There is currently an advertisement running on Global Warming which claims that Category 4-5 Hurricane have doubled in the past 30 years. This is an attempt to influence the public to support the the Global Warming talks scheduled for Copenhagen, Denmark next week.
After my curiosity convinced me to verify this claim I was surprised to learn that this is not necessarily so. But sponsors always hope that their information will be believed even if it is not true. The basis of this claim was an article in Science Magazine in 2005 authored by Dr. Pete Webster of Georgia Tech University and Dr. Greg Holland of the National Center for Atmospheric Research.
However, Dr. Bill Gray of Colorado State University disagrees. He is famous for his successful long range predictions and nearly 50 years of research and forecasting. He stated that he does not agree with the claims that global category 4-5 tropical cyclone activity has been increasing accept in the Atlantic over the last 11 years and that can be attributed to conditions other than warming temperatures. He is supported by Dr. Chris Landsea, Science and Operations Officer for the National Hurricane Center and Dr. John Knaff, Hurricane Researcher at NOAA. The study concluded that because of a large disagreement among scientists, an agreement on such a claim was impossible. Even Dr. Webster agreed that a longer study of the global data record would be required and all scientist involved in the dispute agree that further study and reanalysis was required but there is no funding for such an endeavor.
Bottom line is that it is speculation, much as the whole theory of Global Warming. Recent events in that field may conclude that the United Nations, Al Gore and others may have tried to put a scam on the world for their own political ambitions.