Low Latency Global Carbon Budget Reveals Late 2024 Carbon Losses and Contrasting Early 2025 Land Sink Recovery Signals.

The 2023/24 El Niño strongly reduced land carbon uptake, but the persistence of this anomaly after surface cooling remains uncertain. Here we quantify the July 2024-June 2025 global CO2 budget using low-latency fossil emission estimates, three DGVMs, machine learning ocean flux emulators and OCO-2-constrained atmospheric inversions. The atmospheric CO2 growth rate was 2.62 ± 0.08 ppm yr-1, 6.5% above the 2013-2022 July-to-June mean. DGVMs estimate that the net land sink was 1.32 ± 0.19 GtC yr-1 weaker than the 2015-2022 July-to-June mean, whereas combining bottom-up and top-down constraints gives a smaller deficit of 0.49 GtC yr-1. The annual anomaly is dominated by late-2024 land carbon losses. Early-2025 recovery, however, is method-dependent: DGVMs retain a weak annual land-sink deficit, while all inversions indicate fluxes close to the reference mean and a stronger-than-normal northern sink in late spring 2025. Ocean uptake shows no global weakening. A statistical decomposition links global land flux variability mainly to temperature, with terrestrial water storage contributing more strongly at regional scales. These results identify Northern Hemisphere land-sink recovery as a central uncertainty in low-latency carbon-budget assessments.