Bleaching now affects half of the Great Barrier Reef.

Coral animals often die after bleaching. In the more equatorial parts of the Great Barrier Reef, half of them are dead.

Australian scientists are trying to breed a replacement coral that could survive higher temperatures and higher acidity.

Bravo to them, but supposing if that effort succeeds, it won't avoid disaster. 400 known species of coral that live in the Great Barrier Reef; there may be others as yet unknown to science. Losing all but one, or all but a few, would still be disaster.