Grist / Amelia Urry

Grist / Amelia Urry

What happens to coral reefs as the ocean warms and acidifies over the coming century? Corals might seem removed from human society, but in fact that not-so-simple question leads to an even scarier follow-up: What happens to us?

Coral reefs are the richest ocean ecosystems we have — they support an estimated 25 percent of marine species. According to a 2014 report from the Food and Agriculture Organization, reefs are responsible for 17 percent of the protein we consume globally; in some coastal or island countries, like Sierra Leone or the Maldives, that number can be as high as 70 percent. Reefs serve as offshore larders, nurseries for important commercial fish (like tuna), and shelter for important ecological species (like sharks). They’re storm breaks for populated shores and bait for tourists whose dollars support entire local economies.

We know that reefs are crucial to the oceans as we know them, and to our societies as we’ve made them — and we know they are in serious trouble. According to one 2000 report, we’ve lost 27 percent of coral worldwide, and stand to lose another 32 percent in the next 30 years.

What we don’t know is if there’s anything we can do about it. Luckily, that won’t stop people from trying: Around the world, a scrappy handful of scientists, entrepreneurs, and volunteers are taking on this colossal problem, one branch at a time.From regrowing the reefs we’ve already lost to engineering new corals that may be able to survive hotter, more acidic seas, these innovators are fighting everything from nutrient pollution to overfishing to ocean warming itself. If we want to succeed, we might have to learn how to rebuild an entire ecosystem from the bottom up.

Continue reading here.