What’s Killing Coral Reefs? And How Can We Stop It?

by John Hocevar

April 4, 2016

As I write this, coral reefs across half the Southern Hemisphere are dying. To be more precise, they are being killed.

Great Barrier Reef Coral Bleaching

A side by side comparison of a healthy portion of the Great Barrier Reef (left), compared to a bleached portion (right). As climate change warms ocean temperatures, coral bleaching is reaching epidemic levels. Left photo by Gary Bell / Oceanwideimages.com. Right photo by Greenpeace / Roger Grace.

There are many threats to coral reefs, but by far the biggest is global warming. Spikes in ocean temperatures cause a phenomenon called bleaching, which is often fatal. Right now, the Great Barrier Reef is experiencing the worst bleaching in its history. More than two-thirds of the Great Barrier Reef’s living coral is at risk of dying from this episode.  

Tropical coral reefs are one of the most diverse ecosystems on Earth, home to a quarter of all marine species. Reefs generate billions of dollars in tourism, as well as food for people in 100 countries. Healthy reefs also provide protection for coastal communities from storms, serving as barriers that diminish the power of waves and storm surges.

The Great Barrier Reef is the largest in the world, so big that it is visible from outer space. If it was a state, it would be the fifth-largest in the United States, ranking between Montana and New Mexico. The ecological, cultural, and economic impacts of this man-made disaster are incalculable. The Great Barrier Reef is a World Heritage Site for good reason — but even before this bleaching disaster the reef had lost half of its living coral since being designated in 1981.

The scientist in me wants to explain how bleaching works.

Corals are small colonial animals that form skeletons as they grow. Inside their tissues, corals house symbiotic algae called zooxanthellae, which provide extra food for corals in exchange for a stable home. Warm temperatures cause the corals to expel the algae. Since these algae supply corals’ color, what is left looks white —  the calcareous skeleton becomes visible through the transparent tissues of the corals.

And then, without this vital food source, they usually die.

Which is why the ocean lover in me — the snorkeler and SCUBA diver — wants to focus on culprits and solutions.

If our reefs are being murdered, who is guilty? What can be done?

It comes back, as it so often does, to the fossil fuel industry.

When we burn oil, coal, and gas, it heats up the planet and the oceans, killing coral reefs. The fossil fuel industry has lobbied for years to make sure we have limited alternatives to these choices that disturb our climate and threaten our oceans — to make sure we only have choices that protect its profits. 

How many of us would rather have access to better public transportation so we didn’t need to rely on cars? How many of us would rather have an electric car if they were more affordable? How would you rather power your house, with wind or solar, or with a coal plant? Are you happy that we are risking our coasts with offshore drilling, or would you rather we keep fossil fuels in the ground?

We have known for a long time that relying on fossil fuels is not sustainable. The technology to shift to cleaner, greener renewables has been available for years, and is getting more efficient and affordable every day. Of course, there are things that we can all do to live in a way that minimizes our carbon footprint.

However, the changes that we need are bigger and more urgent than what we can solve that way.

We need leaders that will work with us to create a world where living sustainably is easier and more fulfilling than one where most of us drive from our coal or gas-powered homes to a coal or gas-powered office. We need leaders with vision, who are not in bed with the fossil fuel industry.

I am not willing to accept the scientists’ predictions that coral reefs may be gone in my lifetime. It is getting to the point where many feel like it may be too late, but that is because they do not believe we can change. If we work together, there is still hope.

To save the coral reefs, we need to stop burning coal, oil and gas for energy. The only way to ensure that we do is to keep these fossil fuels in the ground — send a message to President Obama today!

John Hocevar

By John Hocevar

An accomplished campaigner, explorer, and marine biologist, John has helped win several major victories for marine conservation since becoming the director of Greenpeace's oceans campaign in 2004.

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