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Methane levels surged in 2020 despite lockdowns

Methane levels rose in 2020 despite lockdowns

This world map shows the annual increase in methane emissions relative to the global average annual increase and was created using data from the Copernicus Sentinel-5P satellite. Credit: Copernicus Sentinel data (2020), processed by ESA, CC BY-SA 3.0 IGO

Levels of methane, the second most important greenhouse gas in our atmosphere, continued to rise unabated in 2020, despite the economic slowdown caused by the COVID-19 pandemic.

A team of scientists from the University of Leeds has used data from the Copernicus Sentinel-5P satellite to pinpoint sites of high levels of methane emissions. These findings were presented at ESA’s Living Planet Symposium held last month in Bonn, Germany.

Methane has a mixture of both natural and anthropogenic sources. About 40% of methane emissions come from natural sources, while 60% come from anthropogenic sources such as agriculture, fossil fuel exploitation and landfills.

One of the largest sources of methane emissions comes from wetlands — a patch of land that is either covered with water or saturated with water — but there is still uncertainty about how they respond to climate changes and short-term variations, such as the El Niño. Southern Oscillation.

The combination of methane’s high global warming potential and the relatively short lifetime in our atmosphere of about nine years means that if we reduce our methane emissions, we can partially reduce the human impact of climate change in a relatively short period of time, while reducing global carbon dioxide emissions. reduced.

In situ methane measurements from 2020 showed the largest annual increase in methane concentrations since the 1980s, surpassing this record in 2021. The year 2020 was unique due to the global pandemic, but despite a decline in economic activity, methane concentrations continued to rise.

Anthropogenic emissions of methane have contributed to an additional 23% of radiative forcing — a direct measure of the amount of Earth’s energy budget that is out of balance — in the troposphere since 1750.

Methane levels rose in 2020 despite lockdowns

The graph shows monthly average methane concentrations over South Sudan from January 2018 to January 2021. The dotted lines indicate times when Sentinel-5P satellite data is less available. Credit: Emily Dowd – University of Leeds/ESA

It is not entirely clear what is driving the recent trends in global methane concentrations due to uncertainty surrounding sources and sinks. Therefore, it is important to monitor changes in methane in the atmosphere using satellites such as Copernicus Sentinel-5P. The satellite maps a wide range of pollutants, such as nitrogen dioxide, ozone, formaldehyde, sulfur dioxide, carbon monoxide and natural methane.

Using observations obtained from Sentinel-5P, the team found that satellite measurements show the same increase in methane as shown in surface measurements. Using Sentinel-5P’s global coverage capability, the team identified regions that showed significant increases in 2020.

These regions include South Sudan and Uganda in Central Africa, along with northern regions at high latitudes, including Canada and Russia. In 2019, emissions related to large positive precipitation drifts from South Sudan’s Sudd wetlands were found to be more than a quarter of the growth in global emissions.

The positive precipitation anomalies over South Sudan and Uganda continued into 2020. In addition to large amounts of precipitation, there was a high rate of dams from Lake Victoria resulting in increased water flow into the White Nile, which feeds the Ugandan and Sudd wetlands.

The data obtained from Sentinel-5P indicates that 2020 was likely a period of high methane fluxes in these regions. Satellite data was also compared with a chemical transport model called TOMCAT, which simulates methane in our atmosphere.

In South Sudan, there is a seasonal cycle mismatch between the TOMCAT model and the satellite observations, which previous studies have related to the wetlands model used in the study. This means that wetlands could be a dominant factor in driving the high methane concentrations over South Sudan in 2020.

In Canada, by 2020, high concentrations of methane will be found in the east, where there are more wetlands. The regions of high methane growth measured in these satellite observations indicate that wetlands may have been a major contributor to the large increase in methane in 2020, but work is still underway to use TOMCAT to further explore these findings.

Emily Dowd, Ph.D. student from the University of Leeds, said: “Copernicus Sentinel-5P observations have shown that global wetlands continue to be a major contributor to the atmospheric methane budget, and it is important that further work is done to fully understand how they will respond to changes in our climate.”

Methane in the atmosphere sets new record in 2021: NOAA

Provided by European Space Agency

Quote: Methane levels rose in 2020 despite lockdowns (2022, June 24) retrieved June 24, 2022 from https://phys.org/news/2022-06-methane-surged-lockdowns.html

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