High temperatures have become the new global normal, both on land and at sea, according to the latest data from the European climate observatory Copernicus. May 2025 was officially the second hottest May ever recorded on Earth—topped only by May 2024—marking yet another alarming milestone in the era of climate extremes.

While the global temperature in May slipped slightly below the symbolic 1.5°C rise compared to pre-industrial levels, it still reached an average of 15.79°C. That’s just 0.12°C shy of last year’s all-time record and significantly hotter than May 2000, now ranked third in the historical data.

Oceans Under Stress

The oceans showed worrying signs too. With a surface temperature of 20.79°C, May 2025 was the second hottest on record, just behind May 2024. “Unusually high” sea temperatures were widespread, with marine heatwaves in the northeast and northern Atlantic breaking records, and the Mediterranean also running hotter than normal.

Marine Heatwaves and Ecosystem Collapse

Marine heatwaves can cause mass die-offs, disrupt ecosystems, and prevent the ocean from mixing surface and deep waters—blocking vital nutrient flow. Covering over 70% of Earth’s surface, oceans play a key role in regulating climate. Warmer waters also intensify storms, hurricanes, and typhoons, leading to severe flooding and damage in vulnerable areas.

Europe’s Spring of Extremes

In Europe, spring brought not just heat but also extreme dryness. “Some parts of Europe recorded the lowest levels of precipitation and soil moisture since at least 1979,” Copernicus experts warned.
The UK saw multiple temperature records broken this spring, while Denmark and the Netherlands faced their worst droughts in decades, raising serious concerns over both agricultural output and water resources.

A Frightening Trajectory

Looking at the 12-month period from June 2024 to May 2025, the global temperature rise hit 1.57°C above pre-industrial averages—well above the Paris Agreement’s target threshold.

While that limit refers to long-term trends, experts say current warming is already around 1.3°C, and there’s a 50% chance we’ll temporarily exceed 1.5°C by 2035.

Scientists warn that even small increases raise the risk of extreme heat, ecosystem collapse, and other severe impacts—making urgent global action critical.