The frequency of ocean heat waves has surged more than 50 percent since the early 20th century in a threat to fish, corals and other marine life stoked by global warming, an international study showed on Monday.
Abrupt local spikes in temperatures, far less researched than heat waves on land, add to pressures on marine life such as over-fishing and plastic pollution, they wrote in the journal Nature Climate Change.
Around the world's oceans, the number of days of marine heat waves per year rose 54 percent in the period 1987-2016 from 1925-54, according to the scientists in Britain, Australia, Canada, New Zealand, Japan, Spain and the United States.