If you look at the weather records for the northwest, you will notice that the winters in the 1950’s had some amazingly cold weather – most record lows were set in the 1950s. I was always curious about that – this article presents an interesting hypothesis about what caused this.
http://ams.confex.com/ams/90annual/techprogram/paper_157971.htm
Keep this in mind regarding global warming – more articles are appearing regarding geo-engineering as the solution to global warming. See http://en.wikipedia.org/wiki/Geoengineering. Makes me pretty nervous.