Australian perspectives on global climate change and coral bleaching III: The 1998 event on the Great Barrier Reef
Terry Done1), Ray Berkelmans2) and William Skirving1)
1) Australian Institute of Marine Science, PMB 3, Townsville MC, Qld 4810, Australia
2) Great Barrier Reef Marine Park Authority, PO Box 1379, Townsville, Qld, 4810, Australia
This paper reviews the response of coral reefs in the Great Barrier Reef in the hot Austral summer of 1997-98 and compares two scenarios for what might happen to this and other reef systems during the 21st Century if global and regional climates heat up and otherwise change as humans enhance the greenhouse effect by burning fossil fuels. Aerial surveys of over 600 reefs throughout the 11 - 24 degrees of latitude of the Great Barrier Reef reported that the most seriously bleached reefs were in shallow waters within 20 km of the coast between 17 and 19 degrees S, where it led to significant mortality, mainly in faster growing corals around 5 - 30 years of age. The majority of reefs offshore - those where most tourism and diving are conducted - suffered negligible bleaching or death. Region by region projections for increased sea temperatures in the 21st Century, based on assumption of limited adaptive capacity in reefs and reef biota, suggest a very gloomy outlook for coral reefs. If predictions of annual coral bleaching on the Great Barrier Reef by 2030 are realized, and they are accompanied by widespread coral mortality, one may not be confident that the rate of southward migration and/or localised redistribution of corals will prevent a prolonged period of phase shift to algae. These are important subjects for interdisciplinary research.
