Climate Induced Changes in Global-Scale Decomposition Over the Last Hundred Years

Litter decomposition represents the largest annual flux of carbon from terrestrial ecosystems, and is highly sensitive to climate. Using a climate-decomposition index we demonstrate significant changes in litter decomposition rates globally over the last 100 years. Litter decomposition increased by 18% from 40-60 °N and by 29% from 20-40 °S latitude. The greatest relative increases in decomposition were in deserts (+23%), grasslands (+21%), and coniferous forests (+19%). Tropical forest decomposition decreased slightly (-2%). Contrary to expectations, the relative change in decomposition was more sensitive to precipitation than temperature. Results highlight decomposition hotspots that represent significant feedbacks to climate change.