Record Marine Heatwave in the Pacific Raises Climate Concerns

Sun Oct 19 2025 09:47:38 GMT+0300 (Eastern European Summer Time)

A recent marine heatwave in the North Pacific has resulted in record high sea surface temperatures, drawing attention from climate scientists who are puzzled by the persistence of this phenomenon.

The waters of the North Pacific experienced the warmest summer on record, with surface temperatures exceeding previous highs by over 0.25°C. This mysterious marine heatwave, referred to as the 'warm blob,' raises questions about the impact of climate change and natural variability. Researchers warn that this abnormal warming could lead to unpredictable weather patterns in regions far beyond the Pacific, including the UK.

Mystery Heatwave Warms Pacific Ocean to New Record

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

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

While climate change is known to increase the likelihood of marine heatwaves, scientists are struggling to explain why the north Pacific has remained so warm for an extended duration.

This additional heat, within what researchers call the 'warm blob,' could potentially lead to a colder start for winter in the UK, according to several studies.

Record high temperatures in the Pacific Ocean

'There's definitely something unusual going on in the north Pacific,' stated Zeke Hausfather, climate scientist at Berkeley Earth. Such a temperature spike across a vast region is 'quite remarkable,' he noted.

BBC analysts used data from the European Copernicus climate service to determine average temperatures from July through September across the expansive north Pacific region, known for warming trends in the past decades.

Data shows that the area is warming rapidly, with 2025 presenting even higher averages compared to recent years.

Global warming has elevated ocean heat extremes, increasing the number of days with extreme heat threefold. However, the level of warmth observed this summer exceeded predictions made by many climate models.

Natural variability in weather, such as weaker-than-normal winds this summer, has been suggested as a factor, preventing mixing with cooler waters and retaining heat at the surface.

Despite this, Hausfather emphasized that the current warmth cannot be solely attributed to natural variability, indicating additional underlying causes.

One theory posits that recent changes in shipping fuels post-2020 may be influencing the elevated temperatures. Before these changes, high-sulphur fuels contributed aerosols that reflected sunlight, mitigating temperature rises. The removal of these fuels might be unveiling the full extent of human-induced warming.

Due to high temperatures, disruptions have been felt on both sides of the Pacific. In Japan and South Korea, extreme summer heat intensified, while in California, these warm oceanic conditions have fueled supercharged thunderstorms.

Long-term forecasts indicate that the warm conditions in the North Pacific could cause alterations in the weather patterns across the Atlantic and Europe, potentially favoring harsher winters in the UK.

In conclusion, while scientists continue to investigate the permanent causes of this unprecedented heatwave, the implications for climate forecasting and global weather patterns remain significant.