Great Barrier Reef scientist: “And then we wept.”

Professor Hughes recalls his reaction to finding that 93 percent of the Great Barrier Reef’s coral is bleached: “And then we wept.”

Katie Hammer

Professor Hughes recalls his reaction to finding that 93 percent of the Great Barrier Reef’s coral is bleached: “And then we wept.”1

Global warming is not just affecting glaciers and polar bears near the poles, the effects radiate across the globe. Right now our attention is drawn to Australia, where global warming is taking a devastating hit on the country’s iconic World Heritage Site, the Great Barrier Reef.2

Although large, the Great Barrier reef is susceptible to even the slightest change the environment. We are witnessing what is being called the worst global bleaching event in recorded history due to the combination of global warming and El Nino. These conditions can cause irreparable damage to the species found there, particularly the bleaching of coral.

What is Coral Bleaching?

Coral rely on algae for survival. But when they are under stressful conditions, they expel the symbiotic algae, causing them to turn white — or become “bleached”.  Although bleaching and mortality are not synonymous, extended periods of stress make coral much more likely to die.2,3

What role does global warming play?

Global warming plays a leading role in creating stressful conditions for coral. How so? Corals like cooler waters, and as global warming raises ocean temperatures, corals are finding themselves in a ‘stressed’ state longer than they can afford. Also, the ocean is a critical tool used by the atmosphere for storing carbon. As carbon pollution is released into the environment at exceedingly high rates from the coal, gas, and oil industries, the ocean absorbs more and more carbon dioxide — causing the water to become more acidic. This damages the structure of corals, impairing their health and resiliency.2

A map of the Great Barrier Reef shows the results of aerial surveys for 911 reefs. (Tom Bridge and James Kerry/ARC Centre of Excellence for Coral Reef Studies)1

Why is the Great Barrier Reef so important?

As a World Heritage Site, the Great Barrier Reef is recognized for the complex ecosystem it houses.  It is considered to be the largest living structure on the planet and is home to 400 coral species and 1,500 species of fish. This reef system is roughly three quarters the length of California, spanning the eastern coast of Australia. Furthermore, the Great Barrier Reef plays a significant role in the Australian economy, bringing in an estimated $29.8 billion per year from tourism, fisheries, and coastal preservation.2,3

Excellence for Coral Reef Studies, notes “We found only 4 reefs out of 520 that weren’t bleached to some extent, and more than 95 percent of the reefs were in the top 2 most severe bleaching categories.”2

Naturalist Sir David Attenborough warns on the global bleaching event, “The twin perils brought by climate change, and increase in the temperature of the ocean and in its acidity threaten its very existence.”

What can you do about it?

Global warming is a result of human influence. This means that we are the cause, but can also be the solution.

Last year President Obama put the U.S. at the forefront of finalizing the first-ever, legally binding, global climate agreement in Paris. And this Friday — Earth Day — the agreement will be signed by more than 150 nations across the globe.

Join us in thanking President Obama for fighting to protect public health and the natural places affected by global warming. By taking strong action on climate and finalizing the international climate deal, we are on the road to a healthier future. Thank President Obama today!



  1. ‘And then we wept’: Scientists say 93 percent of the Great Barrier Reef now bleached, The Washington Post, April 20, 2016

  2. ‘Severe’ coral bleaching is damaging huge swaths of the Great Barrier Reef, scientists say, Washington Post, March 29, 2016.

  3. Mass coral bleaching now affecting half of Australia’s Great Barrier Reef, The Guardian, April 10, 2016. 

  4. Barrier Reef coral bleaching labeled ‘major and significant’ as Attenborough warns of grave danger, ABC News Australia.



Katie Hammer