AILSA CHANG, HOST:
About half a billion people all around the world depend on ecosystems created by corals. Those plant-like marine animals that cover ocean floors are critical to fishing and tourism industries, and also...
ENRIC SALA: Coral reefs are the best living barrier against the destructive power of storms. So coastal communities in developing countries depend on coral reefs for their survival, their livelihoods and their food security.
CHANG: That is marine ecologist Enric Sala, who recently talked me through a deep-sea mystery and miracle. It started in 2009. He led an expedition with National Geographic to a nearly untouched corner of the South Pacific.
SALA: We wanted to get into a time machine, go back hundreds of years and actually see a coral reef like they used to be everywhere, before we started exploiting them and polluting them and killing them all over the world.
CHANG: His team wanted to see if the vibrant reefs there held any clues that could help them understand how to bring damaged reefs in other parts of the ocean back to health.
SALA: And as soon as our bubbles cleared, the bottom was covered by thriving coral. It was, like, crystal-clear, blue, turquoise water, schools of silverjacks. And then the corals, pastels, oranges and beiges - it was so beautiful. It was like an impressionist painting.
CHANG: Sala's team presented their findings to officials in the island country of Kiribati, also known as Kiribas. The Kiribati government took steps to protect the waters from fishing and other human activity, but between 2015 and 2016, record levels of ocean warming decimated half the coral reefs that Sala's team had been studying.
SALA: We thought that all hope was lost, that even the most pristine coral reefs in the world were going to be destroyed with warming that is increasingly more frequent.
CHANG: But they continued their study and, last year, set out for another dive. Sala told me he was dreading what he might find.
SALA: While my buddies were getting their scuba times in, I just jumped in the water.
(SOUNDBITE OF ARCHIVED RECORDING)
UNIDENTIFIED PERSON #1: And my two divers...
CHANG: No gear.
SALA: Just my wetsuit. And I jump in the water.
(SOUNDBITE OF WATER SPLASHING)
SALA: And I look down, and my first thought is, did anything ever happen to this reef?
CHANG: Sala and his team were ecstatic to see the reef restored. They recorded their reactions during that expedition.
(SOUNDBITE OF ARCHIVED RECORDING)
UNIDENTIFIED PERSON #2: That was incredible.
UNIDENTIFIED PERSON #3: The reef grows back here.
CHANG: Why were things able to turn around so dramatically in just a few short years?
SALA: We believe because of two reasons. One, half of the corals didn't die, so there were enough corals there to help to replenish the space that was left by the corals that died. And the second main reason is because the place is fully protected. It has an abundance of fish that is off the charts. So they were eating all the algae that would smother the dead coral skeletons and make it impossible for the corals to come back, which is what happens in other places like the Caribbean, for example...
CHANG: Oh.
SALA: ...Where the big fish are gone.
CHANG: Right. So by officially protecting the coral reef, it allow all these fish to survive, and they helped resuscitate the reef.
SALA: Exactly. It is a protection that yields resilience. But the fish have to have these huge abundances that can only be achieved in an area that is either fully protected or that has never been fished, and there are very few of these left.
CHANG: But let me ask you, is this official protection of a coral reef scalable? - because realistically, no government is going to totally stop fishing, totally stop commercial activity. I mean, there are entire economies that rely on ocean industry. So how do you suggest striking a balance between protecting parts of the ocean and protecting people's livelihoods?
SALA: Well, the funny thing is that today, there is no balance. That overfishing dominates the ocean because today, less than 3% of the ocean is fully protected from fishing. We also know that highly protected areas - the fish grow so much that many of those fish spill over the boundaries of these protected areas and help to replenish the surrounding fishing grounds. And we have seen in many places around the world that the fishermen are catching more fish around these protected areas than before. And also, the more marine life that is in the ocean, the higher the ability of the ocean to capture and store carbon pollution and help to mitigate climate change. So if countries want a future for the fisheries, they need to manage their fisheries in a more responsible way around areas that are set aside to help regenerate the rest of the ocean.
CHANG: Do you believe that the coral reef rebirth that you saw in Kiribati can actually convince other governments to protect their oceans the way you describe?
SALA: I hope that what we saw in Kiribas is going to be a beacon of hope because all the news that we get about coral reefs are bad news - bleaching, death. We're going to lose 90% of the corals even if we achieve the goals of the Paris climate agreement. So in this sea of bad news, it's great to have an island of hope. It's great to show that protection of biodiversity, protection of marine life can actually provide resilience to global warming.
CHANG: Enric Sala, founder of National Geographic's Pristine Seas project. Thank you so much for being with us.
SALA: Thank you so much for having me.
(SOUNDBITE OF MOSES SUMNEY SONG, "COLOUOUR") Transcript provided by NPR, Copyright NPR.
