The soil microbiome governs the response of microbial respiration to warming across the globe

The sensitivity of soil microbial respiration to warming (Q ₁₀) remains a major source of uncertainty surrounding the projections of soil carbon emissions to the atmosphere as the factors driving Q ₁₀ patterns across ecosystems have been assessed in isolation from each other. Here we report the results of a warming experiment using soils from 332 sites across all continents and major biomes to simultaneously evaluate the main drivers of global Q ₁₀ patterns. Compared with biochemical recalcitrance, mineral protection, substrate quantity and environmental factors, the soil microbiome (that is, microbial biomass and bacterial taxa) explained the largest portion of variation in Q ₁₀ values. Our work provides solid evidence that soil microbiomes largely govern the responses of soil heterotrophic respiration to warming and thus need to be explicitly accounted for when assessing land carbon–climate feedbacks.