Treasury is only modelling global emissions scenarios with a very high risk of triggering runaway climate change, Australian Greens climate change spokesperson, Senator Christine Milne, discovered today in Senate Estimates hearings.
Senator Milne said, "I will be writing to Prime Minister Rudd and Professor Garnaut today, outlining the tremendous danger inherent in the scenarios Treasury is modelling, and calling on them to instruct the modelling team to include safe climate scenarios in their work if it is to be worth anything as a guide to public policy.
"After the Howard Government's 12 year refusal to request any Treasury modelling of climate change impacts and emissions reductions, it is deeply troubling to find that the modelling work now being undertaken for the Rudd Government is restricted to emissions scenarios which would see a very high chance of triggering runaway climate change.
"Far from being a world leader, Prime Minister Rudd appears to be still playing catch-up on the science and politics of climate change.
On questioning from Senator Milne in today's Estimates hearings, Meghan Quinn revealed that her Department is only modelling scenarios leading to global atmospheric concentrations of greenhouse gases at 450 and 550 ppm of carbon dioxide equivalent.
Treasury had not been asked to model lower concentrations, Ms Quinn said.
"If Treasury has not been asked to model safe climate scenarios, I will fill that gap today by calling on the Prime Minister to direct Treasury to model at 350 and 400 ppm as well as 450 ppm and to drop the 550 ppm scenarios as too dangerous for the climate.
"450 ppm gives us a less than even chance of avoiding 2 degrees warming, leading most likely to the complete loss of Arctic summer ice, extinction of polar bears and so many other species in the wild, and potentially setting in train positive feedback loops that could send our climate into an uncontrollable heating cycle.
"550 ppm will send us toward 3 degrees warming, destroy the Great Barrier Reef and almost certainly trigger runaway climate change, leading some to say that there is no such thing as stabilisation at 550 ppm. It should not even be being modelled as it is beyond the point where a safe climate for all living creatures, including humanity, can be imagined.
"If Professor Garnaut and Kevin Rudd are not modelling deeper cuts because they are worried about economic impacts, they should look to the USA where modelling has shown that, beyond a certain threshold, emissions reductions become cheaper with greater cuts because of the effects of scale and learning.
"Unless we aim high, we have no chance of success."