Research output: Contribution to Journal/Magazine › Letter › peer-review
Research output: Contribution to Journal/Magazine › Letter › peer-review
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TY - JOUR
T1 - Global covariation of carbon turnover times with climate in terrestrial ecosystems
AU - Carvalhais, Nuno
AU - Forkel, Matthias
AU - Khomik, Myroslava
AU - Bellarby, Jessica
AU - Jung, Martin
AU - Migliavacca, Mirco
AU - Mu, Mingquan
AU - Saatchi, Sassan
AU - Santoro, Maurizio
AU - Thurner, Martin
AU - Weber, Ulrich
AU - Ahrens, Bernhard
AU - Beer, Christian
AU - Cescatti, Alessandro
AU - Randerson, James T.
AU - Reichstein, Markus
PY - 2014/10/9
Y1 - 2014/10/9
N2 - The response of the terrestrial carbon cycle to climate change is among the largest uncertainties affecting future climate change projections1, 2. The feedback between the terrestrial carbon cycle and climate is partly determined by changes in the turnover time of carbon in land ecosystems, which in turn is an ecosystem property that emerges from the interplay between climate, soil and vegetation type3, 4, 5, 6. Here we present a global, spatially explicit and observation-based assessment of whole-ecosystem carbon turnover times that combines new estimates of vegetation and soil organic carbon stocks and fluxes. We find that the overall mean global carbon turnover time is years (95 per cent confidence interval). On average, carbon resides in the vegetation and soil near the Equator for a shorter time than at latitudes north of 75° north (mean turnover times of 15 and 255 years, respectively). We identify a clear dependence of the turnover time on temperature, as expected from our present understanding of temperature controls on ecosystem dynamics. Surprisingly, our analysis also reveals a similarly strong association between turnover time and precipitation. Moreover, we find that the ecosystem carbon turnover times simulated by state-of-the-art coupled climate/carbon-cycle models vary widely and that numerical simulations, on average, tend to underestimate the global carbon turnover time by 36 per cent. The models show stronger spatial relationships with temperature than do observation-based estimates, but generally do not reproduce the strong relationships with precipitation and predict faster carbon turnover in many semi-arid regions. Our findings suggest that future climate/carbon-cycle feedbacks may depend more strongly on changes in the hydrological cycle than is expected at present and is considered in Earth system models.
AB - The response of the terrestrial carbon cycle to climate change is among the largest uncertainties affecting future climate change projections1, 2. The feedback between the terrestrial carbon cycle and climate is partly determined by changes in the turnover time of carbon in land ecosystems, which in turn is an ecosystem property that emerges from the interplay between climate, soil and vegetation type3, 4, 5, 6. Here we present a global, spatially explicit and observation-based assessment of whole-ecosystem carbon turnover times that combines new estimates of vegetation and soil organic carbon stocks and fluxes. We find that the overall mean global carbon turnover time is years (95 per cent confidence interval). On average, carbon resides in the vegetation and soil near the Equator for a shorter time than at latitudes north of 75° north (mean turnover times of 15 and 255 years, respectively). We identify a clear dependence of the turnover time on temperature, as expected from our present understanding of temperature controls on ecosystem dynamics. Surprisingly, our analysis also reveals a similarly strong association between turnover time and precipitation. Moreover, we find that the ecosystem carbon turnover times simulated by state-of-the-art coupled climate/carbon-cycle models vary widely and that numerical simulations, on average, tend to underestimate the global carbon turnover time by 36 per cent. The models show stronger spatial relationships with temperature than do observation-based estimates, but generally do not reproduce the strong relationships with precipitation and predict faster carbon turnover in many semi-arid regions. Our findings suggest that future climate/carbon-cycle feedbacks may depend more strongly on changes in the hydrological cycle than is expected at present and is considered in Earth system models.
U2 - 10.1038/nature13731
DO - 10.1038/nature13731
M3 - Letter
VL - 514
SP - 213
EP - 217
JO - Nature
JF - Nature
SN - 0028-0836
IS - 7521
ER -