Temperate northern hemisphere dominates the global soil CH_(4) sink

Methane(CH_(4)) is the second largest longlived greenhouse gas after the CO_(2), which contributes 20% of global warming forcing. Global aerated soils remove CH_(4) from the troposphere, but the quantification of its magnitude and spatial variability is still of a large uncertainty. This study collected 1240records of the CH_(4) uptake by soils across the globe.Our estimates update the global soil CH_(4) sink to 31.9+/-0.16 Tg CH_(4) a^(-1), 42% higher than the previous inventory-based estimation, with 56% from temperate regions. Also, our dataset revealed that the global drylands dominated the soil CH_(4) sink, which is different from traditional forest-dominated view.During the past four decades, the soil porosity affected by soil moisture controls the variation in the uptake in the tropics, while warming temperatures benefit methanotrophs in temperate and boreal soils,especially the drylands, where the soil porosity is not limiting. Our simulations indicate that the CH_(4) uptake will increase by 11%–31% by the end of the 21st century, much lower than the previous estimations.This study substantially constrains the global soil CH_(4) sink estimates and reveals the warming temperate northern hemisphere is a dominant CH_(4) uptake region in the past and future, while the uptake decreases in tropical soils under increasing precipitation.