Turnbull who has long publicly favored a market based scheme as opposed to the Liberal's "direct action" policy, is probably guilt of making that unforgivable mistake in politics, telling the truth, without any spin.
So what did Malcolm say?
Well, basically, he explained how the "direct action" policy works.
"Direct action" allows polluters to pollute and then the government uses taxpayers money to buy pollution offsets. While this can decrease "net" pollution, it doesn't create a low carbon economy and as business pollution levels continue to rise you need to buy more and more offsets to reduce your overall levels of pollution. In the long term with Oz needing to cut its carbon pollution emissions by 80% or more, these taxpayer funded offsets would become "very expensive".
"But the way it works is that the taxpayer - the taxpayers' money would be used to buy carbon offsets from farmers, so that as industry pollutes, the Government would then spend taxpayers' dollars to buy carbon offsets to offset that pollution."
"if you want to have a long-term technique of cutting carbon emissions, you know, in a very substantial way to the levels that the scientists are telling us we need to do by mid-century to avoid dangerous climate change, then a direct action policy where the Government - where industry was able to freely pollute, if you like, and the Government was just spending more and more taxpayers' money to offset it, that would become a very expensive charge on the budget in the years ahead."
Turnbull is also in hot water with the Libs, but lauded by Labour, for saying that the "two virtues" of the Libs direct action policy "from the point of view of Mr Abbott and (shadow environment minister) Mr Hunt" are that a direct action policy is easy to stop if 1) climate change isn't real, or 2) if you decide acting on climate change is too hard. Considering the enormous weight of evidence that humans are causing climate change and it is a serious problem we need to deal with, my impression is that Turnbull is telling us the Libs either don't know the science, and/or don't take climate change policy seriously.
Why is all this important?
Probably because since both major parties are offering climate change policies it is important to view each critically. The Liberal's policy isn't efficient and in order to work could be very expensive on the taxpayer. Even more importantly because there would little/no incentive for polluters to cut their pollution, Australia would fail to move to a low carbon economy, a serious problem is the long run.
Update: Malcolm Turnbull has issued this defense/ explanation of his interview comments on his website. Basically he uses a lot more words to say the same thing and points out that what people took as him been critical was simply him accurately explaining the policy (though I think they are probably one and the same).