A massive global coral bleaching event is currently underway

coral bleaching
© Catlin Seaview Survey

According to marine scientists, we're about to experience "a doozy of an event" in the world's oceans, thanks to a perfect storm of a warming climate and a strong El Niño.

Climate change and El Niño are driving a global bleaching event that is devastating coral reefs and killing the ocean's "canary in the coal mine," and putting the lives and livelihoods of hundreds of millions of people at risk.

Warming temperatures in the world's oceans are responsible for triggering massive 'coral bleaching' in reefs around the world, which could sound the death knell for large swaths of the marine ecosystem. When waters are too warm for corals to adapt to, they expel the algae that lives in their tissues, which causes the coral to become completely white, hence the name 'bleaching.' The bleached corals aren't necessarily dead, as some corals may survive the bleaching event, but the reefs are under more stress after it happens, and are more subject to dying without the algae, their major source of food.

According to the National Oceanic and Atmospheric Administration (NOAA), the warming conditions in the ocean are creating "widespread coral bleaching" that is currently spreading across Hawaii, and expanding into the Caribbean, prompting the organization to declare that the "third global coral bleaching event ever on record" is underway.

"The coral bleaching and disease, brought on by climate change and coupled with events like the current El Niño, are the largest and most pervasive threats to coral reefs around the world. As a result, we are losing huge areas of coral across the U.S., as well as internationally. What really has us concerned is this event has been going on for more than a year and our preliminary model projections indicate it’s likely to last well into 2016." - Mark Eakin, NOAA’s Coral Reef Watch coordinator

NOAA is predicting that the bleaching event could affect more than one third (38%) of the coral reefs around the world, and kill off more than 12,000 square kilometers of these important ecosystems, leading one marine scientists to say that his peers are "in shock and awe" about the conditions, and that it is "a doozy of an event."

For those of us who don't spend a lot of time exploring the reefs of the world's oceans, the XL Catlin Seaview Survey is helping to make this massive bleaching event a bit more tangible, thanks to some staggering images and videos of the before and after views of specific reefs.

[A before and after image of the coral bleaching in American Samoa. The first image was taken in December 2014. The second image was taken in February 2015.]

Although coral reefs represent just a small fraction of the ocean's floor (less than 0.1%), the reefs help support approximately 25% of all marine species, enable the livelihoods of some 500 million people, and are responsible for more than $30 billion in income from marine sources, so a massive die-off could have devastating effects worldwide.

“Just like in 1998 and 2010, we’re observing bleaching on a global scale, which will cause massive loss of corals. With hundreds of millions of people relying on fisheries and reefs for sustenance, the repercussions of a global coral bleaching event could be potentially disastrous,” - Professor Ove Hoegh-Guldberg, XL Catlin Seaview Survey’s chief scientist from the Global Change Institute at The University of Queensland

More information on the global coral bleaching event is available at NOAA and at the XL Catlin Seaview Survey's Global Coral Bleaching site.

Related Content on Treehugger.com