Heat wave killing off world’s coral

OSLO: Coral reefs were suffering a severe underwater heat wave this year for the third time on record, including a mysterious warm patch in the Pacific known as “The Blob”, scientists said.

The bout of record high temperatures in parts of the oceans, stoked by climate change, was expected to kill more than 12 000km of reefs, or about 5% of the global total, they said.

The experts, including the US National Oceanic and Atmospheric Administration (NOAA), said similar alerts about damage to reefs had been issued in 2010 and 1998, both extremely warm years.

Corals, tiny creatures that build stony skeletons, eject the colourful algae they live with when under stress. That bleaches the reefs – some corals can bounce back when temperatures fall, but many die from the long-lasting whitening.

Corals are nurseries for many species of fish, and provide livelihoods for millions of people.

“This is the third time we’ve had a global bleaching event,” said Mark Eakin, the co-ordinator at NOAA’s Coral Reef Watch. He said experts would have seen such wide damage to reefs even decades ago when monitoring was less thorough.

“This year has now seen coral bleaching occurring in reefs in the northern Pacific, Indian, equatorial Pacific and western Atlantic Oceans,” the alert said.

A vast mass of warm water known as “The Blob” in the north-eastern Pacific had harmed corals, including in Hawaii, it said.

“It is not well understood how much of ‘The Blob’ is related to climate change… It’s still a bit of a mystery,” Eakin said.

All three global alerts have coincided with El Nino events, which warm the eastern tropical Pacific and can disrupt weather worldwide.

On land, the “equivalent would be tropical forests turning white… and then dying”, said Richard Vevers, the executive director of XL Catlin Seaview Survey.

Eakin said countries could help by reducing stresses on reefs such as over-fishing and pollution. – Reuters