Earth is now absorbing more heat than it releases back into space, and a new study suggests that changing cloud patterns, not cleaner air, are playing the biggest role in this growing imbalance. The findings add a new layer of urgency to climate research and raise concerns that global warming could speed up faster than previously expected.
For the planet to stay stable, energy from the Sun should roughly equal the energy leaving for space. Scientists have tracked this balance for years, and recent data shows a worrying shift. Earth is holding more heat, and that excess energy is warming the atmosphere, oceans, and land.
The study, published in Science Advances, examined nearly twenty years of satellite observations and atmospheric data from 2003 to 2023. Researchers found that Earth’s energy gain has steadily increased by about half a watt per square metre each decade. While that number may sound small, across the entire planet it represents a significant and growing amount of trapped heat.
For a long time, scientists believed air pollution played a major role in this trend. Tiny particles from pollution, called aerosols, can reflect sunlight back into space and cool the planet. As air quality improves in many parts of the world, especially in the Northern Hemisphere, some warming from reduced aerosols was expected.
However, the study found that pollution changes do not explain the global picture. In the north, fewer aerosols allow more sunlight to reach the surface, causing warming. But in the Southern Hemisphere, wildfires and volcanic activity have increased aerosol levels, making clouds more reflective and slightly cooling those regions. Viewed globally, these effects largely cancel each other out.
What stood out instead was the role of clouds. Clouds usually act like a shield, bouncing sunlight away from Earth. The research shows that, on average, clouds have become less reflective over time. This lets more solar energy reach the surface, adding to warming. Changes in sea temperatures, weather patterns, and natural climate cycles appear to influence how clouds form and behave.
This matters because clouds are one of the most complex and uncertain parts of climate science. They are difficult to model accurately, and small changes in their behaviour can have large effects on global temperatures. While greenhouse gases like carbon dioxide remain the main driver of long-term climate change, cloud changes now intensify warming in the near term.
The findings highlight the need for better cloud monitoring and improved climate models. Understanding how clouds respond to a warming planet could help scientists make more accurate predictions and guide better climate policies.
What is clear is that Earth’s heat imbalance is growing, not slowing. As the planet continues to absorb more energy than it emits, the risks of faster warming, more severe weather extremes, and long-term climate disruption grow harder to ignore.
