Jamie Walker, The Australian 3 Feb 10;
KEVIN Rudd's insistence that the Great Barrier Reef could be "destroyed beyond recognition" by global warming grates with new science suggesting it will again escape temperature-related coral bleaching.
The Prime Minister yesterday put the reef at the centre of political combat over climate policy, telling parliament it would be obliterated in the worst-case scenario that "temperatures went through the roof".
But for the second year running, the reef has defied predictions of its imminent demise, with researchers from the Australian Institute of Marine Science reporting that mass coral bleaching was unlikely this summer.
While the finding was welcomed by the research community and those on the Queensland coast whose livelihood depends on the reef, it will entrench scepticism about gloomy forecasts for climate change.
Going head-to-head with Tony Abbott for the first time since he became Opposition Leader, Mr Rudd said the reef would be destroyed if global temperatures increased by 4C.
"I noticed the other day, by the way, that the Leader of the Opposition said that, if the worst-case scenario put out by scientists on the Intergovernmental Panel on Climate Change were to come to pass and we were to see global temperature increases of the order of 4 degrees centigrade, it did not represent any big moral challenge for the future," Mr Rudd said. "Can I say that, if we saw temperature increases like that, as far as the Barrier Reef is concerned, frankly, it would be destroyed beyond recognition."
Mr Rudd's warning reflects the findings of the 2007 report of the IPCC that is under intensifying fire for exaggerating the threat to Himalayan glaciers and the Amazon rainforest. The IPCC predicted the reef would be subject to annual bleaching by 2030 if climate change continued unchecked, destroying much of its coral cover.
But after scouring 14 sites at the vulnerable southern end of the GBR last month, the team from Townsville-based AIMS found only a only a handful of "slightly stressed reefs".
The onset of an El Nino episode in the Pacific -- conducive to hot and still conditions that heat waters on the reef shelf in late summer to the point where corals eject photosythesising algae, whiten and die -- had triggered alarm about the potential for mass bleaching.
Those fears have been now been substantially allayed, with the AIMS scientists, including Kerryn Johns, finding no sign of endemic bleaching on Swains reefs, east of Yeppoon in central Queensland, and only a few cases where corals appeared slightly stressed in the nearby Capricorn Bunker area.
The leader of AIMS's long-term reef monitoring program, Hugh Sweatman, said the reef was "not at a threshold" to bleach widely.
"We saw literally a handful of colonies that are looking pale, mainly in the Capricorn area," he told The Australian, outlining the survey team's preliminary findings. "But you get that every year. So there is no evidence of concerted bleaching across the reef whatsoever."
The Great Barrier Reef Marine Park Authority, having last summer warned of a bleaching outbreak that did not eventuate, rates the risk of one this year as low.
Dr Sweatman said a deep monsoonal trough, reinforced by tropical cyclones Olga and Neville, had averted "doldrums" conditions associated with coral bleaching on the reef.
The team of six AIMS scientists surveyed an area about a fifth of the area of the GBR, Dr Sweatman said. He said widespread bleaching had been evident by this time of year in 2002 and also in 1998, when 42 per cent of the reef was hit. Bleaching generally happens when the temperature of the sea rises in late summer, stressing corals. Scientists fear that mass bleaching events will become more frequent due to global warming, leaving less time for the reef to recover between attacks.
