BishopHill quotes approvingly from a comment made on the Booker column in yesterday’s Sunday Telegraph

I have worked in government for 28 years as an economist, and for the last 20 years I have worked on environmental programs. In that time I have not seen a shred of evidence to justify global warming, let alone man made global warming and I have not seen a shred of evidence that there is going to be a green economic boom. The only evidence I have seen is that there is a green economic bust, that money invested in green technologies is usually wasted and simply consumes investment that could be better used elsewhere. I think that anybody in government or industry who can not understand this is either dishonest, stupid, or both. That applies to Cameron – I think he is both.

For those who support the sentiments expressed should consider trying to convince someone who is a true believer in climate change consensus of their error. If the consensus supporter finds shreds of evidence of global warming, and hints that the warming may be due to anthropogenic factors, then they have refuted this experienced economist. Just as a sceptic who finds fault with the temperature record, or who has read about “hiding the decline” concludes that climate change is all a hoax, or a global conspiracy.

An economist should look at the costs and benefits. In terms of Climate Change there are two sets of costs. First, those of climate change impacts and second, the costs of the policy to contain the global warming. The Stern Review put argument that the mitigation policy costs were 5 to 20 times less than letting climate change progress unchecked. Therefore there is a clear-cut case for global mitigation policy. But crucially Stern does not look at the consequences of ineffective and over-expensive policy. The Booker article “For every new ‘green’ job, nearly four are lost” looks at one aspect of these real policy costs. An economist would also claim that the Greens fail to look at the opportunity costs, claim that the new jobs are a benefit.

I have tried to demonstrate this economic argument for climate change mitigation here. Then I examine why the policy proposed will be ineffective in constraining CO2 rises and the costs will escalate here. I hope to post soon on why the costs of climate change are hugely overstated.

The argument against the climate change policy is not that there is no evidence. Rather, it is that blundering and ineffective policy will be far more costly than five or six degrees of warming bringing on highly variable weather systems. That is an argument for the economists, not the climate scientists.