By Rob Taylor

CANBERRA, Aug 13 (Reuters) - A report questioning climate change and calling global warming a "natural phenomenon" on Monday led to accusations Australia's Prime Minister John Howard was a climate sceptic, possibly denting his re-election hopes.

A group of four government lawmakers -- two of them former ministers -- released the report debating the science of carbon capture and underground storage, or geosequestration, opening a climate rift in the government.

"Climate change is a natural phenomenon that has always been with us and always will be," they said in a document challenging the findings of a cross-party parliamentary report looking at carbon capture options for Australia.

"Whether human activities are disturbing the climate in dangerous ways has yet to be proven."

Howard, 11-years in power, is fighting accusations he has been slow to respond on climate change, which is shaping up as a key issue for national elections widely tipped for November.

He has announced projects to combat climate change as polls show eight in 10 Australians are concerned about global warming. International reports say the already drought-stricken country will be hard hit by rising temperatures and greater extremes in weather.

The four lawmakers -- a majority of the six government MPs on Parliament's Science Committee -- took issue with the parliamentary report recommendation calling for government funding and tenders backing major carbon storage and capture projects.

The Australian Greens said the leader of the four -- former scientist turned MP Dennis Jensen -- was a climate "dinosaur", while Howard remained a self-confessed global warming sceptic.

"His language has changed because he recognises the opinion polls show that Australians are really worried about climate change, are angry that he's done nothing," Greens Senator Christine Milne told radio, referring to Howard.

"While these are the musings of Liberal backbenchers, what they demonstrate is how climate scepticism goes to the heart of the Liberal Party and indeed the coalition," she said.

In a major report, the U.N. climate panel said in February that there was at least a 90 percent probability human activities were the main cause of global warming in the past 50 years.

Delegates who approved the U.N. report at a meeting in Paris agreed a "best estimate" that temperatures will rise by 3 Celsius (5.4 Fahrenheit) by 2100 over pre-industrial levels, the biggest change in a century for thousands of years.

Science Committee chairman Petro Georgiou, a Liberal and frequent critic of Howard's tough immigration policies, said his party colleagues were wrong to question climate change.

"I totally affirm my conclusion that the evidence is compelling and that the link between greenhouse gas emissions from human activity and higher temperatures is convincing," he said.

An ACNielsen poll published in Fairfax newspapers on Monday found support for Howard's coalition was rising, but not enough to ward off a landslide victory for the rival Labor Party.

Support for Labor was at 55 percent against 45 percent for Howard's government. A separate poll at the weekend said Howard was in danger of losing his own Sydney-based seat, which he has held since 1974.

AlertNet news is provided by