LAST MONTH WAS the second-warmest May on record on land and in the oceans, according to the European Union’s climate monitoring service.

According to the Copernicus Climate Change service, the planet’s average surface temperature dipped below the threshold of 1.5 degree Celsius above preindustrial levels, just shy of the record for May set last year.

Some parts of Europe “experienced their lowest levels of precipitation and soil moisture since at least 1979″, Copernicus noted.

For the world’s oceans, the average sea surface temperature last month was 20.79C. This was second only to May last year, with some unprecedented warmth regionally.

“Large areas in the northeast North Atlantic, which experienced a marine heatwave, had record surface temperatures for the month,” Copernicus reported. “Most of the Mediterranean Sea was much warmer than average.”

Earth’s surface was 1.4C above the preindustrial benchmark, defined as the average temperature from 1850 to 1900, before the massive use of fossil fuels caused the climate to dramatically warm.

Parts of north-western Europe saw the lowest precipitation and soil moisture levels since at least 1979. Copernicus Copernicus

“May 2025 interrupts an unprecedentedly long sequence of months above 1.5C,” noted Carlo Buontempo, director of the Copernicus Climate Change Service.

All but one of the previous 22 months crossed this critical threshold, which marks the 2015 Paris Agreement’s most ambitious target for capping global warming.

“This may offer a brief respite for the planet, but we expect the 1.5C threshold to be exceeded again in the near future due to the continued warming of the climate system,” he added.

Over the 12-month period June 2024 to May 2025, warming averaged 1.57C compared to the 1850-1900 benchmark.

However, the Paris treaty target is pegged to a 20-year average in order to account for the influence of natural variability.

The UN’s climate science advisory panel, the IPCC, has said there’s a 50% chance of breaching the 1.5C barrier in line with these criteria between 2030 and 2035.

Using this method of calculation, the world today has warmed by at least 1.3C.

Meanwhile, the UN’s World Meteorological Organisation (WMO) has said there’s a 70% chance the five-year period 2025-2029, on average, will exceed the 1.5C limit.

Scientists stress the importance of limiting global warming as soon and as much as possible because every fraction of a degree increases the risks of more deadly and destructive impacts, on land and in the sea.

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Limiting warming to 1.5C rather than 2C would significantly reduce the most catastrophic consequences, the IPCC concluded in a major report in 2018.

Ice sheet

Separately, a report from the scientific network World Weather Attribution (WWA) Greenland’s ice sheet melted 17 times faster than the past average during a May heatwave that also hit Iceland.  

“The melting rate of the Greenland ice sheet by, from a preliminary analysis, a factor of 17… means the Greenland ice sheet contribution to sea level rise is higher than it would have otherwise been without this heat wave,” one of the authors of the report, Friederike Otto, associate professor in climate science at the Imperial College London, told reporters.

“Without climate change this would have been impossible,” she said.

In Iceland, the temperature exceeded 26 degrees Celsius on 15 May, unprecedented for that time of year on the subarctic island.

In May, 94% of Iceland’s weather stations registered record temperatures, according to the country’s meteorological institute.

With reporting from © AFP 2025