The BBCThe planet has moved a big step closer to warming by more than 1.5C, new data shows, despite world leaders promising a decade ago that they would try to avoid it.
The European Copernicus Climate Service, one of the main global data providers, said on Friday that 2024 was the first calendar year to pass the symbolic threshold, as well as the world's hottest on record.
This does not mean that the international target of 1.5C has been breached because this refers to a long-term average over decades, but it does bring us closer to it as fossil fuel emissions continue to heat the atmosphere.
Last week, UN chief Antonio Guterres described recent record temperatures as a “climate collapse”.
“We must get off 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 period – the time before humans began burning large amounts of fossil fuels – according to Copernicus data.
this broke the record set in 2023 by just over 0.1C, meaning the last 10 years are now the 10 warmest years on record.
The National Weather Service, NASA and other climate groups are due to release their own data later Friday. Everyone is expected to agree that 2024 was the warmest on record, although exact numbers vary slightly.
Last year's heat was largely due to human emissions of planet-warming gases such as carbon dioxide, which are still at record high levels.
Natural climate patterns such as El Niño — where surface waters in the eastern tropical Pacific Ocean become unusually warm — play a smaller role.
“Undoubtedly 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 talks since it was agreed in Paris in 2015, with many of the most vulnerable countries seeing 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 higher under 2C warming than under 1.5C, according to landmark 2018 UN report.
Yet the world is inching ever closer to crossing the 1.5C barrier.
“It is difficult to predict exactly when we will cross the long-term threshold of 1.5C, but now we are clearly very close,” said Miles Allen, from the Department of Physics at Oxford University and an author of the UN report.
The current trajectory is likely to see the world pass 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 like 1.49C is good, it's 1.51C is the apocalypse – every tenth of a degree matters and climate impacts get worse with more warming,” explains Zeke Hausfather, a climatologist at Berkeley Earth, a research group in USA.
Even fractions of a degree of global warming can lead to more frequent and intense extreme weather events, such as heat waves and heavy rainfall.
In 2024 the world saw high temperatures in West Africacontinuously drought in parts of South Americaintense rainfall in Central Europe and some especially strong tropical storms hit North America and South Asia.
These events were only part of them become 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 overwhelmed by 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.
It wasn't just air temperatures that set new records in 2024 global sea level also hit a new daily highwhile the total amount of moisture in the atmosphere reached record levels.
It's no surprise that the world is breaking new records: 2024. it was always expected to be hot, due to the effect of the El Niño weather pattern – which ended around April last year – in addition to human-caused warming.
But the gap of several records in recent years is less expected, with some scientists fearing it could represent an acceleration of warming.
“I think it's safe to say that both the 2023 and 2024 temperatures. surprised most climate scientists – we didn't think we'd see a year above 1.5C so early,” says Dr Hausfater.
“From 2023 we have 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 Goesling, a climate physicist at the Alfred Wegener Institute in Germany.
AFPVarious theories have been offered to explain this “extra” heat, such as an apparent reduction in low cloud cover that tends to cool the planet, and continued ocean warmth after the end of El Niño.
“The question is whether this acceleration is something permanent related to human activities, which means we will have steeper warming in the future, or is it part of natural variability,” adds Dr Goesling.
“It's very difficult to say at the moment.
Despite this uncertainty, scientists stress that humans still have control over the future climate, and sharp cuts in emissions can reduce 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 Hausfater.
“That will be far, far better than if we keep burning coal, oil and gas unabated and end up with 3C or 4C – it still really matters.”
