When we talk about climate change most people think about man made C02 spewing into the atmosphere but that has very little or anything to do with it. The real concern of climate should be focused on what the sun is doing! I actually read an article ( http://environment.newscientist.com/article/dn14724-antarctic-sea-ice-increases-despite-warming.html) yesterday that said the Antartica sea ice extent has been so large (record) because of global warming caused by man, so offically global warming causes global cooling, and drought, and flooding, la nina, el nino, and some are blaming earthquakes on global warming believe it or not! (http://www.livescience.com/environment/070830_gw_quakes.html). Come on, next you will be hearing about manbearpig and crab people.
The main driver behind abrupt climate change is due to the sun! During the past 100 years solar wind, geomagnetic activity, and solar cycles have been very strong which would explain most of the .8 degrees of warming we have expierenced in the past 150 years. The only problem is now that we are very close to Dalton Minimum (http://sesfoundation.org/dalton_minimum.pdf) type activity from the sun which was one of the main causes of the Little Ice Age. In fact you can read up on the current solar cycle state and it's implication here (http://www.warwickhughes.com/agri/Solar_Arch_NY_Mar2_08.pdf)
Anyway the current solar cycle 24 has yet to make an appearance which has caused the solar to drop off big time allowing more cosmic rays from outside space to enter the inner solar system. They hit our atmosphere and create nucleation sites for cloud dropplets to form an with more clouds the suns already weakened energy is reflected back out into space which causes cooling. If the sun doesn't wake up soon some suggest the global temperature will drop by an average of 2 degrees celcius within just a few years!