May 2025 Becomes Second-Hottest on Record
Kathmandu – Global warming continues its alarming acceleration, with May 2025 recorded as the second-warmest May globally. The average surface air temperature for the month was 15.79°C, which is 0.53°C above the 1991–2020 average and 1.40°C higher than the pre-industrial baseline. This follows an unprecedented streak of elevated global temperatures between July 2023 and April 2025, during which monthly anomalies ranged from 1.48°C to 1.78°C.
A new analysis of global temperature trends reveals that as of April 2025, the Earth had warmed by approximately 1.39°C compared to pre-industrial times. If the 30-year warming trend continues, the planet is projected to cross the critical 1.5°C threshold by May 2029. This level of warming is widely recognized as a boundary beyond which the risks of severe climate impacts rise significantly.
May 2025 data also show that while global temperatures remained high, regional variations persist. The average temperature over European land was 12.98°C, 0.29°C below the 1991–2020 average for May. Despite this monthly dip, long-term records indicate that European land areas have warmed by 2.4°C since pre-industrial times. The Arctic has warmed even more rapidly, reaching a five-year average of 3.3°C above pre-industrial levels.
The cryosphere continues to decline. Since 1976, global glaciers have lost approximately 9,200 km³ of ice, with 915 km³ lost in Europe alone. The Greenland Ice Sheet has shed 6,776 km³ of ice over the same period. Arctic sea ice extent has decreased by 2.7 million square kilometers in September months since the 1980s, marking a 36% decline and signaling growing instability in polar regions.
Oceanic indicators also point to persistent and worsening changes. The average sea surface temperature across latitudes between 60°S and 60°N in May 2025 was 20.79°C, making it the second-highest May value on record, just 0.14°C below the 2024 record. Sea levels have risen by 9.4 cm since 1999, driven by both the melting of land ice and the thermal expansion of seawater. Ocean heat content in the upper 2000 meters has risen by 0.16°C since 1993, reflecting the oceans’ critical role in absorbing excess heat.
The accumulation of greenhouse gases continues unabated. Since 2020, carbon dioxide concentrations have increased by 2.4 parts per million per year, while methane levels have risen by 12 parts per billion annually. These gases are the primary drivers of long-term warming and are central to the planetary energy imbalance.
All indicators point to a rapidly narrowing window for climate action. The approach of the 1.5°C threshold is no longer a distant concern but an imminent reality. With rising temperatures, accelerating ice loss, climbing sea levels, and accumulating greenhouse gases, the planet is entering a critical phase. Decisive global efforts are urgently needed to avoid locking in more dangerous and irreversible consequences.
