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Global Coral Bleaching

The 3rd Global Coral Bleaching Event – 2014/2017

This is by far the longest and most widespread event in recorded history

In 1998, a huge underwater heatwave killed 16% of the corals on reefs around the world. Triggered by the El Niño of that year, it was declared the first major global coral bleaching event. The second global bleaching event that struck was triggered by the El Niño of 2010. The US National Oceanic & Atmospheric Administration (NOAA) announced the third global bleaching event in October 2015 and it has already become the longest event recorded, impacting some reefs in consecutive years.

The new phenomenon of global coral bleaching events is caused by ocean warming (93% of climate change heat is absorbed by the ocean). Corals are unable to cope with today’s prolonged peaks in temperatures – they simply haven’t been able to adapt to the higher base temperatures of the ocean. Although reefs represent less than 0.1 percent of the world’s ocean floor, they help support approximately 25 percent of all marine species. As a result, the livelihoods of 500 million people and income worth over $30 billion are at stake.

The two previous events caught us relatively unprepared. The world simply didn’t have the technology, understanding or teams in place to reveal and record them properly. This year is different – sponsored by an insurance company interested in the risk resulting from ocean warming, the XL Catlin Seaview Survey, running off predictions issued by NOAA’s Coral Reef Watch programme (which have proven to be accurate), has been able to respond quickly. A major global bleaching event is considered one of the most visual indicators of climate change. Working together with science partners around the world, these free resources have been developed to help you research and communicate this important issue, and to ensure this event doesn’t stay out of sight and out of mind.

Latest imagery – Released 23 Sept 2016

Imagery from the latest XL Catlin Seaview Survey Reef Response expedition to Okinawa, Japan in September 2016, and just-released spectacular bleaching imagery from New Caledonia earlier this year. Register for new content updates – email

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Other Global Images

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Essential facts

Coral Bleaching - Essential Facts

Your questions answered – compiled by the the XL Catlin Seaview Survey scientists at The University of Queensland.



Infographic 1 © The Ocean Agency / XL Catlin Seaview Survey
Infographic 2 © The Ocean Agency / XL Catlin Seaview Survey

Additional info

Press Release: Scientists Confirm Global Coral Bleaching Event for 2015 – PDF
Press Release: El Niño prolongs longest global coral bleaching event – PDF
Press Release: Dramatic new pictures of coral bleaching on the Great Barrier Reef – PDF
Press Release: Australia’s Coral Reefs Under Threat from Climate Change – PDF
Press Release: U.S. coral reefs facing warming waters, increased bleaching – PDF

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