For the first time, global warming has exceeded 1.5C across an entire year, according to the EU’s climate service.
World leaders promised in 2015 to try to limit the long-term temperature rise to 1.5C, which is seen as crucial to help avoid the most damaging impacts.
This first year-long breach doesn’t break that landmark ‘Paris agreement’, but it does bring the world closer to doing so in the long-term.
Urgent action to cut carbon emissions can still slow warming, scientists say.
“To go over [1.5C of warming] on an annual average is significant,” says Prof Liz Bentley, chief executive of the Royal Meteorological Society.
“It’s another step in the wrong direction. But we know what we’ve got to do.”
Limiting long-term warming to 1.5C above “pre-industrial” levels – before humans started burning large amounts of fossil fuels – has become a key symbol of international efforts to tackle climate change.
A landmark UN report in 2018 said that the risks from climate change – such as intense heatwaves, rising sea-levels and loss of wildlife – were much higher at 2C of warming than at 1.5C.
But temperatures have kept rising at a concerning pace, data from the EU’s Copernicus Climate Change Service from the past year shows, illustrated in the graph below. The period from February 2023 to January 2024 reached 1.52C of warming.
This year-long breach is no major surprise. January was the eighth record warm month in a row.
In fact, one science group, Berkeley Earth, says that the calendar year 2023 was more than 1.5C above pre-industrial levels. Other science bodies, such as Nasa, put the past 12 months slightly below 1.5C of warming.
These small differences are mainly due to the way global temperatures are estimated for the late 1800s, when measurements were more sparse.
But all the major datasets agree on the recent warming trajectory and that the world is in by far its warmest period since modern records began – and likely for much longer.
And the world’s sea surface is also at its highest ever recorded average temperature – yet another sign of the widespread nature of climate records. As the chart below shows, it’s particularly notable given that ocean temperatures don’t normally peak for another month or so.
