William M. "Bill" Gray (born 1929) is a pioneer in the science of forecasting hurricanes. In 1952 he received a B.S. degree in geography from George Washington University, and in 1959 a M.S. in meteorology from the University of Chicago, where he went on to earn a Ph.D. in geophysical sciences in 1964.
Gray is Emeritus Professor of Atmospheric Science at Colorado State University (CSU), and head of the Tropical Meteorology Project at CSU's Department of Atmospheric Sciences. He served as a weather forecaster for the United States Air Force, and as a research assistant in the University of Chicago Department of Meteorology. He joined Colorado State University in 1961. He has been advisor of over 70 Ph.D. and M.S. students.
Gray is noted for his forecasts of Atlantic hurricane season activity. Gray pioneered the concept of "seasonal" hurricane forecasting—predicting months in advance the severity of the coming hurricane season. Gray and his team (including Christopher W. Landsea, Paul W. Mielke Jr., and Kenneth J. Berry, among others) has been issuing seasonal hurricane forecasts since 1984.
After the 2005 Atlantic hurricane season, Gray announced that he was stepping back from the primary authorship of CSU's tropical cyclone probability forecasts, passing the role to Philip J. Klotzbach. Gray indicated that he would be devoting more time to the issue of global warming. He does not attribute global warming to anthropogenic causes, and is critical of those who do.
Gray developed a seasonal hurricane forecasting methodology in the 1980s and began reporting his forecasts to the public. His forecasts are widely discussed in the U.S. media. Preliminary forecasts are released before the start of the hurricane season, and the forecasts are then revised as the season progresses.
Gray is skeptical of current theories of human-induced global warming, which he says is supported by scientists afraid of losing grant funding and promoted by government leaders and environmentalists seeking world government. He believes that humans are not responsible for the warming of the earth and has stated that "We're brainwashing our children." He asked, "How can we trust climate forecasts 50 and 100 years into the future (that can’t be verified in our lifetime) when they are not able to make shorter seasonal or yearly forecasts that could be verified?"
Gray said those who had linked global warming to the increased number of hurricanes in recent years were in error. He cites statistics showing that there were 101 hurricanes from 1900 to 1949, in a period of cooler global temperature, compared to 83 from 1957 to 2006 when the earth warmed.
Gray does not say there has not been any warming, but states "I don't question that. And humans might have caused a very slight amount of this warming. Very slight. But this warming trend is not going to keep on going. My belief is that three, four years from now, the globe will start to cool again, as it did from the middle '40s to the middle '70s."
According to an earlier interview reported by Joel Achenbach, Gray had similarly said that the current warming in the past decades is a natural cycle, driven by a global ocean circulation that manifests itself in the North Atlantic Ocean as the Gulf Stream.
In a December 2006 interview with David Harsanyi of The Denver Post, Gray said, "They've been brainwashing us for 20 years, starting with the nuclear winter and now with the global warming. This scare will also run its course. In 15–20 years, we'll look back and see what a hoax this was." In this interview, Gray cites the global cooling article in Newsweek from 1975 as evidence that such a scare has happened in the past.
In 2006, Gray predicted a cooling trend by 2009-2010.
Peter Webster, a Georgia Institute of Technology professor, has been part of the anonymous peer review on several of Gray's National Science Foundation proposals. In every case he has turned down the global warming research component because he believed it was not up to standards, but recommended that Gray's hurricane research be funded.
Webster, who has co-authored other scientific papers with Gray, is also critical of Gray for his personal attacks on the scientists with whom he disagrees. "Bill, for some very good reasons, has been the go-to man on hurricanes for the last 35 years," says Webster. "All of a sudden there are a lot of people saying things Bill doesn't agree with. And they're getting a lot of press—more press than I like, actually. I like the ivory tower. But he's become more and more radical."