The Atmosphere's Substantial Role in Interannual Variability of Earth's Energy Imbalance

Abstract Earth's Energy Imbalance (EEI) is a key metric to quantify climate change. While the ocean absorbs most excess heat, the atmosphere contributes only 1%–2% to the long‐term mean of EEI. However, our analysis of observational data demonstrates that variations in the atmosphere's energy content play a much larger role in interannual variations of EEI, especially in recent years. Including atmospheric energy uptake substantially improves agreement between observed variations in global net radiative flux at top‐of‐atmosphere (TOA) and ocean heat uptake interannually over 2005–2024. It also reconciles a delay between variability of these two quantities, with oceanic storage variability leading net TOA flux anomalies by ∼2 months. The phase shift can be explained by the atmosphere's important role in buffering and redistributing energy during El Niño – Southern Oscillation. The ability to robustly diagnose these relationships is owing to continuous efforts to monitor and improve estimates of the different EEI components.