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Earth’s energy imbalance has reached a 65-year high, signalling accelerating global warming
WMO says excess heat is rapidly accumulating, with oceans absorbing over 90% of it
Carbon dioxide levels hit a 2-million-year high in 2024, with methane and nitrous oxide also at record levels
Rising emissions are driving extreme weather and threatening progress on key global development goals
Scientists warn impacts will continue even if emissions fall, due to heat already stored in the climate system
Earth’s energy imbalance has reached its highest level in at least 65 years, underscoring the accelerating pace of global warming, according to a new report by the World Meteorological Organization (WMO).
The imbalance — the difference between the energy the planet receives from the Sun and the energy it radiates back into space — is now emerging as a critical climate indicator. The WMO has begun tracking it alongside established measures such as atmospheric carbon dioxide levels, global mean temperature, ocean heat content, sea level rise and ocean acidity.
Earth typically maintains an energy balance, receiving as much energy from the sun as it radiates back into space. This equilibrium is now disrupted, according to the WMO report State of the Climate 2025, released on March 23, 2026.
“Under a balanced system, incoming energy from the Sun is about the same as the amount of outgoing energy, but this is not the case at present,” said John Kennedy, scientific officer at the WMO. “There’s less outgoing energy due to the increased concentrations of greenhouse gases. More energy coming in than going out means that energy is accumulating in the Earth’s system.”
The report shows that the rate at which heat is accumulating has accelerated sharply between 2001 and 2025, driven by human-caused emissions.
Around 91 per cent of this excess energy has been absorbed by the oceans, with 5 per cent warming the land, 3 per cent melting ice, and just 1 per cent heating the atmosphere. “The largest fraction of that absorbed energy is going to the oceans,” Kennedy said.
Ocean temperatures have risen every year for the past nine years, each year setting a new record. Scientists have tracked ocean heat since the 1960s, but the rate of warming between 2005 and 2025 is more than double that observed between 1960 and 2005.
Even if emissions are reduced, the oceans are expected to continue warming for decades because of the heat already stored in the Earth’s system.
About 3 per cent of the excess energy is contributing to the warming and melting of ice, the report says. Ice sheets in Antarctica and Greenland are losing mass, while Arctic sea ice in 2025 was among the lowest levels ever recorded. This, combined with ocean warming, is accelerating sea level rise.
By the end of 2025, global sea levels were around 11 centimetres higher than in 1993, when satellite measurements began.
The rate of rise is also increasing. Between 1993 and 2011, sea levels rose by about 2.65 millimetres (mm) per year. From 2012 to 2025, this nearly doubled to around 4.75 mm per year.
Rising seas pose cascading risks, including coastal flooding, saltwater intrusion into groundwater, damage to infrastructure and the loss of ecosystems, with knock-on effects for livelihoods, food and water security, and health.
The growing energy imbalance is primarily driven by rising concentrations of greenhouse gases.
In 2024, carbon dioxide levels reached their highest in at least two million years, with the largest annual increase since modern measurements began in 1957. Methane and nitrous oxide concentrations are now at levels not seen for at least 800,000 years.
These changes are increasingly threatening progress towards several United Nations-mandated Sustainable Development Goals (SDG), including SDG 3 (good health and well-being), SDG 2 (zero hunger), SDG 11 (sustainable cities and communities), SDG 14 (life below water) and SDG 15 (life on land).
The oceans are not only warming but also becoming more acidic. Between 2015 and 2024, they absorbed about 29 per cent of human-generated carbon dioxide emissions, lowering their pH levels.
Over the past four decades, ocean surface pH has steadily declined. According to the Intergovernmental Panel on Climate Change, current levels are the lowest in at least 26,000 years. Acidification is not uniform. The most significant changes are being observed in the Indian Ocean, Southern Ocean, parts of the Pacific and sections of the Atlantic.
This shift is harming marine ecosystems and affecting fisheries and shellfish production, with implications for food security.
The WMO says the past eleven years, from 2015 to 2025, have been the warmest on record. In 2025, global temperatures were among the second or third highest ever recorded, despite the cooling influence of La Niña conditions.
Overall, global temperatures were about 1.43°C above pre-industrial levels (1850-1900). The year 2024 remains the warmest on record at around 1.55°C above that baseline.
UN Secretary-General António Guterres has described the findings in stark terms. “The State of the Global Climate is in a state of emergency. Planet Earth is being pushed beyond its limits. Every key climate indicator is flashing red,” he said.
“Humanity has just endured the eleven hottest years on record. When history repeats itself eleven times, it is no longer a coincidence. It is a call to act.”
The report also highlights growing risks from heat stress. More than one-third of the world’s workforce (around 1.2 billion people) are exposed to extreme heat at some point each year, particularly those in agriculture and construction.
This not only affects health but also reduces productivity and incomes.
Despite this, by 2023 only about half of countries had heat warning systems tailored for the health sector, and even fewer had fully integrated climate data into health decision-making.
The WMO says there is an urgent need to better link meteorological and health information systems, enabling authorities to move from reactive responses to proactive prevention — and ultimately save lives.