NEW modelling suggests climate change would knock five per cent off Australia’s economic output by 2100 if nothing is done to reduce greenhouse gases.
Early findings of the modelling being produced jointly by CSIRO and ABARE forecast a rise in Australia’s average temperature of 3.5 degrees celsius under the same scenario.
Climate scientists suggest temperature rises above two degrees celsius can trigger dangerous climate change.
The results were presented by Australian Bureau of Agricultural and Resource Economics chief economist Don Gunasekera at the economic research agency’s Outlook 2008 conference in Canberra.
Dr Gunasekera said the project had not yet modelled the impact of mitigation and adaptation measures, such as emissions trading schemes.
”(Firstly) the idea for us was basically to get a snapshot of what the world would look like if don’t do anything,” Dr Gunasekera told the conference.
The Global Integrated Assessment Model (GIAM) shows Australia’s economic output would fall 0.6 per cent by 2050 below the level it would be without climate change, and five per cent by 2100.
Globally, economic output would plunge 11.4 per cent by 2100.
GIAM shows the world’s concentration of greenhouse gases hitting an alarming 1,200 parts per million by 2100 without any action being taken.
The forecast is at the upper end of scenarios mapped by the Intergovernmental Panel on Climate Change (IPCC).
Most global warming strategy aims at keeping concentrations below 550ppm to avoid catastrophic developments.
The modelling showed the 1,200ppm level would increase the global average temperature by 3.4 degrees celsius above 2000 levels, and 3.5 degrees celsius in Australia.
Among major nations, only India and Russia had higher forecasts.
However, IPCC scenarios have shown temperature rises of up to 6.5 degrees under a 1,200ppm scenario.
Dr Gunasekera said in pre-2050 years the GIAM modelling had been broadly consistent with IPCC predictions on temperatures and carbon concentrations.
He said when completed, GIAM would become a useful tool for climate change policy analysis.
"Such a framework will eventually allow us to assess the costs and benefits of climate change response policies in a more effective manner,” he said.
The federal Treasury is also conducting economic modelling on climate change which is expected to be completed mid-year.