Heat waves put corals at risk

Oslo : High ocean temperatures are harming tropical corals almost five times more often than in the 1980s, undermining reefs’ ability to survive marine heat waves caused by man-made climate change, scientists said on Thursday.

The average time between severe “bleachings”, when heat makes the stony-bodied creatures that make up coral reefs expel colourful algae, shortened to six years in 2016 from 25-30 years in the early 1980s, the Australian-led team wrote.

Corals die if bleachings are long-lasting, wrecking reefs that are nurseries for fish, a source of food to millions of people and a destination for scuba-diving tourists.