Scientists and global climate officials have billed 2024 a “record-breaking” watershed year for global temperatures and the first year that was “likely more than 1.5°C above pre-industrial levels”, issuing a stark reminder – if one was needed – that global temperatures continue to rise.

From recent deluges in the UK, life-threatening cold snaps in many US states, and a wildfire current ravaging the Hollywood hills, 2025 has already delivered a hefty reality check when it comes to the extreme weather events symptomatic of a shifting global climate.

Compounding the last 12 months of data, experts have revealed that last year recorded the highest temperature in any year since 1850, making it the eleventh year in succession in the HadCRUT data series – a global temperature dataset – to have equalled or exceeded 1°C above the pre-industrial average period (1850 – 1900).

The global average temperature for 2024 was in fact 1.53°C (+ or – 0.08°C) above the 1850-1900 global average, according to that dataset collated by the Met Office, the University of East Anglia, and the National Centre for Atmospheric Science. For context, 2023’s value of 1.46°C exceeded the previous warmest year – 2016 – by some 0.17°C, making 2024 and 2023 the warmest and second-warmest years on record.

With these latest figures, the world is edging ever-closer to breaching the Paris Agreement target of keeping long-term global average temperatures to 1.5°C. The climate figures released by the Met Office are reflective of those released by climate centres around the globe this week.

The UK’s minister for climate, Kerry McCarthy, said: “There is much more work to be done to keep 1.5°C within reach and prevent climate catastrophe. The scale of the challenge is huge, but through collective action we can deliver change at the scale and pace required.”

The Met Office has been quick to reassure that a single year exceeding 1.5°C above pre-industrial does not mean a breach of the Paris Agreement 1.5°C guard rail. 

“That would require a temperature of at least 1.5°C on average over a longer period,” said the Met Office’s Colin Morice. “However, it does show that the headroom to avoid exceeding 1.5°C, over a sustained period, is now wafer thin.”

The current global warming level (relevant to the Paris Agreement) is a measure of global warming since pre-industrial conditions without the influence of the ups and downs of year-to-year temperature variations. Most of the additional temperature rise since those pre-industrial times is associated with the rise in atmospheric greenhouse gases from human activities.

The world has not yet begun to reduce its use of fossil gas, oil, and coal. As a result, greenhouse gas emissions have not yet peaked and the global temperature continues to rise. 

Professor Rowan Sutton, director of the Met Office Hadley Centre, said: “By itself, 1.5°C does not represent a cliff edge in terms of climate impacts, but every fraction of a degree rise in global temperature increases the frequency and severity of extreme weather events, commits the world to greater rises in sea level, and increases the risk of crossing potential planet-altering tipping points, such as the breakdown of the Amazon rainforest biome or ice sheet collapse in Greenland or the Antarctic.”

It’s common for natural variability in global temperatures to occur and last a year or two. These small variations of 0.1 to 0.2°C can temporarily push the global temperature above or below its underlying warming trend, making an individual year – such as 2024 – exceed 1.5°C, even if the underlying warming has not reached that level.

A key source of this natural variability is El Niño Southern Oscillation (ENSO), a pattern of climate variability in the tropical Pacific, that drives modest year-to-year warming and cooling of the global climate. An El Niño event adds about 0.2°C to the annual global temperature and has affected the temperature values for both 2024 and 2023.

Conversely, La Niña, which brings cooler conditions, slightly suppressed temperature values in 2021 and 2022, with ENSO conditions being neutral during the last part of 2024.

Despite the modest tropical Pacific cooling, however, the surface temperature of the oceans was record-breaking in 2024.

The Met Office has suggested that 2025 is likely to be one of the three warmest years for global average temperature, falling in line just behind 2024 and 2023.

“This notable landmark further highlights the urgency of efforts to minimise future warming,” said Professor Sutton.

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