The planet has taken a big step closer to warming by more than 1.5C, new data shows, despite world leaders pledging a decade ago to try to avoid it.
The European climate service Copernicus, one of the world’s main data providers, said on Friday that 2024 was the first calendar year to pass the symbolic threshold, as well as the warmest year in the world.
This does not mean that the international target of 1.5C has been exceeded, as this refers to the long-term average over decades, but it is getting closer to it as fossil fuel emissions continue to warm the atmosphere.
Last week, UN chief António Guterres described the recent string of record temperatures as a “climate collapse”.
“We must turn from this path to ruin – and we have no time to lose,” he said in his New Year’s message, calling on countries to cut emissions of planet-warming gases by 2025.
Global average temperatures for 2024 were about 1.6C above those of the pre-industrial era – the time before humans started burning large amounts of fossil fuels – according to Copernicus data.
This breaks the record set in 2023 by just over 0.1C, meaning the last 10 years are now the 10 warmest years on record.
The Met Office, Nasa and other climate groups are due to release their own data later on Friday. Everyone is expected to agree that 2024 was the hottest on record, although the precise numbers vary slightly.
Last year’s heat was largely caused by human emissions of planet-warming gases, such as carbon dioxide, which are still at record highs.
Natural weather patterns such as El Niño – where surface waters in the eastern tropical Pacific become unusually warm – played a minor role.
“By far the biggest contributor to our climate is greenhouse gas concentrations in the atmosphere,” Samantha Burgess, deputy director of Copernicus, told the BBC.
The 1.5C figure has become a powerful symbol in international climate negotiations since it was agreed in Paris in 2015, and many of the most vulnerable countries see it as a matter of survival.
The risks of climate change, such as intense heat waves, rising sea levels and the loss of wildlife, would be much greater under 2C warming than under 1.5C warming, according to landmark 2018 UN report.
Nevertheless, the world is getting closer to breaking the 1.5C barrier.
“Exactly when we will cross the long-term threshold of 1.5C is difficult to predict, but now we are clearly very close,” says Myles Allen of the Department of Physics at the University of Oxford and author of the UN report.
The current trajectory would likely see the world exceed 1.5C of long-term warming by the early 2030s. This would be politically significant, but it would not mean the end of the game for climate action.
“It’s not that 1.49C is OK and 1.51C is the apocalypse – every tenth of a degree matters and climate impacts get worse the more warming you do,” explains Zeke Hausfather, a climatologist at Berkeley Earth, a research group in the US.
Even fractions of a degree of global warming can bring more frequent and intense extreme weather events, such as heat waves and heavy rains.
In 2024, the world saw high temperatures in West Africaprolonged drought in parts of South Americaintensively rainfall in Central Europe and some especially strong tropical storms affects North America and South Asia.
These events were just some of them became more intense due to climate change over the past year, according to the World Weather Attribution Group.
Even this week, when the new data was released, Los Angeles was awash in devastating wildfires fueled by high winds and a lack of rain.
While there are many contributing factors to this week’s events, Experts say conditions conducive to wildfires in California are becoming more likely in a warming world.
Not only air temperatures set new marks in 2024 world sea level also reached a new daily highwhile the total amount of moisture in the atmosphere reached record levels.
That the world is breaking new records is no surprise: 2024 was always expected to be hot, due to the influence of the El Niño weather pattern – which finished around April last year – on top of human-caused warming.
But the gap of several records in recent years was less than expected, and some scientists fear it could represent an acceleration of warming.
“I think it’s safe to say that the temperatures in both 2023 and 2024 surprised most climatologists – we didn’t think we’d see a year above 1.5C this early,” says Dr. Hausfather.
“Since 2023, we have had about 0.2C of additional warming that we cannot fully explain, on top of what we expected from climate change and El Niño,” agrees Helge Gößling, a climate physicist at the Alfred Wegener Institute in Germany.
Various theories have been proposed to explain this ‘extra’ heat, such as the apparent decrease in low-level cloud cover that tends to cool the planet and the prolonged warming of the oceans after El Niño ends.
“The question is whether this acceleration is something permanently related to human activities, which means that we will have steeper warming in the future, or whether it is part of natural variability,” adds Dr. Gößling.
– At the moment it is very difficult to say.
Despite this uncertainty, scientists stress that humans still have control over the future climate, and sharp reductions in emissions can lessen the effects of warming.
“Even if 1.5 degrees is out the window, we can still probably limit warming to 1.6C, 1.7C or 1.8C this century,” says Dr. Hausfather.
“That will be far, far better than continuing to burn coal, oil and gas unabated and ending up at 3C or 4C – that’s still really important.”
