Cleaning up existing coal-fired power stations will go a long way to helping Australia meet its carbon emission targets, Environment Minister Greg Hunt says.
A landmark report by the Intergovernmental Panel on Climate Change says emissions of three key greenhouse gases are at their highest in more than 800,000 years.
As the planet heads towards 4C warming over pre-industrial times by 2100, countries should aim to have 80 per cent of power generated by renewables, scientists say.
However, Mr Hunt said the best strategy was to clean up existing power stations using technology to capture emissions, as well as protecting rainforests from destruction.
The $2.55 billion being spent by the Abbott government would allow Australia to meet its target of a five per cent cut in emissions on 2000 levels by 2020, he said.
Green groups and European leaders want the G20 summit in Brisbane to set the scene for an ambitious new climate agreement in Paris in 2015.