The impact of elevated CO on methanogen abundance and methane emissions in terrestrial ecosystems: A meta-analysis.

Methane (CH), one of the major greenhouse gases, plays a pivotal role in global climate change. Elevated CO concentration (eCO) increases soil carbon storage, which may provide a valuable material base for soil methanogenic microorganisms and stimulating their growth, thereby ultimately affecting CH emissions. Therefore, to comprehend the effect of eCO on CH emissions, we conducted a meta-analysis encompassing 398 datasets from 59 publications (total of 50 sample sites). The results show that eCO promotes both the abundance of the functional methanogenic gene and CH emissions. However, this enhancement is modulated by a range of factors, such as the eCO duration, land use types and soil texture, and there are significant interactions. This study offers new insights into the effects of eCO on CH emissions across diverse ecosystems and the underlying driving forces, vital for predicting the response of global terrestrial ecosystems in the face of future climate change.