High predictability of terrestrial carbon fluxes from an initialized decadal prediction system

Interannual variations in the flux of carbon dioxide (CO2) between the land surface and the atmosphere are the dominant component of interannual variations in the atmospheric CO2 growth rate. Here, we investigate the potential to predict variations in these terrestrial carbon fluxes 1-10 years in advance using a novel set of retrospective decadal forecasts of an Earth system model. We demonstrate that globally-integrated net ecosystem production (NEP) exhibits high potential predictability for 2 years following forecast initialization. This predictability exceeds that from a persistence or uninitialized forecast conducted with the same Earth system model. The potential predictability in NEP derives mainly from high predictability in ecosystem respiration, which itself is driven by vegetation carbon and soil moisture initialization. Our findings unlock the potential to forecast the terrestrial ecosystem in a changing environment.