Faster decomposition under increased atmospheric CO₂ limits soil carbon storage.
Soils contain the largest pool of terrestrial organic carbon (C) and are a major source of atmospheric carbon dioxide (CO2). Thus, they may play a key role in modulating climate change. Rising atmospheric CO2 is expected to stimulate plant growth and soil C input but may also alter microbial decomposition. The combined effect of these responses on long-term C storage is unclear. Combining meta-analysis with data assimilation, we show that atmospheric CO2 enrichment stimulates both the input (+19.8%) and the turnover of C in soil (+16.5%). The increase in soil C turnover with rising CO2 leads to lower equilibrium soil C stocks than expected from the rise in soil C input alone, indicating that it is a general mechanism limiting C accumulation in soil.
Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ 86011, USA.
Kees Jan
KJ
van Groenigen
Xuan
X
Qi
Craig W
CW
Osenberg
Yiqi
Y
Luo
Bruce A
BA
Hungate
D001272:Atmosphere / Q000737:chemistry*; D057486:Carbon Cycle; D002245:Carbon Dioxide / Q000737:chemistry*; D057231:Climate Change; D012987:Soil / Q000737:chemistry*
D012987:Soil; D002245:Carbon Dioxide