In addition to another record year added in 2024, the past decade has been the hottest record keeper for nearly 200 years, reported global weather organizations.
“It's never happened before,” said Chris Hewitt, director of the WMO's climate services department. It is only since record keeping began that all of the hottest years of the decade have fallen within the last decade.
2024 was the warmest year on record, surpassing the broader lead of 2023 than other recent years. The planet's surface was about 1.55 degrees warmer than average during the reference period, which approximated the pre-industrial era from 1850 to 1900.
The annual report from the UN agency WMO includes opinions from dozens of experts and agencies around the world, sheds even more light on the record heat of 2024 and places it in the context of climate change from the long-term warming of the planet.
The extra energy in the atmosphere and oceans has helped fuel climate-related disasters around the world. Extreme weather events such as droughts, storms and wildfires have driven hundreds of thousands of people out of their homes, the report says.
The air levels of greenhouse gases released from fossil fuel combustion continue to increase. According to the report, in 2024, there were no visible amounts of carbon dioxide concentrations at least 2 million years.
The concentrations of two other important greenhouse gases, methane and nitrous oxide, have reached invisible levels in at least 800,000 years. Homo Sapiens, or modern humans, appeared about 300,000 years ago, so our species had never experienced an atmosphere loaded with greenhouse gases that warmed the planet.
When the country signed the Paris Agreement in 2015, they agreed to limit global warming to 1.5 degrees above the pre-industrial level.
“A year beyond 1.5 degrees of warming has not shown that the Paris Agreement's long-term temperature targets are out of reach, but increasing the risks of our lives, our economy and our planets is a wake-up call.”
The new report estimates that long-term warming has surpassed pre-industrial levels by 1.25-1.41 degrees, but the margin of error for some estimates is above 1.5 degrees. The authors of the report estimate that El Niño and other factors contributed to an additional temporary warming of 0.1 or 0.2 last year.
El Niño is a natural climate pattern that tends to slightly increase the overall surface temperature of the planet. However, record warmth continued into 2025, even through El Niño's transition to La Niña, the opposite pattern.
“It was truly extraordinary to see the warmth lasting for so long,” John Kennedy, the report's science coordinator and lead author, told reporters in a call.
This warmth is especially evident in oceans where key indicators of climate change are currently accelerating.
The ocean has so far absorbed about 90% of the additional heat trapped within the Earth's atmosphere by greenhouse gases. Ocean heat content – how to measure this warmth through various depths – also reached record highs last year. The report states that in the last 20 years from 2005 to 2024, the ocean has been warmed more than twice as fast as 1960 to 2005.
Increased ocean temperatures have had devastating consequences for marine life. By April 2024, warm water corals had been bleached in every sea basin they grow.
According to the report, global average sea level rise also reached record highs in 2024. The sea's rising speed has more than doubled in recent years, compared to the 2.1 mm per year between 1993 and 2002.
The work of the World Meteorological Organization relies on international cooperation between 101 member states, including the United States.
“Looking at how the weather has progressed since the start of WMO in 1950, we can see that smartphones can make predictions,” said Omar Baddour, director of climate monitoring at WMO. “I can't believe how much collaboration there is in this.”
Data from NASA and the National Maritime and Atmospheric Administration, which recently lost hundreds of staff positions as part of a rapid, massive cut in federal officials that the Trump administration undertook earlier this year, is included in a new WMO report.
