Aerosol–light interactions reduce the carbon budget imbalance

Abstract Current estimates of the global land carbon sink contain substantial uncertainties on interannual timescales which contribute to a non-closure in budget (GCB) any given year. This imbalance (BIM) partly arises due use imperfect models are missing or misrepresenting processes. One such omission is separate treatment downward direct and diffuse solar radiation photosynthesis. Here we evaluate an improved high-resolution (6-hourly), gridded dataset surface fluxes, over 1901–2017, constrained by satellite ground-level observations, drive two models. Results show that tropospheric aerosol–light interactions have potential for impacts (up 0.4 PgCyr-1 enhanced sink) at decadal timescales, however large remain, with disagreeing direction change uptake. On results also enhancement 0.9 PgCyr-1) subsequent reduction BIM 55% years following volcanic eruptions. We therefore suggest GCB assessments include this order improve estimates.