Scientists Confirm 2025 Was Third-Hottest Year, Trailing 2024 and 2023

Article content

Considering that the Pacific last year was in either a neutral phase or a slight tilt toward La Niña, 2025 was hot. It was only negligibly cooler than 2023, a year that saw an El Niño emerge in the summer. In fact, last year was hotter than every El Niño year before 2023. 

Article content

Lower temperatures in the tropics offset surging heat elsewhere in 2025. It was Antarctica’s hottest-ever year and the second hottest for the Arctic. February set a new record low for global sea ice, according to Copernicus. 

Article content

Total precipitation was more or less average, a fact that belies destructive flooding in many parts of the world. 

Article content

In central Texas in early July, flash flooding killed more than 135 people, including 27 children and counselors at Camp Mystic in Kerr County. Pakistan saw a near-repeat of its deadly 2022 floods during its monsoon season. More than 1,750 people perished in Sri Lanka, Indonesia, Malaysia, Vietnam and Thailand in late November, when three cyclones engulfed a region not known for them. 

Article content

Jamaicans, accustomed to hurricanes, watched Melissa approach in early October. It rapidly intensified into a Category 5 storm with the strongest wind gust ever measured — 252 miles per hour. Melissa did $8.8 billion of damage to the island, or 41% of its 2024 GDP, and claimed more than 100 lives across Jamaica, Haiti, the Dominican Republic and Cuba. 

Article content

Article content

“If such a storm just hits you face-on, there is just not much that you can do,” said Friederike Otto, co-founder of World Weather Attribution. Greenhouse gas pollution is making storms more powerful and “the change in intensity really makes a difference.” 

Article content

WWA found that climate change made the high ocean temperatures that fueled Melissa about six times more likely.

Article content

Berkeley Earth expects a 2026 global average temperature similar to last year’s, ranking perhaps 4th on record, with the current La Niña giving way to a neutral phase. It’s too early to predict the next El Niño, which — when it comes — now usually brings a new global temperature record, too.

Article content

The 2025 heat analysis comes after the US, long the world’s anchor of climate science and diplomacy, has moved to abandon that role. The administration has dismissed hundreds of scientists, removed authoritative reports and risk tools from the internet and earlier this month pledged to exit both the foundational 1992 UN climate treaty and the UN’s scientific advisory, the Intergovernmental Panel on Climate Change. 

Article content

Article content

Florian Pappenberger is director general of the European Centre for Medium-Range Weather Forecasts, which operates Copernicus. “Data and observations are essential to our efforts to confront climate change and air-quality challenges,” he said, “and these challenges don’t know any borders.” Pappenberger called the Trump administration’s stance toward climate data “concerning.”

Article content

Despite wild growth in clean-energy technologies, greenhouse gas emissions are at an all-time high and the world consequently is choosing to remain on “a very bad climate trajectory,” Swain said. 

Article content

“We still have the ability to manage this, but we’re not managing it,” he said. A “period of global cooperation, for many different types of things, seems to have at least for now ended.”

Article content

—With assistance from Laura Millan and Sophie Butcher.

Article content