Inventory of anthropogenic methane emissions in mainland China from 1980 to 2010

Abstract

Methane (CH4) has a 28-fold greater global warming potential than CO2 over 100 years. Atmospheric CH4 concentration has tripled since 1750. Anthropogenic CH4 emissions from China have been growing rapidly in the past decades and contribute more than 10 % of global anthropogenic CH4 emissions with large uncertainties in existing global inventories, generally limited to country-scale statistics. To date, a long-term CH4 emission inventory including the major sources sectors and based on province-level emission factors is still lacking. In this study, we produced a detailed annual bottom-up inventory of anthropogenic CH4 emissions from the eight major source sectors in China for the period 1980–2010. In the past 3 decades, the total CH4 emissions increased from 24.4 [18.6–30.5] Tg CH4 yr−1 in 1980 (mean [minimum–maximum of 95 % confidence interval]) to 44.9 [36.6–56.4] Tg CH4 yr−1 in 2010. Most of this increase took place in the 2000s decade with averaged yearly emissions of 38.5 [30.6–48.3] Tg CH4 yr−1. This fast increase of the total CH4 emissions after 2000 is mainly driven by CH4 emissions from coal exploitation. The largest contribution to total CH4 emissions also shifted from rice cultivation in 1980 to coal exploitation in 2010. The total emissions inferred in this work compare well with the EPA inventory but appear to be 36 and 18 % lower than the EDGAR4.2 inventory and the estimates using the same method but IPCC default emission factors, respectively. The uncertainty of our inventory is investigated using emission factors collected from state-of-the-art published literatures. We also distributed province-scale emissions into 0.1° × 0.1° maps using socioeconomic activity data. This new inventory could help understanding CH4 budgets at regional scale and guiding CH4 mitigation policies in China.