Increased soil release of greenhouse gases shrinks terrestrial carbon uptake enhancement under warming

: Warming can accelerate the decomposition of soil organic matter and stimulate the release of soil greenhouse gases (GHGs), but to what extent soil release of methane (CH4 ) and nitrous oxide (N2 O) may contribute to soil C loss for driving climate change under warming remains unresolved. By synthesizing 1845 measurements from 164 peer-reviewed publications, we show that around 1.5 °C (1.16-2.01 °C) of experimental warming significantly stimulates soil respiration by 12.9%, N2 O emissions by 35.2%, and CH4 emissions by 23.4% from rice paddies and by 37.5% from natural wetlands. Rising temperature increases CH4 uptake of upland soils by 13.8%. Warming-enhanced emission of soil CH4 and N2 O corresponds to an overall source strength of 1.19, 1.84 and 3.12 Pg CO2 -equivalent yr-1 under 1 °C, 1.5 °C and 2 °C warming scenarios, respectively, interacting with soil C loss of 1.60 Pg CO2 yr-1 in terms of contribution to climate change. The warming-induced rise in soil CH4 and N2 O emissions (1.84 Pg CO2 -equivalent year-1 ) could reduce mitigation potential of terrestrial net ecosystem production by 8.3% (NEP, 22.25 Pg CO2 year-1 ) under warming. Soil respiration and CH4 release are intensified following the mean warming threshold of 1.5 °C scenario, as compared to soil CH4 uptake and N2 O release with a reduced and less positive response, respectively. Soil C loss increase to a larger extent under soil warming than under canopy air warming. Warming-raised emission of soil GHGs increases with the intensity of temperature rise but decreases with the extension of experimental duration. This synthesis takes the lead to quantify the ecosystem C and N cycling in response to warming and advances our capacity to predict terrestrial feedback to climate change under projected warming scenarios.