The State of the Global Climate 2025 report, by the World Meteorological Organization (WMO), shows that the period from 2015 to 2025 was the hottest ever recorded since measurements began, in 1850. The document came out this Monday (the 23rd), World Meteorological Day.
The year 2025 is among the hottest in the series, at about 1.43 °C above pre-industrial levels (1850–1900).
"When history repeats itself eleven times"
"The state of the global climate is one of emergency. Planet Earth is being pushed beyond its limits. All the main climate indicators are on maximum alert," said the Secretary-General of the United Nations (UN), António Guterres.
"Humanity has just lived through the eleven hottest years ever recorded. When history repeats itself eleven times, it is no longer a coincidence. It is a call to action."
He added a reading that links climate and security: "In this era of war, climate stress is also exposing another truth: our dependence on fossil fuels is destabilizing both the climate and global security."
Where the heat goes
The report uses Earth's energy imbalance as an indicator — the difference between the solar energy that comes in and the energy the planet radiates back out. In a stable climate, the two are close to each other. With the rise in carbon dioxide, methane and nitrous oxide, they have come apart, and the imbalance has been growing since observations began, in 1960, above all over the past 20 years.
Where that excess ends up is uneven:
- 91% goes to the ocean, which works as a buffer against warming on land
- about 5% stays in the continental land masses
- 3% warms and melts Arctic and Antarctic ice
- 1% stays in the atmosphere
In 2025, the heat stored in the ocean down to 2,000 meters deep reached its highest level since 1960, surpassing the 2024 record.
The WMO states that the changes in the warming and in the pH of the ocean depths are irreversible on scales of centuries to millennia. The rise in mean sea level has accelerated since satellite measurements began, in 1993.
Health and work
More than a third of the global workforce — 1.2 billion people — faces heat-related risks in the workplace, above all in agriculture and construction.
The body also warns of the increase in vector-borne and waterborne diseases, and of the stress on the mental health of vulnerable populations. It argues for integrating meteorological data into health information systems, so that the response is preventive rather than reactive.
"In our day-to-day lives, our climate has been becoming more extreme," said the Secretary-General of the WMO, Celeste Saulo. "In 2025, heatwaves, wildfires, droughts, tropical cyclones, storms and floods caused thousands of deaths, affected millions of people and generated billions in economic losses."
With information from Agência Brasil. Original report by Camila Boehm, published on March 23, 2026.
