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Abstract:
The respiratory release of CO2 from the land surface is a major flux in the global carbon cycle, antipodal to photosynthetic CO2 uptake. Understanding the sensitivity of respiratory processes to temperature is central for quantifying the climate-carbon cycle feedback. Here, we approximate the sensitivity of terrestrial ecosystem respiration to air temperature (Q10) across 60 FLUXNET sites using a methodology that circumvents confounding effects. Contrary to previous findings, our results suggest that Q10 is independent of mean annual temperature, does not differ among biomes, and is confined to values around 1.4 ({+/-}0.1). The strong relation between photosynthesis and respiration, instead, is highly variable among sites. Overall, the results partly explain a less pronounced climate-carbon cycle feedback than suggested by current carbon cycle climate models.
