Soil methanotrophy is the only biological process that removes methane (CH₄) from the atmosphere. There is good agreement about the size of the global sink but great uncertainty about its interannual variability and regional responses to changes in key environmental drivers. We used the process-based methanotrophy model Methanotrophy Model (MeMo) v1.0 and output from global climate models to simulate regional and global changes in soil uptake of atmospheric CH₄ from 1900 to 2100. The annual global uptake doubled from 17.1 ± 2.4 to 37.2 ± 3.3 Tg yr⁻¹ from 1900-2015 and could increase further to 82.7 ± 4.4 Tg yr⁻¹ by 2100 (RCP8.5), primarily due to enhanced diffusion of CH₄ into soil as a result of increases in atmospheric CH₄ mole fraction. We show that during the period 1980–2015 temperature became an important influence on the increasing rates of soil methanotrophy, particularly in the Northern Hemisphere. In RCP-forced simulations the relative influence of temperature on changes in the uptake continues to increase, enhancing the soil sink through higher rates of methanotrophic metabolic activity, increases in the global area of active soil methanotrophy and length of active season. During the late 21st century under RCP6.0, temperature is predicted to become the dominant driver of changes in global mean soil uptake rates for the first time. Regionally, in Europe and Asia, nitrogen inputs dominate changes in soil methanotrophy, while soil moisture is the most important influence in tropical South America. These findings highlight that the soil sink could change in response to drivers other than atmospheric CH₄ mole fraction.

中文翻译：

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1900 年至 2100 年全球土壤对大气甲烷的吸收

土壤甲烷营养是唯一从大气中去除甲烷 (CH ₄ ) 的生物过程。关于全球汇的规模有很好的一致性，但其年际变化和区域对关键环境驱动因素变化的反应存在很大的不确定性。我们使用基于过程的甲烷营养模型 (MeMo) v1.0 和全球气候模型的输出来模拟1900 年至 2100 年大气 CH ₄土壤吸收的区域和全球变化。全球年吸收量从 17.1 ± 2.4 翻番至1900-2015年为 37.2 ± 3.3 Tg yr ^-1，到2100年可能进一步增加至 82.7 ± 4.4 Tg yr ^-1 (RCP8.5)，主要是由于 CH _{4 的}扩散增强由于大气 CH ₄增加而进入土壤摩尔分数。我们表明，在 1980 年至 2015 年期间，温度成为影响土壤甲烷氧化速率增加的重要因素，尤其是在北半球。在 RCP 强制模拟中，温度对吸收变化的相对影响继续增加，通过更高的甲烷氧化代谢活动率、全球活跃土壤甲烷氧化面积和活跃季节长度的增加来增强土壤汇。在 RCP6.0 的 21 世纪后期，预计温度将首次成为全球平均土壤吸收率变化的主要驱动因素。从区域来看，在欧洲和亚洲，氮输入主导着土壤甲烷营养的变化，而土壤水分是南美洲热带地区最重要的影响。₄摩尔分数。