Great Barrier Reef at risk without 90 per cent emissions cut, say scientists

Australia's iconic Great Barrier Reef is at risk of dying unless the world's industrialised countries cut carbon emissions by up to 90 per cent by 2050, according to scientists.

Rising sea temperatures have already resulted in the bleaching and death of coral on the reef, a group of Australia's top reef and climate scientists told parliament yesterday, adding that the world's largest reef could soon be wiped out, putting A$5.4bn (US$5bn) of economic activity at risk.

If CO2 output from industrialised nations was not reduced at least 25 per cent on 2000 levels by 2020, the reef would have only a 50 per cent chance of survival, the group said.

The reef is already growing at its slowest rate in 400 years, Terry Hughes, director of the ARC Centre of Excellence for Coral Reef Studies at Queensland’s James Cook University, told Australian MPs.

"We've seen the evidence with our own eyes. Climate change is already impacting the Great Barrier Reef," said Hughes.

The scientists outlined the risk to Australia’s tourism industry if the reef were to die. A study carried out by John Quiggin, a professor at University of Queensland's school of economics, estimated that the reef contributes A$5.4bn annually to the country's economy, with A$5.1bn coming from tourism, $153m from recreational activities and $139m from commercial fishing

A sea temperature rise of more than two degrees Celsius would be " catastrophic" for not only the reef, but also tourism in North Queensland state, which is already suffering as a result of the global recession, Quiggin told parliament.

The coalition's appeal to MPs precedes a parliament vote next week on a proposed Carbon Pollution Reduction Scheme, which would seek to curb Australia's carbon emissions through a cap-and-trade scheme.

The possible demise of the Great Barrier Reef was highlighted in a previous report by the UN Intergovernmental Panel on Climate Change.

A 2007 study by the panel predicted that the reef could be "functionally extinct" within decades, with coal bleaching – a condition that causes coral to expel sustenance-providing microalgae, possibly leading to death – likely to become more common due to sea waters becoming warmer and more acidic.