Some interesting points in this thread a good read. Loafer a quick question, is it that you don't think temperatures at the surface/lower troposphere have been rising in the last century or is it that you don't believe that man-made emissions are responsible for warming? I think some of the best evidence for warming temperatures come from mountain glacier retreat particularly photographic evidence of them moving up mountains in the alps in particular but also many other parts of the world since the early 1900's. This then causes less debate over satellites and the possible problems with using them to measure temperature, sea ice, etc.
I notice there was some debate over The Sun's influence on climate as well, I think sun spot cycles are now widely recognised as having some influence on the climate of recent decades, they are currently estimated to have accounted for approximately 10% of warming since 1900 (0.07C), this is still an area actively researched in climate science and I wouldn't surprised if this estimate was say 50% out either way. There all still high levels of uncertainty in aspects of climate science but this doesn't make the science invalid.
Ice cores are considered one of the best proxies of atmospheric composition, the records can be brought right up to modern instrumental measurements of CO2 and they show a very good match with them. The oxygen isotopes contained within them can be used to record glacial periods, the timing of negative intrusions of the heavier 18 oxygen isotopes match closely with data gathered from the rock record.
As a final point I don't think too many people doubt that the greenhouse effect exists and causes averge global temperatures to be 30C warmer than they would be otherwise. So why is it then that people don't think that our emissions of CO2, CH4 (rice paddies and cattle), CFCs, NOx and many more greenhouse gases are (and will continue to) causing climate to warm on a global scale? Of course levels of greenhouse gases have varied over geological time, collisions of continents, solar variation, volcanic emissions(?) and the development of large organisms have driven these changes in the past but today it is my opinion that anthropogenic emissions are causing climate to change, it is not that our emissions are greater than natural emissions (they're not) it is that they have gone beyond the level that the carbon cycle can absorb.