Record temperatures over the past year have thrust the world into “unknown territory”, the head of the UN’s climate science body said, after the critical benchmark of 1.5C above pre-industrial levels was breached in the past year.

Jim Skea, who took over last July as chair of the Intergovernmental Panel on Climate Change, said that he was “surprised, in one sense”, that the average global temperature last year exceeded the 1.5C threshold set out in the Paris agreement.

“Last year really was much quicker than we all anticipated,” Skea told the audience at the FT Climate Capital Live conference in London. “Some of it can be explained with the start of an El Ni?o cycle, which will push temperatures up a bit. But it was still unexpected?.?.?.?there’s more science needed to actually understand why 2023 was such a distinctive year.”