WEBVTT FILE

1
00:00:02.910 --> 00:00:06.641
Methane, like carbon dioxide, is
an important greenhouse gas

2
00:00:06.703 --> 00:00:10.434
that's contributed to about 1/3
of global warming. In recent

3
00:00:10.496 --> 00:00:13.792
years, atmospheric methane
levels have reached record

4
00:00:13.854 --> 00:00:17.399
highs. While fossil fuels,
agriculture and landfills make

5
00:00:17.461 --> 00:00:21.130
up a large percentage of human
caused sources, about 1/3 of

6
00:00:21.192 --> 00:00:24.861
methane emissions actually comes
from wetlands. What you're

7
00:00:24.923 --> 00:00:28.281
seeing here is a visualized
dataset of wetland methane

8
00:00:28.344 --> 00:00:32.013
emissions from around the globe
throughout the last several

9
00:00:32.075 --> 00:00:35.308
decades. These highlighted
regions are of particular

10
00:00:35.371 --> 00:00:38.729
interest because of their
concentrated wetland methane

11
00:00:38.791 --> 00:00:42.460
sources, which scientists are
working to better understand.

12
00:00:42.522 --> 00:00:46.253
Wetlands act as both a source
and sink for greenhouse gases,

13
00:00:46.315 --> 00:00:50.171
which means they both release
and store them. Wetland habitats

14
00:00:50.233 --> 00:00:53.280
are filled with things like
waterlogged soils and

15
00:00:53.342 --> 00:00:57.198
permafrost, which is what makes
them sizable carbon sinks. But

16
00:00:57.260 --> 00:01:00.867
as a warming climate causes
wetland soils to warm or flood

17
00:01:00.929 --> 00:01:04.536
carbon is released into the
atmosphere as methane. Methane

18
00:01:04.598 --> 00:01:08.329
is produced when there's a lack
of oxygen available for tiny

19
00:01:08.392 --> 00:01:12.309
carbon digesting microbes that
live in the soil. So in wetlands

20
00:01:12.371 --> 00:01:16.227
were flooded soils are deprived
of oxygen, those microbes that

21
00:01:16.289 --> 00:01:20.020
would have otherwise produced
carbon dioxide instead produce

22
00:01:20.083 --> 00:01:23.316
methane. NASA uses remote
sensing to monitor methane

23
00:01:23.378 --> 00:01:27.358
emissions from wetlands through
instruments like EMIT aboard the

24
00:01:27.420 --> 00:01:31.027
International Space Station,
airplane mountain instruments

25
00:01:31.089 --> 00:01:34.945
like AVIRIS NG and satellites
like Landsat and Europe Sentinel

26
00:01:35.007 --> 00:01:38.863
5 P. Locating and measuring the
sources of atmospheric methane

27
00:01:38.925 --> 00:01:42.843
is key to understanding how to
limit them so we can make better

28
00:01:42.905 --> 00:01:44.460
decisions for our future.