"...you must have misread Stockwell and Cox..."

This is getting weirder by the minute.

You do realise, Agronomist, the you are currently debating the "Cox" of Stockwell and Cox....as in cohenite.

And is mass-debating Cox(s) something one should be doing in public?

This is how I see it.
I am no scientist, but I have read fairly widely on it and have tried
to understand some of the scientific papers.
There is a widespread argument between people who know a lot more than me.

What is certain is that the science is NOT settled.

What I do know is that the relationship between CO2 & temperature is logarithmic.
ie each increase has less effect than the previous same increase.
I also believe that the models used do not use the latest availability of fossil fuels.

I am sufficiently computer literate to know never put too much trust in someones computer program.
Together with a number of other "doubts" about which I have read
I am not prepared to come to conclusion that we know it all.

As a consequence I think we are being stupid to lay out so much money
on various dubious co2 schemes, especially ETSs.

Bazz,

One common error in AGW discussions is to conflate the "environmental" with the "economic".

I am satisfied that AGW is a robust idea. There is a broad consensus among climate scientists, who have cross-checked each others' computer models against each other, against historical records, and are checking against predictions of the near future.

The arguments against AGW are being mainly advocated by folks like our professor Ollier, a retired soil scientist. For these folks, there will always be a debate.

As for economic interventions to lessen the impact of AGW, the arguments are far less conclusive. No wonder. Now we are talking about $$$ billions, and advocates' vested interests range from the political through the economic, on past the barking mad. Their proposals (from do nothing, through injecting the ocean(s) with iron/injecting the atmosphere with sunlight-reflective particles, through meditating with amethyst crystals) are likewise varied.

My reason for wanting a halt to AGW is based on the precautionary principle. There is a recognised risk of a tipping point, beyond which feedback leads toward catastrophy for the global economic network (and its parts, both large and small).

You know what happens when you get a microphone too close to the speakers that amplify its sound. That is an example of catastrophic feedback, although the catastrophe is minor and usually easily reversed.

The Arctic sea ice record over the past 30+ years provides an example of change that may well reach a tipping point. Its disappearance could cause a shift to a warmer climate regime that will have far-reaching economic impacts, or perhaps it could initiate a feedback cycle that has catastrophic impacts.

I am satisfied that increased CO2 in the atmosphere increases the risk of catastrophe. On a geological scale, the planet and the biosphere will survive. On a human-history scale, most of us will be in for hard times. I include myself in this, though I often wonder whether people like prof Ollier do likewise, as go about adding to the dithering and confusion about a settled question.

Here's a link to the Arctic sea ice record:
http://nsidc.org/arcticseaicenews

"I am satisfied that AGW is a robust idea."

And to justify your leap of faith you refer to the consensus, precautionary principle and the tipping point arguments, none of which have any scientific substance.

In respect of the consensus, it is problematic in any event:

http://theclimatescepticsparty.blogspot.com.au/2012/03/consensus-myth-97-of-nothing.html

But even if a majority of scientists did support the concept of AGW that does not mean the science is settled; science is never settled. As Richard Feynman said [The Meaning of it All, 1999]:

"The exception proves that the rule is wrong. That is the principle of science. If there is an exception to any rule, and if it can be proved by observation, that rule is wrong."

There is plenty of observational evidence that AGW is wrong.

The precautionary principle is Pascal's Wager rebadged: that approach is critiqued here:

http://www.abc.net.au/unleashed/43878.html

In respect of tipping points; there is no doubt recent climatic history has featured what are known as Dansgaard-Oeschger [DO] events, which are sudden movements in teperature. However, since the PETM there have been no warming DO's [and even the PETM seems to be independent of CO2 levels] and the cooling ones appear to be periodic as this paper suggests:

http://friendsofginandtonic.org/assets/Loehle_Singer_2010.pdf

So, basically your "robust idea" is a matter of emotional conviction by you unsupported by any scientific evidence of any substance at all.

This thread simply gives oxygen to the fraud backers.

AGW is dead, but they will not let up. The nonsense which csteele raises does not warrant a reply, and avoids the fact that there is no scientific basis for the assertion that human activity has any but a trivial effect on climate. So trivial that it is not measurable.

The fraud backer approach is to raise irrelevant points as if they have any significance to AGW, which they do not, in the absence of any scientific basis for the assertion of an effect, other than trivial, by human emissions.

The likes of bonmot, Poirot, Kenny and others, contribute nothing but nonsensical remarks, of no significance, but always backing the AGW fraud.

I believe a good comparison is the termination of hostilities with Japan in WW11. Thousands of Japanese soldiers on Pacific islands were unaware that the war was over, and some were discovered decades after peace was declared, still carrying on their military activities, without support or supplies, or even an enemy.

Once Gillard is outed and we get rid of the scurrilous carbon tax, we will be able to forget AGW, leaving the fraud backers to their now pointless, baseless activity, which we can then ignore.