There is many issues around "global warming" - temperature proxies and reconstructions, CO2 levels, methane levels, impact of water vapour, urban heat islands, reduced satellite data, glacier studies, research funding sources and inherent biases, sea level changes, and the effect on the gulf stream and the imapct of this on the climate in northern europe.
There is a lot of political froth and speculation in this space. Wading through all the data and commentary to get some sense of the science is a nightmare. I am concerned the reputation science will have when global warmings wild predictions fail to materialise. Michael Crichton in "Climate of Fear" compared global warming science to the now discredited "science" of eugenitics.
A good summary site is:
http://www.junkscience.com/MSU_Temps...ng_Proxies.htm
No one really knows what causes climate change over geologic history. No-one knows the mechanisms. The current view seems to blame CO2 emission from cars and planes and industry, however the temperatures in the 1970's were going down as CO2 was going up.
If the gulf stream "shuts off" will europe be uninhabitable? Maybe, maybe not.
Maybe europe is in terminal decline as they are not breeding enough to replace their population. Women want careers, ski holidays and condos not kids.
I have found that the future is always not only totally different from what you can imagine, but totally different from what could possibly be envisaged.