“Now that it looks as if some sort of agreement may come out of Copenhagen, its natural to ask what sort of agreement we need. The current targets being proposed suggest that warming should be limited to 2 degrees over the next century. That implies stabilising atmospheric C2 concentrations at 450 ppm, and an agreement to cut developed country emissions by 20-25 per cent by 2020, with convergence to a level 90 per cent below current developed country levels by 2050 would be adequate (note that this part of the post is based on my reading of Garnaut, Stern & IIPCC, not my own expertise).

At least some discussion in Australia suggests that these targets are hopelessly weak and by implication that it would be better to oppose any action than to lock ourselves into an agreement of this kind. I disagree, and I will try to spell out why.

First up, as in other debates about climate change, it is important to pay attention to the science, rather than to rely on prejudice or on supposed authorities who are either unqualified or whose qualifications aren:t relevant. Thats why I have refused to debate climate science delusionists here, instead pointing them to the results of scientific research, summarised by the IPCC and other bodies.

But the case here is a bit different. The big impacts of climate change will be on agricultural production and natural environments and the relevant experts are ag scientists/economists and ecologists. The views of climate scientists like James Hansen, while very important in projecting the climatic effects of CO2 emissions, have no particular standing when it comes to assessing the damage associated with any particular climatic change.”

(Read more over at John Quiggin‘s blog)