A top hurricane forecaster called Al Gore "a gross alarmist" Friday for making an Oscar-winning documentary about global warming.

"He's one of these guys that preaches the end of the world type of things. I think he's doing a great disservice and he doesn't know what he's talking about," Dr. William Gray said in an interview with The Associated Press at the National Hurricane Conference in New Orleans, where he delivered the closing speech.

A spokeswoman said Gore was on a flight from Washington, D.C., to Nashville Friday; he did not immediately respond to Gray's comments.

Gray, an emeritus professor at the atmospheric science department at Colorado State University, has long railed against the theory that heat-trapping gases generated by human activity are causing the world to warm.

Over the past 24 years, Gray, 77, has become known as America's most reliable hurricane forecaster; recently, his mentee, Philip Klotzbach, has begun doing the bulk of the forecasting work.

Gray's statements came the same day the Intergovernmental Panel on Climate Change approved a report that concludes the world will face dire consequences to food and water supplies, along with increased flooding and other dramatic weather events, unless nations adapt to climate change.

Rather than global warming, Gray believes a recent uptick in strong hurricanes is part of a multi-decade trend of alternating busy and slow periods related to ocean circulation patterns. Contrary to mainstream thinking, Gray believes ocean temperatures are going to drop in the next five to 10 years.

Gore's documentary, "An Inconvenient Truth," has helped fuel media attention on global warming.

Kerry Emanuel, an MIT professor who had feuded with Gray over global warming, said Gray has wrongly "dug (his) heels in" even though there is ample evidence that the world is getting hotter.