Fact 1

The number of Category 4 and 5 hurricanes has almost doubled in the last 30 years.

Source 1-http://www.commondreams.org/headlines06/0502-05.htm
Political activists Craig Brown and his late wife, Lina Newhouser.I think the source is credible. The source basically says that hurricanes, and their categories have increased over the last decade. I believe the source, it was started by activists.

Source 2-http://ezinearticles.com/
Christopher M. Knight manages the site along with a dedicated team of developers and associate editors. Lily Wilson wrote the article, she is a weather girl, but not the professional kind. The site is basically saying that hurricanes have increased in category recently. I believe the source.

Source 3-http://www.wunderground.com/education/webster.asp
Perry Samson, and Jeff Masters. Weather Underground is a good credential. PhD. The site is basically saying that the number of 4 and 5 category hurricanes have increased, it has graphs too. I believe the source.