The year 2024 could be warmer than 2023 – as some of the record ocean surface heat escapes into the atmosphere – although the “weird” behavior of the current El Niño means it’s hard to be sure, Dr Hausfather says.

The year 2023, according to a BBC report, has been confirmed as the warmest on record, driven by human-caused climate change and boosted by the natural El Niño weather event.

But there is a possibility that 2024 may even surpass the key 1.5C warming threshold across the entire calendar year for the first time, according to the UK Met Office.

Nearly 200 countries agreed in Paris in 2015 to try to limit warming to this level, to avoid the worst effects of global warming.

It refers to long-term averages over 20 or 30 years, so a year-long breach in 2024 wouldn’t mean the Paris Agreement had been broken.

But it highlights the concerning direction of travel, with each hot year bringing the world closer to passing 1.5C over the longer term.

Human activities are behind this long-term global warming trend, even though natural factors like El Niño can raise or reduce temperatures for individual years, and the temperatures experienced in 2023 go far beyond simply natural causes.

 At the time, 1998 and 2016 were record-breaking years, boosted by strong El Niño warming. But these don’t come close to the new 2023 records, marked in the darkest reds.

“2023 was an exceptional year, with climate records tumbling like dominoes,” concludes Dr Samantha Burgess, Deputy Director of the Copernicus Climate Change Service.

This latest warning comes shortly after the COP28 climate summit, where countries agreed for the first time on the need to tackle the main cause of rising temperatures – fossil fuels.

While the language of the deal was weaker than many wanted – with no obligation for countries to act – it’s hoped that it will help to build on some recent encouraging progress in areas like renewable power and electric vehicles.

This can still make a crucial difference in limiting the consequences of climate change, researchers say, even though the 1.5C target looks likely to be missed.

“Even if we end up at 1.6C instead, it will be so much better than giving up and ending up close to 3C, which is where current policies would bring us,” says Dr. Friederike Otto, a senior lecturer in climate science at Imperial College London, adding that “Every tenth of a degree matters.”