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expert reaction to data showing (a) Jan 2024 was warmest on record globally and (b) Feb 2023 – Jan 2024 was the warmest on record at 1.52°C above the 1850-1900 pre-industrial average

Scientists react to Copernicus data showing that January 2024 and the last 12 months were the warmest on record.


Prof Joeri Rogelj, Professor of Climate Science and Policy at Imperial College London, said:

“The succession of very hot years is bad news for both nature and people who are experiencing the devastating impacts of these extreme years. It also shows that the world is getting closer to exceeding the lowest temperature limit of the UN Paris Agreement.

“Irrespective of these hot years showing a very worrying trend, this new data doesn’t mean the 1.5C limit has now been breached. That limit refers to global warming without the ups and downs of single years. Unless global emissions are urgently brought down to zero, the world will soon fly past the safety limits set out in the Paris climate agreement.

“Here I explain in a bit more detail the difference between annual temperature and global warming:


Dr Matt Patterson, Postdoctoral research assistant in atmospheric physics at the University of Oxford, said:

“It is a significant milestone to see the global mean temperature for a twelve month period exceed 1.5C above pre-industrial temperatures for the first time. Warm ocean temperatures related to the El Niño event in the tropical Pacific will have contributed to the warm global temperatures, but the primary cause is increasing greenhouse gas concentrations in the atmosphere from burning of fossil fuels.

“A single year above the 1.5C threshold is not enough to breach the Paris climate agreement as the agreement concerns temperatures averaged over 20 to 30 years. However, exceeding 1.5C in one year underlines the rapidly shrinking window of time humanity has to make deep emissions cuts and avoid dangerous climate change.”


Prof Richard Betts, Head of Climate Impacts Research, Met Office Hadley Centre, said:

“This does not mean we’ve breached the Paris global warming mark of 1.5°C – that refers to long-term warming, which is currently about 1.25°C. Nevertheless, it is yet another reminder of the profound changes we’ve already made to our global climate which we now need to adapt to, whilst urgently re-doubling our efforts to limit further heating of the planet.”


Prof Sir Brian Hoskins, Chair of the Grantham Institute, Imperial College London, said:

“It’s not the case that we are all safe for a temperature rise of 1.4C and doomed at 1.6C. The first time that a 12-month average temperature rise has exceeded 1.5C, the Paris aspirational 1.5C upper bound, is not a signal that it has already been breached as it applies to an average of a decade or more. Having said that, it is a stark warning of the urgency for the action that is required to limit climate change at anything like the Paris targets.”




Declared interests

Richard Betts: I am employed by the Met Office and my research is funded by the UK government

Brian Hoskins: No conflicts to declare

For all other experts, no reply to our request for DOIs was received.

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