Tom, you may be interested to know that I am by training and education a climatologist, although my research has been done almost entirely outside the mainstream since 1980. I feel that I have been unofficially blacklisted by EC which as you can guess means also by the entire atmos-sci community in Canada and therefore the world, but my views are fairly well known in the community (this is not my climate name).
I have come to the conclusion that the human contribution to global temperature increases, such as they are, is in the neighbourhood of 20-30 per cent of the total, and natural variability provides the other 70-80 per cent.
Probably like yourself, I have been rather skeptical of the magnitude of these increases as often stated, and entirely skeptical of the projections of any observed trends into the future.
I do believe that natural variation has led to warmer temperatures in two or three regions mainly in subarctic latitudes, especially the northeast Atlantic basin.
This past twelve months has seen, in my opinion, a fairly significant downturn in the previous warmer regime, and provides considerable evidence of my contention that human activity is not the main driver. It could be holding back the full extent of cooling that natural processes alone would support given the circulation patterns observed this winter.
It was also very interesting to me that after the large ice-free anomaly in the high arctic last autumn, there was rather quick feedback in the form of the heavier snowfall and plunging temperatures over the central arctic, which remained very cold all winter.
Anyway, I voted in the somewhat higher 10-30 per cent category in your poll, because I don't entirely dismiss the theory, but I think it is still on very shaky grounds and that we should be more concerned about the possibility of long-term natural cycles leading to disruption that we could at least plan for.
Many skeptics point to the probability that changes in solar activity expected over the next 30-50 years could be the main player in future developments and I have no reason to dispute that opinion, but I do feel that if that proves not to be the case, the chances are about 2 to 1 that natural variation would point in the upward direction, so for that reason and not Al Gore's reason, I do feel there is a reasonable chance we will lose the arctic ice pack at some point after 2030. I rate the chances of that at about one in three. This would have some predictable consequences, and would possibly place stress on the land ice around the basin, but at the same time, after this past winter, I also wonder if it might naturally destabilize the climate processes and ultimately lead to a colder regime or even an ice age scenario (because of the increasing snowfall over subarctic regions).
I also think that because of the political realities, we have already turned a corner socially in terms of public acceptance of the need for cleaner technology, and this is not in itself such a bad thing as long as we don't sacrifice intellectual curiosity and freedom of speech along the way to lower greenhouse gas emissions.
And I am a very strong believer that China should clean up, because the one thing that gets lost in the shuffle of this debate is sooty deposition in the arctic, for which China and southeast Asia are mainly responsible. That is a different human-caused process than greenhouse gases, as you know, if you change albedo (reflectivity) you change melt rates, and in fact I believe that the considerable soot deposits from Asian pollution have led to the observed thinning of the Beaufort Sea ice, more so than atmospheric warming, but then of course a thinner ice pack will allow more warmth to reach the lower levels of the atmosphere.
One final note, as a long-time forecaster, I am quite convinced that weather patterns as such have not changed as the AGW lobby likes to pretend. Nor has the frequency or distribution of them changed very much, except in those few areas where storm tracks have shifted like the northeast Atlantic.
One of the biggest myths of the climate change lobby is that increased severe storm activity has already begun and is some consequence of greenhouse gas increases. If anything, I would expect the opposite to be scientifically valid, because much of our severe storm activity takes place when cold arctic air gets involved in the mid-latitude circulation. The intense windstorms here in Vancouver in December 2006 that did so much damage in Stanley Park represent a particular example of this faulty logic. First of all, there was a stronger windstorm in October, 1962. But besides that unwelcome factoid, the main reason for the windstorms in November and December 2006 was an unusually strong jet stream driven by strong conflicting air masses. Global warming was supposed to shift all that further north and reduce the contrast between warm and cold air masses. So it was really an example of an opposite natural process that seemed to accelerate this past winter when the strongest winds were in Oregon and northern California.
(feel free to use this perspective in any way you find helpful in your work ... I will now get back to my gulag duties which involve moving uranium around with my bare hands ... what's left of them)