Climate is warmer today but not any warmer than it had been 1000 years ago when there were no cars, no big cities and no anthropogenic global warming (AGW). Climate change: yes, and it is science. Global warming: no, and its all politics. The most elementary evidence being the existence and otherwise of a wine industry in England.
Here is a nice commentary that summarizes the information and even cites the uber-AGW blog, realclimate, which is suitable irony (and possibly the one and only time that site can mentioned in this blog).
Scientifically, the existence of the medieval warm period indicates that climate varies on a cyclical basis. Add to this the fact that mean temperatures over the past 100 years have risen by only 0.6C +/- 0.2C. Where is Armageddon in that? Are we modifying the climate? Yes, but the degree of change and the rate of that change do not equate with any doomsday scenario and there is every reason to believe that increases in temperatures in the coming "warm period" will be as advantageous to humanity as in the last such occurrence.
Oh, I know that marks me as an optimist. But as George Bernanos stated 'Hope is a risk that must be run'.