Biomass allocation in plants is fundamental for understanding and predicting terrestrial carbon storage. A meta-analysis of over 300 studies shows that average warming of 2.50 °C significantly increases biomass allocation to roots (8.1% mean increase in root:shoot ratio, R/S). Mean annual precipitation and mycorrhizal type significantly influence this response. Warming-induced root allocation is greater in drier habitats (+15.1% in R/S) and more frequent in plants with arbuscular mycorrhizal fungi compared to ectomycorrhizal fungi. These results highlight the impact of precipitation variability and mycorrhizal association on terrestrial carbon dynamics in a warming world.
