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Abstract. Interannual variations in air–sea fluxes of carbon dioxide (CO2) impactthe global carbon cycle and climate system, and previous studies suggest thatthese variations may be predictable in the near term (from a year to a decadein advance). Here, we quantify and understand the sources of near-termpredictability and predictive skill in air–sea CO2 flux on global andregional scales by analyzing output from a novel set of retrospective decadalforecasts of an Earth system model. These forecasts exhibit the potential topredict year-to-year variations in the globally integrated air–sea CO2flux several years in advance, as indicated by the high correlation of theforecasts with a model reconstruction of past CO2 flux evolution. Thispotential predictability exceeds that obtained solely from foreknowledge ofvariations in external forcing or a simple persistence forecast, with thelongest-lasting forecast enhancement in the subantarctic Southern Ocean andthe northern North Atlantic. Potential predictability in CO2 fluxvariations is largely driven by predictability in the surface ocean partialpressure of CO2, which itself is a function of predictability in surfaceocean dissolved inorganic carbon and alkalinity. The potentialpredictability, however, is not realized as predictive skill, as indicated bythe moderate to low correlation of the forecasts with anobservationally based CO2 flux product. Nevertheless, our results suggestthat year-to-year variations in ocean carbon uptake have the potential to bepredicted well in advance and establish a precedent for forecasting air–seaCO2 flux in the near future.
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High predictability of terrestrial carbon fluxes from an initialized decadal prediction system
Abstract 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 CO2growth 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.
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- Award ID(s):
- 1752724
- PAR ID:
- 10303293
- Publisher / Repository:
- IOP Publishing
- Date Published:
- Journal Name:
- Environmental Research Letters
- Volume:
- 14
- Issue:
- 12
- ISSN:
- 1748-9326
- Page Range / eLocation ID:
- Article No. 124074
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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