Former US vice-president Al Gore has told a Melbourne breakfast that climate change is both the most dangerous threat and the greatest opportunity that civilisation has faced.
Calling on community leaders to take a stand, Mr Gore said the projections of climate change due to rising greenhouse gas emissions had worsened through four reports by the United Nations' Intergovernmental Panel on Climate Change, yet political leaders had so far failed to act.
"We can see that we are standing in front of a fork in the road. We can take one of two different directions," he said.
"We can say to the scientists, `we don't want to listen to you. We would prefer to seek out the one or two per cent of the naysayers who stand against this growing and building consensus'.
"If we continue on that path it leads to a catastrophic outcome. It is difficult to ignore that the cyclones are getting stronger, that the fires are getting bigger, that the sea level is rising, that the refugees are beginning to move from places they have long called home."
He called on the 1000 community leaders at the breakfast for the launch of non-governmental organisation Safe Climate Australia to take a stand and push for change. He said people must respond not only to the danger, but the opportunity.
"The economists tell us the obvious response is to find opportunities to invest sensibly in the building of new infrastructure that can make our countries stronger and put people to work and give them money that they can spend to the the economy moving again," he said.
Mr Gore, who broadened concern about climate change with his 2006 film An Inconvenient Truth, said the world had everything it needed to solve the climate crisis "with the possible exception of political will".
"But in the United States and Australia we know that political will is a renewable resource," he said.
Mr Gore had earlier said he chose "to be very optimistic" about negotiations towards a new climate treaty due to be signed in Copenhagen, despite concern little progress has been made.
Mr Gore praised Safe Climate Australia for planning to develop a practical transition plan towards a low-carbon economy.
The launch included an announcement that emergency service workers would volunteer in November to run 6000 kilometres from north Queensland, down the east coast, along the Murray River and finishing to Melbourne along the Great Ocean Road to raise awareness about climate change.
A small group of climate sceptics protested outside the Docklands venue.