Global warming main threat to coral reefs

By Anna McLauchlin

Date: 09/12/04

Global warming is the main threat to the world's coral reefs, a new report argues. If governments do not tackle climate change, it predicts that up to 50% of the world's coral reefs, currently worth more than €20 billion every year, will be destroyed or damaged.

eef Monitoring Network, compiles the findings of 240 experts from 96 countries and is supported by UNESCO, the United Nations Environment Programme and the World Bank, among others.

According to the report, carbon dioxide emissions have had the effect of warming the sea, which causes a process known as 'coral bleaching'. The warmth causes corals to eject the algae that live within them and can kill or weaken them.

Increasing acidity owing to the higher concentration of carbon dioxide in the water slows calcification - the building of coral skeletons. According to the report, calcification will reduce by up to 40% if CO2 emissions double by 2050, which is expected if no global action is taken.

In 1998 over 16% of the world's reefs were destroyed by a freak disruption of the ocean-atmosphere system in the tropical Pacific known as El Niño and the report warns that this type of ecological disaster could become increasingly frequent.

"Increasing sea surface temperatures and CO2 concentrations provide clear evidence of global climate change in the tropics and current predictions are that the extreme events of 1998 will become more common in the next 50 years," reads the report.

Around 30 million of the world's poorest people depend entirely on coral reefs for food, and nearly 500m people depend on them for their livelihoods. Many small islands have few resources other than coral reefs and some are entirely made up of reefs. For these countries, ecotourism, the fastest growing major industry in the world, is the best chance to develop sustainable economies.

The reefs most at risk of being degraded are in east Africa, east Asia and throughout the Caribbean. Scientists estimate that the Caribbean will suffer yearly economic losses of up to €650m by 2015 if its reefs are not better protected.

The 'Status of Coral Reefs of the World' 2004 report from the Global Coral Reef Monitoring Network brings together experts' findings on the devastating influence of global warming on the world's coral reefs.

GCRMN: Infocenter: Publications: The Status of Coral Reefs of the World 2004 report http://www.aims.gov.au/pages/research/coral-bleaching/scr2004/

---