Global temperatures in 2025 have reached 1.48°C above the preindustrial average, tying with 2023 for the second warmest year after 2024's 1.6°C mark. Despite the cooling influence of La Niña, record fossil fuel emissions have driven this trend. Extreme weather events this year have caused widespread devastation and loss of life.
According to the European Union’s Copernicus Climate Change Service (C3S), the mean temperature for 2025 stands at 1.48°C above preindustrial levels, placing it on par with 2023 and behind only 2024. This assessment comes amid a shift to the La Niña phase, where cooler waters in the tropical Pacific typically moderate global heat. However, fossil fuel emissions hit a new high in 2025, ensuring an upward trajectory in temperatures.
Extreme weather has defined the year. Samantha Burgess at C3S notes, “The reality is that it’s the extreme events that impact people, impact society, impact our ecosystems, and we know that those extreme events increase in their frequency and in their severity in a warmer world.” She adds, “Storms get worse because the atmosphere holds more moisture.”
Heatwaves this summer led to 16,500 additional deaths in Europe due to climate change. October brought Hurricane Melissa, the strongest ever to strike Jamaica, resulting in over 80 fatalities and $8.8 billion in damages. World Weather Attribution determined that climate change boosted the storm's rainfall by 16 percent and wind speeds by 7 percent.
November saw cyclones and storms cause landslides and flooding in Sri Lanka, Indonesia, Thailand, Malaysia, and Vietnam, claiming more than 1,600 lives. Arctic sea ice has reached its lowest extent for this period on record, with Antarctic sea ice also below average.
The three-year average temperature is poised to surpass 1.5°C above preindustrial levels for the first time. C3S anticipates a long-term breach of this Paris Agreement threshold by 2029. Burgess warns, “There’s no magical cliff at 1.5 degrees, but we know that extreme events will get worse … as we exceed 1.5 degrees,” with tipping points drawing nearer.
An October report indicates the irreversible die-off of tropical coral reefs has already occurred, while risks mount for Amazon rainforest dieback and collapses of the Greenland, West Antarctic ice sheets, and Antarctic sea ice.