Some of the most intense marine heat increases on Earth have developed in seas around the UK and Ireland, the European Space Agency (Esa) says.
Water temperatures are as much as 3 to 4C above the average for this time of year in some areas, according to analysis by Esa and the Met Office.
The sea is particularly warm off the UK's east coast from Durham to Aberdeen, and off north-west Ireland.
The Met Office says the reason is partly human-caused climate change.
But other, less-understood natural and man-made factors appear to be driving temperatures up further.
The Esa data shows sea water around virtually the entire coastline of the British Isles is warmer than usual.
More about:
