Recent decrease of the impact of tropical temperature on the carbon cycle linked to increased precipitation

• Published in: Nature Communications
• Main Authors: Zhang, Wenmin, Schurgers, Guy, Peñuelas, Josep, Fensholt, Rasmus, Yang, Hui, Tang, Jing, Tong, Xiaowei, Ciais, Philippe, Brandt, Martin
• Format: Text
• Language: English
• Published: Nature Publishing Group UK 2023
• Subjects: Article; South Pole; South pole
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9944254/; http://www.ncbi.nlm.nih.gov/pubmed/36810352; https://doi.org/10.1038/s41467-023-36727-2

The atmospheric CO(2) growth rate (CGR) variability is largely controlled by tropical temperature fluctuations. The sensitivity of CGR to tropical temperature [Formula: see text] has strongly increased since 1960, but here we show that this trend has ceased. Here, we use the long-term CO(2) records from Mauna Loa and the South Pole to compute CGR, and show that [Formula: see text] increased by 200% from 1960–1979 to 1979–2000 but then decreased by 117% from 1980–2001 to 2001–2020, almost returning back to the level of the 1960s. Variations in [Formula: see text] are significantly correlated with changes in precipitation at a bi-decadal scale. These findings are further corroborated by results from a dynamic vegetation model, collectively suggesting that increases in precipitation control the decreased [Formula: see text] during recent decades. Our results indicate that wetter conditions have led to a decoupling of the impact of the tropical temperature variation on the carbon cycle.