May 2024 was the warmest May on record, marking the 12th consecutive month in which the global average temperature reached a record value for the corresponding month, according to new data from the EU's Copernicus Climate Change Service (C3S).

The C3S data were cited by the UN Secretary General in a call for urgent action, as two new reports detailing aspects of climate change are published.

The global average temperature for May 2024 was 0.65°C above the 1991–2020 average and1.52°C above the 1850–1900 pre-industrial average, marking the 11th consecutive month (since July 2023) for which the global average temperature reached or exceeded 1.5°C above pre-industrial levels.

Reflecting the succession of record-breaking monthly temperatures, the global average temperature for the last 12 months (June 2023 – May 2024) is the highest on record, at 0.75°C above the 1991–2020 average and 1.63°C above the 1850–1900 pre-industrial average, according to the C3S data.

Monthly global surface air temperature anomalies (°C) relative to 1850–1900 from January 1940 to May 2024, plotted as time series for all 12-month periods spanning June to May of the following year. The last 12 months (June 2023 – May 2024) are shown with a thick red line while all other years with thin lines shaded according to the decade, from blue (1940s) to brick red (2020s). Data source: ERA5. Credit: C3S/ECMWF.

“It is shocking but not surprising that we have reached this 12-month streak. While this sequence of record-breaking months will eventually be interrupted, the overall signature of climate change remains and there is no sign in sight of a change in such a trend,” said C3S Director Carlo Buontempo.

A stark warning

The C3S data are in line with the latest Global Annual to Decadal Climate Update from the World Meteorological Organization (WMO), which issues a stark warning that we are getting ever closer to the thresholds set in the Paris Agreement on climate change. According to the report, the global mean near-surface temperature for each year between 2024 and 2028 is predicted to be between 1.1°C and 1.9°C higher than the 1850-1900 baseline.

The report, which was released to coincide with a call from United Nations Secretary-General António Guterres for more ambitious climate action, states that there is an 80% likelihood of at least one year between 2024 and 2028 temporarily exceeding 1.5°C, and a 47% likelihood that the global temperature averaged over the entire 2024-2028 five-year period will exceed 1.5°C above the pre-industrial era.

“For the past year, every turn of the calendar has turned up the heat. Our planet is trying to tell us something. But we don't seem to be listening. We’re shattering global temperature records and reaping the whirlwind. It’s climate crunch time. Now is the time to mobilise, act and deliver,” Mr Guterres said.

Human-induced warming at all-time high

Some of the staff at C3S have also contributed to the Indicators of Global Climate Change report, which notes that global warming caused by humans is currently advancing at 0.26°C per decade – the highest rate since records began.

Now in its second edition, the annual report,notes that human-induced warming has risen to 1.19°C over the past decade (2014-2023), up from 1.14°C in last year’s report.

The report also notes that the remaining carbon budget, referring to how much carbon dioxide can be emitted before committing us to 1.5 °C of global warming, is only around 200 gigatonnes (billion tonnes), which is around five years' worth of emissions at the current rate.

“We are living in unprecedented times, but we also have unprecedented skill in monitoring the climate and this can help inform our actions. This string of hottest months will be remembered as comparatively cold but if we manage to stabilize the concentrations of GHGs in the atmosphere in the very near future we might be able to return to these “cold” temperatures by the end of the century,” Buontempo said.

C3S is implemented by the European Centre for Medium-Range Weather Forecasts with funding from the European Commission.