Historically, volcanoes are associated with cooling, poor summers and starvation. This occurred in the late stone age/early bronze age again in the early Dark Ages (500ADs) and at other discernable points in history too.
In other words they do impact on climate and they do have serious reprecussions. However, they are not generally considered to be vehicles for global warming.
The rise in CO2 in the atmosphere is measureable and can be compared with core samples taken for various periods in the past. We have impacted on the atmosphere and the Greenland ice sheet is melting. As far as I can see the predictive models do struggle with all the permutations. The indications appear to be that the UK, for example, is likely to get colder (this is a bit of a bummer in my view). Of course natural cycles have occurred and these have in the past self corrected. The inordinately warm period in the 12th century was followed in the 14th to 17th centuries with a mni-ice age. It may be that if we have messed up the balance Mother Nature will spank everything back into shape (although not necessarily in a way to our liking).
Bookmarks