2024 will be the first to exceed the 1.5 °C warming limit

The planet has taken a significant step towards warming of more than 1.5°C, new data shows, despite world leaders promising a decade ago that they would try to avoid it.

The European climate service Copernicus, a leading provider of global data, said on Friday that 2024 was the first calendar year to exceed the symbolic threshold, as well as the warmest on record in the world.

This does not mean that the international 1.5°C target has been missed, because it refers to a long-term average over decades, but it brings us closer to achieving it as fossil fuel emissions continue to warm the atmosphere.

Last week, UN chief António Guterres described the recent string of temperature records as a “climate crisis”.

“We must get off this path to ruin, and we have no time to waste,” he said in his New Year’s message, calling on countries to reduce emissions of planet-warming gases by 2025.

According to Copernicus data, global average temperatures for 2024 were about 1.6°C higher than the pre-industrial period, the time before humans began burning large amounts of fossil fuels.

This breaks the record set in 2023 by just over 0.1°C, meaning the last 10 years are now the 10 warmest years on record.

The Met Office, NASA and other climate groups will release their own data later on Friday. Everyone is expected to agree that 2024 was the warmest year on record, although precise figures vary slightly.

Last year’s heat was mainly due to emissions of planet-warming gases such as carbon dioxide, which are still at record levels.

Natural weather patterns like El Niño, where the surface waters of the eastern tropical Pacific Ocean become unusually warm, played a minor role.

“By far the largest contribution affecting our climate is the concentrations of greenhouse gases in the atmosphere,” Samantha Burgess, deputy director of Copernicus, tells the BBC.

The 1.5°C figure has become a powerful symbol in international climate negotiations since it was agreed in Paris in 2015, and is seen by many of the most vulnerable countries as a matter of survival.

Climate change risks, such as intense heat waves, sea level rise and loss of wildlife, would be much greater with 2°C of warming than with 1.5°C, according to a landmark UN report from 2018.

However, the world has come closer to breaking the 1.5°C barrier.

“It is difficult to predict when exactly we will cross the 1.5°C threshold in the long term, but we are obviously already very close,” says Myles Allen, from the Department of Physics at the University of Oxford and author of the UN report.

The current trajectory would likely see the world surpass 1.5°C of long-term warming by the early 2030s. This would be politically significant, but it would not be the end of the game for climate action.

“It’s not that 1.49ºC is good and 1.51ºC is the apocalypse: every tenth of a degree matters and climate impacts get progressively worse the more warming we have,” explains Zeke Hausfather, a climate scientist at Berkeley Earth, a research group in the United States. Joined.

Even fractions of a degree of global warming can lead to more frequent and intense extreme weather conditions, such as heat waves and heavy rain.

In 2024, the world saw Scorching temperatures in West Africaprolonged drought in parts of South Americaintense rains in central Europe and some particularly strong tropical storms hitting North America and South Asia.

These events were just some of those intensified by climate change over the past year, according to the World Weather Attribution group.

Even this week, as new numbers are released, Los Angeles has been overwhelmed by destructive wildfires fueled by high winds and lack of rain.

While there are many factors contributing to this week’s events, Experts say fire conditions in California are becoming more likely. in a warming world.

It wasn’t just air temperatures that set new records in 2024. The global sea surface also hit a new daily high.while the total amount of moisture in the atmosphere reached record levels.

That the world is breaking new records is not a surprise: the year 2024 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 man-made warming.

But the margin of several records in recent years was less expected, and some scientists fear it could represent an acceleration of warming.

“I think it’s safe to say that the temperatures of 2023 and 2024 surprised most climate scientists; we didn’t think we’d see a year above 1.5°C so early,” says Dr. Hausfather.

“Since 2023 we have had about 0.2°C 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.

Several theories have been suggested to explain this “extra” heat, including an apparent reduction in low-level cloud cover that tends to cool the planet and prolonged ocean warming following the end of El Niño.

“The question is whether this acceleration is something persistent related to human activities that means we will have more pronounced warming in the future, or whether it is part of natural variability,” adds Dr. Gößling.

“At the moment it’s very difficult to say.”

Despite this uncertainty, scientists emphasize that humans still have control over the future climate and that a sharp reduction in emissions can mitigate the consequences of warming.

“Even if 1.5 degrees is outside the window, we can probably still limit warming to 1.6°C, 1.7°C or 1.8°C this century,” says Dr. Hausfather.

“That’s going to be much, much better than if we keep burning coal, oil and gas endlessly and end up at 3ºC or 4ºC; it’s still really important.”