Almost all shallow-water coral reefs now face extinction risk, study warns

JUST IN: Almost all shallow-water coral reefs now face extinction risk, with 96% of assessed reef systems classified as 'critically endangered' and total extinction possible by 2075, a new IUCN study warns.

Ninety six percent of the world's coral reef systems are now critically endangered.

That's the finding of a new global assessment from the IUCN, the world authority on threatened wildlife, and it comes with a date attached. Total extinction is possible by 2075. This is what we stand to lose, reefs like this one, home to a quarter of all marine species and the livelihoods of millions of coastal people.

The assessment covered 127 reef systems across more than 188 thousand square kilometres, and the famous ones are all on the list. The Great Barrier Reef, you can see it here, the Coral Triangle, the Red Sea reefs, all critically endangered. The scientists used a middle of the road climate scenario, not a worst case, and warned that this year's super El Nino adds even more heat to already stressed oceans.

When a reef collapses, the coral is replaced by algae and rubble, and the ecosystem does not come back. Fifty years is the window the science gives us.

This is Sara White, reporting for HIT.