Planet Breaches 1.5°C Mark for a Full Year for the First Time
The 12-month period ending January 2025 was the hottest such span on record, a grim milestone that scientists said was a preview of the permanent climate to come.
BRUSSELS — The Copernicus Climate Change Service confirmed on 6 February 2025 that the global average temperature for the period February 2024 through January 2025 was 1.52°C above pre-industrial levels. It was the first full 12-month period in recorded history to breach the symbolic 1.5°C threshold set by the Paris Agreement.
The number matters because 1.5°C is the more ambitious goal of the 2015 climate accord, representing the level beyond which scientists warn that the risks of catastrophic climate impacts — from coral reef die-offs to the collapse of ice sheets — increase sharply. A single year above the line does not mean the Paris target is officially lost, which is defined as a long-term average over decades. But the direction of travel is unmistakable.
Every month in 2024 was the warmest or among the warmest for that month on record. The oceans, which absorb most of the excess heat trapped by greenhouse gases, were exceptionally warm. Sea surface temperatures hit record highs in the North Atlantic and parts of the Southern Ocean. Antarctic sea ice shrank to its second-lowest extent on record.
The primary driver remains the relentless accumulation of carbon dioxide and methane in the atmosphere from burning fossil fuels, industrial agriculture, and deforestation. An El Niño event that began in mid-2023 amplified the warming, but scientists at Copernicus and NASA emphasised that the dominant cause was human emissions. “Even without El Niño, we’d still be knocking on the door of 1.5,” one Copernicus scientist told reporters.
The consequences were written in headlines across 2024. Unprecedented heatwaves killed hundreds in Southeast Asia and southern Europe. Wildfires of historic intensity burned in Canada, the Amazon, and California. Floods displaced millions in Bangladesh, Pakistan, and East Africa. In the United States, Hurricanes Helene and Milton powered up over record-warm Gulf of Mexico waters and devastated large parts of the Southeast.
International climate diplomacy remains stalled. The COP29 summit in Baku in late 2024 ended with a modest new finance target for developing countries but little new ambition on emissions cuts. The re-election of Donald Trump, who has promised to pull the US out of the Paris agreement again and expand fossil fuel production, cast a pall over the proceedings.
Scientists who have spent decades modelling the climate say the 1.5°C breach is not a cliff edge — things get worse incrementally, not all at once — but a signal that the window for avoiding the worst outcomes is closing rapidly. The next landmark, they warned, is 2°C.