Bleached Staghorn coral, Australia

Coral reefs

These beautiful structures protect coastal regions and provide food and livelihoods for hundreds of millions of people

Corals are the most biodiverse parts of the ocean, but are especially susceptible to climate change owing to their sensitivity to temperature and acidification. Many coral communities around the world suffered mass ‘bleaching’ – in which the symbiotic relationship between the coral and the organisms living in its tissues is disrupted – in 1998, which many attribute to El Niño.

Sarcophyton soft corals in the waters of the western Indian Ocean, off the coast of Zanzibar.
Sarcophyton soft corals in the waters of the western Indian Ocean, off the coast of Zanzibar.

Todd Lajeunesse, Penn State University

According to the 2014 Intergovernmental Panel on Climate Change (IPCC) report, coral reefs are one of the most vulnerable marine ecosystems and more than half of the world’s reefs are now at a medium or high risk of degradation.

Tropical cyclones, coral predators, and thermal stress-related coral bleaching and mortality have hit the Great Barrier Reef hard, causing coral cover to decline by 51 per cent between 1985 and 2012.

Will coral reefs survive? There is some hope that coral will be able to adapt to higher temperatures – one study in 2010 found that corals in the Indian Ocean are partnering with a species of algae-like protozoa that is able to withstand higher temperatures.

Lead image:

Bleached staghorn coral (Acropora cervicornis), Australia.

Matt Kieffer/Flickr CC BY


About this resource

This resource was first published in ‘Health and Climate Change’ in January 2009 and reviewed and updated in September 2014.

Ecology and environment, Health, infection and disease
Health and Climate Change
Education levels:
14–16, 16–19, Continuing professional development