May 2025 Second-Warmest on Record: Global Warming Intensifies Climate Challenges
GENEVA, June 11, 2025 – The month of May 2025 has officially been recorded as the second-hottest May globally, with surface air temperatures averaging 15.01°C, which is 0.65°C above the 1991–2020 average and 1.53°C warmer than the pre-industrial benchmark (1850–1900), according to data released by the Copernicus Climate Change Service (C3S). This marks the 22nd out of the past 23 months where global temperatures have exceeded the critical 1.5°C threshold, intensifying concerns about accelerating climate change caused by unchecked greenhouse gas emissions.
The World Meteorological Organization (WMO) projects an 80% probability that at least one year between 2025 and 2029 will surpass 2024—which was the warmest year ever recorded at 1.55°C above pre-industrial levels. There’s a 70% probability that the global average temperature for the period 2025 to 2029 will remain above the 1.5°C threshold. Meanwhile, Arctic regions are expected to warm at an even faster rate, with winters from November to March likely to see 2.4°C above the 1991–2020 average. Changing rainfall patterns are also becoming evident, with wetter conditions in areas like the Sahel, northern Europe, Alaska, and Siberia, while drier trends continue across the Amazon Basin.
Oceanic heat levels, which absorb approximately 90% of the planet’s excess warming, reached historic highs in 2024. May 2025 sea surface temperatures (SSTs) came in at 20.93°C, the second-highest ever for May, driving a surge in extreme weather phenomena including floods, intense heatwaves, and wildfires around the world.
Although a mild La Niña emerged in late 2024, typically associated with cooler global temperatures, the continued warming trend demonstrates that human-induced climate change is now overpowering natural climate patterns. Social media users, such as @PGDynes on X, expressed alarm, suggesting that humanity has now crossed the “1.5°C Rubicon,” with climate tipping points approaching rapidly and calling for urgent global mitigation efforts.
In Europe, May temperatures were 0.88°C above the norm, with the highest anomalies observed in eastern Europe and parts of western Russia. Meanwhile, Antarctic sea ice was 10% below the long-term average, ranking as the 10th lowest May extent on record.
Atmospheric carbon dioxide concentrations hit an alarming 430.5 ppm in May 2025, an increase of 3.5 ppm over the previous year, further compounding risks to ecosystems, food security, and economic stability. With 2024 having already crossed the 1.5°C annual average for the first time and 2025 poised to join the ranks of the hottest years on record, scientists are warning of intensifying climate impacts unless global carbon emissions are drastically reduced.
As the world prepares for COP30, pressure is mounting on governments to revise their Nationally Determined Contributions (NDCs) under the Paris Agreement. However, political divisions remain, particularly as U.S. President-elect Donald Trump continues to express skepticism toward international climate action, casting uncertainty over future commitments.
