Can coral reefs survive climate change and a warming ocean? | Oceana
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Corals, with a diver in the background

Corals in the waters of Punta de Choros, Chile

Photo Credit: Oceana/Eduardo Sorensen

It's no secret that coral reefs are in jeopardy. Scientists predict that almost all of the world’s reefs will be threatened by 2050 if current levels of greenhouse gas emissions continue. It’s also clear that changes are already underway: Three-quarters of global reefs are now vulnerable to man-made problems.

Climate change, of course, is one of the main culprits. It makes oceans warmer and more acidic, weakening the calcium carbonate that forms a coral's skeleton. While balmier waters may seem ideal to vacationers, they can be deadly to coral reefs. Temperature fluctuations can cause corals to eject the symbiotic algae that live inside their tissues, where they provide vital nutrients and also give corals their vibrant hues. This effect, known as “coral bleaching,” explains why unhealthy corals turn a ghostly shade of white.

So in an ever-warming world, are corals – and the marine ecosystems and coastal communities they support – completely doomed? Perhaps not. A new study of more than 2,500 reefs in the Indian and Pacific oceans revealed that the majority of the reefs analyzed (54 percent) had been harmed by previous mass bleaching events, but not beyond repair. Another 17 percent had minimal bleaching between 2014-2017 and were healthy and thriving.

“The good news is that functioning coral reefs still exist, and our study shows that it is not too late to save them,” said Dr. Emily Darling, the lead author of the study and the head of the Wildlife Conservation Society’s global coral reef monitoring program.

The study, which appears in the journal “Nature Ecology and Evolution,” was supported in part by Bloomberg Philanthropies’ Vibrant Oceans Initiative, which also supports Oceana's campaigns. More than 80 marine scientists contributed to the study and suggested three strategies for managing coral populations. They are:

1. Protect functioning reefs.

2. Recover reefs that are stressed from past bleaching events.

3. Transform coastal communities that have historically been dependent on corals, but whose reefs are no longer functional.

For the “protect” and “recover” strategies to work, there needs to be global action to mitigate the effects of climate change, as well as intervention on a smaller, local scale, according to the study’s authors. As Dr. Georgina Gurney of James Cook University explains, “While coral reef sustainability depends largely on reducing carbon emissions, identifying reefs that are likely to respond – or importantly, not respond – to local management is critical to targeting development and management strategies to build the well-being of the millions of people dependent on coral reefs across the globe.”

These findings demonstrate the importance of an “all of the above” approach that attacks the coral crisis from all angles. One way of protecting corals on a country-by-country basis is by establishing Marine Protected Areas (MPAs). To date, Oceana has protected more than 4.5 million square miles of ocean – roughly the size of Canada’s and Argentina’s land cover combined – including places that contain important corals. The Benham Bank MPA that Oceana pushed through in the Philippines contains 100 percent coral cover in some places, and is one example of the preventative measures that can be taken to protect and preserve coral reefs before it’s too late.

It may seem counterintuitive, but sometimes the healthiest corals are the ones that could use our protection the most. After all, it's easier to prevent future harm than it is to deal with the consequences of neglect. That’s why Oceana, Bloomberg Philanthropies and other organizations are teaming up to protect at least 50 reefs that are less susceptible to the effects of climate change. These flourishing reefs can then be used to help repopulate other reefs in the future. For the Philippines in particular, we are working to establish one new coral-rich MPA by 2022. While this campaign is still in the early stages, we are currently collaborating with local stakeholders to find the most suitable location.

When coral reefs are properly managed and protected, a square kilometer of tropical reef can yield 15 tons of seafood per year. There are economic benefits at stake, too. According to a White House climate report from last year, the U.S. is expected to lose $140 billion by 2100 as climate change wreaks havoc on coral reef recreational activities.

But as the Indo-Pacific reef study demonstrates, it doesn’t have to end badly. Decisive global action, coupled with protective measures on a local level, can ensure that corals have a bright and vibrant future in our oceans.