Responses of ecosystem carbon cycle to experimental warming:a meta-analysis

Background/Question/Methods Global warming potentially alters terrestrial ecosystem carbon (C) cycle, feeding back to further climate warming. However, how ecosystem C cycle responds and feed backs to warming remain unclear. We here used a meta-analysis to quantify response ratios of 18 variables of ecosystem C cycle to experimental warming.

Results/Conclusions Our results showed that warming stimulated gross ecosystem photosynthesis (GEP) by 15.7%, net primary production (NPP) by 4.4%, and above- and belowground plant C pools by 6.8% and 7.0%, respectively. The experimental warming also accelerated litter mass loss by 6.8%, soil respiration by 9.0%, and dissolved organic C leaching by 12.1%. In addition, the responses of some of those variables to experimental warming differed among the ecosystem types. The warming effects on C influx and efflux are roughly counterbalanced with each other, resulting in insignificant changes in litter and soil C contents, and net ecosystem exchange (NEE). The minor changes in soil C storage and NEE across ecosystems suggest that climate warming might not trigger strong carbon-climate feedback from terrestrial ecosystems. Our results are also potentially useful for parameterizing and benchmarking land surface models in terms of C cycle responses to climate warming.