Warming homogenizes apparent temperature sensitivity of ecosystem respiration

Abstract

Warming-induced carbon loss through terrestrial ecosystem respiration (<i>Re</i>) is likely getting stronger in high latitudes and cold regions because of the more rapid warming and higher temperature sensitivity of <i>Re</i> (<i>Q</i> ₁₀). However, it is not known whether the spatial relationship between <i>Q</i> ₁₀ and temperature also holds temporally under a future warmer climate. Here, we analyzed apparent <i>Q</i> ₁₀ values derived from multiyear observations at 74 FLUXNET sites spanning diverse climates and biomes. We found warming-induced decline in <i>Q</i> ₁₀ is stronger at colder regions than other locations, which is consistent with a meta-analysis of 54 field warming experiments across the globe. We predict future warming will shrink the global variability of <i>Q</i> ₁₀ values to an average of 1.44 across the globe under a high emission trajectory (RCP 8.5) by the end of the century. Therefore, warming-induced carbon loss may be less than previously assumed because of <i>Q</i> ₁₀ homogenization in a warming world.