Earth is absorbing more heat as the gap between incoming solar energy and outgoing radiation grows, and a joint NASA-NOAA analysis found the planet’s energy imbalance has approximately doubled from 2005 to 2019. That growing imbalance, supported by independent satellite and ocean measurements, indicates the climate system is storing heat at a faster rate than it was in the mid-2000s.
How Scientists Measure the Planet’s Heat Budget
Earth’s energy imbalance, often abbreviated EEI, represents the difference between solar energy the planet absorbs and the thermal radiation it sends back to space. When that number is positive, the climate system is storing heat. The CERES instrument suite aboard NASA satellites tracks this balance by measuring radiation at the top of the atmosphere, while a global network of ocean floats independently gauges how much heat the seas are taking in. A joint NASA and NOAA analysis found that both methods tell the same story: EEI approximately doubled from 2005 to 2019, signaling a rapid increase in the rate at which the planet is storing energy.
That agreement between two very different observing systems matters. Satellite sensors can drift over time, and ocean measurements depend on where floats happen to be deployed. The fact that both approaches converge on the same trend gives researchers high confidence the signal is real, not an artifact of instrument error. Maintaining that continuity across successive satellites and instruments is itself a technical challenge that calibration teams have worked to solve, as documented in recent work on radiative forcing and the climate system’s response.
To turn raw satellite measurements into a coherent climate data record, scientists process the observations into gridded products that span the globe and extend back in time. One key dataset is the CERES Energy Balanced and Filled (EBAF) series, which adjusts for known biases and fills gaps in coverage. A NASA announcement of the latest EBAF release describes how the Edition 4.2 product refines estimates of top-of-atmosphere radiation and surface fluxes, giving researchers a clearer picture of how much extra energy is entering the climate system each year.
Why the Imbalance Keeps Growing
The observed positive trend in EEI is not random variation. Research published in Nature Communications attributed the long-term increase primarily to human-driven greenhouse gas emissions and the climate system’s response to that forcing. Carbon dioxide, methane, and other gases trap outgoing infrared radiation, reducing the amount of heat that escapes to space and pushing the energy budget out of balance.
But the story has a less intuitive wrinkle: cleaner air may be making things worse in the short term. Sulfate and other aerosols from burning fossil fuels once reflected sunlight and exerted a cooling influence that partially masked greenhouse warming. According to a study in Communications Earth & Environment, recent reductions in aerosol emissions have increased Earth’s energy imbalance, because fewer reflective particles in the atmosphere mean more solar energy reaches the surface.
That finding creates an uncomfortable tension: policies that improve air quality and protect public health simultaneously remove a brake on warming. Yet the aerosol story is not the whole picture. Some research suggests changes in cloud properties may also be contributing to the imbalance. Variations in cloud cover, thickness, and altitude alter how much sunlight the planet reflects and how much thermal energy escapes. If cloud feedbacks continue to amplify warming, the imbalance could widen even if aerosol levels stabilize, locking in a faster pace of temperature rise.
The 2022–2023 Heat Surge
On top of the long-term trend, the climate system experienced what researchers describe as an extreme energy uptake episode in 2022 and 2023. A study in Nature Geoscience reported that the transition from a multi-year La Niña toward El Niño conditions was associated with the spike. During La Niña, intensified trade winds push warm surface water westward across the Pacific and draw up cooler water in the east, temporarily suppressing global surface temperatures even as the planet continues to gain heat overall.
When the pattern flipped to El Niño, the stored ocean heat surged back toward the surface and into the atmosphere, adding a natural boost on top of the ongoing human-caused warming. That sequence helps explain why global temperatures seemed to jump so sharply between 2022 and 2024. The underlying energy imbalance had been building for years, loading the climate system with excess heat. The El Niño transition simply made that hidden energy visible in surface temperature records.
Internal variability like El Niño does not create new heat; it redistributes energy that the imbalance has already trapped. The oceans act as a vast reservoir, absorbing more than 90 percent of the excess energy. When circulation patterns shift, some of that stored heat is released, driving short bursts of rapid warming. As long as EEI remains strongly positive, each future El Niño is likely to start from a higher baseline, making it more probable that temperature records set in 2023 and 2024 will fall again.
What a Wider Imbalance Means for the Future
A synthesis in AGU Advances frames EEI as a core metric of how fast heat is accumulating in the climate system. When the imbalance is small, the planet adjusts slowly and surface warming proceeds at a more moderate pace. When it more than doubles, as recent satellite and ocean data indicate, the rate of heat storage in oceans, ice sheets, and the atmosphere accelerates in tandem, committing the world to more rapid changes.
Most of that excess energy ends up in the ocean, raising sea levels through thermal expansion and melting of marine-terminating glaciers. Warmer waters also disrupt marine ecosystems, driving coral bleaching, altering fish migration routes, and increasing the risk of marine heatwaves that can devastate kelp forests and coastal food webs. On land, a larger imbalance translates into more frequent and intense heat extremes, longer wildfire seasons, and shifts in precipitation patterns that can swing between severe drought and damaging floods.
The practical consequence is that some additional warming is expected in the coming decades, even as emissions change, because the climate system responds over long timescales. Research published by Springer Nature argues that positive climate feedbacks will lead to further warming even if anthropogenic greenhouse gas output is sharply reduced, because processes such as ice loss and vegetation changes continue to amplify the initial perturbation. As Arctic sea ice and glaciers retreat, darker ocean and land surfaces absorb more sunlight, further increasing the net energy gain and reinforcing the imbalance.
That does not mean mitigation is futile. Reducing emissions as quickly as possible remains the only way to stop EEI from growing even larger and eventually bring it back toward zero. The current imbalance reflects the cumulative effect of past and present emissions; stabilizing the climate requires not just slowing the growth of greenhouse gases but ultimately reaching net zero so that incoming and outgoing energy can rebalance. The longer the world waits, the more heat accumulates and the more difficult it becomes to avoid crossing thresholds that trigger irreversible changes.
In the meantime, understanding Earth’s energy imbalance offers a clearer view of what lies ahead than temperature records alone can provide. Temperatures fluctuate from year to year with El Niño, volcanic eruptions, and other natural variations, but EEI tracks the underlying trajectory of the climate system. As long as satellites and ocean instruments continue to show a large positive imbalance, the risk of further warming, sea-level rise, and ecosystem disruption remains elevated. The numbers now emerging from those measurements leave little doubt: the planet is not just warmer than it used to be; it is still rapidly heating up.
More from Morning Overview
*This article was researched with the help of AI, with human editors creating the final content.
