A new analysis finds the planet absorbing 40% more heat than six years ago, with declining aerosol pollution accelerating the rise faster than emissions alone would predict.
Earth is taking in roughly 40% more heat from the Sun than it sends back out into space compared with 2019, a jump that puts the planet's energy budget further out of balance than at any point in the modern record. The shift, documented in a new analysis from the International Greenhouse Gas Centre team, carries a counter-intuitive warning: the steepest accelerant is not the steady climb in carbon dioxide. It is the slow disappearance of the cooling mask that air pollution once provided.
Earth's energy imbalance is a single, measurable number: the difference between the solar radiation the planet absorbs and the heat it radiates back toward space. When the number is positive, the climate system is gaining energy. When it rises, that gain is accelerating. The 10-year average reached about 1.12 watts per square meter over 2013-2025, the highest on record, more than double the long-term baseline and well above what most climate models projected for this period, according to a guest post by the IGCC authors on Carbon Brief and the underlying paper, currently posted as an ESSD preprint by Forster and colleagues.
Two things make the new figure significant. First, the imbalance is now outrunning the models. The IGCC team reports that observed increases have outpaced the projections in the latest assessment reports, which means future warming is more likely to land on the higher end of model ranges than on the lower. Second, the rise is not just a story of greenhouse gases accumulating. Carbon dioxide, methane, and nitrous oxide all hit record atmospheric concentrations in 2025, with CO2 at 425.6 parts per million, CH4 at 1936.3 parts per billion, and N2O at 339.4 parts per billion, all up sharply from 2019 levels. But the IGCC analysis attributes part of the recent jump to something else: a decline in sulphur dioxide and other aerosol emissions from power plants, shipping, and industry.
Aerosols reflect sunlight and brighten clouds, a cooling effect that has partially offset greenhouse warming for decades. As air-quality rules clean up those emissions, the cooling mask thins. Removing it does not add new heat to the system, but it lets more of the trapped energy show up in the imbalance record. The IGCC team frames the aerosol decline as a significant contributor to the post-2019 acceleration, a finding that, if borne out in the published version of the paper, would harden the case that near-term warming depends on air-quality choices as much as on carbon choices.
The physical consequences are already visible where the energy goes. About 90% of the excess heat ends up in the ocean, and the average number of marine heatwave days in 2025 reached 65 globally, roughly three times the count in the early 1990s. Sea level, set by a mix of thermal expansion and melting ice, has climbed to a cumulative 23 centimeters since 1901 and is now rising at 3.67 millimeters per year over 2006-2025, more than double the 1.69 millimeters per year of 1976-1995. On land, the average maximum daily temperature over 2016-2025 sat about 1.92°C above the pre-industrial baseline, already past the 1.5°C Paris guardrail for extreme-heat days.
The IGCC analysis also updates the human-warming estimate. Human-induced warming reached 1.37°C in 2025, up from 1.0°C in the AR6 reference period, a rate of roughly 0.27°C per decade. The team's projection that the global average will cross the 1.5°C Paris limit around 2030 is a model-based estimate, not an observation, and depends on assumptions about aerosol trends and emissions paths. The published version of the Forster et al. paper is still in the ESSD preprint queue and has not yet completed peer review, a caveat worth holding onto when citing specific numbers.
What makes the energy imbalance useful as a public indicator is that it compresses a complicated climate story into one number with a clear direction. A flat or falling imbalance would mean the climate system is regaining equilibrium. A rising one means it is not. Over the next one to three years, the watch items are whether the post-2019 acceleration holds, whether the aerosol attribution survives peer review, and whether ocean heat content keeps setting records even as surface temperatures fluctuate with El Niño and La Niña. Carbon dioxide is the long game. The energy imbalance is the near-term scoreboard.