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Energy Imbalance and Cloud Cover In order to understand the high rates of warming in 2023 and 2024 it is useful to examine Earth’s energy imbalance (EEI). The energy imbalance is the difference between how much energy the Earth absorbs from the Sun and how much subsequently escapes back into space as thermal radiation. It is a direct measure of how much extra energy is being trapped in the Earth system as a result of changes in greenhouse gases and other factors. As long as the energy imbalance is positive, we can expect the Earth to continue warming. In the decades since satellites began reliably measuring Earth’s energy imbalance, the values observed in 2023 are the largest on record. This imbalance has subsequently reduced somewhat in 2024.

https://berkeleyearth.org/wp-content/uploads/2025/01/2024-EEI-1024x564.png



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Spatially, the recent change in Earth’s energy imbalance is concentrated over the North Atlantic, South Atlantic, North Pacific, Europe, and the Southern Ocean. The change in the Southern Ocean is primarily related to record low sea ice cover in recent years. The changes in other ocean basins may be directly related to the reduction in marine sulfur aerosol emissions, which would be expected to allow more sunlight to reach the Earth’s surface.

https://berkeleyearth.org/wp-content/uploads/2025/01/EEI_Map-1024x564.png

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Recent work by Goessling and colleagues has found that the changes in Earth’s energy imbalance are in large part the result of recent decreases in low cloud cover. This leads to a corresponding decrease in Earth’s albedo and allows a greater portion of incoming sunlight to be absorbed rather than reflected back into space. Though changes in low cloud cover can explain changes in absorbed solar radiation, they aren’t really a primary cause. Cloud cover responds to other changes in the environment and can reasonably be understood as a sort of feedback or amplifier of other changes. Knowing that cloud cover changes are playing an important role in recent warming is very useful, but then requires one to determine why the cloud cover has changed.

Increasing temperatures mean the air can hold more water vapor so condensation is less likely to happen.

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Future Long-term Trend Though it is interesting to understand the characteristics of individual years, global warming is ultimately about the long-term evolution of Earth’s climate. The exceptional nature of the warming in 2023/2024 makes future forecasting more difficult, since it likely points to a deviation from the historical trend. Since 1980, the overall trend has been about +0.20 °C/decade (+0.36 °F/decade). The extreme warmth in 2023/2024 likely points to a period of greater warming. However, whether that greater warming rate persists over the long-term or is only present briefly is hard to predict. To the extent that excess recent warming is likely driven by reductions in man-made aerosol pollution, future warming from this source will also depend directly on human choices regarding the regulation of such aerosols. That said, our long-term trend estimate (a 30-year LOESS smooth) has already crossed 1.4 °C (2.5 °F) above the average temperature from 1850-1900. Given recent rates of warming is may take only ~5 years for our long-term trend to reach 1.5 °C (2.7 °F). The Paris Agreement on Climate Change aims to keep the long-term average global temperature rise to well below 2 °C (3.6 °F) and encourages parties to strive for warming of no more than 1.5 °C (2.7 °F). It has been clear for sometime that the 1.5 °C (2.7 °F) goal will not be achieved. Too little time remains and efforts at mitigation fall far short of what would have been needed to meet that target. Nonetheless, effective mitigation can still limit global warming and reduce the severity of negative outcomes. The increasing abundance of greenhouse gases in the atmosphere due to human activities is the primary cause of recent global warming. If the Paris Agreement’s goal of no more than 2 °C (3.6 °F) warming is to be reached, significant progress towards reducing greenhouse gas emissions needs to be made soon. Global Mean Temperature Prediction for 2025 Based on historical variability and current conditions, it is possible to roughly estimate what global mean temperature might be expected in 2025. Our current estimate is that 2025 is likely to be cooler than 2024. With the end of the 2023/2024 El Niño and the shift towards a weak La Niña, it is likely that 2025 will cool relative to 2024 and 2023. As a result, we expect that 2025 will be roughly the 3rd warmest year in the instrumental record. However, the newly formed La Niña is expected to be weak, and a return to El Niño by the end of 2025 is possible. The swings from El Niño to La Niña and back again are the largest source of predictable interannual variability in the global temperature record. Estimated probabilities of annual average rank in 2025: 1st place: 6% 2nd place: 19% 3rd place: 63% 4th – 6th place: 11% 7th place or lower: 1%

https://berkeleyearth.org/wp-content/uploads/2025/01/GroupCompareEarlyBase-1024x576.png

Smoothed:

https://berkeleyearth.org/wp-content/uploads/2025/01/GroupCompareSmooth-1024x564.png

https://berkeleyearth.org/global-temperature-report-for-2024/