Coral reef comparisons
The same reef in American Samoa before, during, and after a coral bleaching event. Photographed by The Ocean Agency / XL Catlin Seaview Survey / Richard Vevers.

A healthy coral reef teems with life. Fish, sea anemones, and other creatures live on and around the reef. And inside the corals live mutually beneficial algae which provide them with critical nutrients.

But when oceans get too warm, corals expel the algae and turn stark white. It’s called coral bleaching, and when it’s severe, corals die and whole ecosystems are destroyed.

Eakin: “It’s an impact that takes this beautiful system and just turns it into a graveyard.”

Mark Eakin directs the National Oceanic and Atmospheric Administration’s Coral Reef Watch. In just the last three years, more than 70 percent of the world’s coral reefs experienced extremely warm water temperatures. Eakin says this caused the most widespread bleaching event on record.

NOAA says this particular event has likely ended, but corals remain at risk. And as oceans warm, corals have less time to recover between bleaching events.

Eakin says the survival of many coral reefs around the world depends on whether or not humans reduce carbon pollution.

Eakin: “If we don’t get climate change under control, the reefs don’t have a chance.”

Reporting credit: Sarah Kennedy/ChavoBart Digital Media.

Bruce Lieberman, a long-time journalist, has covered climate change science, policy, and politics for nearly two decades. A newspaper reporter for 20 years, Bruce worked for The San Diego Union-Tribune...