Scientists believe 90 percent of the world’s coral reefs will succumb to rising global temperatures by 2050. Already in the past three decades, half of the richly diverse “underwater rainforests” have turned into gray, skeletal wastelands. During the El Nino of 2015-2016, there has been an unprecedented phase of bleaching.
What is killing the coral reefs?
Unexpected high water temperatures force corals to expel the protective algae that live in them and, in a way, feed them. This expulsion exposes the corals and turns the coral white, hence the term bleaching. Bleaching of coral doesn’t necessarily mean that the coral dies. However corals don’t always survive this heat stress, and death is certain if water temperatures stay high and the algae loss is prolonged for months.
Corals worldwide are also affected by pollution, over-fishing, agricultural runoff and coastal development.
Urgent efforts are ongoing by an initiative called 50 Reefs, to identify and protect the reefs that have greater chances of survival.
Where are the reefs most affected?
The Great Barrier Reef in Australia has already lost 67 percent of its coral. Reefs in Japan, Florida, and Hawaii have also been hard-hit by large-scale bleaching in recent months.
Around the Maldives in the Indian Ocean, 73 percent of coral reefs suffered from bleaching in 2016. Many areas in the central Pacific have also seen large scale bleaching.
What this means for us.
Coral reefs support one fourth of the world’s marine life and half a billion people. Corals also produce some of the oxygen we breathe. They absorb some of the force of storms and therefore protect coastlines. Together coral reefs worldwide provide billions of dollars of revenue from fishing, tourism and other industries.
A new initiative called 50 Reefs has taken on the task of identifying those reefs that have the best chance of survival.
50 Reefs also wants to raise awareness about how to protect corals that survive climate change, from other issues that threaten them.
Some signs of life stirring on the coral reefs at badly-affected Kiritimati Islands are giving some hope. And scientists are urgently experimenting with methods to keep extinction at bay.
One 50 Reefs project involves the breeding of coral in Hawaii that can adapt to rising temperatures. There is also some effort to ‘train’ corals to survive high temperatures by exposing them to heat stress in the hope that their memory will retain the stress and survive heat in the future.
Scientists are predicting another rise in ocean temperatures in the coming months. If the ocean waters don’t cool soon, corals that have suffered bleaching may not have time to recover before the next heat wave hits.