Emissions from the Oil and Gas Sectors, Coal Mining and Ruminant Farming Drive Methane Growth over the Past Three Decades

ournal of the Meteorological Society of Japan

article

Naveen CHANDRA¹  Ryo FUJITA³  Masayuki TAKIGAWA¹  Shingo WATANABE¹  Naoko SAITOH⁶  Josep G. CANADELL⁷  Prabir K. PATRA¹  Jagat S. H. BISHT¹  Akihiko ITO²  Taku UMEZAWA²  Nobuko SAIGUSA²  Shinji MORIMOTO³  Shuji AOKI³  Greet JANSSENS-MAENHOUT⁸ 

[1] Japan Agency for Marine-Earth Science and Technology (JAMSTEC);National Institute for Environmental Studies;Graduate School of Science, Tohoku University;Department of Physics, Imperial College London;Meteorological Research Institute;Center for Environmental Remote Sensing, Chiba University;CSIRO Oceans and Atmosphere;Joint Research Centre (JRC)

关键词: atmospheric chemistry-transport model;    inversion model;    greenhouse gases;    methane (CH4);   

DOI  :  10.2151/jmsj.2021-015

来源: Meteorological Society of Japan

【 摘 要 】

Methane (CH 4 ) is an important greenhouse gas and plays a significant role in tropospheric and stratospheric chemistry. Despite the relevance of methane (CH 4 ) in human-induced climate change and air pollution chemistry, there is no scientific consensus on the causes of changes in its growth rates and variability over the past three decades. We use a well-validated chemistry–transport model for simulating CH 4 concentration and estimation of regional CH 4 emissions by inverse modeling during 1988–2016. The control simulations are conducted using seasonally varying hydroxyl (OH) concentrations and assumed no interannual variability. Using inverse modeling of atmospheric observations, emission inventories, a wetland model, and a δ 13 C-CH 4 box model, we show that reductions in emissions from Europe and Russia since 1988, particularly from oil–gas exploitation and enteric fermentation, led to decreased CH 4 growth rates in the 1990s. This period was followed by a quasi-stationary state of CH 4 in the atmosphere during the early 2000s. CH 4 resumed growth from 2007, which we attribute to increases in emissions from coal mining mainly in China and the intensification of ruminant farming in tropical regions. A sensitivity simulation using interannually varying OH shows that regional emission estimates by inversion are unaffected for the mid- and high latitude areas. We show that meridional shift in CH 4 emissions toward the lower latitudes and the increase in CH 4 loss by hydroxyl (OH) over the tropics finely balance out, keeping the CH 4 gradients between the southern hemispheric tropical and polar sites relatively unchanged during 1988–2016. The latitudinal emissions shift is confirmed using the global distributions of the total column CH 4 observations via satellite remote sensing. During our analysis period, there is no evidence of emission enhancement due to climate warming, including the boreal regions. These findings highlight key sectors for effective emission reduction strategies toward climate change mitigation.

【 授权许可】

Unknown