2024 was hottest on record and first to exceed 1.5C benchmark

The EU's climate watchdog has confirmed 2024 as not just the warmest year on record globally, but also the first calendar year whose average global temperature exceeded 1.5 degrees C above its pre-industrial level. 

Scientists at the Copernicus Climate Change Service (C3S) – an EU program implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) – monitored key climate indicators, and documented unprecedented daily, monthly, and annual temperature records over 2024. 

Human-induced climate change remains the primary driver of extreme air and sea surface temperatures – but other factors, such as the El Niño Southern Oscillation, also contributed to the unusual temperatures observed during the year.

Europe's record average temperature of 10.69 degrees Celsius was 1.47 degrees above the average for the 1991-2020 reference period, and 0.28 degrees warmer than the previous record set in 2020.

Europe also recorded its warmest spring (March-May) and summer (June-August), with spring's average temperature being 1.50 degrees higher than the 1991-2020 seasonal average and summer's being 1.54 degrees above that average.

Worldwide, the year was the warmest on records which date back to 1850. The global average of 15.10 degrees was 0.72 degrees above the 1991-2020 average, and 0.12 degrees above the previous warmest year, 2023. That makes it 1.60 degrees above an estimate of the 1850-1900 temperature, designated to be the pre-industrial level.

Why the 1.5-degree mark matters

Scientists and politicians have established the 1.5-degree increase as a crucial benchmark. Under the 2016 Paris Agreement, countries agreed to substantially reduce global greenhouse gas emissions, with the aim of keeping the average temperature increase well below 2 degrees, and pledged to try to limit the increase to 1.5 degrees. These pledges were affirmed at COPs 26, 27 and 28. 

Although the World Meteorological Organization does not condemn monthly and annual breaches of the 1.5 degree mark as failures under the Paris Agreement, reasoning that long-term temperature changes should be considered on at least a 20-year timescale, the level is still viewed as significant.

Not only was 2024 the first calendar year to record more than 1.5 degrees above the pre-industrial level, but 11 of the 12 months also did so – and going back further, all months since July 2023, except for July 2024, have exceeded that level. 

Each month from January to June 2024 was warmer than the corresponding month in any previous year on record. Each month from July to December was the second warmest, after 2023, for that month – except August, which tied with August 2023 as the warmest.

On the longer-term scale, each of the past 10 years (2015–2024) was one of the 10 warmest on record. Zooming in to the daily scale, a new record high for daily global average temperature – 17.16 degrees – was reached on July 22nd. 

"We are now teetering on the edge of passing the 1.5-degree level defined in the Paris Agreement, and the average of the last two years is already above this level," said Samantha Burgess, the ECMWF's Strategic Lead for Climate. 

"These high global temperatures, coupled with record global atmospheric water vapour levels in 2024, meant unprecedented heatwaves and heavy rainfall events, causing misery for millions of people."

"All of the internationally produced global temperature datasets show that 2024 was the hottest year since records began in 1850," said Carlo Buontempo, ECMWF's Director of the Copernicus Climate Change Service. 

"Humanity is in charge of its own destiny but how we respond to the climate challenge should be based on evidence. The future is in our hands - swift and decisive action can still alter the trajectory of our future climate."