In one more bleached Pacific reef, some corals are 'back from the brink'

Just last year, scientists conducting research dive off the coast of Kiritimati, a small island in the Pacific Ocean, found that 85 percent of the coral was dead, with another 10 percent ailing because of coral bleaching. Only 5 percent was alive and well.

When the same scientists returned to the reef last month, however, they discovered a surprising change: 6 to 7 percent of the coral is alive. Many of the fish that rely on the coral component of the ecosystem have returned as the coral rebounds, showing its resilience in the face of environmental change – and challenging the dominant narrative that coral, one of climate change's prominent victims, are in irreversible decline.

"We left with a sense of dread and came back with a renewed purpose because there are some corals that literally came back from the brink," Georgia Tech climate scientist Kim Cobb, who returned from the expedition earlier, told the Associated Press. "It's the best we could have hoped for."

Coral bleaching can happen when ocean temperatures rise. Oceans are currently experiencing the longest stretch of coral bleaching on record, which is exacerbated by climate change, but ultimately driven by the naturally occurring El Niño event that warms the Pacific and disrupts weather patterns around the globe.

Long durations of warm water can cause coral to release the symbiotic zooxanthellae algae that live inside them. Without the nutrients provided by the algae that give the coral its bright colors, the coral calcifies, turns white, and can eventually die if ocean temperatures do not stabilize and the algae does not return.

Many scientists have reported that the 2015-2016 El Niño is one of the strongest ever recorded, effectively spelling a death sentence for the Pacific reefs.

"But despite this mass mortality, there are a few small signs of hope," University of Victoria coral reef scientist Julia Baum, told the Associated Press from the island. "It's clear that coral reefs have great resilience and the coral here is trying to recover … there are coral babies that have settled on the reef sometime in the last year to year and half and these are the reef's best hope for recovery."

The reef off Kiritimati is not the only reef to have rebounded.  The Coral Castles Reef was declared dead in 2003, but is now teaming with life, and in April, an entirely new reef was discovered at the mouth of the Amazon River.

Scientists are currently studying these success stories to develop better conservation practices for those reefs that are still struggling, such as the world-famous Great Barrier Reef.

“It’s critical that we understand what happened there [around the Phoenix Islands], because that would help us understand how corals might be able to cope with climate change in the long run,” Verena Schoepf, a coral expert at the University of Western Australia, told The New York Times, referring to the Coral Castles reef recovery.

The National Oceanic and Atmospheric Administration has issued a statement, saying that saving the coral will require a shift in thought about the organism's conservation: calling for a local efforts and global initiatives to curb climate change and deal with the root problem, rather than its effects.

But we must also rethink which areas need the most protecting.

"Most conservation approaches aim to identify and protect places of high ecological integrity under minimal threat," Joshua Cinner, a researcher at the Australian Research Council Centre of Excellence for Coral Reef Studies, wrote in a paper published in the journal Nature. "Yet, with escalating social and environmental drivers of change, conservation actions are also needed where people and nature coexist, especially where human effects are already severe."

Material from the Associated Press contributed to this report.