Drivers of 2023–2024 Atmospheric CO ₂ Growth: Role of Northern Mid‐to‐High Latitude Land Carbon Cycle

Abstract The global atmospheric CO 2 growth rate in 2023–2024 reached an unprecedented level, exceeding all records since modern monitoring began. Using a CO 2 flux inversion, constrained by column‐averaged CO 2 observations from Greenhouse gases Observing SATellite (GOSAT), we investigated spatio‐temporal drivers of this anomaly. The 2023–2024 El Niño seem to have increased non‐fossil CO 2 fluxes globally; however, unlike the former big 2015–2016 El Niño, which was dominated by tropical anomalies (0.96 PgC year −1 ), the 2023–2024 event exhibited not only distinct tropical increases (1.11 Pg C year −1 ) but also notable weakening of net CO 2 uptake (0.42 PgC year −1 ) across northern mid‐to‐high latitudes, whose flux variations have less sensitivity to El Niño in the past. The flux variability in the northern mid‐to‐high latitudes was primarily temperature‐associated, while fire emissions contributed only weakly and episodically.