I’ve only been looking at AGW as a “proper sceptic” for 6 months or so, and the points you raise sum up the crux of the argument really nicely I think.

AGW alarmists keep on trotting out the 50/50 probability/cost/action argument all the time (its safer to do something now rather than nothing or something later given the odds and what’s at stake, and look at the polar bears and wont somebody think of the grandchildren.. blah blah) and it gets right up my nose. I think you show that the case is rather more uncertain than they realise and we need to get that message across more clearly.

Doing nothing on climate change is a totally valid policy purely based on the odds of point one alone, let alone them all together.

I think there is still a chance, that ETSs and Cap and Trade legislation will get through based on that model of probability. It gives the fence sitters and vote chasers a nice option – “I don’t really believe it, the IPCC hasn’t convinced me, but we’ll do it just in case they’re right, and besides, we need energy efficiency anyway..”

Efficiency and encouraging resource conservation and migration to more sustainable technologies is a good thing, but is a *totally* different conversation. Mixing this and AGW together is a really bad idea – again, this is something that needs to be more clearly communicated in the debate!

Remarkably fine post, very clear-minded in seeing the forest for the trees.

Regarding assumption 1: I am not aware of a reliable signal of global warming, there are simply surface data that are said to be rising, but its a weak trend that can be easily explained by measurement difficulties (e.g., urban heat islands).
Various Hockey Sticks have been contrived to suggest the earth is rapidly warming, but these are not well-founded in terms of scientific methods. Authors have over-reached to try to generate evidence to support the Warmist narrative and their reputations are now in tatters. Since so many Warmists have over-reached or blindly championed what is now evidently bad science, there are great problems of credibility for Warming Advocates. Even if the earth were warming, its now very hard to believe any scientist who claims this, because of the ridiculously over-stated past claims (that the science is clear and only ignorant flat earthers would be skeptics).

It used to be Anthropogenic Global Warming. Then the marketeers of the Left wanted to change the topic to Climate Change, since that is intrinsically undefinable. Now they are trying to relabel their cause as Clean Energy, because who does not like something clean? Unfortunately the global recession and gross over-spending by governments will make it harder to pour public dollars into a hopeful quest for new technologies to make electricity. If left-wingers once mis-led society by massive exaggeration about the now deeply discredited myth of Global Warming, how can the same folks now be smart enough to develop new energy technologies? Sigh.

In any event, this web site reflects highly on your integrity, courage, and broad inter-disciplinary learnedness.

The precautionary principle is also being trotted out again as scientific arguments fall by the wayside. Your calculation that the proposed expenditures have less than 1part in 10E7 of being effective is exactly the argument needed to demonstrate the absurdity.

The business as usual assumptions assume global productions of fossil fuels can triple.

A 2008 study by the USGS of US coal reserves broken down on page 12 of the report into
Not Recoveralable, Not economically recoverable and recoverable is sobering.

http://pubs.usgs.gov/pp/1625f/downloads/ChapterD.pdf