Low latency global carbon budget reveals strong land sink recovery in 2025

Philippe Ciais; Piyu Ke; Xiangjun Tian; Stephen Sitch; Wei Li; Xiaomeng Du; Xiaofan Gui; Ben Poulter; Thomas Colligan; Auke M. van der Woude; Anne-Wil van den Berg; Wouter Peters; Zhu Liu; Zhu Deng; Zhe Jin; Yilong Wang; Junjie Liu; Sudhanshu Pandey; Chris O'Dell; Jiang Bian; John Miller; Xin Lan; Jefferson Goncalves De Souza; Michael O'Sullivan; Pierre Friedlingstein; Youngryel Ryu; Helin Zhang; Julien Alléon; Yi Xi; Daniel S. Goll; Lei Zhu; Guido R. van der Werf; Yitong Yao; Shilong Piao; Frédéric Chevallier

arXiv · 2609.34226

Low latency global carbon budget reveals strong land sink recovery in 2025

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Abstract

The atmospheric CO2 growth rate fell sharply in 2025, from a record 3.76 $\pm$ 0.09 ppm yr-1 in 2024 to 2.06 $\pm$ 0.09 ppm yr-1 (NOAA marine boundary layer observations), below the 2015-2022 mean of 2.47 ppm yr-1, even as fossil CO2 emissions rose by 0.7% to 10.38 GtC yr-1. Here we present a low-latency global and regional carbon budget for 2025, combining three dynamic global vegetation models (DGVMs) and ocean model emulators with four atmospheric inversions constrained by OCO-2 satellite retrievals. The global net land sink reached 2.36 $\pm$ 0.16 GtC yr-1 in 2025 (DGVMs: 2.04 $\pm$ 0.24; inversions: 2.68 $\pm$ 0.20 GtC yr-1), strengthening by 2.81 $\pm$ 0.31 GtC yr-1 from 2024 and exceeding the 2015-2022 mean by 0.71 $\pm$ 0.13 GtC yr-1. Ocean uptake (3.11 $\pm$ 0.36 GtC yr-1) remained similar to 2024, making the land sink rebound the dominant driver of the slowdown in CO2 growth. Tropical lands shifted from net sources in 2024 to net sinks in 2025, with enhanced uptake across much of Africa and northern Eurasia, and land flux anomalies covaried with GRACE terrestrial water storage. Where the sink had weakened substantially in 2023-2024, about 80% of the area showed some recovery, with overall recovery of 87.3% (DGVMs) to 99.5% (inversions). Recovery exceeded 100% in the tropics but remained incomplete in the northern extratropics, indicating a strong but spatially uneven rebound of the land carbon sink.

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Philippe Ciais, Piyu Ke, Xiangjun Tian, Stephen Sitch, Wei Li, Xiaomeng Du, Xiaofan Gui, Ben Poulter, Thomas Colligan, Auke M. van der Woude, Anne-Wil van den Berg, Wouter Peters, Zhu Liu, Zhu Deng, Zhe Jin, Yilong Wang, Junjie Liu, Sudhanshu Pandey, Chris O'Dell, Jiang Bian, John Miller, Xin Lan, Jefferson Goncalves De Souza, Michael O'Sullivan, Pierre Friedlingstein, Youngryel Ryu, Helin Zhang, Julien Alléon, Yi Xi, Daniel S. Goll, Lei Zhu, Guido R. van der Werf, Yitong Yao, Shilong Piao, Frédéric Chevallier. 2026-09-28. Low latency global carbon budget reveals strong land sink recovery in 2025. https://arxiv.org/abs/2609.34226

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