FY 2026

The atmosphere’s recent substantial role in interannual variability of Earth’s energy imbalance

Mayer, M., N.G. Loeb, J.M. Lyman, and G.C. Johnson

Geophys. Res. Lett., 53(3), e2025GL119833, doi: 10.1029/2025GL119833, View open access article at AGU/Wiley (external link) (2026)

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.

Plain Language Summary. The increase of human-made greenhouse gases in the atmosphere results in a net global energy flux at the top of the atmosphere. In the long-term mean, most of this excess heat is absorbed by the ocean due to its large thermal capacity. A comparatively small fraction warms the land, melts ice, and warms and moistens the atmosphere. However, here we show that atmospheric storage plays a non-trivial role on shorter timescales. We investigate the balance among variations in the global flux at the top of the atmosphere, the rate of atmospheric warming, and the rate of oceanic warming from year to year over the past 2 decades. We find that changes in ocean warming lead the net energy flux at the top of the atmosphere by 2 months, and these two time-series are fairly well correlated on these interannual time scales, but the sum of atmospheric and oceanic rates of energy uptake are better correlated with a maximum correspondence at zero time lag. Hence the atmosphere is playing an important role in buffering and redistributing year-to-year energy uptake by the climate system, most notably during El Niño and La Niña events, but especially in 2023, when surface temperatures increased remarkably.