Heatwaves across Europe and South Asia have recently drawn global attention, but scientists emphasize that these extreme weather events are symptoms of a deeper and more significant trend: the rapid accumulation of heat within the Earth’s climate system. According to a new assessment by an international team of climate researchers, Earth’s energy imbalance has reached record levels and has doubled over recent decades. This imbalance refers to the difference between the amount of solar energy entering the planet and the amount of energy escaping back into space. In a stable climate, these values would be roughly equal. However, increasing concentrations of greenhouse gases have disrupted this balance, causing the Earth to retain more heat than it releases.
The growing Earth’s energy imbalance is one of the clearest indicators of human-driven climate change. Since the 1970s, the planet has steadily accumulated excess heat, but recent observations show that this process is accelerating faster than many scientists expected. Researchers are continuing to investigate the reasons behind this rapid increase, but the consequences are already visible across the globe.
Approximately 90% of the excess heat generated by Earth’s energy imbalance is absorbed by the oceans. While this helps prevent even more dramatic increases in atmospheric temperatures, it creates significant impacts throughout the climate system. Ocean temperatures are rising, glaciers and ice sheets are melting, and vast areas of permafrost are beginning to thaw. These changes contribute directly to rising sea levels through both the expansion of warming seawater and the addition of meltwater from land-based ice.
Global sea levels have risen by about 23 centimeters since 1901. Although this increase may appear modest, it significantly increases the risk of coastal flooding, storm surge damage, and ecosystem disruption. The rate of sea level rise has also accelerated considerably. Between 1901 and 2018, sea levels rose at an average rate of approximately 1.7 millimeters per year. Over the past two decades, that rate has more than doubled to over 3.6 millimeters annually.
Warmer oceans are also increasing the frequency and intensity of marine heatwaves. These prolonged periods of unusually high ocean temperatures now occur about three times more often than they did in the early 1990s. In 2025, the average ocean area experienced approximately 65 marine heatwave days, compared with only three to four days annually under natural conditions. Such events can damage marine ecosystems, disrupt fisheries, and weaken coastal habitats that help protect communities from storms.
The impacts extend beyond the oceans. Warmer seas increase evaporation, adding more moisture to the atmosphere and creating conditions that support stronger heatwaves, heavier rainfall, and more severe droughts. Natural climate patterns such as El Niño can further amplify these effects. Scientists are currently monitoring the possibility of an exceptionally strong El Niño event developing in the near future. While El Niño is a naturally occurring climate phenomenon, it now operates within a much warmer world, increasing the likelihood of extreme weather impacts.
In 2025, human-caused warming reached approximately 1.37°C above pre-industrial levels, bringing the world closer to the 1.5°C threshold associated with significantly greater climate risks. Scientists stress that as long as Earth’s energy imbalance persists, global temperatures will continue to rise. Reducing greenhouse gas emissions and ultimately achieving net-zero emissions remain essential steps for restoring balance to the climate system and limiting the severity of future climate impacts.
https://theconversation.com/earths-energy-imbalance-has-doubled-heres-why-that-matters-284877