Rich 2, Bonmot, Nicco et al persist with defending the existence of AGW, when its actual status is that of an unproved hypothesis. Despite billions of dollars of research, no one has yet succeeded in proving it.

The best that AGW proponents can do is assert, for example:

. the IPCC: “We believe that most of the increase in global temperatures during the second half of the twentieth century, were very likely due to the increases in the concentration of atmospheric carbon dioxide”;
. the government’s Multi-party Climate Change Committee's sole scientist member, ANU’s Professor Will Steffen: " there is 100% certainty that the earth is warming, and that there is a very high level of certainty it will continue to warm unless efforts are made to reduce the levels of carbon pollution being sent into the atmosphere."

neither statement qualifying as scientific evidence of the linkage between anthropogenic CO2 emissions and dangerous global warming.

The compelling scientific evidence that is required to prove the AGW hypothesis has not been produced. In fact, the following statement of Dr Nicol says it all: " the data representing the earth’s effective temperature over the past 150 years, show that a global human contribution to this temperature cannot be distinguished or isolated at a measurable level above that induced by clearly observed and understood, natural effects, such as the partially cyclical, redistribution of surface energy in the El Nino. "

Don and Raycom.

I have already pointed out to you gently that Dr Nicol and Lubas Motl have unimpressive scientific pedigree but I see you both continue to reference them. You are using them both as "expert witnesses" and as in a court it is entirely appropriate to test them to see if they are the "experts" you claim. They are clearly not and I don't see that testing as an ad hominem attack merely common sense.

Don - as an example #13 on the link you supplied has Lubas Motl claiming "Even 5 °C of warming would be a net positive." Is that a statement you feel comfortable with?

Raycom - you talk a lot about the need to have AGW proved. Check out this link to a 10 minute video http://scienceblogs.com/insolence/2011/05/the_best_ten_minute_summing_up_of_a_scie.php
The video sums up "multiple lines of evidence supporting AGW. The same sort of reasoning applies to every major scientific consensus, be it evolution, the germ theory of disease, the scientific consensus that vaccines do not cause autism, or whatever. There is no single study that "proves" a scientific consensus. Nearly always, there are many lines of mutually supporting evidence that converge on the same conclusion or set of conclusions. That's the one thing advocates of pseudoscience just don't get. They have a tendency to think that there's a "magic bullet," one study that "proves" the consensus, hence their demand for "just one study" that "proves" a consensus, a demand I've seen from creationists, anti-vaccine activists, and supporters of various forms of quackery. In most cases, there ain't no such beast. That isn't how science works."

Rich 2, you obviously do not like to acknowledge the fact that there is no scientific evidence of the linkage between anthropogenic CO2 emissions and dangerous global warming.

Instead of denigrating Dr Nicol and rambling on about your AGW beliefs, can you simply address and be specific about the problems you have with his statement: " the data representing the earth’s effective temperature over the past 150 years, show that a global human contribution to this temperature cannot be distinguished or isolated at a measurable level above that induced by clearly observed and understood, natural effects, such as the partially cyclical, redistribution of surface energy in the El Nino

Rich 2

I join with Raycom. It's no good just repeating what you said before. If that were any kind of argument, it would be called 'argument by repetition'.

Read what I said again. I didn't say that Motl was always right. I said that he had an easier task, since he only had to show errors in data and evidence, while SS had to plead a case. In my opinion, as I said above, Motl is more often correct. I don't have to agree with everything he says. I try to get close to the reality by assessing data and comparing arguments. It is time-consuming, and I said it was.

And as for your quote, I don't think that there are multiple lines of evidence supporting AGW, though that's such a vague statement it might mean anything. There is, as yet, no clear AGW signal that can be detected from within the noise of natural variability.If you think that there is, for heaven's sake tell us of a few papers that convincingly show that, and not just quote somebody else' assertion.

Raycom,

There are three key problems with the statement from Dr. Nicol to the effect that natural cycles explain the earth's effective temperature over the past 150 years:

1) A natural cycle requires a forcing, and no known forcing exists that fits the fingerprints of observed warming - except anthropogenic greenhouse gases. For the full story http://www.skepticalscience.com/global-warming-natural-cycle.htm

2) Dr. John Nicol and The Australian Climate Science Coalition (ACSC)do not qualify as a reputable source of scientific knowledge. Their views are driven by the political interests they represent not by a desire to find the scientific "truth".
The ACSC has links which go back to The Institute of Public Affairs (IPA). IPA is a right-wing corporate funded think tank based in Melbourne. A key policy is to refute the science involved with environmental issues such as climate change. It relies heavily on funding from a small number of conservative corportions such as BHP Billiton, Shell, Mobil and Woodside Petroleum.
In 2005 the IPA set up the Australian Environment Foundation which, in turn, set up the ACSC. Dr. John Nicol is Chairman of the ACSC. It has as a "core principle" that "Global climate is always changing in accordance with natural causes and recent changes are not unusual". It says its mission is to "promote open scientific debate on the causes of climate change" .............. yet it starts of with a view of what the science says?!
That doesn't seem right to me - does it seem right to you Raycom?

3) In the field of climate science, the consensus is unequivocal: human activities are causing climate change. There are no national or major scientific institutions anywhere in the world that dispute the theory of anthropogenic climate change. Not one. If the natural cycles theory has any merit at all there should be but there isn't.

Don and Raycom - Did you watch the video I provided the link for? Did you find it useful? Has it caused even a shadow of doubt in your mind?
Your calls for "where is the evidence?" I addressed in my previous post.

Rich 2:

We're not going to get anywhere. You are stuck on the view that consensus is really really important, that 'the science' has multiple lines of evidence, that learned academies are disinterested and always right, and that people's arguments and evidence can be dismissed if they seem to be associated with groups of whom you disapprove. So you keep on repeating the same stuff.

You say that a natural cycle requires a 'forcing', as though this was clear and self-evident. It's neither, and it presupposes that there is somehow an equilibrium in climate which carbon dioxide is disturbing. What is that equilibrium, and when have we experienced it?

I watched the video for a couple of minutes, and I can see why you like it, because it starts from the same premises as you do. But when I saw the cigarette I knew what was to come, and switched off. I've seen it before — that's old stuff, and it doesn't help, because lung cancer and global warming are two quite different issues.

I leave you to your consensus.