Experts warn that some marine species are at risk of ‘mass mortality events’ in ever-warming oceans UK waters are being hit with an “extreme” marine heatwave, the Met Office has said, as scientists warn the high ocean temperatures globally could result in “mass-mortality events” for some species. The forecasters said these elevated temperatures have developed rapidly because of last month’s heat dome, during which most of Europe sweltered in its worst ever heatwave that scientists said would hav