Recent reductions in anthropogenic aerosol emissions have contributed to an increased Earth's energy imbalance. Climate models show that the observed positive trend in Earth's energy imbalance over the past two decades is not explained by internal variability alone but is driven by anthropogenic forcing and the resulting climate system response. Using climate models forced with observed sea-surface temperatures, the study finds that the effective radiative forcing from anthropogenic aerosol emission reductions has strengthened the 2001–2019 energy imbalance trend by 0.2 ± 0.1 W m⁻² decade⁻¹. The multi-model ensemble reproduces the observed imbalance trend of 0.47 ± 0.17 W m⁻² decade⁻¹ but with an underestimation of 10–40%. Future scenarios predict further rapid reductions in aerosol emissions due to air quality legislation, which may continue to strengthen Earth's energy imbalance, on top of the greenhouse gas contribution. This could lead to accelerated surface temperature warming in this decade. The Earth's Energy Imbalance (EEI) is the difference between net downward shortwave (SW) and outgoing longwave (LW) radiative flux at the top-of-atmosphere. It is mainly estimated by ocean heat content observations, which absorb about 90% of the excess heat due to EEI. Recent estimates for 2010–2022 show a value of 0.89 ± 0.26 W m⁻², increasing from 0.79 ± 0.27 W m⁻² for 2006–2018. The CERES satellite data show a positive EEI trend of 0.50 ± 0.47 W m⁻² decade⁻¹ from 2005–2019, consistent with ocean-derived trends. Climate models indicate that the recent trend is only explained when anthropogenic forcing and response are included. The EEI can be seen as the sum of effective radiative forcing (ERF) and the radiative response to the forcing, which includes global mean surface temperature change and associated climate feedbacks. A positive EEI confirms the lag of the climate system in responding to forcing and implies that additional global warming will take place even without further forcing changes. On shorter time scales, EEI is modulated by internal variability such as the El-Niño Southern Oscillation (ENSO). The recent positive trend in EEI is mainly caused by reductions in the reflection of SW radiation while LW radiation changes are smaller and slightly reduce the positive net EEI trend. The latest generation of global climate models (GCMs) can reproduce the pattern of TOA radiative flux changes from CERES when forced with observed sea-surface temperatures and sea-ice until 2017, but model simulations for a longer time period (until 2019/Recent reductions in anthropogenic aerosol emissions have contributed to an increased Earth's energy imbalance. Climate models show that the observed positive trend in Earth's energy imbalance over the past two decades is not explained by internal variability alone but is driven by anthropogenic forcing and the resulting climate system response. Using climate models forced with observed sea-surface temperatures, the study finds that the effective radiative forcing from anthropogenic aerosol emission reductions has strengthened the 2001–2019 energy imbalance trend by 0.2 ± 0.1 W m⁻² decade⁻¹. The multi-model ensemble reproduces the observed imbalance trend of 0.47 ± 0.17 W m⁻² decade⁻¹ but with an underestimation of 10–40%. Future scenarios predict further rapid reductions in aerosol emissions due to air quality legislation, which may continue to strengthen Earth's energy imbalance, on top of the greenhouse gas contribution. This could lead to accelerated surface temperature warming in this decade. The Earth's Energy Imbalance (EEI) is the difference between net downward shortwave (SW) and outgoing longwave (LW) radiative flux at the top-of-atmosphere. It is mainly estimated by ocean heat content observations, which absorb about 90% of the excess heat due to EEI. Recent estimates for 2010–2022 show a value of 0.89 ± 0.26 W m⁻², increasing from 0.79 ± 0.27 W m⁻² for 2006–2018. The CERES satellite data show a positive EEI trend of 0.50 ± 0.47 W m⁻² decade⁻¹ from 2005–2019, consistent with ocean-derived trends. Climate models indicate that the recent trend is only explained when anthropogenic forcing and response are included. The EEI can be seen as the sum of effective radiative forcing (ERF) and the radiative response to the forcing, which includes global mean surface temperature change and associated climate feedbacks. A positive EEI confirms the lag of the climate system in responding to forcing and implies that additional global warming will take place even without further forcing changes. On shorter time scales, EEI is modulated by internal variability such as the El-Niño Southern Oscillation (ENSO). The recent positive trend in EEI is mainly caused by reductions in the reflection of SW radiation while LW radiation changes are smaller and slightly reduce the positive net EEI trend. The latest generation of global climate models (GCMs) can reproduce the pattern of TOA radiative flux changes from CERES when forced with observed sea-surface temperatures and sea-ice until 2017, but model simulations for a longer time period (until 2019/