Emissions from the Oil and Gas Sectors, Coal Mining and Ruminant Farming Drive Methane Growth over the Past Three Decades
Emissions from the Oil and Gas Sectors, Coal Mining and Ruminant Farming Drive Methane Growth over the Past Three Decades
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DOI：
10.2151/jmsj.2021-015
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发表时间：
2021-04-01
影响因子：
3.1
通讯作者：
Canadell, Josep G.
中科院分区：
文献类型：
--
作者：
Chandra, Naveen;Patra, Prabir K.;Canadell, Josep G.
甲烷（CH 4）是一种重要的温室气体，在对流层和平流层化学中起着重要的作用。尽管甲烷（CH 4）在人类引起的气候变化和空气污染化学中具有相关性，但在过去三十年中，对其增长率和变异性变化的原因没有科学共识。我们使用一个经过充分验证的化学传输模型来模拟CH 4浓度，并通过逆模型估计1988-2016年期间的区域CH 4排放量。控制模拟进行使用季节性变化的羟基（OH）浓度，并假设没有年际变化。利用大气观测、排放清单、湿地模型和三角洲C-13-CH 4箱模型的逆模型，我们发现自1988年以来欧洲和俄罗斯的排放量减少，特别是石油天然气开采和肠道发酵，导致20世纪90年代CH 4增长率下降。这一时期之后是21世纪初大气中甲烷的准静止状态。CH 4从2007年开始恢复增长，我们将其归因于主要在中国的煤炭开采排放的增加以及热带地区反刍动物养殖的加强。使用年际变化的OH的敏感性模拟表明，区域排放量反演估计不受影响的中高纬度地区。我们发现，CH 4排放量向低纬度的纬向移动和热带地区羟基（OH）造成的CH 4损失的增加很好地平衡了，在1988-2016年期间，南半球热带和极地站点之间的CH 4梯度保持相对不变。通过卫星遥感观测的甲烷总柱的全球分布证实了排放的纬向转移。在我们的分析期间，没有证据表明由于气候变暖，包括北方地区的排放增加。这些研究结果突出了有效减排战略以减缓气候变化的关键部门。
Methane (CH4) is an important greenhouse gas and plays a significant role in tropospheric and stratospheric chemistry. Despite the relevance of methane (CH4) 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 CH4 concentration and estimation of regional CH4 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 delta C-13-CH4 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 CH4 growth rates in the 1990s. This period was followed by a quasi-stationary state of CH4 in the atmosphere during the early 2000s. CH4 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 CH4 emissions toward the lower latitudes and the increase in CH4 loss by hydroxyl (OH) over the tropics finely balance out, keeping the CH4 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 CH4 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.