The Gillard Government’s policy:
In the core policy scenario, Australia will meet the emission reduction target of 5 per cent below 2000 levels in 2020.
The effect of that policy, as calculated for the Sunday Age by IPCC lead author Roger Jones, assuming a strong causation between emissions and temperature:
THE policy of both major parties is to reduce Australia’s carbon dioxide emissions by 5 per cent by 2020 … Victoria University climate scientist Professor Roger Jones has calculated that if the rest of the world did not act and Australia reduced emissions until 2020, then did nothing else, 0.0038 degrees off the global temperature rise by 2100.
Enter Professor John Quggin, appointed by the Gillard Government to advise it on how deep to make future cuts.
Quiggin’s own estimate of the effect of the Gillard Government’s proposed cuts:
Quiggin’s explanation why his estimate is five times that of the expert:
I was at the Australian Conference of Economists earlier in the week, and had a chat with Roger Jones, who has occasionally commented here. I asked him about his estimates of the impact of emissions mitigation policies in Australia, and was able to confirm that our estimates, although reached in very different ways, are in quite close agreement. Roger is cited here and here, estimating that a 5 per cent reduction in Australia’s emissions would result in a reduction in equilibrium global temperature of 0.0034 degrees. In a blog comment, I made the estimate that a 25 per cent reduction, relative to business as usual (the official target of the carbon price policy and also of the Opposition’s ‘direct action’ alternative) would result in a reduction in equilibrium global temperature of 0.02 degrees. Unfortunately, Andrew Bolt did not observe the reason for the difference, and suggested that we disagreed by a factor of five.
Quiggin’s excuse is that Jones was actually providing an estimate for a five per cent cut in emissions from what we’d otherwise expect by 2020, while Quiggin’s own estimate is for a 25 per cent cut, to bring us back to the Government’s target of a five per cent cut in what our emissions were in 2000. (The bigger cut is needed to reach the target because our emissions have meanwhile grown.)
Quiggin says that means his cuts are five times what Jones was working on, and therefore would produce five times the temperature cut.
But check again what Jones was asked by the Sunday Age to calculate and what he was reported as having done – the difference “Australia’s policy” would make. That policy is exactly the cut the Quiggin was working on. No one is advocating a cut of just 5 per cent of business-as-usual emissions.
So unless Jones somehow misled the Sunday Age or was misreported, or doesn’t even understand his own Government’s policy, his estimate of the effect of the Government’s carbon tax is still just one fifth of Quiggin’s.
I’ll repeat. Qiuggin seems overheated.
Andrew Bolt’s columns appear in Melbourne’s Herald Sun, Sydney’s Daily Telegraph and Adelaide’s Advertiser. He runs the most-read political blog in Australia and hosts Channel 10’s The Bolt Report each Sunday at 10am, and his book Still Not Sorry remains very widely read.