According to the European Union’s Copernicus Climate Change Service, the global average sea surface temperature reached 20.96°C in June, the highest for the month since records began.

The data, released on July 8, indicates that ocean temperatures have remained persistently elevated since early 2023, contributing to widespread marine heatwaves and intensified weather patterns globally.

In the Mediterranean, sea surface temperatures have also climbed significantly in recent weeks to reach as much as 30°C in some isolated cases.

The Spanish meteorological agency AEMET reported that temperatures in parts of the western Mediterranean now exceed 28°C, only slightly below the all-time high of 30°C recorded in July 2023. These temperatures are well above seasonal averages and raise concerns about the ecological and climatic impacts across southern Europe and North Africa.

“The Mediterranean is again experiencing marine heatwave conditions that can affect marine biodiversity and coastal economies,” said Julien Nicolas, senior climate scientist at Copernicus, in a statement on July 8. He added that unusually warm waters could also contribute to more intense summer heatwaves on land.

As bne IntelliNews reported, the heating of seas can have dramatic effects on rainfall and also power deadly storms that suck up the energy on offer from hot water. In 2023 Storm Daneil was powered by an overly hot Mediterranean and eventually killed over 11,000 people when it made landfall in Libya.

Marine heatwaves have become more frequent and severe due to climate change, with warmer seas disrupting fisheries, coral reefs, and weather systems. Scientists warn that a tipping point has already been reached that will kill off coral around the world that will dramatically affect the fish ecosystem. The Mediterranean, already one of the fastest-warming seas globally, is particularly vulnerable due to its enclosed geography and limited water exchange with the Atlantic.

The World Meteorological Organization warned in June that sustained high ocean temperatures are likely to continue into the second half of 2025, driven by ongoing greenhouse gas emissions and the after-effects of El Niño conditions.

“The persistent marine heat is a worrying signal of accelerating climate trends,” said WMO Secretary-General Celeste Saulo during a climate briefing in Geneva on July 4.