Low latency global carbon budget reveals land sink decline during 2023 to 2024 El Niño

Résumé fourni par la source

El Niño droughts can weaken tropical land carbon uptake and accelerate atmospheric CO 2 growth. We updated the low-latency global CO 2 budget through June 2024 using near-real-time fossil emissions, four dynamic global vegetation models (DGVMs), ocean carbon emulators, and three OCO-2 atmospheric inversions. From July 2023 to June 2024, atmospheric CO 2 grew by 3.66 ± 0.09 ppm yr −1 , the highest July-to-July rate since 1979; after detrending, the anomaly was 1.1 ppm yr −1 , comparable to previous major El Niño events. The anomaly was mainly driven by a 2.24 GtC yr −1 weakening of the net land sink, partly offset by 0.38 GtC yr −1 stronger ocean uptake. The tropics accounted for 97.5% of the land anomaly, led by the Amazon, central Africa, and Southeast Asia. This update shows how recent El Niño droughts drove the high CO 2 growth rate through mid-2024 and how low-latency budgets can track carbon cycle extremes.

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