Unprecedented Marine Heatwave Raises Alarm in the North Pacific

Mon Oct 20 2025 01:24:48 GMT+0300 (Eastern European Summer Time)

This summer, the North Pacific Ocean experienced its hottest temperatures on record, raising concerns among climate scientists regarding the ongoing changes in our climate system.

A marine heatwave in the North Pacific has led to record-high sea surface temperatures, surpassing the previous year's by 0.25°C. This change, connected to climate change, has bewildered experts and shows significant impacts on global weather patterns, potentially affecting winter temperatures in the UK and beyond.

The waters of the North Pacific have had their warmest summer on record, according to a BBC analysis of a mysterious marine heatwave that has confounded climate scientists.

Sea surface temperatures between July and September were more than 0.25C above the previous high of 2022 - a significant increase across an area roughly ten times the size of the Mediterranean.

While climate change is known to make marine heatwaves more likely, scientists are struggling to explain why the North Pacific has been so hot for so long. Some researchers believe that this extra heat in the so-called 'warm blob' could contribute to a colder start to winter in the UK.

There's definitely something unusual going on in the North Pacific, commented Zeke Hausfather, a climate scientist at Berkeley Earth, a research institution in the US. The remarkable jump in temperatures across such a vast region increases concerns about the ongoing impacts of climate change.

Analysis of data from the European Copernicus climate service reveals that 2025 marks not only a rapid warming trend in the past decades, but also a notable spike compared to recent years.

Although global warming has already increased the frequency of extreme ocean heat events, the recorded temperatures in the North Pacific this year have exceeded many climate models' forecasts, indicating less than a 1% chance of occurring in any single year.

Factors contributing to this phenomenon include alterations in shipping fuel regulations that have removed sulphur dioxide, a pollutant that once had a cooling effect on atmospheric temperatures.

Impacts are not limited to the Pacific, as such conditions are likely to influence weather patterns elsewhere, boosting summer temperatures in regions like Japan and South Korea and potentially affecting winter conditions in Europe.

With these changes in marine temperatures coming at the same time as the emergence of weak La Niña conditions in the tropical Pacific, the complex interaction of these factors calls for further investigation as they may forecast colder winters ahead for the UK, albeit with multiple seasonal nuances still in play.