Using the methane observation data of Japanese carbon monitoring satellite, researchers from lasg and other units conducted in-depth research on methane emission from 20 10 to 20 19. They found that from 20 10 to 20 19, methane emission from tropical land contributed more than 80% to the increase of global methane concentration, and proposed for the first time that the change of ocean surface temperature can be used to predict the change of global atmospheric methane. Related research results were published online in Nature-Communication on March 16.
Methane is widely distributed in nature and is the main component of natural gas and biogas. Methane emission sources are mainly divided into man-made sources and natural sources, among which man-made sources mainly include coal and oil and gas exploitation, agricultural production, livestock and landfill. Natural resources include wetlands, inland fresh water, biomass burning, geological leakage and frozen soil.
Besides carbon dioxide, methane is the second largest man-made factor leading to global warming. Compared with the retention time of carbon dioxide in the atmosphere for about a hundred years, the "life" of methane is much shorter, and its life cycle is only 8- 1 1 year.
However, methane is a greenhouse gas, which has a greater impact on the atmosphere than carbon dioxide. Compared with carbon dioxide, the warming intensity caused by methane with the same mass is much higher than that of carbon dioxide.
"In the time scale of 20 years, the warming intensity caused by methane is 84 times that of carbon dioxide." Liu Yi, a researcher in lasg and one of the authors of the paper, said that reducing methane emissions can achieve the goal of restraining global warming in a short time compared with controlling carbon dioxide.
Since the industrial revolution, the concentration of methane in the atmosphere has more than doubled, and the greenhouse effect caused by the doubling of methane contributes about 20% to global warming.
Tropical region is the main source of methane emissions, accounting for about 60% of the total global methane emissions. However, "we found that the contribution of methane emissions in tropical areas in 20 10-20 19 to the growth and change of global atmospheric methane concentration in the same period can reach 84%." Liu Yi stressed.
At the same time, "how to use the existing observation and forecasting methods to predict the change of atmospheric methane concentration? This issue is more difficult, and this aspect is still a weak link in research. " Liu Yi pointed out.
Using the inversion data of methane column concentration of Japan Carbon Monitoring Satellite (GOSAT) and the observation data of methane concentration station of Greenhouse Gas Ground Monitoring Network (NOAA/GML), combined with the carbon assimilation model, the researchers found for the first time that there is a strong seasonal correlation between the change of ocean surface temperature and the change of methane emission in tropical South America and Central Africa.
"We believe that the current SST forecast can be used to help predict the change of global atmospheric methane." The first author of the paper, Dr. Feng Liang from the School of Earth Sciences, University of Edinburgh, UK, said.
Methane emission plays an important role in the overall pattern of greenhouse gas emission reduction in China. However, "at present, there is no unified understanding of methane emission and its change in China. In the future, the research team will further use multi-platform observation data to provide more accurate methane emission assessment results in China and provide scientific and technological support for China to achieve the goal of' double carbon'. " Liu Yi said.