist<00:14:10.880> of<00:14:11.120> two<00:14:11.440> electrons. 12:58.114 --> 12:58.124 align:start position:0% they consist of two electrons. 12:58.124 --> 13:00.114 align:start position:0% they consist of two electrons. When<00:14:13.360> it<00:14:13.480> breaks,<00:14:14.080> one<00:14:14.280> of<00:14:14.400> those<00:14:14.640> electrons 13:00.114 --> 13:00.124 align:start position:0% When it breaks, one of those electrons 13:00.124 --> 13:02.074 align:start position:0% When it breaks, one of those electrons goes<00:14:15.480> to<00:14:15.560> the<00:14:15.680> carbon<00:14:16.240> and<00:14:16.520> one<00:14:16.920> to<00:14:17.040> the 13:02.074 --> 13:02.084 align:start position:0% goes to the carbon and one to the 13:02.084 --> 13:04.114 align:start position:0% goes to the carbon and one to the chlorine,<00:14:18.040> giving<00:14:18.280> them<00:14:18.400> an<00:14:18.520> unpaired 13:04.114 --> 13:04.124 align:start position:0% chlorine, giving them an unpaired 13:04.124 --> 13:06.994 align:start position:0% chlorine, giving them an unpaired electron<00:14:19.960> each.<00:14:20.920> Species<00:14:21.400> like<00:14:21.600> these<00:14:21.920> are 13:06.994 --> 13:07.004 align:start position:0% electron each. Species like these are 13:07.004 --> 13:09.634 align:start position:0% electron each. Species like these are called<00:14:22.480> free<00:14:22.880> radicals<00:14:23.560> and<00:14:23.720> they<00:14:23.920> are<00:14:24.120> very 13:09.634 --> 13:09.644 align:start position:0% called free radicals and they are very 13:09.644 --> 13:11.594 align:start position:0% called free radicals and they are very reactive. 13:11.594 --> 13:11.604 align:start position:0% reactive. 13:11.604 --> 13:13.914 align:start position:0% reactive. chlorine<00:14:27.240> radicals<00:14:27.720> collides<00:14:28.240> with<00:14:28.360> an<00:14:28.520> ozone 13:13.914 --> 13:13.924 align:start position:0% chlorine radicals collides with an ozone 13:13.924 --> 13:15.753 align:start position:0% chlorine radicals collides with an ozone molecule,<00:14:29.680> it<00:14:29.920> breaks<00:14:30.400> one<00:14:30.560> of<00:14:30.640> its 13:15.753 --> 13:15.763 align:start position:0% molecule, it breaks one of its 13:15.763 --> 13:18.914 align:start position:0% molecule, it breaks one of its oxygen-oxygen<00:14:32.000> bonds,<00:14:32.880> creating<00:14:33.400> oxygen<00:14:33.880> and 13:18.914 --> 13:18.924 align:start position:0% oxygen-oxygen bonds, creating oxygen and 13:18.924 --> 13:22.874 align:start position:0% oxygen-oxygen bonds, creating oxygen and a<00:14:34.080> chlorine<00:14:34.720> monoxide<00:14:35.600> radical,<00:14:36.280> ClO.<00:14:37.720> This 13:22.874 --> 13:22.884 align:start position:0% a chlorine monoxide radical, ClO. This 13:22.884 --> 13:25.034 align:start position:0% a chlorine monoxide radical, ClO. This can<00:14:38.120> react<00:14:38.440> with<00:14:38.560> another<00:14:39.120> ozone<00:14:39.560> molecule, 13:25.034 --> 13:25.044 align:start position:0% can react with another ozone molecule, 13:25.044 --> 13:27.753 align:start position:0% can react with another ozone molecule, producing<00:14:40.600> oxygen<00:14:41.160> and<00:14:41.360> another<00:14:42.120> chlorine 13:27.753 --> 13:27.763 align:start position:0% producing oxygen and another chlorine 13:27.763 --> 13:29.753 align:start position:0% producing oxygen and another chlorine radical,<00:14:43.640> which<00:14:43.800> goes<00:14:44.040> on<00:14:44.240> to<00:14:44.360> react<00:14:44.680> with 13:29.753 --> 13:29.763 align:start position:0% radical, which goes on to react with 13:29.763 --> 13:32.394 align:start position:0% radical, which goes on to react with more<00:14:45.240> and<00:14:45.440> more<00:14:45.800> and<00:14:46.000> more<00:14:46.320> and<00:14:46.520> more.<00:14:47.280> In 13:32.394 --> 13:32.404 align:start position:0% more and more and more and more. In 13:32.404 --> 13:34.474 align:start position:0% more and more and more and more. In fact,<00:14:47.760> just<00:14:48.000> one<00:14:48.360> chlorine<00:14:48.960> radical<00:14:49.400> can 13:34.474 --> 13:34.484 align:start position:0% fact, just one chlorine radical can 13:34.484 --> 13:36.834 align:start position:0% fact, just one chlorine radical can break<00:14:49.839> down<00:14:50.080> more<00:14:50.200> than<00:14:50.360> 100,000<00:14:51.520> ozone 13:36.834 --> 13:36.844 align:start position:0% break down more than 100,000 ozone 13:36.844 --> 13:39.434 align:start position:0% break down more than 100,000 ozone molecules<00:14:52.760> into<00:14:53.080> oxygen. 13:39.434 --> 13:39.444 align:start position:0% molecules into oxygen. 13:39.444 --> 13:40.914 align:start position:0% molecules into oxygen. Now,<00:14:54.760> given<00:14:54.960> that<00:14:55.040> it's<00:14:55.160> necessary<00:14:55.560> for<00:14:55.680> life 13:40.914 --> 13:40.924 align:start position:0% Now, given that it's necessary for life 13:40.924 --> 13:42.314 align:start position:0% Now, given that it's necessary for life on<00:14:56.120> our<00:14:56.240> planet,<00:14:56.560> you<00:14:56.680> could<00:14:56.839> be<00:14:56.960> forgiven<00:14:57.280> for 13:42.314 --> 13:42.324 align:start position:0% on our planet, you could be forgiven for 13:42.324 --> 13:43.994 align:start position:0% on our planet, you could be forgiven for thinking<00:14:57.680> that<00:14:57.800> more<00:14:58.000> oxygen<00:14:58.440> would<00:14:58.600> be<00:14:58.800> a 13:43.994 --> 13:44.004 align:start position:0% thinking that more oxygen would be a 13:44.004 --> 13:46.674 align:start position:0% thinking that more oxygen would be a good<00:14:59.400> thing,<00:15:00.040> right?<00:15:00.760> Well,<00:15:01.040> it's<00:15:01.280> good<00:15:01.560> if 13:46.674 --> 13:46.684 align:start position:0% good thing, right? Well, it's good if 13:46.684 --> 13:48.674 align:start position:0% good thing, right? Well, it's good if you're<00:15:01.960> on<00:15:02.240> Earth's<00:15:02.720> surface<00:15:03.280> and<00:15:03.400> you<00:15:03.480> need 13:48.674 --> 13:48.684 align:start position:0% you're on Earth's surface and you need 13:48.684 --> 13:50.634 align:start position:0% you're on Earth's surface and you need to<00:15:03.880> breathe,<00:15:04.440> but<00:15:04.560> it's<00:15:04.720> not<00:15:05.040> so<00:15:05.240> good<00:15:05.480> in<00:15:05.640> the 13:50.634 --> 13:50.644 align:start position:0% to breathe, but it's not so good in the 13:50.644 --> 13:52.194 align:start position:0% to breathe, but it's not so good in the stratosphere,<00:15:06.560> where<00:15:06.680> you'd<00:15:06.839> rather<00:15:07.080> have 13:52.194 --> 13:52.204 align:start position:0% stratosphere, where you'd rather have 13:52.204 --> 13:55.674 align:start position:0% stratosphere, where you'd rather have the<00:15:07.520> ozone<00:15:08.080> keeping<00:15:08.480> those<00:15:08.760> UV<00:15:09.080> rays<00:15:09.440> at<00:15:09.680> bay. 13:55.674 --> 13:55.684 align:start position:0% the ozone keeping those UV rays at bay. 13:55.684 --> 13:58.154 align:start position:0% the ozone keeping those UV rays at bay. The<00:15:10.960> ozone-munching<00:15:11.920> part<00:15:12.320> of<00:15:12.480> this<00:15:12.680> story<00:15:13.040> is 13:58.154 --> 13:58.164 align:start position:0% The ozone-munching part of this story is 13:58.164 --> 14:00.634 align:start position:0% The ozone-munching part of this story is one<00:15:13.480> most<00:15:13.760> people<00:15:14.200> already<00:15:14.600> know,<00:15:15.360> but<00:15:15.560> what 14:00.634 --> 14:00.644 align:start position:0% one most people already know, but what 14:00.644 --> 14:02.874 align:start position:0% one most people already know, but what most<00:15:16.000> people<00:15:16.360> don't<00:15:16.760> realize<00:15:17.240> is<00:15:17.400> that<00:15:17.600> while 14:02.874 --> 14:02.884 align:start position:0% most people don't realize is that while 14:02.884 --> 14:05.274 align:start position:0% most people don't realize is that while chlorine<00:15:18.440> radicals<00:15:18.960> do<00:15:19.160> ultimately<00:15:19.640> destroy 14:05.274 --> 14:05.284 align:start position:0% chlorine radicals do ultimately destroy 14:05.284 --> 14:07.954 align:start position:0% chlorine radicals do ultimately destroy ozone,<00:15:21.320> they<00:15:21.440> don't<00:15:21.680> necessarily<00:15:22.520> do<00:15:22.720> it 14:07.954 --> 14:07.964 align:start position:0% ozone, they don't necessarily do it 14:07.964 --> 14:09.674 align:start position:0% ozone, they don't necessarily do it immediately. 14:09.674 --> 14:09.684 align:start position:0% immediately. 14:09.684 --> 14:12.194 align:start position:0% immediately. They<00:15:24.880> require<00:15:25.360> a<00:15:25.480> very<00:15:26.080> special<00:15:26.640> set<00:15:27.040> of 14:12.194 --> 14:12.204 align:start position:0% They require a very special set of 14:12.204 --> 14:14.874 align:start position:0% They require a very special set of conditions,<00:15:28.160> and<00:15:28.400> this<00:15:29.280> Well,<00:15:29.400> this<00:15:29.560> is<00:15:29.720> where 14:14.874 --> 14:14.884 align:start position:0% conditions, and this Well, this is where 14:14.884 --> 14:16.754 align:start position:0% conditions, and this Well, this is where Antarctica<00:15:30.760> comes<00:15:31.080> in.<00:15:31.520> You<00:15:31.640> may<00:15:31.760> have 14:16.754 --> 14:16.764 align:start position:0% Antarctica comes in. You may have 14:16.764 --> 14:18.314 align:start position:0% Antarctica comes in. You may have noticed<00:15:32.160> that<00:15:32.280> the<00:15:32.440> hole<00:15:32.920> in<00:15:33.040> all<00:15:33.160> of<00:15:33.240> these 14:18.314 --> 14:18.324 align:start position:0% noticed that the hole in all of these 14:18.324 --> 14:20.274 align:start position:0% noticed that the hole in all of these satellite<00:15:33.760> images<00:15:34.040> is<00:15:34.160> always<00:15:34.560> mostly<00:15:35.040> over 14:20.274 --> 14:20.284 align:start position:0% satellite images is always mostly over 14:20.284 --> 14:21.874 align:start position:0% satellite images is always mostly over Antarctica,<00:15:36.080> and<00:15:36.160> there's<00:15:36.280> a<00:15:36.360> very<00:15:36.680> good 14:21.874 --> 14:21.884 align:start position:0% Antarctica, and there's a very good 14:21.884 --> 14:23.914 align:start position:0% Antarctica, and there's a very good reason<00:15:37.360> for<00:15:37.480> that.<00:15:38.080> Antarctica<00:15:38.680> is<00:15:38.800> the 14:23.914 --> 14:23.924 align:start position:0% reason for that. Antarctica is the 14:23.924 --> 14:26.594 align:start position:0% reason for that. Antarctica is the highest,<00:15:39.640> driest,<00:15:40.320> windiest,<00:15:41.040> and<00:15:41.280> coldest 14:26.594 --> 14:26.604 align:start position:0% highest, driest, windiest, and coldest 14:26.604 --> 14:29.234 align:start position:0% highest, driest, windiest, and coldest place<00:15:42.080> on<00:15:42.400> Earth.<00:15:43.120> It's<00:15:43.280> a<00:15:43.320> continent<00:15:43.840> with<00:15:44.000> no 14:29.234 --> 14:29.244 align:start position:0% place on Earth. It's a continent with no 14:29.244 --> 14:31.434 align:start position:0% place on Earth. It's a continent with no countries<00:15:44.920> and<00:15:45.120> no<00:15:45.320> permanent<00:15:45.880> population<00:15:46.400> to 14:31.434 --> 14:31.444 align:start position:0% countries and no permanent population to 14:31.444 --> 14:33.674 align:start position:0% countries and no permanent population to speak<00:15:47.000> of,<00:15:47.560> unless<00:15:47.800> you<00:15:48.000> count<00:15:48.240> the<00:15:48.320> penguins, 14:33.674 --> 14:33.684 align:start position:0% speak of, unless you count the penguins, 14:33.684 --> 14:35.394 align:start position:0% speak of, unless you count the penguins, which<00:15:49.320> I<00:15:49.440> do. 14:35.394 --> 14:35.404 align:start position:0% which I do. 14:35.404 --> 14:37.554 align:start position:0% which I do. So,<00:15:50.560> this<00:15:50.800> can't<00:15:51.120> be<00:15:51.320> CFC<00:15:51.840> ground<00:15:52.160> zero.<00:15:52.520> How 14:37.554 --> 14:37.564 align:start position:0% So, this can't be CFC ground zero. How 14:37.564 --> 14:39.314 align:start position:0% So, this can't be CFC ground zero. How many<00:15:52.840> penguins<00:15:53.200> are<00:15:53.280> using<00:15:53.560> fridges<00:15:53.960> and<00:15:54.240> air 14:39.314 --> 14:39.324 align:start position:0% many penguins are using fridges and air 14:39.324 --> 14:41.114 align:start position:0% many penguins are using fridges and air conditioners<00:15:54.920> and<00:15:55.200> hairsprays?<00:15:56.080> Well, 14:41.114 --> 14:41.124 align:start position:0% conditioners and hairsprays? Well, 14:41.124 --> 14:42.474 align:start position:0% conditioners and hairsprays? Well, here's<00:15:56.480> what's<00:15:56.720> happening.<00:15:57.080> The<00:15:57.280> Earth's 14:42.474 --> 14:42.484 align:start position:0% here's what's happening. The Earth's 14:42.484 --> 14:44.754 align:start position:0% here's what's happening. The Earth's atmosphere<00:15:58.040> is<00:15:58.160> continuously<00:15:59.040> being<00:15:59.320> stirred 14:44.754 --> 14:44.764 align:start position:0% atmosphere is continuously being stirred 14:44.764 --> 14:47.474 align:start position:0% atmosphere is continuously being stirred by<00:16:00.120> winds.<00:16:00.880> So,<00:16:01.200> ozone-depleting<00:16:02.120> gases 14:47.474 --> 14:47.484 align:start position:0% by winds. So, ozone-depleting gases 14:47.484 --> 14:49.394 align:start position:0% by winds. So, ozone-depleting gases could<00:16:02.800> end<00:16:02.920> up<00:16:03.320> anywhere. 14:49.394 --> 14:49.404 align:start position:0% could end up anywhere. 14:49.404 --> 14:52.754 align:start position:0% could end up anywhere. 90%<00:16:05.280> of<00:16:05.480> CFCs<00:16:06.200> and<00:16:06.480> halons,<00:16:07.160> their<00:16:07.400> bromine 14:52.754 --> 14:52.764 align:start position:0% 90% of CFCs and halons, their bromine 14:52.764 --> 14:54.594 align:start position:0% 90% of CFCs and halons, their bromine equivalents,<00:16:08.760> have<00:16:08.920> been<00:16:09.080> released<00:16:09.480> in<00:16:09.600> the 14:54.594 --> 14:54.604 align:start position:0% equivalents, have been released in the 14:54.604 --> 14:56.714 align:start position:0% equivalents, have been released in the northern<00:16:10.080> hemisphere,<00:16:10.960> Europe,<00:16:11.440> Russia, 14:56.714 --> 14:56.724 align:start position:0% northern hemisphere, Europe, Russia, 14:56.724 --> 14:59.394 align:start position:0% northern hemisphere, Europe, Russia, Japan,<00:16:12.320> and<00:16:12.520> North<00:16:12.800> America.<00:16:13.840> But,<00:16:13.920> they<00:16:14.120> rise 14:59.394 --> 14:59.404 align:start position:0% Japan, and North America. But, they rise 14:59.404 --> 15:01.194 align:start position:0% Japan, and North America. But, they rise up<00:16:14.640> to<00:16:14.720> the<00:16:14.800> stratosphere<00:16:15.440> in<00:16:15.600> the<00:16:15.720> tropics, 15:01.194 --> 15:01.204 align:start position:0% up to the stratosphere in the tropics, 15:01.204 --> 15:04.194 align:start position:0% up to the stratosphere in the tropics, and<00:16:16.400> they<00:16:16.520> are<00:16:16.640> then<00:16:16.960> blown<00:16:17.480> polewards.<00:16:18.920> And, 15:04.194 --> 15:04.204 align:start position:0% and they are then blown polewards. And, 15:04.204 --> 15:06.754 align:start position:0% and they are then blown polewards. And, as<00:16:19.480> we<00:16:19.560> mentioned,<00:16:20.000> Antarctica<00:16:20.600> is<00:16:20.840> cold, 15:06.754 --> 15:06.764 align:start position:0% as we mentioned, Antarctica is cold, 15:06.764 --> 15:08.874 align:start position:0% as we mentioned, Antarctica is cold, very<00:16:22.120> cold.<00:16:22.840> In<00:16:22.920> the<00:16:23.000> long<00:16:23.160> months<00:16:23.480> of<00:16:23.680> winter 15:08.874 --> 15:08.884 align:start position:0% very cold. In the long months of winter 15:08.884 --> 15:11.234 align:start position:0% very cold. In the long months of winter darkness,<00:16:24.520> a<00:16:24.720> whirlpool<00:16:25.520> of<00:16:25.760> winds<00:16:26.080> called 15:11.234 --> 15:11.244 align:start position:0% darkness, a whirlpool of winds called 15:11.244 --> 15:14.314 align:start position:0% darkness, a whirlpool of winds called the<00:16:26.480> polar<00:16:26.880> vortex<00:16:27.839> traps<00:16:28.440> super<00:16:28.800> cold<00:16:29.160> air 15:14.314 --> 15:14.324 align:start position:0% the polar vortex traps super cold air 15:14.324 --> 15:16.834 align:start position:0% the polar vortex traps super cold air over<00:16:29.880> this<00:16:30.280> region,<00:16:31.000> allowing<00:16:31.320> the<00:16:31.400> formation 15:16.834 --> 15:16.844 align:start position:0% over this region, allowing the formation 15:16.844 --> 15:19.474 align:start position:0% over this region, allowing the formation of<00:16:32.160> polar<00:16:32.600> stratospheric<00:16:33.480> clouds.<00:16:34.400> Now, 15:19.474 --> 15:19.484 align:start position:0% of polar stratospheric clouds. Now, 15:19.484 --> 15:22.354 align:start position:0% of polar stratospheric clouds. Now, these<00:16:34.839> clouds<00:16:35.200> are<00:16:35.440> perfect<00:16:36.280> for<00:16:36.520> CFCs<00:16:37.280> to 15:22.354 --> 15:22.364 align:start position:0% these clouds are perfect for CFCs to 15:22.364 --> 15:24.874 align:start position:0% these clouds are perfect for CFCs to start<00:16:37.760> breaking<00:16:38.120> down<00:16:38.839> into<00:16:39.120> those<00:16:39.440> chlorine 15:24.874 --> 15:24.884 align:start position:0% start breaking down into those chlorine 15:24.884 --> 15:26.434 align:start position:0% start breaking down into those chlorine radicals. 15:26.434 --> 15:26.444 align:start position:0% radicals. 15:26.444 --> 15:27.834 align:start position:0% radicals. When<00:16:41.680> the<00:16:41.800> sunlight<00:16:42.160> returns<00:16:42.760> in<00:16:42.839> the 15:27.834 --> 15:27.844 align:start position:0% When the sunlight returns in the 15:27.844 --> 15:30.314 align:start position:0% When the sunlight returns in the Antarctic<00:16:43.600> spring,<00:16:44.560> that<00:16:44.880> chlorine<00:16:45.240> that's 15:30.314 --> 15:30.324 align:start position:0% Antarctic spring, that chlorine that's 15:30.324 --> 15:32.354 align:start position:0% Antarctic spring, that chlorine that's been<00:16:45.560> building<00:16:45.960> up<00:16:46.160> all<00:16:46.440> winter<00:16:46.880> starts<00:16:47.280> to 15:32.354 --> 15:32.364 align:start position:0% been building up all winter starts to 15:32.364 --> 15:34.834 align:start position:0% been building up all winter starts to kick<00:16:47.800> into<00:16:48.200> gear,<00:16:48.920> shredding<00:16:49.480> through<00:16:49.720> the 15:34.834 --> 15:34.844 align:start position:0% kick into gear, shredding through the 15:34.844 --> 15:37.474 align:start position:0% kick into gear, shredding through the ozone<00:16:50.320> at<00:16:50.440> an<00:16:50.560> incredible<00:16:51.400> rate. 15:37.474 --> 15:37.484 align:start position:0% ozone at an incredible rate. 15:37.484 --> 15:39.194 align:start position:0% ozone at an incredible rate. The<00:16:52.680> hole<00:16:52.960> just<00:16:53.160> keeps<00:16:53.400> growing<00:16:53.720> bigger<00:16:54.080> and 15:39.194 --> 15:39.204 align:start position:0% The hole just keeps growing bigger and 15:39.204 --> 15:41.154 align:start position:0% The hole just keeps growing bigger and bigger<00:16:54.600> and<00:16:54.839> bigger<00:16:55.080> until<00:16:55.280> it<00:16:55.440> stabilizes 15:41.154 --> 15:41.164 align:start position:0% bigger and bigger until it stabilizes 15:41.164 --> 15:43.114 align:start position:0% bigger and bigger until it stabilizes with<00:16:56.360> the<00:16:56.520> weakening<00:16:57.000> of<00:16:57.160> the<00:16:57.280> polar<00:16:57.640> vortex 15:43.114 --> 15:43.124 align:start position:0% with the weakening of the polar vortex 15:43.124 --> 15:45.674 align:start position:0% with the weakening of the polar vortex as<00:16:58.480> summer<00:16:58.880> arrives.<00:16:59.440> And<00:16:59.520> then,<00:16:59.760> next<00:17:00.200> year, 15:45.674 --> 15:45.684 align:start position:0% as summer arrives. And then, next year, 15:45.684 --> 15:48.194 align:start position:0% as summer arrives. And then, next year, the<00:17:00.880> cycle<00:17:01.280> begins<00:17:01.839> again. 15:48.194 --> 15:48.204 align:start position:0% the cycle begins again. 15:48.204 --> 15:50.674 align:start position:0% the cycle begins again. This<00:17:03.720> is<00:17:03.960> why<00:17:04.120> the<00:17:04.240> hole<00:17:04.600> is<00:17:04.920> seasonal,<00:17:05.520> and 15:50.674 --> 15:50.684 align:start position:0% This is why the hole is seasonal, and 15:50.684 --> 15:53.074 align:start position:0% This is why the hole is seasonal, and that<00:17:06.120> is<00:17:06.319> why<00:17:06.520> it's<00:17:06.680> nearly<00:17:07.120> always<00:17:07.839> over 15:53.074 --> 15:53.084 align:start position:0% that is why it's nearly always over 15:53.084 --> 15:54.753 align:start position:0% that is why it's nearly always over Antarctica. 15:54.753 --> 15:54.763 align:start position:0% Antarctica. 15:54.763 --> 15:55.873 align:start position:0% Antarctica. But,<00:17:10.000> just<00:17:10.199> because<00:17:10.400> it's<00:17:10.520> all<00:17:10.600> the<00:17:10.680> way<00:17:10.800> over 15:55.873 --> 15:55.883 align:start position:0% But, just because it's all the way over 15:55.883 --> 15:57.353 align:start position:0% But, just because it's all the way over there<00:17:11.120> in<00:17:11.240> Antarctica<00:17:11.839> on<00:17:11.959> a<00:17:12.040> largely 15:57.353 --> 15:57.363 align:start position:0% there in Antarctica on a largely 15:57.363 --> 15:59.233 align:start position:0% there in Antarctica on a largely uninhabited<00:17:13.079> continent<00:17:13.680> doesn't<00:17:14.000> make<00:17:14.199> the 15:59.233 --> 15:59.243 align:start position:0% uninhabited continent doesn't make the 15:59.243 --> 16:01.314 align:start position:0% uninhabited continent doesn't make the ozone<00:17:14.560> hole<00:17:14.720> any<00:17:14.880> less<00:17:15.560> dangerous.<00:17:16.079> It<00:17:16.199> just 16:01.314 --> 16:01.324 align:start position:0% ozone hole any less dangerous. It just 16:01.324 --> 16:03.594 align:start position:0% ozone hole any less dangerous. It just means<00:17:16.600> it's<00:17:17.040> further<00:17:17.480> away. 16:03.594 --> 16:03.604 align:start position:0% means it's further away. 16:03.604 --> 16:05.873 align:start position:0% means it's further away. Plus,<00:17:18.959> what<00:17:19.120> are<00:17:19.199> called<00:17:19.520> finger<00:17:20.000> extensions 16:05.873 --> 16:05.883 align:start position:0% Plus, what are called finger extensions 16:05.883 --> 16:07.634 align:start position:0% Plus, what are called finger extensions can<00:17:21.240> shift<00:17:21.560> and<00:17:21.680> expand<00:17:22.160> the<00:17:22.240> hole<00:17:22.520> over 16:07.634 --> 16:07.644 align:start position:0% can shift and expand the hole over 16:07.644 --> 16:10.474 align:start position:0% can shift and expand the hole over cities<00:17:23.079> in<00:17:23.240> New<00:17:23.480> Zealand<00:17:23.839> and<00:17:24.079> South<00:17:24.480> America. 16:10.474 --> 16:10.484 align:start position:0% cities in New Zealand and South America. 16:10.484 --> 16:13.394 align:start position:0% cities in New Zealand and South America. I<00:17:25.600> mean,<00:17:25.760> back<00:17:26.000> in<00:17:26.160> 2000,<00:17:27.280> residents<00:17:27.760> of<00:17:28.000> Punta 16:13.394 --> 16:13.404 align:start position:0% I mean, back in 2000, residents of Punta 16:13.404 --> 16:15.674 align:start position:0% I mean, back in 2000, residents of Punta Arenas<00:17:28.960> in<00:17:29.240> Chile<00:17:29.680> were<00:17:29.840> warned<00:17:30.160> to<00:17:30.320> stay<00:17:30.600> at 16:15.674 --> 16:15.684 align:start position:0% Arenas in Chile were warned to stay at 16:15.684 --> 16:17.954 align:start position:0% Arenas in Chile were warned to stay at home<00:17:31.080> during<00:17:31.360> one<00:17:31.520> of<00:17:31.600> the<00:17:31.840> largest<00:17:32.560> seasonal 16:17.954 --> 16:17.964 align:start position:0% home during one of the largest seasonal 16:17.964 --> 16:20.914 align:start position:0% home during one of the largest seasonal ozone<00:17:33.400> holes<00:17:33.800> on<00:17:34.200> record.<00:17:35.160> UV<00:17:35.440> levels<00:17:35.760> had 16:20.914 --> 16:20.924 align:start position:0% ozone holes on record. UV levels had 16:20.924 --> 16:23.954 align:start position:0% ozone holes on record. UV levels had skyrocketed<00:17:36.840> into<00:17:37.080> the<00:17:37.200> danger<00:17:37.680> zone. 16:23.954 --> 16:23.964 align:start position:0% skyrocketed into the danger zone. 16:23.964 --> 16:25.754 align:start position:0% skyrocketed into the danger zone. Quite<00:17:39.240> simply,<00:17:39.520> without<00:17:40.000> action,<00:17:40.400> this<00:17:40.600> hole 16:25.754 --> 16:25.764 align:start position:0% Quite simply, without action, this hole 16:25.764 --> 16:27.354 align:start position:0% Quite simply, without action, this hole would<00:17:40.960> have<00:17:41.120> kept<00:17:41.480> growing,<00:17:41.840> not<00:17:42.000> just<00:17:42.240> over 16:27.354 --> 16:27.364 align:start position:0% would have kept growing, not just over 16:27.364 --> 16:30.194 align:start position:0% would have kept growing, not just over Antarctica,<00:17:43.040> but<00:17:43.640> everywhere.<00:17:44.720> The<00:17:44.800> warnings 16:30.194 --> 16:30.204 align:start position:0% Antarctica, but everywhere. The warnings 16:30.204 --> 16:33.114 align:start position:0% Antarctica, but everywhere. The warnings were<00:17:45.520> stark.<00:17:46.560> By<00:17:46.720> 2040,<00:17:47.560> the<00:17:47.680> hole<00:17:47.920> would<00:17:48.040> have 16:33.114 --> 16:33.124 align:start position:0% were stark. By 2040, the hole would have 16:33.124 --> 16:36.834 align:start position:0% were stark. By 2040, the hole would have gone<00:17:48.600> global.<00:17:49.520> By<00:17:49.680> 2065,<00:17:50.760> the<00:17:50.880> UV<00:17:51.280> index<00:17:51.760> in 16:36.834 --> 16:36.844 align:start position:0% gone global. By 2065, the UV index in 16:36.844 --> 16:39.434 align:start position:0% gone global. By 2065, the UV index in the<00:17:52.040> US<00:17:52.400> would<00:17:52.520> be<00:17:52.680> 30.<00:17:53.760> Usually,<00:17:54.080> it's<00:17:54.200> just 16:39.434 --> 16:39.444 align:start position:0% the US would be 30. Usually, it's just 16:39.444 --> 16:41.834 align:start position:0% the US would be 30. Usually, it's just nine.<00:17:55.280> Strong<00:17:55.560> enough<00:17:55.800> to<00:17:55.920> cause<00:17:56.240> sunburn<00:17:56.800> in 16:41.834 --> 16:41.844 align:start position:0% nine. Strong enough to cause sunburn in 16:41.844 --> 16:43.954 align:start position:0% nine. Strong enough to cause sunburn in cities<00:17:57.320> like<00:17:57.480> Washington,<00:17:57.920> D.C.<00:17:58.480> in<00:17:58.680> just 16:43.954 --> 16:43.964 align:start position:0% cities like Washington, D.C. in just 16:43.964 --> 16:47.914 align:start position:0% cities like Washington, D.C. in just five<00:17:59.680> minutes.<00:18:00.840> DNA-mutating<00:18:02.120> UV<00:18:02.480> radiation 16:47.914 --> 16:47.924 align:start position:0% five minutes. DNA-mutating UV radiation 16:47.924 --> 16:49.994 align:start position:0% five minutes. DNA-mutating UV radiation would<00:18:03.080> be<00:18:03.240> up<00:18:03.440> 500%. 16:49.994 --> 16:50.004 align:start position:0% would be up 500%. 16:50.004 --> 16:51.314 align:start position:0% would be up 500%. There<00:18:05.160> would<00:18:05.280> be<00:18:05.400> more<00:18:05.680> cancers,<00:18:06.200> more 16:51.314 --> 16:51.324 align:start position:0% There would be more cancers, more 16:51.324 --> 16:52.914 align:start position:0% There would be more cancers, more cataracts,<00:18:07.000> more<00:18:07.120> compromised<00:18:07.600> immune 16:52.914 --> 16:52.924 align:start position:0% cataracts, more compromised immune 16:52.924 --> 16:55.354 align:start position:0% cataracts, more compromised immune systems.<00:18:08.840> Plants,<00:18:09.320> animals,<00:18:09.760> and<00:18:09.960> crops 16:55.354 --> 16:55.364 align:start position:0% systems. Plants, animals, and crops 16:55.364 --> 16:58.114 align:start position:0% systems. Plants, animals, and crops would<00:18:10.640> struggle.<00:18:11.040> Entire<00:18:11.680> ecosystems<00:18:12.880> would 16:58.114 --> 16:58.124 align:start position:0% would struggle. Entire ecosystems would 16:58.124 --> 17:00.034 align:start position:0% would struggle. Entire ecosystems would collapse. 17:00.034 --> 17:00.044 align:start position:0% collapse. 17:00.044 --> 17:02.074 align:start position:0% collapse. And<00:18:15.200> it<00:18:15.320> wasn't<00:18:15.560> just<00:18:15.760> harmful<00:18:16.240> UV<00:18:16.520> radiation 17:02.074 --> 17:02.084 align:start position:0% And it wasn't just harmful UV radiation 17:02.084 --> 17:04.914 align:start position:0% And it wasn't just harmful UV radiation that<00:18:17.280> was<00:18:17.400> the<00:18:17.520> problem.<00:18:18.480> By<00:18:18.600> the<00:18:18.680> late<00:18:18.920> 1980s, 17:04.914 --> 17:04.924 align:start position:0% that was the problem. By the late 1980s, 17:04.924 --> 17:06.314 align:start position:0% that was the problem. By the late 1980s, scientists<00:18:20.560> were<00:18:20.640> already<00:18:20.920> seeing 17:06.314 --> 17:06.324 align:start position:0% scientists were already seeing 17:06.324 --> 17:09.234 align:start position:0% scientists were already seeing wide-ranging<00:18:22.440> climate<00:18:23.000> impacts. 17:09.234 --> 17:09.244 align:start position:0% wide-ranging climate impacts. 17:09.244 --> 17:11.394 align:start position:0% wide-ranging climate impacts. Jet<00:18:24.520> streams<00:18:24.920> were<00:18:25.040> changing.<00:18:25.760> Australia<00:18:26.240> got 17:11.394 --> 17:11.404 align:start position:0% Jet streams were changing. Australia got 17:11.404 --> 17:13.034 align:start position:0% Jet streams were changing. Australia got drier,<00:18:26.840> while<00:18:27.000> parts<00:18:27.280> of<00:18:27.400> Uruguay,<00:18:27.760> Brazil, 17:13.034 --> 17:13.044 align:start position:0% drier, while parts of Uruguay, Brazil, 17:13.044 --> 17:15.994 align:start position:0% drier, while parts of Uruguay, Brazil, Paraguay,<00:18:28.480> and<00:18:28.560> Argentina<00:18:29.200> got<00:18:29.520> more<00:18:29.800> rain. 17:15.994 --> 17:16.004 align:start position:0% Paraguay, and Argentina got more rain. 17:16.004 --> 17:17.874 align:start position:0% Paraguay, and Argentina got more rain. The<00:18:31.120> nature<00:18:31.600> of<00:18:31.720> the<00:18:31.840> chain<00:18:32.160> reactions<00:18:32.760> meant 17:17.874 --> 17:17.884 align:start position:0% The nature of the chain reactions meant 17:17.884 --> 17:19.794 align:start position:0% The nature of the chain reactions meant that<00:18:33.080> our<00:18:33.200> atmosphere<00:18:33.680> was<00:18:33.920> already<00:18:34.400> loaded 17:19.794 --> 17:19.804 align:start position:0% that our atmosphere was already loaded 17:19.804 --> 17:22.834 align:start position:0% that our atmosphere was already loaded with<00:18:35.160> decades<00:18:35.920> of<00:18:36.160> CFCs<00:18:37.000> yet<00:18:37.320> to<00:18:37.440> even<00:18:37.680> make 17:22.834 --> 17:22.844 align:start position:0% with decades of CFCs yet to even make 17:22.844 --> 17:25.274 align:start position:0% with decades of CFCs yet to even make their<00:18:38.080> impact.<00:18:38.960> CFCs<00:18:39.560> have<00:18:39.720> a<00:18:39.800> long 17:25.274 --> 17:25.284 align:start position:0% their impact. CFCs have a long 17:25.284 --> 17:27.554 align:start position:0% their impact. CFCs have a long atmospheric<00:18:41.040> lifespan.<00:18:42.000> They<00:18:42.160> can<00:18:42.400> hang 17:27.554 --> 17:27.564 align:start position:0% atmospheric lifespan. They can hang 17:27.564 --> 17:28.994 align:start position:0% atmospheric lifespan. They can hang around<00:18:43.040> in<00:18:43.080> the<00:18:43.160> stratosphere<00:18:43.720> causing 17:28.994 --> 17:29.004 align:start position:0% around in the stratosphere causing 17:29.004 --> 17:30.954 align:start position:0% around in the stratosphere causing trouble<00:18:44.520> way<00:18:44.880> after<00:18:45.120> they<00:18:45.280> were<00:18:45.400> used<00:18:45.720> down<00:18:45.920> on 17:30.954 --> 17:30.964 align:start position:0% trouble way after they were used down on 17:30.964 --> 17:35.114 align:start position:0% trouble way after they were used down on the<00:18:46.120> surface.<00:18:47.200> CFC-11s<00:18:48.440> can<00:18:48.600> last<00:18:48.920> 55<00:18:49.920> years, 17:35.114 --> 17:35.124 align:start position:0% the surface. CFC-11s can last 55 years, 17:35.124 --> 17:36.914 align:start position:0% the surface. CFC-11s can last 55 years, and<00:18:50.320> CFC-12s, 17:36.914 --> 17:36.924 align:start position:0% and CFC-12s, 17:36.924 --> 17:39.154 align:start position:0% and CFC-12s, 140<00:18:53.200> years. 17:39.154 --> 17:39.164 align:start position:0% 140 years. 17:39.164 --> 17:41.154 align:start position:0% 140 years. Something<00:18:54.880> needed<00:18:55.240> to<00:18:55.360> be<00:18:55.480> done,<00:18:55.880> and 17:41.154 --> 17:41.164 align:start position:0% Something needed to be done, and 17:41.164 --> 17:45.074 align:start position:0% Something needed to be done, and quickly.<00:18:57.040> And<00:18:57.400> surprisingly,<00:18:58.760> well,<00:18:58.880> it<00:18:59.000> was. 17:45.074 --> 17:45.084 align:start position:0% quickly. And surprisingly, well, it was. 17:45.084 --> 17:47.794 align:start position:0% quickly. And surprisingly, well, it was. For<00:19:00.400> once,<00:19:00.840> the<00:19:01.040> entire<00:19:01.640> world<00:19:02.520> quite 17:47.794 --> 17:47.804 align:start position:0% For once, the entire world quite 17:47.804 --> 17:50.234 align:start position:0% For once, the entire world quite literally<00:19:03.320> came<00:19:03.640> together<00:19:04.040> to<00:19:04.240> act. 17:50.234 --> 17:50.244 align:start position:0% literally came together to act. 17:50.244 --> 17:51.754 align:start position:0% literally came together to act. And<00:19:05.480> it<00:19:05.600> worked. 17:51.754 --> 17:51.764 align:start position:0% And it worked. 17:51.764 --> 17:55.954 align:start position:0% And it worked. In<00:19:07.000> 1987,<00:19:08.320> 197<00:19:09.560> UN<00:19:09.840> member<00:19:10.160> states<00:19:10.520> adopted 17:55.954 --> 17:55.964 align:start position:0% In 1987, 197 UN member states adopted 17:55.964 --> 17:58.874 align:start position:0% In 1987, 197 UN member states adopted the<00:19:11.160> Montreal<00:19:11.880> Protocol,<00:19:13.080> or<00:19:13.360> to<00:19:13.520> give<00:19:13.640> it<00:19:13.720> its 17:58.874 --> 17:58.884 align:start position:0% the Montreal Protocol, or to give it its 17:58.884 --> 18:01.434 align:start position:0% the Montreal Protocol, or to give it its full<00:19:14.200> title,<00:19:14.880> the<00:19:15.040> Montreal<00:19:15.720> Protocol<00:19:16.320> on 18:01.434 --> 18:01.444 align:start position:0% full title, the Montreal Protocol on 18:01.444 --> 18:04.154 align:start position:0% full title, the Montreal Protocol on Substances<00:19:17.200> that<00:19:17.320> Deplete<00:19:17.800> the<00:19:18.000> Ozone<00:19:18.480> Layer. 18:04.154 --> 18:04.164 align:start position:0% Substances that Deplete the Ozone Layer. 18:04.164 --> 18:06.914 align:start position:0% Substances that Deplete the Ozone Layer. How<00:19:19.400> grand.<00:19:20.240> It<00:19:20.360> was<00:19:20.520> the<00:19:20.760> only<00:19:21.200> UN<00:19:21.520> treaty 18:06.914 --> 18:06.924 align:start position:0% How grand. It was the only UN treaty 18:06.924 --> 18:08.994 align:start position:0% How grand. It was the only UN treaty ever<00:19:22.320> to<00:19:22.480> be<00:19:22.560> ratified<00:19:23.080> by<00:19:23.280> every<00:19:23.680> single 18:08.994 --> 18:09.004 align:start position:0% ever to be ratified by every single 18:09.004 --> 18:11.114 align:start position:0% ever to be ratified by every single country<00:19:24.520> on<00:19:24.720> the<00:19:24.880> planet. 18:11.114 --> 18:11.124 align:start position:0% country on the planet. 18:11.124 --> 18:12.714 align:start position:0% country on the planet. This<00:19:26.440> landmark<00:19:26.960> global<00:19:27.320> agreement 18:12.714 --> 18:12.724 align:start position:0% This landmark global agreement 18:12.724 --> 18:14.794 align:start position:0% This landmark global agreement introduced<00:19:28.360> a<00:19:28.480> plan<00:19:28.840> for<00:19:29.080> phasing<00:19:29.560> out<00:19:29.760> and 18:14.794 --> 18:14.804 align:start position:0% introduced a plan for phasing out and 18:14.804 --> 18:17.434 align:start position:0% introduced a plan for phasing out and eventually<00:19:30.320> banning<00:19:30.880> CFCs,<00:19:32.000> with<00:19:32.200> other 18:17.434 --> 18:17.444 align:start position:0% eventually banning CFCs, with other 18:17.444 --> 18:20.074 align:start position:0% eventually banning CFCs, with other ozone-depleting<00:19:33.280> substances<00:19:33.880> like<00:19:34.160> HFCs<00:19:34.960> or 18:20.074 --> 18:20.084 align:start position:0% ozone-depleting substances like HFCs or 18:20.084 --> 18:21.834 align:start position:0% ozone-depleting substances like HFCs or hydrofluorocarbons 18:21.834 --> 18:21.844 align:start position:0% hydrofluorocarbons 18:21.844 --> 18:24.034 align:start position:0% hydrofluorocarbons being<00:19:37.200> added<00:19:37.560> as<00:19:37.800> they<00:19:37.960> were<00:19:38.040> discovered. 18:24.034 --> 18:24.044 align:start position:0% being added as they were discovered. 18:24.044 --> 18:26.114 align:start position:0% being added as they were discovered. Montreal<00:19:39.640> was<00:19:39.880> a<00:19:40.040> real<00:19:40.400> turning<00:19:40.760> point,<00:19:41.080> a 18:26.114 --> 18:26.124 align:start position:0% Montreal was a real turning point, a 18:26.124 --> 18:29.194 align:start position:0% Montreal was a real turning point, a plan<00:19:42.160> to<00:19:42.320> save<00:19:42.680> the<00:19:42.840> ozone<00:19:43.240> layer. 18:29.194 --> 18:29.204 align:start position:0% plan to save the ozone layer. 18:29.204 --> 18:31.194 align:start position:0% plan to save the ozone layer. And<00:19:44.360> guess<00:19:44.600> what?<00:19:44.960> All<00:19:45.160> these<00:19:45.400> decades<00:19:45.880> later, 18:31.194 --> 18:31.204 align:start position:0% And guess what? All these decades later, 18:31.204 --> 18:33.874 align:start position:0% And guess what? All these decades later, it's<00:19:46.560> still<00:19:47.120> working.<00:19:47.880> CFC<00:19:48.440> emissions<00:19:48.800> have 18:33.874 --> 18:33.884 align:start position:0% it's still working. CFC emissions have 18:33.884 --> 18:36.514 align:start position:0% it's still working. CFC emissions have fallen<00:19:49.240> by<00:19:49.320> an<00:19:49.400> incredible<00:19:49.960> 99% 18:36.514 --> 18:36.524 align:start position:0% fallen by an incredible 99% 18:36.524 --> 18:38.794 align:start position:0% fallen by an incredible 99% since<00:19:52.480> the<00:19:52.600> Montreal<00:19:53.120> Protocol<00:19:53.640> was 18:38.794 --> 18:38.804 align:start position:0% since the Montreal Protocol was 18:38.804 --> 18:40.954 align:start position:0% since the Montreal Protocol was implemented,<00:19:54.880> and<00:19:55.240> ozone-depleting 18:40.954 --> 18:40.964 align:start position:0% implemented, and ozone-depleting 18:40.964 --> 18:42.754 align:start position:0% implemented, and ozone-depleting substances<00:19:56.520> in<00:19:56.600> the<00:19:56.680> stratosphere,<00:19:57.720> well, 18:42.754 --> 18:42.764 align:start position:0% substances in the stratosphere, well, 18:42.764 --> 18:44.714 align:start position:0% substances in the stratosphere, well, they're<00:19:58.080> falling<00:19:58.560> too.<00:19:59.240> Since<00:19:59.480> peaking 18:44.714 --> 18:44.724 align:start position:0% they're falling too. Since peaking 18:44.724 --> 18:46.594 align:start position:0% they're falling too. Since peaking around<00:20:00.120> the<00:20:00.240> year<00:20:00.440> 2000,<00:20:01.280> levels<00:20:01.560> have 18:46.594 --> 18:46.604 align:start position:0% around the year 2000, levels have 18:46.604 --> 18:48.994 align:start position:0% around the year 2000, levels have declined<00:20:02.040> by<00:20:02.160> about<00:20:02.360> a<00:20:02.440> third<00:20:03.520> relative<00:20:03.880> to 18:48.994 --> 18:49.004 align:start position:0% declined by about a third relative to 18:49.004 --> 18:51.794 align:start position:0% declined by about a third relative to pre-ozone<00:20:05.160> hole<00:20:05.560> levels. 18:51.794 --> 18:51.804 align:start position:0% pre-ozone hole levels. 18:51.804 --> 18:53.194 align:start position:0% pre-ozone hole levels. Yeah,<00:20:07.120> as<00:20:07.280> you<00:20:07.360> probably<00:20:07.640> already<00:20:07.880> guessed<00:20:08.160> by 18:53.194 --> 18:53.204 align:start position:0% Yeah, as you probably already guessed by 18:53.204 --> 18:55.314 align:start position:0% Yeah, as you probably already guessed by now,<00:20:08.480> things<00:20:08.800> had<00:20:09.000> to<00:20:09.080> get<00:20:09.320> worse<00:20:09.640> before<00:20:10.160> they 18:55.314 --> 18:55.324 align:start position:0% now, things had to get worse before they 18:55.324 --> 18:57.274 align:start position:0% now, things had to get worse before they got<00:20:10.720> better.<00:20:11.440> All<00:20:11.560> of<00:20:11.640> those<00:20:11.880> chemical 18:57.274 --> 18:57.284 align:start position:0% got better. All of those chemical 18:57.284 --> 18:59.354 align:start position:0% got better. All of those chemical reactions<00:20:12.800> were<00:20:12.920> baked<00:20:13.480> into<00:20:13.800> the<00:20:13.920> system, 18:59.354 --> 18:59.364 align:start position:0% reactions were baked into the system, 18:59.364 --> 19:01.034 align:start position:0% reactions were baked into the system, but<00:20:14.600> it<00:20:14.880> could<00:20:15.040> have<00:20:15.160> been<00:20:15.320> a<00:20:15.640> whole<00:20:15.920> lot 19:01.034 --> 19:01.044 align:start position:0% but it could have been a whole lot 19:01.044 --> 19:03.474 align:start position:0% but it could have been a whole lot worse.<00:20:17.040> And<00:20:17.240> this<00:20:17.560> is<00:20:17.760> where<00:20:17.880> it<00:20:18.000> becomes<00:20:18.440> a 19:03.474 --> 19:03.484 align:start position:0% worse. And this is where it becomes a 19:03.484 --> 19:05.674 align:start position:0% worse. And this is where it becomes a proper<00:20:19.240> good<00:20:19.520> news<00:20:19.800> story,<00:20:20.440> because<00:20:20.640> the 19:05.674 --> 19:05.684 align:start position:0% proper good news story, because the 19:05.684 --> 19:07.394 align:start position:0% proper good news story, because the ozone<00:20:21.000> layer<00:20:21.120> hasn't<00:20:21.360> just<00:20:21.520> stopped<00:20:21.840> growing, 19:07.394 --> 19:07.404 align:start position:0% ozone layer hasn't just stopped growing, 19:07.404 --> 19:10.514 align:start position:0% ozone layer hasn't just stopped growing, it's<00:20:22.760> actually<00:20:23.240> started<00:20:24.120> healing. 19:10.514 --> 19:10.524 align:start position:0% it's actually started healing. 19:10.524 --> 19:12.634 align:start position:0% it's actually started healing. The<00:20:25.720> Antarctic<00:20:26.360> ozone<00:20:26.760> hole<00:20:26.960> has<00:20:27.120> been<00:20:27.320> slowly 19:12.634 --> 19:12.644 align:start position:0% The Antarctic ozone hole has been slowly 19:12.644 --> 19:14.954 align:start position:0% The Antarctic ozone hole has been slowly improving<00:20:28.400> in<00:20:28.680> area<00:20:29.120> and<00:20:29.440> depth,<00:20:29.840> if<00:20:29.960> you 19:14.954 --> 19:14.964 align:start position:0% improving in area and depth, if you 19:14.964 --> 19:16.874 align:start position:0% improving in area and depth, if you remember<00:20:30.280> those<00:20:30.520> Dobson<00:20:30.920> units,<00:20:31.600> since<00:20:31.840> the 19:16.874 --> 19:16.884 align:start position:0% remember those Dobson units, since the 19:16.884 --> 19:18.994 align:start position:0% remember those Dobson units, since the turn<00:20:32.320> of<00:20:32.520> the<00:20:32.600> millennium.<00:20:33.600> Now,<00:20:33.800> full 19:18.994 --> 19:19.004 align:start position:0% turn of the millennium. Now, full 19:19.004 --> 19:21.314 align:start position:0% turn of the millennium. Now, full recovery<00:20:34.600> is<00:20:34.800> still<00:20:35.120> decades<00:20:35.720> away,<00:20:36.000> but<00:20:36.160> it's 19:21.314 --> 19:21.324 align:start position:0% recovery is still decades away, but it's 19:21.324 --> 19:23.834 align:start position:0% recovery is still decades away, but it's tantalizingly<00:20:37.520> within<00:20:37.960> reach.<00:20:38.720> It's 19:23.834 --> 19:23.844 align:start position:0% tantalizingly within reach. It's 19:23.844 --> 19:26.314 align:start position:0% tantalizingly within reach. It's predicted<00:20:39.320> we'll<00:20:39.480> see<00:20:39.720> a<00:20:39.800> return<00:20:40.280> to<00:20:40.400> 1980 19:26.314 --> 19:26.324 align:start position:0% predicted we'll see a return to 1980 19:26.324 --> 19:29.754 align:start position:0% predicted we'll see a return to 1980 values<00:20:41.760> by<00:20:41.960> 2040<00:20:43.360> for<00:20:43.480> the<00:20:43.600> global<00:20:44.120> average. 19:29.754 --> 19:29.764 align:start position:0% values by 2040 for the global average. 19:29.764 --> 19:32.394 align:start position:0% values by 2040 for the global average. That<00:20:45.040> stretches<00:20:45.400> to<00:20:45.520> 2045<00:20:46.680> for<00:20:46.840> the<00:20:47.080> Arctic 19:32.394 --> 19:32.404 align:start position:0% That stretches to 2045 for the Arctic 19:32.404 --> 19:34.034 align:start position:0% That stretches to 2045 for the Arctic and<00:20:47.600> 2066 19:34.034 --> 19:34.044 align:start position:0% and 2066 19:34.044 --> 19:36.194 align:start position:0% and 2066 in<00:20:49.280> the<00:20:49.560> Antarctic,<00:20:50.560> because,<00:20:50.840> yeah,<00:20:51.040> those 19:36.194 --> 19:36.204 align:start position:0% in the Antarctic, because, yeah, those 19:36.204 --> 19:38.034 align:start position:0% in the Antarctic, because, yeah, those polar<00:20:51.560> stratospheric<00:20:52.000> clouds,<00:20:52.920> well,<00:20:53.000> they 19:38.034 --> 19:38.044 align:start position:0% polar stratospheric clouds, well, they 19:38.044 --> 19:39.634 align:start position:0% polar stratospheric clouds, well, they really<00:20:53.280> make<00:20:53.440> a<00:20:53.480> difference. 19:39.634 --> 19:39.644 align:start position:0% really make a difference. 19:39.644 --> 19:42.074 align:start position:0% really make a difference. A<00:20:54.840> recent<00:20:55.280> MIT-led<00:20:56.120> study<00:20:56.440> published<00:20:56.920> in<00:20:57.040> the 19:42.074 --> 19:42.084 align:start position:0% A recent MIT-led study published in the 19:42.084 --> 19:44.314 align:start position:0% A recent MIT-led study published in the journal<00:20:57.600> Nature<00:20:58.000> added<00:20:58.240> the<00:20:58.440> cherry<00:20:58.920> on<00:20:59.080> top 19:44.314 --> 19:44.324 align:start position:0% journal Nature added the cherry on top 19:44.324 --> 19:46.634 align:start position:0% journal Nature added the cherry on top of<00:20:59.560> the<00:20:59.720> cake.<00:21:00.600> Ozone<00:21:01.000> layer<00:21:01.120> recovery<00:21:01.520> has 19:46.634 --> 19:46.644 align:start position:0% of the cake. Ozone layer recovery has 19:46.644 --> 19:49.034 align:start position:0% of the cake. Ozone layer recovery has been<00:21:01.840> observed<00:21:02.280> in<00:21:02.520> the<00:21:02.640> past,<00:21:03.080> but<00:21:03.280> this, 19:49.034 --> 19:49.044 align:start position:0% been observed in the past, but this, 19:49.044 --> 19:50.794 align:start position:0% been observed in the past, but this, well,<00:21:04.200> this<00:21:04.360> is<00:21:04.440> the<00:21:04.560> first<00:21:04.960> study<00:21:05.240> to<00:21:05.400> confirm 19:50.794 --> 19:50.804 align:start position:0% well, this is the first study to confirm 19:50.804 --> 19:53.554 align:start position:0% well, this is the first study to confirm healing<00:21:06.400> as<00:21:06.680> a<00:21:06.760> direct<00:21:07.280> result<00:21:07.800> of<00:21:08.160> global 19:53.554 --> 19:53.564 align:start position:0% healing as a direct result of global 19:53.564 --> 19:56.074 align:start position:0% healing as a direct result of global actions<00:21:09.720> rather<00:21:10.120> than<00:21:10.280> natural<00:21:10.640> influences 19:56.074 --> 19:56.084 align:start position:0% actions rather than natural influences 19:56.084 --> 19:57.754 align:start position:0% actions rather than natural influences like<00:21:11.560> weather. 19:57.754 --> 19:57.764 align:start position:0% like weather. 19:57.764 --> 19:59.114 align:start position:0% like weather. The<00:21:12.920> team<00:21:13.160> borrowed<00:21:13.480> what<00:21:13.640> are<00:21:13.680> known<00:21:13.920> as 19:59.114 --> 19:59.124 align:start position:0% The team borrowed what are known as 19:59.124 --> 20:00.954 align:start position:0% The team borrowed what are known as fingerprinting<00:21:14.960> techniques<00:21:15.400> from<00:21:15.640> climate 20:00.954 --> 20:00.964 align:start position:0% fingerprinting techniques from climate 20:00.964 --> 20:03.074 align:start position:0% fingerprinting techniques from climate science,<00:21:16.760> matching<00:21:17.160> the<00:21:17.240> specific<00:21:17.800> pattern 20:03.074 --> 20:03.084 align:start position:0% science, matching the specific pattern 20:03.084 --> 20:05.234 align:start position:0% science, matching the specific pattern of<00:21:18.360> ozone<00:21:18.800> changes<00:21:19.360> across<00:21:19.680> different<00:21:20.000> months 20:05.234 --> 20:05.244 align:start position:0% of ozone changes across different months 20:05.244 --> 20:07.794 align:start position:0% of ozone changes across different months and<00:21:20.520> altitudes<00:21:21.200> against<00:21:22.200> what<00:21:22.480> models 20:07.794 --> 20:07.804 align:start position:0% and altitudes against what models 20:07.804 --> 20:10.514 align:start position:0% and altitudes against what models predict.<00:21:24.040> It<00:21:24.240> helped<00:21:24.480> researchers<00:21:25.080> confirm 20:10.514 --> 20:10.524 align:start position:0% predict. It helped researchers confirm 20:10.524 --> 20:12.634 align:start position:0% predict. It helped researchers confirm and<00:21:25.840> quantify<00:21:26.480> the<00:21:26.640> role<00:21:26.880> of<00:21:27.000> us<00:21:27.280> fridge 20:12.634 --> 20:12.644 align:start position:0% and quantify the role of us fridge 20:12.644 --> 20:15.754 align:start position:0% and quantify the role of us fridge buying<00:21:28.160> hairspray<00:21:28.840> using<00:21:29.400> pesky<00:21:29.840> humans. 20:15.754 --> 20:15.764 align:start position:0% buying hairspray using pesky humans. 20:15.764 --> 20:18.274 align:start position:0% buying hairspray using pesky humans. Basically,<00:21:31.720> we<00:21:31.880> broke<00:21:32.240> it 20:18.274 --> 20:18.284 align:start position:0% Basically, we broke it 20:18.284 --> 20:19.914 align:start position:0% Basically, we broke it and<00:21:33.440> then<00:21:33.560> we<00:21:33.640> fixed<00:21:33.920> it.<00:21:34.600> And<00:21:34.680> this<00:21:34.800> is<00:21:34.920> all 20:19.914 --> 20:19.924 align:start position:0% and then we fixed it. And this is all 20:19.924 --> 20:22.194 align:start position:0% and then we fixed it. And this is all obviously<00:21:35.400> great<00:21:35.760> news,<00:21:36.040> but<00:21:36.200> what's<00:21:36.440> more<00:21:37.040> is 20:22.194 --> 20:22.204 align:start position:0% obviously great news, but what's more is 20:22.204 --> 20:24.034 align:start position:0% obviously great news, but what's more is fixing<00:21:37.680> the<00:21:37.760> hole<00:21:38.040> in<00:21:38.160> the<00:21:38.400> ozone<00:21:38.800> layer<00:21:39.000> is 20:24.034 --> 20:24.044 align:start position:0% fixing the hole in the ozone layer is 20:24.044 --> 20:25.914 align:start position:0% fixing the hole in the ozone layer is even<00:21:39.400> helping<00:21:39.720> us<00:21:39.920> with<00:21:40.120> things<00:21:40.400> like<00:21:40.600> climate 20:25.914 --> 20:25.924 align:start position:0% even helping us with things like climate 20:25.924 --> 20:27.034 align:start position:0% even helping us with things like climate change. 20:27.034 --> 20:27.044 align:start position:0% change. 20:27.044 --> 20:28.794 align:start position:0% change. Another<00:21:42.560> study<00:21:42.800> published<00:21:43.160> in<00:21:43.320> Nature<00:21:43.640> found 20:28.794 --> 20:28.804 align:start position:0% Another study published in Nature found 20:28.804 --> 20:30.954 align:start position:0% Another study published in Nature found that<00:21:44.080> if<00:21:44.320> CFCs<00:21:44.840> hadn't<00:21:45.240> been<00:21:45.480> banned<00:21:45.840> in<00:21:45.920> the 20:30.954 --> 20:30.964 align:start position:0% that if CFCs hadn't been banned in the 20:30.964 --> 20:33.554 align:start position:0% that if CFCs hadn't been banned in the 1980s,<00:21:47.520> they<00:21:47.680> could<00:21:47.840> have<00:21:48.000> raised<00:21:48.320> average 20:33.554 --> 20:33.564 align:start position:0% 1980s, they could have raised average 20:33.564 --> 20:37.034 align:start position:0% 1980s, they could have raised average global<00:21:48.960> temperatures<00:21:49.400> by<00:21:49.560> another<00:21:50.680> 2.5°<00:21:51.720> C, 20:37.034 --> 20:37.044 align:start position:0% global temperatures by another 2.5° C, 20:37.044 --> 20:38.634 align:start position:0% global temperatures by another 2.5° C, which<00:21:52.280> if<00:21:52.400> you've<00:21:52.520> seen<00:21:52.720> this<00:21:52.880> channel,<00:21:53.520> you 20:38.634 --> 20:38.644 align:start position:0% which if you've seen this channel, you 20:38.644 --> 20:40.874 align:start position:0% which if you've seen this channel, you know<00:21:53.920> we<00:21:54.080> really<00:21:54.320> can't<00:21:54.560> be<00:21:54.680> doing. 20:40.874 --> 20:40.884 align:start position:0% know we really can't be doing. 20:40.884 --> 20:44.434 align:start position:0% know we really can't be doing. We<00:21:56.200> can't<00:21:56.560> get<00:21:56.720> complacent<00:21:57.440> though.<00:21:58.120> In<00:21:58.320> 2025, 20:44.434 --> 20:44.444 align:start position:0% We can't get complacent though. In 2025, 20:44.444 --> 20:46.114 align:start position:0% We can't get complacent though. In 2025, the<00:21:59.720> ozone<00:22:00.080> hole<00:22:00.320> was<00:22:00.480> only<00:22:00.640> the<00:22:00.800> fifth 20:46.114 --> 20:46.124 align:start position:0% the ozone hole was only the fifth 20:46.124 --> 20:48.794 align:start position:0% the ozone hole was only the fifth smallest<00:22:01.920> since<00:22:02.240> 1992 20:48.794 --> 20:48.804 align:start position:0% smallest since 1992 20:48.804 --> 20:52.274 align:start position:0% smallest since 1992 and<00:22:04.040> it<00:22:04.160> was<00:22:04.400> still<00:22:04.760> on<00:22:04.960> average<00:22:05.720> 18.71 20:52.274 --> 20:52.284 align:start position:0% and it was still on average 18.71 20:52.284 --> 20:55.074 align:start position:0% and it was still on average 18.71 million<00:22:08.000> square<00:22:08.440> kilometers.<00:22:09.560> That's<00:22:09.880> still 20:55.074 --> 20:55.084 align:start position:0% million square kilometers. That's still 20:55.084 --> 20:58.074 align:start position:0% million square kilometers. That's still twice<00:22:10.640> the<00:22:10.760> size<00:22:11.560> of<00:22:11.680> the<00:22:11.760> contiguous<00:22:12.560> United 20:58.074 --> 20:58.084 align:start position:0% twice the size of the contiguous United 20:58.084 --> 21:00.594 align:start position:0% twice the size of the contiguous United States.<00:22:14.040> In<00:22:14.160> a<00:22:14.520> cruel<00:22:14.920> twist<00:22:15.240> of<00:22:15.360> irony, 21:00.594 --> 21:00.604 align:start position:0% States. In a cruel twist of irony, 21:00.604 --> 21:02.834 align:start position:0% States. In a cruel twist of irony, climate<00:22:16.160> change<00:22:16.720> isn't<00:22:17.080> helping. 21:02.834 --> 21:02.844 align:start position:0% climate change isn't helping. 21:02.844 --> 21:04.594 align:start position:0% climate change isn't helping. Temperature,<00:22:18.560> weather,<00:22:19.000> shifts<00:22:19.480> in<00:22:19.600> the 21:04.594 --> 21:04.604 align:start position:0% Temperature, weather, shifts in the 21:04.604 --> 21:06.874 align:start position:0% Temperature, weather, shifts in the polar<00:22:19.960> vortex,<00:22:20.400> they<00:22:20.520> can<00:22:20.720> all<00:22:21.000> cause<00:22:21.520> ozone 21:06.874 --> 21:06.884 align:start position:0% polar vortex, they can all cause ozone 21:06.884 --> 21:09.354 align:start position:0% polar vortex, they can all cause ozone depletion.<00:22:23.040> Extreme<00:22:23.520> wildfires<00:22:24.080> can<00:22:24.240> be 21:09.354 --> 21:09.364 align:start position:0% depletion. Extreme wildfires can be 21:09.364 --> 21:11.474 align:start position:0% depletion. Extreme wildfires can be doubly<00:22:24.960> devastating,<00:22:26.000> producing 21:11.474 --> 21:11.484 align:start position:0% doubly devastating, producing 21:11.484 --> 21:13.634 align:start position:0% doubly devastating, producing pyrocumulonimbus<00:22:27.880> clouds<00:22:28.280> funneling<00:22:28.640> a 21:13.634 --> 21:13.644 align:start position:0% pyrocumulonimbus clouds funneling a 21:13.644 --> 21:15.914 align:start position:0% pyrocumulonimbus clouds funneling a cocktail<00:22:29.160> of<00:22:29.320> chemical<00:22:29.760> components<00:22:30.360> into<00:22:30.800> the 21:15.914 --> 21:15.924 align:start position:0% cocktail of chemical components into the 21:15.924 --> 21:17.714 align:start position:0% cocktail of chemical components into the upper<00:22:31.280> atmosphere. 21:17.714 --> 21:17.724 align:start position:0% upper atmosphere. 21:17.724 --> 21:19.634 align:start position:0% upper atmosphere. Those<00:22:33.040> compounds<00:22:33.560> contain,<00:22:34.160> yep,<00:22:34.520> you've 21:19.634 --> 21:19.644 align:start position:0% Those compounds contain, yep, you've 21:19.644 --> 21:21.874 align:start position:0% Those compounds contain, yep, you've guessed<00:22:35.080> it,<00:22:35.360> chlorine,<00:22:36.080> which<00:22:36.400> reacts<00:22:36.760> with 21:21.874 --> 21:21.884 align:start position:0% guessed it, chlorine, which reacts with 21:21.884 --> 21:24.674 align:start position:0% guessed it, chlorine, which reacts with the<00:22:37.120> ozone<00:22:37.520> to<00:22:37.680> break<00:22:38.040> it<00:22:38.200> down<00:22:38.560> again. 21:24.674 --> 21:24.684 align:start position:0% the ozone to break it down again. 21:24.684 --> 21:26.394 align:start position:0% the ozone to break it down again. It's<00:22:39.920> also<00:22:40.160> hard<00:22:40.360> to<00:22:40.440> account<00:22:40.800> for<00:22:41.120> rogue 21:26.394 --> 21:26.404 align:start position:0% It's also hard to account for rogue 21:26.404 --> 21:28.554 align:start position:0% It's also hard to account for rogue actors<00:22:41.880> who<00:22:42.080> might<00:22:42.360> be<00:22:42.480> ignoring<00:22:42.960> the<00:22:43.080> ban<00:22:43.400> by 21:28.554 --> 21:28.564 align:start position:0% actors who might be ignoring the ban by 21:28.564 --> 21:32.474 align:start position:0% actors who might be ignoring the ban by still<00:22:44.160> using<00:22:44.520> CFCs<00:22:45.240> illegally.<00:22:46.280> In<00:22:46.440> 2017,<00:22:47.440> a 21:32.474 --> 21:32.484 align:start position:0% still using CFCs illegally. In 2017, a 21:32.484 --> 21:34.594 align:start position:0% still using CFCs illegally. In 2017, a crack<00:22:48.000> squad<00:22:48.360> of<00:22:48.520> scientists<00:22:49.120> at<00:22:49.280> Bristol 21:34.594 --> 21:34.604 align:start position:0% crack squad of scientists at Bristol 21:34.604 --> 21:37.274 align:start position:0% crack squad of scientists at Bristol University<00:22:50.760> noticed<00:22:51.320> rising<00:22:51.720> emissions<00:22:52.120> of 21:37.274 --> 21:37.284 align:start position:0% University noticed rising emissions of 21:37.284 --> 21:40.874 align:start position:0% University noticed rising emissions of CFC-11,<00:22:53.760> banned<00:22:54.120> since<00:22:54.400> 2010,<00:22:55.440> and<00:22:55.680> turned 21:40.874 --> 21:40.884 align:start position:0% CFC-11, banned since 2010, and turned 21:40.884 --> 21:44.274 align:start position:0% CFC-11, banned since 2010, and turned detective<00:22:57.000> to<00:22:57.160> trace<00:22:57.560> it<00:22:57.720> back<00:22:58.000> to<00:22:58.240> China.<00:22:59.240> The 21:44.274 --> 21:44.284 align:start position:0% detective to trace it back to China. The 21:44.284 --> 21:45.834 align:start position:0% detective to trace it back to China. The factories<00:22:59.760> were<00:22:59.840> eventually<00:23:00.200> shut<00:23:00.560> down<00:23:00.840> and 21:45.834 --> 21:45.844 align:start position:0% factories were eventually shut down and 21:45.844 --> 21:47.874 align:start position:0% factories were eventually shut down and the<00:23:01.000> emissions<00:23:01.520> did<00:23:01.720> drop,<00:23:02.200> not<00:23:02.440> just<00:23:02.760> in 21:47.874 --> 21:47.884 align:start position:0% the emissions did drop, not just in 21:47.884 --> 21:50.434 align:start position:0% the emissions did drop, not just in China,<00:23:03.360> but<00:23:03.840> globally.<00:23:04.760> Someone<00:23:05.080> else<00:23:05.360> had 21:50.434 --> 21:50.444 align:start position:0% China, but globally. Someone else had 21:50.444 --> 21:53.234 align:start position:0% China, but globally. Someone else had been<00:23:05.720> breaking<00:23:06.120> the<00:23:06.200> rules,<00:23:06.600> but<00:23:06.960> exactly<00:23:07.480> who 21:53.234 --> 21:53.244 align:start position:0% been breaking the rules, but exactly who 21:53.244 --> 21:55.274 align:start position:0% been breaking the rules, but exactly who still<00:23:08.560> remains<00:23:08.880> a<00:23:08.920> mystery. 21:55.274 --> 21:55.284 align:start position:0% still remains a mystery. 21:55.284 --> 21:56.674 align:start position:0% still remains a mystery. It's<00:23:10.520> tricky<00:23:10.760> because<00:23:11.000> we<00:23:11.120> all<00:23:11.240> still<00:23:11.480> want<00:23:11.680> to 21:56.674 --> 21:56.684 align:start position:0% It's tricky because we all still want to 21:56.684 --> 21:58.834 align:start position:0% It's tricky because we all still want to have<00:23:11.960> fridges<00:23:12.360> and<00:23:12.600> aerosols<00:23:13.280> and<00:23:13.520> foam 21:58.834 --> 21:58.844 align:start position:0% have fridges and aerosols and foam 21:58.844 --> 22:01.274 align:start position:0% have fridges and aerosols and foam insulation,<00:23:14.880> but<00:23:15.040> they<00:23:15.160> all<00:23:15.280> need<00:23:15.560> some<00:23:16.040> sort 22:01.274 --> 22:01.284 align:start position:0% insulation, but they all need some sort 22:01.284 --> 22:04.714 align:start position:0% insulation, but they all need some sort of<00:23:16.480> chemical<00:23:16.920> cocktail<00:23:17.400> to<00:23:17.560> make<00:23:17.840> them<00:23:18.040> work. 22:04.714 --> 22:04.724 align:start position:0% of chemical cocktail to make them work. 22:04.724 --> 22:07.314 align:start position:0% of chemical cocktail to make them work. Replacements<00:23:20.480> for<00:23:20.720> CFCs<00:23:21.480> can<00:23:21.680> have<00:23:21.920> their<00:23:22.160> own 22:07.314 --> 22:07.324 align:start position:0% Replacements for CFCs can have their own 22:07.324 --> 22:09.314 align:start position:0% Replacements for CFCs can have their own consequences.<00:23:23.640> For<00:23:23.800> a<00:23:23.880> while, 22:09.314 --> 22:09.324 align:start position:0% consequences. For a while, 22:09.324 --> 22:11.594 align:start position:0% consequences. For a while, hydrochlorofluorocarbons, 22:11.594 --> 22:11.604 align:start position:0% hydrochlorofluorocarbons, 22:11.604 --> 22:14.994 align:start position:0% hydrochlorofluorocarbons, or<00:23:26.960> HCFCs,<00:23:28.360> looked<00:23:29.120> like<00:23:29.400> they<00:23:29.560> might<00:23:29.840> do<00:23:29.960> the 22:14.994 --> 22:15.004 align:start position:0% or HCFCs, looked like they might do the 22:15.004 --> 22:16.514 align:start position:0% or HCFCs, looked like they might do the trick,<00:23:30.440> but<00:23:30.600> they<00:23:30.760> were<00:23:30.920> also<00:23:31.240> found<00:23:31.520> to 22:16.514 --> 22:16.524 align:start position:0% trick, but they were also found to 22:16.524 --> 22:18.634 align:start position:0% trick, but they were also found to destroy<00:23:31.960> ozone,<00:23:32.480> so<00:23:32.760> they<00:23:32.960> too<00:23:33.280> had<00:23:33.440> to<00:23:33.560> be 22:18.634 --> 22:18.644 align:start position:0% destroy ozone, so they too had to be 22:18.644 --> 22:22.674 align:start position:0% destroy ozone, so they too had to be phased<00:23:34.240> out.<00:23:35.040> Then<00:23:35.480> HFCs<00:23:36.760> came<00:23:37.040> along,<00:23:37.400> but 22:22.674 --> 22:22.684 align:start position:0% phased out. Then HFCs came along, but 22:22.684 --> 22:25.074 align:start position:0% phased out. Then HFCs came along, but they<00:23:37.960> were<00:23:38.080> a<00:23:38.160> potent<00:23:38.560> greenhouse<00:23:39.000> gas,<00:23:39.400> so 22:25.074 --> 22:25.084 align:start position:0% they were a potent greenhouse gas, so 22:25.084 --> 22:28.114 align:start position:0% they were a potent greenhouse gas, so they're<00:23:40.400> out,<00:23:40.600> too.<00:23:41.360> Hydrofluoroolefins, 22:28.114 --> 22:28.124 align:start position:0% they're out, too. Hydrofluoroolefins, 22:28.124 --> 22:32.114 align:start position:0% they're out, too. Hydrofluoroolefins, aka<00:23:43.760> HFOs,<00:23:44.920> were<00:23:45.080> mooted<00:23:45.560> as<00:23:45.840> an<00:23:45.960> alternative, 22:32.114 --> 22:32.124 align:start position:0% aka HFOs, were mooted as an alternative, 22:32.124 --> 22:33.914 align:start position:0% aka HFOs, were mooted as an alternative, but<00:23:47.360> they<00:23:47.520> have<00:23:47.720> another<00:23:48.120> side<00:23:48.400> effect<00:23:48.800> in<00:23:48.920> the 22:33.914 --> 22:33.924 align:start position:0% but they have another side effect in the 22:33.924 --> 22:35.914 align:start position:0% but they have another side effect in the formation<00:23:49.560> of<00:23:49.680> a<00:23:49.760> forever<00:23:50.200> chemical, 22:35.914 --> 22:35.924 align:start position:0% formation of a forever chemical, 22:35.924 --> 22:37.474 align:start position:0% formation of a forever chemical, trifluoroacetic 22:37.474 --> 22:37.484 align:start position:0% trifluoroacetic 22:37.484 --> 22:39.554 align:start position:0% trifluoroacetic acid.<00:23:53.480> You<00:23:53.640> might<00:23:53.880> have<00:23:54.000> heard<00:23:54.120> of<00:23:54.200> it<00:23:54.400> as 22:39.554 --> 22:39.564 align:start position:0% acid. You might have heard of it as 22:39.564 --> 22:42.394 align:start position:0% acid. You might have heard of it as PFAS,<00:23:55.480> a<00:23:55.680> poly-<00:23:56.200> or<00:23:56.440> perfluorinated 22:42.394 --> 22:42.404 align:start position:0% PFAS, a poly- or perfluorinated 22:42.404 --> 22:44.154 align:start position:0% PFAS, a poly- or perfluorinated substance<00:23:58.000> that<00:23:58.120> will<00:23:58.280> never,<00:23:58.680> ever,<00:23:59.000> ever 22:44.154 --> 22:44.164 align:start position:0% substance that will never, ever, ever 22:44.164 --> 22:45.954 align:start position:0% substance that will never, ever, ever break<00:23:59.560> down,<00:24:00.200> and<00:24:00.280> is<00:24:00.400> ringing<00:24:00.600> alarm<00:24:00.800> bells 22:45.954 --> 22:45.964 align:start position:0% break down, and is ringing alarm bells 22:45.964 --> 22:47.314 align:start position:0% break down, and is ringing alarm bells all<00:24:01.160> around<00:24:01.320> the<00:24:01.360> world<00:24:01.600> for<00:24:01.800> human<00:24:02.240> and 22:47.314 --> 22:47.324 align:start position:0% all around the world for human and 22:47.324 --> 22:49.394 align:start position:0% all around the world for human and environmental<00:24:03.000> health,<00:24:03.800> and<00:24:04.040> quite<00:24:04.240> rightly 22:49.394 --> 22:49.404 align:start position:0% environmental health, and quite rightly 22:49.404 --> 22:50.434 align:start position:0% environmental health, and quite rightly so. 22:50.434 --> 22:50.444 align:start position:0% so. 22:50.444 --> 22:52.114 align:start position:0% so. Now,<00:24:05.640> looming<00:24:05.960> over<00:24:06.200> all<00:24:06.360> of<00:24:06.480> this<00:24:06.880> is<00:24:07.040> the 22:52.114 --> 22:52.124 align:start position:0% Now, looming over all of this is the 22:52.124 --> 22:55.194 align:start position:0% Now, looming over all of this is the meteoric<00:24:07.880> rise<00:24:08.280> of<00:24:08.480> nitrous<00:24:09.280> oxide,<00:24:09.920> commonly 22:55.194 --> 22:55.204 align:start position:0% meteoric rise of nitrous oxide, commonly 22:55.204 --> 22:57.554 align:start position:0% meteoric rise of nitrous oxide, commonly known<00:24:10.560> as<00:24:10.800> laughing<00:24:11.280> gas,<00:24:11.880> but<00:24:12.040> predominantly 22:57.554 --> 22:57.564 align:start position:0% known as laughing gas, but predominantly 22:57.564 --> 22:59.954 align:start position:0% known as laughing gas, but predominantly used<00:24:12.920> in<00:24:13.240> agriculture.<00:24:14.400> In<00:24:14.520> the<00:24:14.560> last<00:24:14.880> four 22:59.954 --> 22:59.964 align:start position:0% used in agriculture. In the last four 22:59.964 --> 23:02.474 align:start position:0% used in agriculture. In the last four decades,<00:24:15.600> human-caused<00:24:16.640> nitrous<00:24:17.200> oxide 23:02.474 --> 23:02.484 align:start position:0% decades, human-caused nitrous oxide 23:02.484 --> 23:05.834 align:start position:0% decades, human-caused nitrous oxide emissions<00:24:18.440> have<00:24:18.640> soared<00:24:19.040> by<00:24:19.240> 40%. 23:05.834 --> 23:05.844 align:start position:0% emissions have soared by 40%. 23:05.844 --> 23:09.194 align:start position:0% emissions have soared by 40%. It's<00:24:21.080> now<00:24:21.360> the<00:24:21.560> most<00:24:21.920> significant<00:24:22.800> ODS,<00:24:24.000> or 23:09.194 --> 23:09.204 align:start position:0% It's now the most significant ODS, or 23:09.204 --> 23:12.034 align:start position:0% It's now the most significant ODS, or ozone-depleting<00:24:25.240> substance,<00:24:26.240> that<00:24:26.360> we<00:24:26.480> have, 23:12.034 --> 23:12.044 align:start position:0% ozone-depleting substance, that we have, 23:12.044 --> 23:13.994 align:start position:0% ozone-depleting substance, that we have, and<00:24:27.240> it's<00:24:27.400> not<00:24:27.840> covered<00:24:28.240> by<00:24:28.400> the<00:24:28.520> Montreal 23:13.994 --> 23:14.004 align:start position:0% and it's not covered by the Montreal 23:14.004 --> 23:15.954 align:start position:0% and it's not covered by the Montreal Protocol.<00:24:29.960> In<00:24:30.120> fact,<00:24:30.400> the<00:24:30.520> Montreal 23:15.954 --> 23:15.964 align:start position:0% Protocol. In fact, the Montreal 23:15.964 --> 23:17.994 align:start position:0% Protocol. In fact, the Montreal Assessment<00:24:31.600> Panel<00:24:31.880> says<00:24:32.120> it's<00:24:32.320> a<00:24:32.400> serious 23:17.994 --> 23:18.004 align:start position:0% Assessment Panel says it's a serious 23:18.004 --> 23:21.194 align:start position:0% Assessment Panel says it's a serious threat<00:24:33.480> for<00:24:34.240> stratospheric<00:24:35.120> ozone. 23:21.194 --> 23:21.204 align:start position:0% threat for stratospheric ozone. 23:21.204 --> 23:23.154 align:start position:0% threat for stratospheric ozone. Good,<00:24:36.720> another<00:24:37.000> one. 23:23.154 --> 23:23.164 align:start position:0% Good, another one. 23:23.164 --> 23:25.314 align:start position:0% Good, another one. But<00:24:38.360> this<00:24:38.640> alphabet<00:24:39.240> soup<00:24:39.560> of<00:24:39.800> chemicals 23:25.314 --> 23:25.324 align:start position:0% But this alphabet soup of chemicals 23:25.324 --> 23:27.634 align:start position:0% But this alphabet soup of chemicals isn't<00:24:40.680> the<00:24:40.800> only<00:24:41.120> potential<00:24:41.800> ozone<00:24:42.320> killer 23:27.634 --> 23:27.644 align:start position:0% isn't the only potential ozone killer 23:27.644 --> 23:30.154 align:start position:0% isn't the only potential ozone killer out<00:24:42.960> there.<00:24:43.600> To<00:24:43.800> paraphrase<00:24:44.600> Sir<00:24:44.840> Isaac 23:30.154 --> 23:30.164 align:start position:0% out there. To paraphrase Sir Isaac 23:30.164 --> 23:34.914 align:start position:0% out there. To paraphrase Sir Isaac Newton,<00:24:46.160> what<00:24:46.520> goes<00:24:47.040> up<00:24:47.880> must<00:24:48.280> come<00:24:48.640> down.<00:24:49.760> In 23:34.914 --> 23:34.924 align:start position:0% Newton, what goes up must come down. In 23:34.924 --> 23:37.234 align:start position:0% Newton, what goes up must come down. In 1985,<00:24:51.120> the<00:24:51.280> year<00:24:51.560> the<00:24:51.760> ozone<00:24:52.080> hole<00:24:52.200> was 23:37.234 --> 23:37.244 align:start position:0% 1985, the year the ozone hole was 23:37.244 --> 23:39.154 align:start position:0% 1985, the year the ozone hole was actually<00:24:52.640> discovered,<00:24:53.720> there<00:24:53.880> were<00:24:53.960> around 23:39.154 --> 23:39.164 align:start position:0% actually discovered, there were around 23:39.164 --> 23:42.234 align:start position:0% actually discovered, there were around 120<00:24:55.200> successful<00:24:56.120> rocket<00:24:56.480> launches,<00:24:56.920> that's 23:42.234 --> 23:42.244 align:start position:0% 120 successful rocket launches, that's 23:42.244 --> 23:45.074 align:start position:0% 120 successful rocket launches, that's satellites,<00:24:57.920> payloads,<00:24:58.480> and<00:24:58.600> a<00:24:58.680> record<00:24:59.200> nine 23:45.074 --> 23:45.084 align:start position:0% satellites, payloads, and a record nine 23:45.084 --> 23:47.434 align:start position:0% satellites, payloads, and a record nine space<00:25:00.760> shuttle<00:25:01.240> missions.<00:25:01.680> It<00:25:01.760> was<00:25:01.880> a<00:25:02.040> busy 23:47.434 --> 23:47.444 align:start position:0% space shuttle missions. It was a busy 23:47.444 --> 23:50.754 align:start position:0% space shuttle missions. It was a busy old<00:25:02.720> year<00:25:02.880> for<00:25:03.000> space.<00:25:04.040> Now,<00:25:04.200> in<00:25:04.320> 2025,<00:25:05.760> an 23:50.754 --> 23:50.764 align:start position:0% old year for space. Now, in 2025, an 23:50.764 --> 23:52.794 align:start position:0% old year for space. Now, in 2025, an incredible<00:25:06.320> 4,510 23:52.794 --> 23:52.804 align:start position:0% incredible 4,510 23:52.804 --> 23:55.514 align:start position:0% incredible 4,510 objects<00:25:08.480> were<00:25:08.680> also<00:25:09.120> launched<00:25:09.600> into<00:25:09.920> space, 23:55.514 --> 23:55.524 align:start position:0% objects were also launched into space, 23:55.524 --> 23:58.394 align:start position:0% objects were also launched into space, overtaking<00:25:11.120> the<00:25:11.240> previous<00:25:11.720> record<00:25:12.080> in<00:25:12.200> 2023 23:58.394 --> 23:58.404 align:start position:0% overtaking the previous record in 2023 23:58.404 --> 24:01.594 align:start position:0% overtaking the previous record in 2023 of<00:25:13.720> 2,903. 24:01.594 --> 24:01.604 align:start position:0% of 2,903. 24:01.604 --> 24:04.194 align:start position:0% of 2,903. There's<00:25:16.960> currently<00:25:17.360> around<00:25:17.760> 15,000 24:04.194 --> 24:04.204 align:start position:0% There's currently around 15,000 24:04.204 --> 24:05.994 align:start position:0% There's currently around 15,000 satellites<00:25:19.920> orbiting<00:25:20.360> the<00:25:20.600> Earth<00:25:20.960> with 24:05.994 --> 24:06.004 align:start position:0% satellites orbiting the Earth with 24:06.004 --> 24:07.874 align:start position:0% satellites orbiting the Earth with another<00:25:21.360> 50,000 24:07.874 --> 24:07.884 align:start position:0% another 50,000 24:07.884 --> 24:10.314 align:start position:0% another 50,000 set<00:25:23.200> to<00:25:23.320> join<00:25:23.560> them<00:25:23.680> by<00:25:23.840> 2030. 24:10.314 --> 24:10.324 align:start position:0% set to join them by 2030. 24:10.324 --> 24:11.634 align:start position:0% set to join them by 2030. And<00:25:25.600> once<00:25:25.800> they're<00:25:25.960> finished<00:25:26.320> studying<00:25:26.640> the 24:11.634 --> 24:11.644 align:start position:0% And once they're finished studying the 24:11.644 --> 24:14.314 align:start position:0% And once they're finished studying the planet<00:25:27.080> or<00:25:27.280> guiding<00:25:27.720> your<00:25:27.920> car<00:25:28.160> GPS<00:25:28.600> system, 24:14.314 --> 24:14.324 align:start position:0% planet or guiding your car GPS system, 24:14.324 --> 24:16.274 align:start position:0% planet or guiding your car GPS system, often<00:25:29.800> satellites<00:25:30.320> are<00:25:30.360> allowed<00:25:30.640> to<00:25:30.880> fall 24:16.274 --> 24:16.284 align:start position:0% often satellites are allowed to fall 24:16.284 --> 24:18.114 align:start position:0% often satellites are allowed to fall into<00:25:31.640> the<00:25:31.760> atmosphere,<00:25:32.480> and<00:25:32.840> that's<00:25:33.120> a 24:18.114 --> 24:18.124 align:start position:0% into the atmosphere, and that's a 24:18.124 --> 24:19.474 align:start position:0% into the atmosphere, and that's a problem. 24:19.474 --> 24:19.484 align:start position:0% problem. 24:19.484 --> 24:20.634 align:start position:0% problem. See,<00:25:34.720> what<00:25:34.840> happens<00:25:35.080> when<00:25:35.160> they<00:25:35.240> do<00:25:35.400> that<00:25:35.600> is 24:20.634 --> 24:20.644 align:start position:0% See, what happens when they do that is 24:20.644 --> 24:23.954 align:start position:0% See, what happens when they do that is they<00:25:35.920> burn<00:25:36.440> up<00:25:36.840> on<00:25:37.120> reentry,<00:25:37.720> and<00:25:37.960> as<00:25:38.200> they<00:25:38.400> do, 24:23.954 --> 24:23.964 align:start position:0% they burn up on reentry, and as they do, 24:23.964 --> 24:25.994 align:start position:0% they burn up on reentry, and as they do, they<00:25:39.200> release<00:25:39.600> teeny<00:25:40.080> tiny<00:25:40.400> particles<00:25:40.880> of 24:25.994 --> 24:26.004 align:start position:0% they release teeny tiny particles of 24:26.004 --> 24:28.314 align:start position:0% they release teeny tiny particles of aluminum<00:25:41.680> dioxide.<00:25:42.440> And<00:25:42.600> yep,<00:25:42.960> you<00:25:43.080> guessed 24:28.314 --> 24:28.324 align:start position:0% aluminum dioxide. And yep, you guessed 24:28.324 --> 24:30.234 align:start position:0% aluminum dioxide. And yep, you guessed it,<00:25:43.520> what<00:25:43.640> does<00:25:43.760> aluminum<00:25:44.120> dioxide<00:25:44.560> do? 24:30.234 --> 24:30.244 align:start position:0% it, what does aluminum dioxide do? 24:30.244 --> 24:32.594 align:start position:0% it, what does aluminum dioxide do? Depletes<00:25:45.800> the<00:25:45.960> ozone<00:25:46.320> layer. 24:32.594 --> 24:32.604 align:start position:0% Depletes the ozone layer. 24:32.604 --> 24:34.194 align:start position:0% Depletes the ozone layer. The<00:25:47.760> problem<00:25:48.040> is<00:25:48.200> that<00:25:48.360> the<00:25:48.480> new<00:25:48.720> generation 24:34.194 --> 24:34.204 align:start position:0% The problem is that the new generation 24:34.204 --> 24:36.234 align:start position:0% The problem is that the new generation of<00:25:49.520> satellites<00:25:50.040> are<00:25:50.160> extremely<00:25:50.720> short-lived, 24:36.234 --> 24:36.244 align:start position:0% of satellites are extremely short-lived, 24:36.244 --> 24:38.834 align:start position:0% of satellites are extremely short-lived, maybe<00:25:51.640> 5<00:25:52.040> years.<00:25:52.640> So,<00:25:52.880> dozens<00:25:53.320> of<00:25:53.400> satellites 24:38.834 --> 24:38.844 align:start position:0% maybe 5 years. So, dozens of satellites 24:38.844 --> 24:40.594 align:start position:0% maybe 5 years. So, dozens of satellites could<00:25:54.120> be<00:25:54.240> hurtling<00:25:54.640> back<00:25:54.840> to<00:25:55.080> Earth<00:25:55.360> quite 24:40.594 --> 24:40.604 align:start position:0% could be hurtling back to Earth quite 24:40.604 --> 24:42.194 align:start position:0% could be hurtling back to Earth quite literally<00:25:56.160> every<00:25:56.560> day,<00:25:56.880> each<00:25:57.160> one 24:42.194 --> 24:42.204 align:start position:0% literally every day, each one 24:42.204 --> 24:43.514 align:start position:0% literally every day, each one potentially<00:25:57.760> destroying<00:25:58.120> the<00:25:58.200> ozone<00:25:58.440> layer 24:43.514 --> 24:43.524 align:start position:0% potentially destroying the ozone layer 24:43.524 --> 24:46.074 align:start position:0% potentially destroying the ozone layer we've<00:25:58.880> worked<00:25:59.200> so<00:25:59.480> hard<00:26:00.320> to<00:26:00.440> rebuild<00:26:00.800> back<00:26:01.000> up 24:46.074 --> 24:46.084 align:start position:0% we've worked so hard to rebuild back up 24:46.084 --> 24:47.274 align:start position:0% we've worked so hard to rebuild back up again. 24:47.274 --> 24:47.284 align:start position:0% again. 24:47.284 --> 24:49.434 align:start position:0% again. For<00:26:02.440> now<00:26:02.680> though,<00:26:02.920> the<00:26:03.160> ozone<00:26:03.640> layer<00:26:03.880> is<00:26:04.200> still 24:49.434 --> 24:49.444 align:start position:0% For now though, the ozone layer is still 24:49.444 --> 24:50.994 align:start position:0% For now though, the ozone layer is still healing,<00:26:05.000> and<00:26:05.160> I<00:26:05.360> think<00:26:05.600> we<00:26:05.680> have<00:26:05.800> to<00:26:05.920> take 24:50.994 --> 24:51.004 align:start position:0% healing, and I think we have to take 24:51.004 --> 24:52.834 align:start position:0% healing, and I think we have to take that<00:26:06.320> as<00:26:06.480> a<00:26:06.560> win,<00:26:07.000> while<00:26:07.160> making<00:26:07.440> sure<00:26:07.680> that 24:52.834 --> 24:52.844 align:start position:0% that as a win, while making sure that 24:52.844 --> 24:55.234 align:start position:0% that as a win, while making sure that these<00:26:08.200> new<00:26:08.520> threats<00:26:08.880> don't<00:26:09.200> undo<00:26:09.800> all<00:26:09.960> of<00:26:10.080> that 24:55.234 --> 24:55.244 align:start position:0% these new threats don't undo all of that 24:55.244 --> 24:57.714 align:start position:0% these new threats don't undo all of that hard<00:26:10.640> work.<00:26:11.560> The<00:26:11.640> truth<00:26:11.960> is<00:26:12.160> life<00:26:12.480> is 24:57.714 --> 24:57.724 align:start position:0% hard work. The truth is life is 24:57.724 --> 25:00.034 align:start position:0% hard work. The truth is life is complicated,<00:26:13.920> and<00:26:14.120> us<00:26:14.360> humans<00:26:14.800> like<00:26:15.000> to 25:00.034 --> 25:00.044 align:start position:0% complicated, and us humans like to 25:00.044 --> 25:02.354 align:start position:0% complicated, and us humans like to complicate<00:26:15.640> it<00:26:15.760> even<00:26:16.080> further.<00:26:17.040> The<00:26:17.120> bottom 25:02.354 --> 25:02.364 align:start position:0% complicate it even further. The bottom 25:02.364 --> 25:04.074 align:start position:0% complicate it even further. The bottom line<00:26:17.640> is<00:26:17.760> that<00:26:17.880> when<00:26:18.040> you<00:26:18.120> mess<00:26:18.360> with<00:26:18.520> nature, 25:04.074 --> 25:04.084 align:start position:0% line is that when you mess with nature, 25:04.084 --> 25:06.594 align:start position:0% line is that when you mess with nature, you're<00:26:19.480> always<00:26:19.840> going<00:26:20.120> to<00:26:20.240> pay<00:26:20.440> the<00:26:20.560> price. 25:06.594 --> 25:06.604 align:start position:0% you're always going to pay the price. 25:06.604 --> 25:08.474 align:start position:0% you're always going to pay the price. But,<00:26:22.000> on<00:26:22.160> the<00:26:22.280> whole,<00:26:22.600> as<00:26:22.760> climate<00:26:23.120> change 25:08.474 --> 25:08.484 align:start position:0% But, on the whole, as climate change 25:08.484 --> 25:10.674 align:start position:0% But, on the whole, as climate change burns<00:26:23.960> all<00:26:24.080> around<00:26:24.480> us,<00:26:25.120> I'd<00:26:25.280> like<00:26:25.480> to<00:26:25.560> think 25:10.674 --> 25:10.684 align:start position:0% burns all around us, I'd like to think 25:10.684 --> 25:12.994 align:start position:0% burns all around us, I'd like to think the<00:26:25.920> healing<00:26:26.400> of<00:26:26.520> the<00:26:26.680> ozone<00:26:27.080> hole<00:26:27.320> is<00:26:27.560> still 25:12.994 --> 25:13.004 align:start position:0% the healing of the ozone hole is still 25:13.004 --> 25:15.354 align:start position:0% the healing of the ozone hole is still basically<00:26:28.640> a<00:26:28.760> good<00:26:29.120> news<00:26:29.440> story,<00:26:29.880> and 25:15.354 --> 25:15.364 align:start position:0% basically a good news story, and 25:15.364 --> 25:16.834 align:start position:0% basically a good news story, and sometimes<00:26:30.960> we<00:26:31.040> just<00:26:31.240> need<00:26:31.400> a<00:26:31.440> bit<00:26:31.600> of<00:26:31.720> good 25:16.834 --> 25:16.844 align:start position:0% sometimes we just need a bit of good 25:16.844 --> 25:20.554 align:start position:0% sometimes we just need a bit of good news,<00:26:32.480> especially<00:26:33.120> in<00:26:33.240> climate<00:26:33.680> science. 25:20.554 --> 25:20.564 align:start position:0% news, especially in climate science. 25:20.564 --> 25:23.834 align:start position:0% news, especially in climate science. So,<00:26:36.040> yes,<00:26:36.720> we<00:26:37.000> fixed<00:26:37.560> the<00:26:37.680> hole<00:26:38.120> in<00:26:38.280> the<00:26:38.440> ozone. 25:23.834 --> 25:23.844 align:start position:0% So, yes, we fixed the hole in the ozone. 25:23.844 --> 25:25.514 align:start position:0% So, yes, we fixed the hole in the ozone. That's<00:26:39.320> why<00:26:39.520> we<00:26:39.640> don't<00:26:39.880> really<00:26:40.080> hear<00:26:40.240> about<00:26:40.520> it 25:25.514 --> 25:25.524 align:start position:0% That's why we don't really hear about it 25:25.524 --> 25:27.154 align:start position:0% That's why we don't really hear about it anymore,<00:26:41.320> but<00:26:41.440> that<00:26:41.560> doesn't<00:26:41.840> mean<00:26:41.960> we<00:26:42.080> should 25:27.154 --> 25:27.164 align:start position:0% anymore, but that doesn't mean we should 25:27.164 --> 25:29.114 align:start position:0% anymore, but that doesn't mean we should just<00:26:42.600> forget<00:26:42.960> about<00:26:43.320> it. 25:29.114 --> 25:29.124 align:start position:0% just forget about it. 25:29.124 --> 25:31.474 align:start position:0% just forget about it. This<00:26:44.440> cautionary<00:26:45.120> tale<00:26:45.560> is<00:26:45.720> a<00:26:45.800> reminder<00:26:46.360> that 25:31.474 --> 25:31.484 align:start position:0% This cautionary tale is a reminder that 25:31.484 --> 25:34.394 align:start position:0% This cautionary tale is a reminder that each<00:26:46.840> one<00:26:47.000> of<00:26:47.120> our<00:26:47.280> actions<00:26:47.800> has<00:26:48.200> an<00:26:48.320> impact.<00:26:49.440> I 25:34.394 --> 25:34.404 align:start position:0% each one of our actions has an impact. I 25:34.404 --> 25:36.074 align:start position:0% each one of our actions has an impact. I mean,<00:26:49.680> who'd<00:26:49.880> have<00:26:50.000> thought<00:26:50.320> a<00:26:50.440> deodorant 25:36.074 --> 25:36.084 align:start position:0% mean, who'd have thought a deodorant 25:36.084 --> 25:38.714 align:start position:0% mean, who'd have thought a deodorant used<00:26:51.480> in<00:26:51.680> Detroit<00:26:52.800> could<00:26:53.000> end<00:26:53.160> up<00:26:53.280> destroying 25:38.714 --> 25:38.724 align:start position:0% used in Detroit could end up destroying 25:38.724 --> 25:40.874 align:start position:0% used in Detroit could end up destroying a<00:26:53.920> vital<00:26:54.400> part<00:26:54.720> of<00:26:54.920> Earth's<00:26:55.240> life<00:26:55.480> support 25:40.874 --> 25:40.884 align:start position:0% a vital part of Earth's life support 25:40.884 --> 25:43.474 align:start position:0% a vital part of Earth's life support system<00:26:56.440> over<00:26:56.920> Antarctica. 25:43.474 --> 25:43.484 align:start position:0% system over Antarctica. 25:43.484 --> 25:45.794 align:start position:0% system over Antarctica. We<00:26:58.680> could<00:26:59.040> have<00:26:59.160> ignored<00:26:59.640> the<00:26:59.760> warnings,<00:27:00.680> but 25:45.794 --> 25:45.804 align:start position:0% We could have ignored the warnings, but 25:45.804 --> 25:48.834 align:start position:0% We could have ignored the warnings, but we<00:27:01.080> didn't.<00:27:02.160> Collective<00:27:02.760> action<00:27:03.120> on<00:27:03.240> a<00:27:03.320> global 25:48.834 --> 25:48.844 align:start position:0% we didn't. Collective action on a global 25:48.844 --> 25:50.954 align:start position:0% we didn't. Collective action on a global scale<00:27:04.400> turned<00:27:04.720> the<00:27:04.880> ozone<00:27:05.400> hole<00:27:05.720> into<00:27:05.960> an 25:50.954 --> 25:50.964 align:start position:0% scale turned the ozone hole into an 25:50.964 --> 25:53.914 align:start position:0% scale turned the ozone hole into an environmental<00:27:06.840> success<00:27:07.520> story<00:27:08.400> rather<00:27:08.840> than 25:53.914 --> 25:53.924 align:start position:0% environmental success story rather than 25:53.924 --> 25:56.434 align:start position:0% environmental success story rather than a<00:27:09.040> planetary<00:27:09.800> emergency. 25:56.434 --> 25:56.444 align:start position:0% a planetary emergency. 25:56.444 --> 25:58.114 align:start position:0% a planetary emergency. This<00:27:11.760> to<00:27:11.880> me<00:27:12.000> is<00:27:12.160> unequivocal<00:27:12.800> proof<00:27:13.040> that 25:58.114 --> 25:58.124 align:start position:0% This to me is unequivocal proof that 25:58.124 --> 25:59.914 align:start position:0% This to me is unequivocal proof that science<00:27:13.640> plus<00:27:13.920> public<00:27:14.240> awareness<00:27:14.640> plus 25:59.914 --> 25:59.924 align:start position:0% science plus public awareness plus 25:59.924 --> 26:03.394 align:start position:0% science plus public awareness plus crucially<00:27:15.640> political<00:27:16.320> action<00:27:16.840> can<00:27:17.840> equal 26:03.394 --> 26:03.404 align:start position:0% crucially political action can equal 26:03.404 --> 26:06.634 align:start position:0% crucially political action can equal results.<00:27:19.720> The<00:27:19.800> only<00:27:20.040> sobering<00:27:20.560> thought<00:27:20.960> is<00:27:21.560> it 26:06.634 --> 26:06.644 align:start position:0% results. The only sobering thought is it 26:06.644 --> 26:08.314 align:start position:0% results. The only sobering thought is it happened<00:27:22.080> once<00:27:22.440> and<00:27:22.520> it<00:27:22.640> doesn't<00:27:23.040> feel<00:27:23.240> like 26:08.314 --> 26:08.324 align:start position:0% happened once and it doesn't feel like 26:08.324 --> 26:10.594 align:start position:0% happened once and it doesn't feel like it's<00:27:23.840> going<00:27:24.000> to<00:27:24.080> happen<00:27:24.360> again.<00:27:25.120> If<00:27:25.280> this<00:27:25.480> same 26:10.594 --> 26:10.604 align:start position:0% it's going to happen again. If this same 26:10.604 --> 26:13.354 align:start position:0% it's going to happen again. If this same situation<00:27:26.160> was<00:27:26.280> happening<00:27:26.560> now<00:27:26.800> in<00:27:26.880> 2026, 26:13.354 --> 26:13.364 align:start position:0% situation was happening now in 2026, 26:13.364 --> 26:15.114 align:start position:0% situation was happening now in 2026, would<00:27:28.640> we<00:27:28.800> all<00:27:28.920> rally<00:27:29.120> together<00:27:29.600> in<00:27:29.800> the<00:27:29.880> same 26:15.114 --> 26:15.124 align:start position:0% would we all rally together in the same 26:15.124 --> 26:16.194 align:start position:0% would we all rally together in the same way? 26:16.194 --> 26:16.204 align:start position:0% way? 26:16.204 --> 26:18.274 align:start position:0% way? I'm<00:27:31.400> not<00:27:31.560> convinced.<00:27:32.360> The<00:27:32.480> success<00:27:33.080> of<00:27:33.200> the 26:18.274 --> 26:18.284 align:start position:0% I'm not convinced. The success of the 26:18.284 --> 26:20.154 align:start position:0% I'm not convinced. The success of the ozone<00:27:33.760> hole<00:27:34.080> shows<00:27:34.400> what<00:27:34.520> humanity<00:27:35.000> is 26:20.154 --> 26:20.164 align:start position:0% ozone hole shows what humanity is 26:20.164 --> 26:21.634 align:start position:0% ozone hole shows what humanity is capable<00:27:35.680> of<00:27:35.800> doing<00:27:36.120> when<00:27:36.320> we<00:27:36.440> all<00:27:36.520> come 26:21.634 --> 26:21.644 align:start position:0% capable of doing when we all come 26:21.644 --> 26:23.674 align:start position:0% capable of doing when we all come together<00:27:37.080> for<00:27:37.280> one<00:27:37.480> unified<00:27:37.960> cause.<00:27:38.240> My<00:27:38.440> worry 26:23.674 --> 26:23.684 align:start position:0% together for one unified cause. My worry 26:23.684 --> 26:26.114 align:start position:0% together for one unified cause. My worry is<00:27:39.320> that<00:27:39.720> we<00:27:39.840> don't<00:27:40.040> do<00:27:40.160> that<00:27:40.280> enough.<00:27:41.000> Let<00:27:41.120> me 26:26.114 --> 26:26.124 align:start position:0% is that we don't do that enough. Let me 26:26.124 --> 26:27.274 align:start position:0% is that we don't do that enough. Let me know<00:27:41.320> what<00:27:41.440> you<00:27:41.560> think<00:27:41.800> in<00:27:41.920> the<00:27:42.000> comments 26:27.274 --> 26:27.284 align:start position:0% know what you think in the comments 26:27.284 --> 26:29.194 align:start position:0% know what you think in the comments about<00:27:42.560> this<00:27:42.800> ozone<00:27:43.200> situation<00:27:43.960> and<00:27:44.080> whether 26:29.194 --> 26:29.204 align:start position:0% about this ozone situation and whether 26:29.204 --> 26:31.194 align:start position:0% about this ozone situation and whether this<00:27:44.520> is<00:27:44.760> the<00:27:44.960> only<00:27:45.280> time<00:27:45.640> that<00:27:45.840> you<00:27:45.960> can<00:27:46.080> think 26:31.194 --> 26:31.204 align:start position:0% this is the only time that you can think 26:31.204 --> 26:33.074 align:start position:0% this is the only time that you can think of<00:27:46.360> as<00:27:46.480> well<00:27:46.680> that<00:27:47.120> humanity's<00:27:47.560> come<00:27:47.800> together 26:33.074 --> 26:33.084 align:start position:0% of as well that humanity's come together 26:33.084 --> 26:36.594 align:start position:0% of as well that humanity's come together for<00:27:48.520> a<00:27:48.800> wider,<00:27:49.320> greater<00:27:50.000> climate<00:27:50.480> good<00:27:50.800> cuz 26:36.594 --> 26:36.604 align:start position:0% for a wider, greater climate good cuz 26:36.604 --> 26:37.554 align:start position:0% for a wider, greater climate good cuz I<00:27:51.800> struggle<00:27:52.040> to<00:27:52.120> think<00:27:52.280> of<00:27:52.360> too<00:27:52.480> many 26:37.554 --> 26:37.564 align:start position:0% I struggle to think of too many 26:37.564 --> 26:39.554 align:start position:0% I struggle to think of too many examples.<00:27:53.680> Thanks<00:27:53.920> for<00:27:54.000> watching<00:27:54.480> and<00:27:54.560> we'll 26:39.554 --> 26:39.564 align:start position:0% examples. Thanks for watching and we'll 26:39.564 --> 26:40.874 align:start position:0% examples. Thanks for watching and we'll see<00:27:54.720> you<00:27:54.760> in<00:27:54.840> the<00:27:54.880> next<00:27:55.080> one. 26:39.564 --> 26:39.574 align:start position:0% you want to do something right now to 26:39.564 --> 26:43.764 align:start position:0% you want to do something right now to help<00:28:06.880> the<00:28:07.000> planet,<00:28:07.880> please<00:28:08.120> do<00:28:08.240> get<00:28:08.360> involved.