Terrestrial greenhouse gas fluxes under climate warming: A global meta‐analysis

Abstract:

Greenhouse gas (GHG) emissions contribute to global warming and are, in turn, substantially affected by warming. Although studies focusing on GHG emissions have increased, the impacts of warming on global-scale GHG budgets remain poorly understood. Here, we conducted a meta-analysis of 1374 globally obtained observations from multiple terrestrial ecosystems (i.e., forests, shrublands, grasslands, wetlands, croplands and tundra) to determine the response of GHG emissions to warming. Across the dataset, warming increased the CO₂, CH₄ and N₂O emissions by 15.4%, 15.2% and 13.5%, respectively, and the CH₄ uptake by 7.7%. However, the effects of warming on GHG emissions were highly dependent on the ecosystem biomes, the climate of individual experiments and the warming treatments (e.g., method, intensity and duration). In addition, warming affected plant growth, soil moisture and substrate availability, and microbial growth and function, which were related to the changes in GHG emissions under warming. Globally, net soil GHG emissions increased by 28.57 Pg CO₂-Geq (CO₂ equivalents) at 1°C warming, and tundra contributed 40.4% to the total net CO₂ equivalent emissions. However, CO₂ emissions from terrestrial ecosystems were the largest GHG sources, accounting for 92.0% of the total net CO₂ equivalent emissions. Our findings indicate that warming significantly impacts GHG emissions and highlight the importance of incorporating this feedback into climate models for future climate change.