Transcript for Scientists breed 'super-corals' to recuse reefs from global warming
We witnessed the devastation of the great barrier reef of Australia, the largest living organism on Earth now in the throes of death. As scientists point to warming waters due to climate change. On the island of oahu, one researcher has discovered a glimmer of hope. Reporter: The once resplendent reefs of Australia revealed the ugly truth. Huge mortality to the cradle of much of what lives in the sea. Dive after dive revealed dead or dying reef. But 4,600 miles away, these infant corals, babies coddled in cargo nets in the gentle currents of Hawaii, could hold a key to the species' survival. We've met up with the shepherd of this little flock of sea creatu creatures in the bay off oahu. Quite a rendezvous at sea. Hi, Ruth. Nice to meet you. We can do things here that can't be done anywhere else in the world. This is the great location to experiment, because this is the future. That's the holy grail. To plant a reef that can actually persist in the conditions that we know are probably going to kill them if we don't attempt to adapt them for the future. On a scale that's large enough to make a difference? Absolutely. Reporter: We suit up for another coral dive. Something miraculous appears to be happening. You can see we have almost 100% cover of coral here. Astonishing. Really not a lot of species diversity, but many, many corals packed into the space. It's so different than what we saw in the great barrier reef. You think this is 100%. We saw maybe 40% that was alive. Unfortunately, if you got to the great barrier reef prior to the bleaching event, it would have look the like this fields of coral. Reporter: We swim to the underwater lab. The cargo nets are holding super coral, growing at a super-fast rate to be able to withstand higher temperatures and ocean acidification. How would you define the process that these coral are going through? Call it training. We're essentially putting coral through their paces. In different environments that we find throughout this bay. We want to find the best conditions that enable coral to grow well and thrive. Reporter: The thing about this coral, for decades most of oahu's sewage flowed into this bay. Six species managed to survive after the sewage was repiped offshore. Those species now make up one of the healthiest reefs in the world. Here we are. Cool! Reporter: We dry off and meet in her lab in coconut island. The lab's basically a boot camp for coral. The apparatus you see around us on this side is all selective breeding. Essentially choosing the offspring of the fittest of the fittest to combine them with the other fittest. That's right, like taking two super athletes, putting them together, and looking at what their offspring can do. Reporter: Gates acknowledges the limitations. There are coral scientists who say, listen, it's great, but it's not feasible over something that is as large as the great barrier reef. Yep. 1,300, 1,400 miles long. In many ways, they may be right. That it's not feasible over that space. But it is feasible on reefs around island nations who depend on those reefs. Do we sit down, watch, and give up? Or do we try and be prepared to fail? Reporter: As we walk through this maze of tanks harboring these super corals, Dr. Gates, like most of the scientists we spoke to, offers this warning. If things continue the way they are in terms of warming oceans, acidification, how much time does the world's coral have left? I think we need to be actively intervening in the next ten years to stabilize more than the 10% we predict could survive to 2050. Reporter: Her work isn't going to repopulate the world's coral. It's geared to create a recipe that can be used by anyone to quickly grow the strongest of the strong. From the caribbean to the great barrier reef. And just maybe give us all a sliver of hope. For "Nightline," I'm Matt Gutman reporting across the pacific.
This transcript has been automatically generated and may not be 100% accurate.