WEBVTT FILE 1 00:00:00.767 --> 00:00:05.538 Recently, two separate NASA studies illustrated the complex relationship 2 00:00:05.538 --> 00:00:08.108 between human activity and our atmosphere. 3 00:00:09.542 --> 00:00:13.646 First up, a team led by scientists at NASA's Jet Propulsion Laboratory 4 00:00:13.646 --> 00:00:18.451 focused on drops in nitrogen oxide emissions during the COVID 19 lockdowns. 5 00:00:20.020 --> 00:00:24.190 Nitrogen oxide comes from sources like power plants and car exhaust 6 00:00:24.557 --> 00:00:28.361 and reacts to form surface level ozone, which is harmful to human health. 7 00:00:30.163 --> 00:00:31.631 Using NASA satellites, 8 00:00:31.631 --> 00:00:35.769 the team saw that the lockdowns left a distinct 'fingerprint' on ozone levels 9 00:00:35.769 --> 00:00:39.272 in the lower atmosphere, which dropped about 2% globally. 10 00:00:40.206 --> 00:00:43.443 And while this may seem small, such a drop in harmful 11 00:00:43.443 --> 00:00:46.646 ozone would take about 15 years to achieve under even 12 00:00:46.646 --> 00:00:49.382 the most aggressive emission control scenarios. 13 00:00:50.283 --> 00:00:54.120 Interestingly enough, the team found that these drops were not uniform 14 00:00:54.120 --> 00:00:55.255 across the globe. 15 00:00:55.255 --> 00:00:57.090 That where and when the lockdowns 16 00:00:57.090 --> 00:01:00.660 occurred was very important in determining the impact on the atmosphere. 17 00:01:01.194 --> 00:01:04.431 Taking a look at these regions with blue representing below 18 00:01:04.431 --> 00:01:06.766 normal levels of ozone in the lower atmosphere, 19 00:01:07.100 --> 00:01:09.803 we could see that both Asia and the United States have 20 00:01:09.803 --> 00:01:13.139 a substantial impact on harmful global ozone levels. 21 00:01:14.207 --> 00:01:15.375 Factors like prevailing 22 00:01:15.375 --> 00:01:19.312 winds, air temperature and moisture content all impact 23 00:01:19.312 --> 00:01:22.415 how efficiently ozone is produced and moves 24 00:01:22.415 --> 00:01:23.983 throughout the globe. 25 00:01:27.587 --> 00:01:31.458 Like ozone, CO2 is a long lived gas that is easily 26 00:01:31.458 --> 00:01:35.662 transported through the atmosphere, which means that any changes in emissions 27 00:01:35.662 --> 00:01:39.232 is mixed with many different influences from both near and far. 28 00:01:40.567 --> 00:01:43.937 This makes it challenging to track and measure how local changes in 29 00:01:43.937 --> 00:01:47.607 human activity actually impact the levels of this greenhouse gas. 30 00:01:49.709 --> 00:01:53.480 Using NASA's OCO -2 instrument and the GEOS model, NASA 31 00:01:53.480 --> 00:01:58.017 researchers were able to spot short-term regional fluctuations in the atmosphere 32 00:01:58.351 --> 00:02:01.921 due to drops in human activity related to the lockdowns. 33 00:02:02.922 --> 00:02:05.191 This is the first time changes in CO2 34 00:02:05.191 --> 00:02:08.728 measurements have been tracked at such a scale all over the globe. 35 00:02:10.263 --> 00:02:11.231 The team's results 36 00:02:11.231 --> 00:02:15.401 showed that the CO2 emissions dropped significantly in the Northern Hemisphere 37 00:02:15.401 --> 00:02:18.771 from February through May and rebounded during the summer 38 00:02:18.771 --> 00:02:22.175 when some restrictions eased. 39 00:02:23.176 --> 00:02:23.910 The team 40 00:02:23.910 --> 00:02:27.914 was also able to better distinguish which monthly CO2 fluctuations 41 00:02:27.914 --> 00:02:31.184 were due to human activities and which were due to natural causes, 42 00:02:31.518 --> 00:02:34.787 like the Australian wildfires and ocean circulation patterns. 43 00:02:35.788 --> 00:02:39.692 This is important because distinguishing between human and natural causes 44 00:02:39.926 --> 00:02:43.730 is a critical step towards measuring human activities' collective effects 45 00:02:43.730 --> 00:02:46.299 on CO2 emissions in near real time. 46 00:02:48.301 --> 00:02:52.272 The lockdown surrounding COVID 19 were an unprecedented global event 47 00:02:52.272 --> 00:02:56.509 that highlighted the complex relationships between emissions and the atmosphere. 48 00:02:56.910 --> 00:02:57.710 By studying 49 00:02:57.710 --> 00:03:01.514 these relationships, we can gain insights that could help us better design 50 00:03:01.514 --> 00:03:05.518 sustainable measures that can improve both human health and the climate.