[quote=AstralTraveller;369234]
Archy,
I'll defend Ian terminology - it is accurate and benefits from not being a cliche.......
The amount of energy trapped by CO2 certainly doesn't increase linearly with CO2 concentration and I can believe it's a log function. However the climatic response to CO2 increase in certainly more complex. That is why I have real problems with people who tell me they know what will happen. They don't. What we do know is that CO2 concentrations are increasing and that this will trap more outbound IR radiation. Other factors may swamp this for a time but it is hard to believe it can have no effect in the long term. The geological record it quite clear that CO2 increase does warm the climate.
At the moment we are at sunspot minimum and so the insolation is at a minimum. Some people are trying to claim that that is the reason why temperatures are rising slower than predicted. I don't accept that. As I recall, there is no statistical correlation in the instrumental record between temperature and the 11 year sunspot cycle. [I should be more certain of this than I am, given that I knew the person who did the study and went to his supervisor's retirement party this afternoon. If I get a chance I'll look it up next week.] Of course, if solar output decreased for an extended period, such as during the Maunder Minimum, then we would expect temperatures to fall much as they did during the Little Ice Age.
Doing something about potential human-induced climate change may be a waste of money. The trouble is, if the predictions are correct doing nothing will cost a whole lot more. Personnally I think that moving to more efficient technologies will be worth the effort no matter what happens. On the other hand I recognise the damage that can be done to scientific credibility by crying 'wolf'.
This leads me to you last paragraph, which is an unfortunate case of playing the man and not the ball. I'll take it as read that I know more scientists, and specifically earth scientists involved in palaeo studies and climate studies than you. To suggest that even a small number of them would falsify results for any reason is to misunderstand their psychie completely. What I do see happening is, becasuse of the funding climate, people trying to show that their research proposal (for research that they would do in any case) is relevant to the understanding of climate change or its effects. Sometimes they draw such a long bow that it cracks me up. I haven't yet seen the study of Neolithic stone tools termed relevant to understanding the effects of climate change but they're getting there .....
Oh dear is that the time...
Nevertheless "Climate Change" is a cliche.
The question is not whether changes in atmospheric carbon dioxide levels lead to temperature changes, but to what extent.
The question is not whether increases in global temperatures are man made , but to what extent.
Until these questions are answered with data, not models with dubious feedback mechanisms, we are in no position to assess the economics, let alone to be able to say
"doing nothing will cost a whole lot more"