Earth’s Energy Imbalance: Oceans Warming at Record Rate, UN Warns
The world is experiencing a record energy imbalance, with oceans absorbing more than 90% of the excess heat, according to a novel report from the World Meteorological Organization (WMO). The findings, released Monday, confirm that the period from 2015 to 2025 was the warmest eleven-year stretch ever recorded, but reveal a far more concerning trend: the rate of warming within the Earth system as a whole is significantly faster than what is felt at the surface.
While surface temperatures have risen at an alarming rate, the WMO report indicates that this represents only approximately 1% of the total heat accumulating within the Earth system. More than 90% of this excess energy is being absorbed by the oceans, resulting in the highest ocean heat content in history. The rate of ocean warming has more than doubled in the past two decades compared to the preceding 45 years.
The report attributes this imbalance to the release of heat-trapping greenhouse gases – carbon dioxide, methane, and nitrous oxide – from the burning of fossil fuels and deforestation. These gases are currently at their highest levels in at least 800,000 years, disrupting the planet’s natural energy equilibrium. Since at least 1960, a heat surplus has been building, with a marked acceleration between 2005 and 2025, increasing by roughly 11 zettajoules annually. Last year alone, the increase exceeded double that average.
The consequences of this energy imbalance are already being felt globally. While the oceans absorb the vast majority of the excess heat, the remaining energy is distributed as follows: 5% warms the land, 1% heats the atmosphere, and 3% contributes to the melting of ice at the poles and on high mountains. Even the small fraction of extra energy impacting surface temperatures is driving alarming increases, with last year ranking as either the second or third-hottest on record.
UN Secretary-General António Guterres described the situation as a “state of emergency,” stating, “Planet Earth is being pushed beyond its limits. Every key climate indicator is flashing red.” He emphasized that the consecutive record-breaking years are not coincidental, but rather “a call to act.”
The effects on the oceans are particularly concerning, with sea levels rising at an accelerating pace and sea ice reaching its third-lowest level ever recorded. The report highlights that more heat is penetrating the ocean depths, impacting circulation patterns and potentially locking in consequences for millennia. Nearer the surface, ocean heatwaves and acidification pose growing threats to coral reefs and marine life. The melting of ice further exacerbates the problem by reducing the planet’s ability to reflect solar radiation.
Looking ahead, the WMO anticipates further warming. The Pacific Ocean is transitioning out of a La Niña phase, typically associated with cooler global temperatures, and forecasts suggest a potential shift to El Niño conditions by the end of the year. Dr. John Kennedy, lead author of the WMO report, warned that “If we transition to El Niño we will notice an increase in global temperature again and potentially to record levels.”