23 October 2000

Recent work by University of Queensland researchers shows that the Great Barrier Reef may be dead within 50 to 100 years, having a devastating impact on marine life and even coastal communities.

These findings will be presented to the 9th International Coral Reef Symposium in Bali, Indonesia on October 27 by Professor Ove Hoegh-Guldberg, Director of UQ’s Centre for Marine Studies.

Professor Hoegh-Guldberg first issued a dire warning about the future of the Great Barrier Reef in October 1999, and he says data collected since then has confirmed his earlier finding.

He predicts that the increasing temperature of the oceans will lead to more common episodes of coral bleaching and mortality and, ultimately, the death of the Reef as we know it today.

"The reef-building corals that make the Reef possible are likely to become very rare indeed if warming continues unabated. Corals do not survive the tropical sea temperatures predicted by 99% of all global climate experts." said Professor Hoegh-Guldberg.

Using results of climate modeling by various international research organisations and knowledge of the maximum temperatures that coral can withstand, the predictions point to some reefs suffering major damage in as few as 20 years from now with most coral reefs unable to survive the century.

The data has been circulated widely throughout the scientific community and most scientists agree with the conclusions.

"As much as I would love to be proven wrong, it is very hard to argue around it," said Professor Hoegh-Guldberg. "We now have more evidence that corals cannot fully recover from bleaching episodes such as the major event in 1998. Although some small areas of coral can bounce back, the overall damage is irreparable.

"People react very badly to this news because they don't want it to be true. However, we can't escape the consequences of environmental damage and we need to take urgent steps to ensure the survival of these crucial marine ecosystems."

Taking into account various environmental fluctuations such as the El Nino and La Nina cycles, ocean temperatures are rising 1-2C per century and the capacity for corals to adapt to the rising temperatures has already been exceeded. A recent press release from NOAA (National Oceanographic and Atmospheric Administration) in Washington has increased concern with the observation that northern tropical oceans are warming even faster now at 5oC per hundred years.

The temperature rise is primarily due to atmospheric carbon dioxide and chlorofluorocarbons (CFCs). Even pristine reefs in isolated locations far from direct human influence are suffering damage due to changes in the atmosphere.

Professor Hoegh-Guldberg stresses the importance of a global approach including commitments from governments and international organisations.

"Many researchers have pointed out significant problems in marine environments but we are still lacking a unified approach. It is no good saving dugongs and whales from hunting if the reefs and associated ecosystems that supply their food sources disappear," said Professor Hoegh-Guldberg.

He said that although many Australians think of the Great Barrier Reef as a tourist attraction, it
plays a much more significant role in the health of Australian marine ecosystems. If the Reef is compromised by climate change, serious consequences are inevitable.

Professor Hoegh-Guldberg gives the example that once the Reef no longer calcifies, it is likely to be eroded by wave action.

"Reefs like the Great Barrier Reef are a balance between calcification and erosion. Take away calcification, the process powered by corals, and whammo-the reef will begin to erode away. Ultimately, the Reef protects the coast of Queensland and if destroyed, waves will then reach the coast and destroy mangrove habitats, the breeding ground for many species of fish."

The extra impact of the oceans on the coastline would have a significant effect on the geography of coastal areas. Sand would be displaced, waterways would change and the stability of some coastal areas could be seriously jeopardised. "Add the half a metre rise in sea level expected by the end of this century and you have major problem for most coastal communities." A recent study by the Hadley Centre in the United Kingdom has estimated that 200 million people globally will be directly affected by the increased storm surge and coastal flooding associated with sea level rise.

With all the evidence of problems, Professor Hoegh-Guldberg says that the Australian Government needs to ensure that these likely impacts are seriously considered within the context of its greenhouse strategy.

"Clearly showing leadership on the greenhouse emission reduction targets that have been set internationally is a start. Given that the Great Barrier Reef (a billion dollar export earner) is one of the potential victims of climate change in the next few decades, the Australian government has an additional motivation to pursue sensible policies in this area."

"Although it will probably take more catastrophic coral bleaching episodes to convince governments to take action, it behooves us as an ocean-loving nation to take this threat seriously. Not to, is to let Australia and its future down."

Professor Ove Hoegh-Guldberg is attending the Symposium in Bali and he can be contacted either through his email (oveh@bigpond.com or oveh@uq.edu.au) or through the conference organisers - Royalindo Convention International (Phone: 62-21 314 0982, Fax: 62-21 334 470, 62-21 315 0886). Peter McCutcheon at UQ Communications is available on 07 3365 1088.