Will climate warming of terrestrial ecosystem contribute to increase soil greenhouse gas fluxes in plot experiment? A global meta-analysis

One of the main manifestations of global climate change is its profound impact on the emission of greenhouse gases from terrestrial soil. Numerous field warming experiments have explored the effects of different temperature rise intensities and durations on soil greenhouse gas fluxes in the growing season of different terrestrial ecosystems. However, the results were inconsistent due to the variations in vegetation, soil, and climatic conditions in different ecosystems. In the present work, we carried meta-analysis to synthesize 99 datasets from 52 field warming experiments in growing seasons of terrestrial ecosystems to evaluate the response of soil greenhouse gas fluxes to global warming. The results showed that warming greatly stimulated soil CO2 in temperate forest and farmland by 12.64% and 25.57%, respectively, significantly increased soil N2O emissions in grassland (27.23%), farmland (44.33%), and shrubland (223.36%), and increased soil CH4 uptake by 57.81% in grasslands. However, no significant impact on the greenhouse gas fluxes in other ecosystems was observed. Generally, short-and medium-term (<= 3 years) warming can promote soil greenhouse gas fluxes. Also, low temperature and low-medium temperature (<= 2 degrees C) significantly promoted N2O emission and CH4 absorption, and medium temperature (2-4 degrees C) considerably assisted CO2 flux, but high temperature (> 4 degrees C) had no significant effect on greenhouse gas flux. Our results demonstrated that soil greenhouse gas fluxes in terrestrial ecosystems during the growing season do not increase linearly with the increasing climate warming, and it is still uncertain whether there is acclimatization to long-term climate warming.