SYDNEY - Australia faces a possible 300 percent increase in extreme bushfires by 2050 unless world leaders can agree to dramatically cut greenhouse gas emissions, a new report said on Thursday.

The report, commissioned by Australia's firefighters and environmental group Greenpeace, said the failure of U.N. climate talks in Copenhagen to agree on a treaty to tackle climate change had left Australia facing future catastrophic bushfire seasons.

The "Future Risk: Battling Australia's Bushfires" report comes only days before the Copenhagen Accord Jan 31. deadline for nations to announce emissions reduction targets.

"Bushfire conditions are clearly changing and there is strong evidence that global warming is making Australia's climate more bushfire-prone," said Jim Casey, secretary of the Fire Brigade Employees Union in Australia's New South Wales state.

"Bushfire seasons are getting longer and fires are becoming more frequent and intense. We have the power to reverse this trend or we can shrug our shoulders, do nothing and play Russian roulette with our lives," Casey said in releasing the report.

Bushfires are a natural phenomenon in Australia, due to the hot, dry climate.

Australia's most deadly bushfires occurred in February 2009 and were blamed on a decade long drought and extreme heatwaves. The "Black Saturday" infernos killed 173 people and destroyed thousands of homes in the southern state of Victoria state.

This Australian summer has again seen extreme bushfires.

THREE SCENARIOS

The bushfire report, based on studies by Australia's peak scientific body the Commonwealth Scientific & Industrial Research Organization (CSIRO), painted three scenarios:

* Under a global climate treaty based on current promises to cut greenhouse gases, Australia's mean temperature would rise by 2 degrees Celsius above 1990 levels by 2050.

This would double the number of severe bushfire days in Australia's most populated southeast corner by 2050. Severe bushfire days would occur once every six months in Sydney.

* Without a legally binding climate treaty the upper forecast temperature rise of 6.4 degrees Celsius globally, by the end of the century, would see Australia experience a 2.8 degree Celsius rise above 1990 levels by 2050.

This is the worst case scenario for Australia which could see up to a 300 percent rise in extreme bushfire days by 2050.

* Under a global treaty with dramatic greenhouse gas cuts, which could see Australia halve its greenhouse emissions by 2050, extreme bushfire danger days would rise by only 8-17 percent.

"Future bushfire danger in Australia will depend heavily on how fast and by how much we act to tackle global warming," said the report.

"The best chance of avoiding a high global warming scenario is through a fair, ambitious and legally binding international treaty to cut emissions," it said.

The firefighters and Greenpeace called on the Australian government to dramatically increase its greenhouse emissions target cuts, but Climate Change Minister Penny Wong on Wednesday announced Australia would stick to its 5 to 25 percent emissions cut range under the non-binding "Copenhagen Accord".

Wong said any decision to opt for a 15 or 25 percent target depended in part on strong steps by India and China to reduce the growth of their greenhouse gas emissions.

"This report shows that unless governments ramp up their targets for cutting greenhouse emissions, we'll be facing more frequent bushfire tragedies on an even greater scale," said Casey.

(Editing by Alex Richardson)

© Thomson Reuters 2009 All rights reserved