Reconciling Earth’s growing energy imbalance with ocean warming
Rising greenhouse gas concentrations and declining global aerosol emissions are causing energy to accumulate in Earth’s climate system at an increasing rate. Incomplete understanding of increases in Earth’s energy imbalance and ocean warming reduces the capability to accurately prepare for near term climate change and associated impacts. Here, satellite-based observations of Earth’s energy budget and ocean surface temperature are combined with the ERA5 atmospheric reanalysis over 1985–2024 to improve physical understanding of changes in Earth’s net energy imbalance and resulting ocean surface warming. A doubling of Earth’s energy imbalance from 0.6±0.2 Wm−2 in 2001–2014 to 1.2±0.2 Wm−2 in 2015–2023 is primarily explained by increases in absorbed sunlight related to cloud-radiative effects over the oceans. Observed increases in absorbed sunlight are not fully captured by ERA5 and determined by widespread decreases in reflected sunlight by cloud over the global ocean. Strongly contributing to reduced reflection of sunlight are the Californian and Namibian stratocumulus cloud regimes, but also recent Antarctic sea ice decline in the Weddell Sea and Ross Sea. An observed increase in near-global ocean annual warming by 0.1