Quote from unretired:
The issue is whether man is the sole cause.
He is some cause ... but not the sole cause.
Quite so, humans are not the sole cause of warming - just the main one. Best estimates of warming since pre-industrial times attribute 75% to humans. Some increase of sun's brightness
up until around 1950 probably accounts for most of the rest. There is no evidence of increasing trend in sun since 1950. Currently we are at the bottom an extended 11 year solar cycle but temperatures are amongst the highest ever recorded (2005 hottest year and 2009 second hottest according to NASA surface temperature record).
The evidence of glaciers is in fact evidence ... that is easy.
Whether that evidence fully supports that man is the sole cause ...
that is entirely unsupported and only a theory that is unproven.
As a matter of fact, the greenhouse effect has been
formally proven in this paper by theoretical physicist Arthur Smith:
http://arxiv.org/PS_cache/arxiv/pdf/0802/0802.4324v1.pdf
Of course this does not tell us how much the earth will warm or the specific causes. There is a mountain of evidence allowing for well informed conclusions to be drawn:
These are facts:
1. CO2 is rapidly rising in the atmosphere from about 275 PPM (pre-industrial) to 390PPM now.
2. The change in CO2 is due to humans burning fossil fuels is shown by isotopic studies of atmospheric CO2.
3. CO2 is a greenhouse gas.
4. The infrared absorption of CO2 has been directly measured by satellite.
5. Feedback effects (increasing water vapor in the atmosphere, reduced albedo due to shrinking ice cover and others) increase the warming effect of CO2. This is known with some certainty by paleoclimate studies which show that the earth could never have emerged from previous ice ages without feedbacks.
The degree of warming is of course uncertain, but IPCC puts it between 2C and 5.4C in this century. How much it warms depends very much on what we do about it. 5.4C would be catastrophic and would be uneven with some places warming much more.
All this is not new. There is almost 2 centuries of scientific research to back it up. See the free online book "Discovery of Global Warming"
http://www.aip.org/history/climate/
Other better scientific models prove contrary points.
There are no better models. If you want to make such claims you need to cite the published research and demonstrate that it has achieved acceptance in the scientific community. It is a myth that scientists are divided - there is virtually no new research being published that disputes AGW.