'Consequences for hundreds or thousands of years': What the UN says after measuring a new climate indicator
The amount of heat accumulated by the Earth reached a record level in 2025, with worrying consequences for hundreds, even thousands of years, the World Meteorological Organization (WMO), a UN agency, warned on Monday, according to AFP.
“The world's climate is in a state of emergency. The Earth is being pushed beyond its limits. All key climate indicators are in the red zone,” UN Secretary-General Antonio Guterres warned at the release of the annual WMO State of the Climate report.
The energy imbalance has reached record levels
For the first time, this report includes among the key climate indicators the Earth's energy imbalance, which reflects the rate at which energy flows in and out of the planetary system.
In a stable climate, the amount of incoming solar energy is roughly equal to the amount of outgoing energy. But this balance is disturbed by increasing concentrations of greenhouse gases (CO2, methane and nitrous oxide), which lead to continuous warming of the atmosphere and ocean, as well as melting of glaciers.
The imbalance has widened since records began in 1960, and especially over the past 20 years, to reach “a new record high in 2025,” the WMO notes.
“Human activities are increasingly disrupting the natural balance, and we will have to live with these consequences for hundreds, even thousands of years,” warns the secretary general of the organization, Celeste Saulo.
2025, in the top three hottest years of the Earth
In its report, the WMO confirms that the years 2015-2025 are the 11 warmest years on record, with 2025 ranking second or third, with a temperature about 1.43 degrees above the 1850-1900 average.
The year 2024, which began under the influence of a strong El Niño episode, remains the warmest year ever observed, the organization points out.
“Extreme phenomena that have occurred around the world, especially episodes of intense heat, heavy rains and tropical cyclones, have caused disruption and damage and highlighted the vulnerability of our interconnected economies and societies,” recalls the WMO.
Warming oceans and melting glaciers are leading to a long-term rise in global mean sea level, which has accelerated since satellite measurements began in 1993. In 2025, this level was about 11 cm higher than when measurements began.
91% of the excess heat is stored in the ocean, which acts as a buffer against rising temperatures on land. But according to the WMO, “ocean heat content reached a new record in 2025, and the rate of warming doubled between 1960-2005 and 2005-2025.”
At the same time, the Antarctic and Greenland ice sheets have both lost considerable mass, and the average annual extent of Arctic sea ice in 2025 ranks first or second among the smallest areas ever measured since the beginning of the satellite era, the UN organization points out.
“Back to normal by mid-year”
John Kennedy, a WMO expert, told the media that, for now, the climate remains under the influence of a La Niña episode, associated with lower global temperatures.
“Forecasts generally indicate a return to normality by the middle of the year, with a possible appearance of the El Niño phenomenon later in the year (…) We could therefore see a further rise in temperatures in 2027,” he explained, stating that nothing is certain at this stage.
“To be honest, the situation is quite alarming (…) We are using this information to improve our forecasts and justify the need for early warning systems, to do everything we can to mitigate the consequences, but (…) these indicators are not evolving in a direction that allows us to see a favorable outcome,” WMO Deputy Secretary-General Ko Barrett told the press.
“The report published today should be accompanied by a warning: climate chaos is accelerating and any hesitation will be fatal,” insisted Antonio Guterres, for his part.
