Last decade was Earth's hottest ever as CO2 levels reach an 800,000-year high, says UN report

Last year was the hottest year on record, the top 10 hottest years were all in the past decade and planet-heating carbon dioxide levels in the atmosphere are at an 800,000-year high, a report Wednesday said.

In its annual State of the Climate report, the World Meteorological Organization laid bare all the markings of an increasingly warming world with oceans at record high temperatures, sea levels rising and glaciers retreating at record speed.

“Our planet is issuing more distress signals," said António Guterres, United Nations Secretary-General. He noted that the report says the international goal of limiting warming to 1.5 degrees Celsius (2.8 Fahrenheit) since pre-industrial times is still possible. "Leaders must step up to make it happen — seizing the benefits of cheap, clean renewables for their people and economies,” he said.

The report attributed the heating to human activity — like the burning of coal, oil and gas — and in a smaller part to the naturally occurring El Nino weather phenomenon. An El Nino formed in June 2023 and dissipated a year later, adding extra heat and helping topple temperature records. In 2024, the world surpassed the 1.5 C limit for the first time — but just for a single year. Scientists measure breaching the climate goal as Earth staying above that level of warming over a longer time period.

The report said global heating is contributing to more extreme weather events that have led the highest levels of displacement for 16 years, contributed to worsening food crises and caused massive economic losses. There were at least 151 “unprecedented” extreme weather events in 2024 alone, it said.

“It is a wake-up call that we are increasing the risks to our lives, economies and to the planet,” said Celeste Saulo, WMO's Secretary-General.

The report's warnings come as the United States President Donald Trump has issued a series of rollbacks on climate commitments and cast doubt on climate science. The U.S. is the world’s second biggest polluter currently and the largest emitter of greenhouse gases historically. It's left some worried that other countries will also have less ambitious targets as a result.

“The science is indisputable. Attempts to hide climate science from the public will not stop us from feeling the dire impacts of climate change," said Brenda Ekwurzel of the U.S.-based not-for-profit, Union of Concerned Scientists.

Vanessa Nakate, a Ugandan climate activist also warned that “the longer we delay emissions cuts, the worse it will get.”

"Phasing out fossil fuels is not a choice—it is an emergency response to a crisis unfolding before our eyes,” she said. ___

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