As I see it the parameters used for climate sensitivity calculation are increase in global temperature and increase in atmospheric concentrations of CO2 in the atmosphere. The change in global temperute is caused by the TOTAL forcing of which CO2 only plays a part if at all. The Consensous argument goes that the current pause in warming is caused by natural cycles that have cancelled the CO2 effect. (I don't give any credance to the heat being held in the deep oceans; I believe it has been reflected out into space by clouds) However cycles by their nature have both positive and negative phases so the measured warming must have a large element of natural warming. (50% at least). To my way of thinking this leaves CO2 as having a very very small or negligible effect. As climate sensitivity as defined is complete rubish we (the skeptics) make a big mistake to lach on to it as an argument. It implies the we accept it's validity which, I think could be a big mistake.

Climate sensitivity to CO2 is just a figure AFAIK. It tries to assign a multiplyer to the 1.2C for a doubling of CO2. More than 1 there is positive feedback. Less than 1 there is negative feedback and if the sensitivity was negative CO2 would be a cooling gas. I'm not wedded to a lab value of 1.2C but until someone comes up with significant proof against that figure it remains valid.

To prove CO2 has no effect at all is a lot of rewriting and not necessary to buy more time to observe reality. If climate is as complicated as it appears to be then it could take centuries to untangle climate (if ever) and in the mean time temperatures could go up as well as down, quite naturally. If you state catagorically that CO2 is now a spent force before you can accurately explain climate then you can't explain any future temperature changes any better than warmists can explain the 'pause'. What if the water vapour feedback is a variable? Sometimes it might be positive, sometimes it might be negative and those effects could be from solar activity.

A big part of climate science's failure is over confidence. They say they don't want to drive policy but have exagerrated the science to do exactly that. They instictively know that if they'd told the truth, the whole truth and nothing but the truth then society would not have started acting. The sceptic power is by pointing out the flaws and if we make guesses or grasp at suitable explanations we become no better than them. It's not for us to say society can't spend money on cutting CO2 if it wants to but we can and should try to stop them doing it for fabricated reasons.

We don't need to solve climate to effect a 'wait and see' policy.

Climate sensitivity to CO2 is just a figure AFAIK. It tries to assign a multiplyer to the 1.2C for a doubling of CO2. More than 1 there is positive feedback. Less than 1 there is negative feedback and if the sensitivity was negative CO2 would be a cooling gas. I'm not wedded to a lab value of 1.2C but until someone comes up with significant proof against that figure it remains valid.

To prove CO2 has no effect at all is a lot of rewriting and not necessary to buy more time to observe reality. If climate is as complicated as it appears to be then it could take centuries to untangle climate (if ever) and in the mean time temperatures could go up as well as down, quite naturally. If you state catagorically that CO2 is now a spent force before you can accurately explain climate then you can't explain any future temperature changes any better than warmists can explain the 'pause'. What if the water vapour feedback is a variable? Sometimes it might be positive, sometimes it might be negative and those effects could be from solar activity.

A big part of climate science's failure is over confidence. They say they don't want to drive policy but have exagerrated the science to do exactly that. They instictively know that if they'd told the truth, the whole truth and nothing but the truth then society would not have started acting. The sceptic power is by pointing out the flaws and if we make guesses or grasp at suitable explanations we become no better than them. It's not for us to say society can't spend money on cutting CO2 if it wants to but we can and should try to stop them doing it for fabricated reasons.

We don't need to solve climate to effect a 'wait and see' policy.

I swear Captcha hates me. First it starts posting impossible words (non English characters) now it rejects my first attempt then posts both tries a minute later. It's like that cartoon where one kid asks another-

"How did you do on your exams?"
"Yesterday was terrible, first it asked for Henry the VIII's third wife. Then it asked for the cases of WWI and finally it asked for an essay on the Romans"
"Maaan, that's one tough history exam."
"Nah, that was just the Captcha."

Mr D, what is this 'empirical evidence' for a 200ppm limit? Is it more substantial than your anecdote about Alec and his furnaces? That sounds like the Internet equivalent of, "a bloke down the pub told me..."

How should I know why it stopped? Your certainty on these issues is perplexing. You support or have "faith" in Salby and his ideas, presumably including that proxy CO2 measurements are inaccurate, yet you can without evident irony claim that CO2 levels were lower in previous inter-glacials. You use evidence derived from ice cores to support your views and yet you would probably barf at suggestions that we know anything definite about the last few thousand years. You claim empirical evidence for a limit on the effectiveness of CO2 of 200ppmv ("all the effects of CO2 cease at concentrations higher than 200ppm") according to Alec the plumber (or whatever) and yet cannot produce such evidence. And yet you seem to have no better scientific understanding the me. How can you sustain these apparently conflicting opinions all at the same time?

Mr D, there you go again, defending the IPCC's CO2 records against suggestions by Salby (in whom you say you have faith) that the proxy record of CO2 is wrong. Your faith in the IPCC and the accuracy of ice core data is quite surprising.

Let me be thick for a minute (some will recognise this as inescapable). CS quantifies how the climate responds to an increase in CO2, right? So if there is no change, the CS = 0, If it's 3, it's 3?

So, why does ECS not exist? If the sensitivity of the climate (at a certain level of CO2) is 0. Why does it not exist?

CS sensitivity is shorthand for saying "we're modelling this as if it's a simple linear system" - it's no surprise the concept came out of the modelling community.