What Coral Reefs are Telling us About Climate Change

What Coral Reefs are Telling us About Climate Change


With the arrival of the El Niño Southern Oscillation (ENSO), and the announcement that global temperatures have risen by 1oC, scientists have predicted that 2015 will be the hottest year on record, according to the World Meteorological Organization.

Coral bleaching in Santelmo, Philippines (Photo from: © WWF-Philippines/Lory Tan)

Coral bleaching in Santelmo, Philippines
(Photo from: © WWF-Philippines/Lory Tan)

As home to over 600 species of coral, the Coral Triangle and its rich, life-giving reefs are particularly vulnerable to such temperature changes. Corals provide food and shelter for many forms of life, and are essential to the marine ecosystem. “They are the building blocks of reefs,” says Filipino coral expert Dr Wilfredo “Al” Licuanan of the Capturing Coral Reef & Related Ecosystem Services (CCRES) project, a professor of biology at De La Salle University in the Philippines. “Think of them as foundation or habitat-building species.”

Corals are also the most obvious indicators of any deadly environmental change, particularly as a result of increased seawater temperatures of as much as 2 degrees over the average, over a period of 2 to 4 weeks. “Coral bleaching is one of the most visual indicators of thermal stress due to climate change,” states the website

“The plants living inside the coral animal’s body, called zooxanthellae, are expelled when the coral is stressed,” explains Dr Licuanan. Corals eliminate these algae because the extreme heat and continuous exposure to sunlight can make them toxic.

“Bleaching also occurs when the pigments inside these algae are degraded. In both cases, the coral’s tissues become transparent, and the white skeleton shows,” Dr Licuanan explains. “In some intermediate stages, the pastel colours of the secondary pigments are revealed—pigments that are important for photosynthesis at different depths, where light is modified by the water.” The corals first appear to “bloom” with bright colors, before eventually turning white and dying.

Mass bleaching occurs when entire reef systems, and not just individual corals, turn white. The National Oceanic and Atmospheric Administration’s (NOAA) Coral Reef Watch recorded such an event in 1997-1998, which killed 16% of the world’s coral reefs.

In 2010, WWF reported a mass bleaching in the Coral Triangle, where 76% of the Earth’s known coral species can be found. The destruction of reefs was seen in Batangas and Palawan in the Philippines, Tioman and Redang in Malaysia, Aceh and Bali in Indonesia, and other areas.

This year, NOAA is already predicting a third global bleaching event, which has begun in the United States and Hawaii and is expected to spread globally because of El Niño. “We’re very likely to see the bleaching that’s going on this year go on into 2016, and even be worse in 2016,” said NOAA Coral Reef Watch coordinator C. Mark Eakin in an interview with the New York Times, for the article “The Pacific Ocean becomes a caldron” by John Schwartz.

Developing island nations in the Coral Triangle are particularly vulnerable to climate change-related disasters, which impose serious constraints on food security. According to a WWF report, The Coral Triangle and Climate Change: Ecosystems, People and Societies at Risk, without action on climate change, coral reefs in the Coral Triangle will disappear by 2100, the ability of the region’s coastal environments to feed people will decline by 80%, and the livelihoods of around 100 million people will have been lost or severely impacted.

What WWF has consistently pushed for in the Coral Triangle are long-term conservation strategies than can address many environmental stressors simultaneously. The establishment and proper management of Marine Protected Areas (MPAs) can help prevent coastal and marine pollution, keep fisheries healthy, and control indiscriminate or harmful development in areas of high conservation value, resulting in the building up of an area’s climate resiliency. Through MPAs and accompanying awareness campaigns, areas affected by coral bleaching can also be protected while in the process of recovery.

WWF is using its global experience in policy and advocacy to push for on-the-ground investments in actions that enable people and natural systems to adapt to a changing climate. Reports on a new mass coral bleaching event could only emphasize the importance of the 2015 Paris Climate Conference or Conference of Parties (COP) 21, to be held from November 30 to December 11 in France, where the leading agenda is an international agreement, involving developing as well as developed countries, to reduce greenhouse gas emissions in order to keep global warming below 1.5oC. Beyond this temperature, scientists believe the earth’s communities and ecosystems will be unable to survive.

One of WWF’s expected outcomes from Paris is the “protection of the vulnerable,” specifically the protection of forests and ecosystems. WWF proposes that this be supported by an independent loss and damage mechanism to deal with any threats, and adaptation goals that can be universally applied.

(Story courtesy of WWF.)

Avatar of Coral Triangle Written by Coral Triangle

No Comments

Leave a Reply

Your email address will not be published. Required fields are marked *