Actually there is some new scientific thought (and concern) that has recently been featured on television. The premise is that a slow global warming could be nothing more than a natural event, primarily associated with major volcanic eruptions, that can create a follow-on mini ice age in a very short period of time. The premise is supported by ice core taps in the Arctic regions, Greenland, Siberia, etc., with short-term higher concentrations of trapped carbon dioxide and carbom monoxide emissions.

As described above, the theory is that a warming event creates glacial melt (even over land areas) and the runoff creates a significant increase of freshwater in the near-Arctic regions. The freshwater does not sink and can shut off any warm thermal current (i.e., the Gulf Stream). In this scenario, the North Atlantic loop current (and others) shuts down. Without the influence of the warm loop currents, the polar regions then rapidly cool and a mini ice age follows (with temperatures dropping about 7 degrees F along the entire east coast). Core samples suggest that sometimes this whole process can take place in less than two decades, i.e., much faster than previously thought.
ED