This Is What Climate Change Has Done To The Great Barrier Reef

A new aerial survey of the Great Barrier Reef shows the vast extent of a “severe” bleaching event that’s caused widespread coral death over the past several weeks.

The National Coral Bleaching Taskforce study found 95 percent of individual reefs in the most pristine section of the ecosystem showed severe bleaching. The research covered 520 reefs across more than 600 miles of coastline and found just four that didn’t show signs of damage.

Coral becomes “bleached” when the usually kaleidoscopic reefs are harmed by warmer oceans or other environmental factors. The colorful algae that feed coral polyps leave the structures during times of stress, leading to the ghostly white appearance.

If the stressors go away — the ocean cools down or pollutants dissipate — the algae is able to return and coral can recover.

If the oceans don’t normalize, the bleaching can spread and entire structures can die. That’s exactly what’s happening across the Great Barrier Reef, the largest living structure on Earth.

Terry Hughes, a professor at Australia’s James Cook University and the convener of the National Coral Bleaching Taskforce, said the data reflected the worst widespread bleaching across the reef ever seen. Up to 50 percent of the damaged coral could die, he said. The last major bleaching event in 2002 only saw 18 percent of reefs severely damaged.

Hughes said the prime driver behind the bleaching is warmer temperatures caused by man-made climate change. Corals are highly sensitive to even minuscule temperature shifts, and a prolonged increase of just 1 degree Celsius above normal for a few weeks can cause bleaching.

“In each case, the bleaching mapped perfectly onto where the hottest water was occurring,” Hughes said. “There’s —> Read More

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