ConservationBytes.com

Corey J. A. Bradshaw, Flinders University; Clelia Mulà, The University of Western Australia, and Giovanni Strona, University of Helsinki

Coral reefs are much more than just a pretty place to visit. They are among the world’s richest ecosystems, hosting about a third of all marine species.

These reefs also directly benefit more than a billion people, providing livelihoods and food security, as well as protection from storms and coastal erosion.

Without coral reefs, the world would be a much poorer place. So when corals die or become damaged, many people try to restore them. But the enormity of the task is growing as the climate keeps warming.

In our new research, we examined the full extent of existing coral restoration projects worldwide. We looked at what drives their success or failure, and how much it would actually cost to restore what’s already been lost. Restoring the reefs we’ve already lost around the world could cost up to A$26 trillion.

Global losses

Sadly, coral reefs are suffering all over the world. Global warming and marine heatwaves are the main culprits. But overfishing and pollution make matters worse.

When sea temperatures climb above the seasonal average for sustained periods, corals can become bleached. They lose colour as they expel their symbiotic algae when stressed, revealing the white skeleton underneath. Severe bleaching can kill coral.