High Spatial and Temporal Resolution Methane Emissions Inventory from Terrestrial Ecosystems in China, 2010-2020

Methane (CH4) is not only an important greenhouse gas next to carbon dioxide (CO2), but also an important chemically active gas. Under the background of climate warming, the measurement of CH4 emissions from terrestrial ecosystems in China is not only very important for exploring the impact of climate change on the ecological environment, but also of great significance for the in-depth study of ecosystem carbon cycling. In this study, we used the Emission-Factor Approach to estimate CH4 emissions from terrestrial ecosystems in China from 2010-2020 and explored the spatial distribution characteristics of CH4 emissions. The estimated CH4 emission inventory of terrestrial ecosystems with 0.05 spatial resolution on monthly time scale is in good agreement with the results of the latest emission inventory. It is estimated that CH4 emissions from terrestrial ecosystems in China are 19.955 Tg yr(-1), including 18.61% (3.713 Tg yr(-1)) from vegetation, 21.47% (4.285 Tg yr(-1)) from wetlands and 59.92% (11.957 Tg yr(-1)) from paddy fields, with the largest contribution from paddy fields. The regions with high CH4 emissions from terrestrial ecosystems in China are mainly located in the central, eastern and southeastern regions of China, and show a decreasing trend from southeast to northwest. The CH4 emission from terrestrial ecosystems in China has obvious seasonal variation characteristics, with the lowest emission in January (0.248 Tg month(-1)) and the highest emission in August (3.602 Tg month(-1)). The emissions are high in summer and autumn and low in spring and winter. CH4 emissions from terrestrial ecosystems in China showed an overall upward trend from 2010-2020.