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Authors: Paulo Ceppi
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Abstract

Abstract. From mid-2003 to mid-2024, a decrease in low-cloud amount enhanced the absorption of solar radiation by 0.22±0.07 W m-2 decade-1 (±1σ range), accelerating the energy imbalance trend during that period (0.44 W m-2 decade-1). Through controlling factor analysis, here we show that the low-cloud trend is due to a combination of cloud feedback and adjustments to aerosols and greenhouse gases (respectively 0.07±0.01, 0.06±0.01, and 0.05±0.03 W m-2 decade-1), which jointly account for 82 % of the trend. The contribution of natural climate variability is weak but uncertain (0.03±0.07 W m-2 decade-1), owing to a poorly constrained trend in boundary-layer inversion strength. Importantly, the observed low-cloud radiative trend lies well within the range of values simulated by contemporary global climate models under conditions close to present day. Any systematic model error in the representation of present-day global energy imbalance trends is thus likely to originate in processes other than low clouds.

Fields of Study & Subjects

Atmospheric aerosols and clouds Climate variability and models Meteorological Phenomena and Simulations

Publication details

Publication date
27 January 2026