September 1999 -- Is the weather really getting worse or more extreme?

After all, hurricanes and tropical storms are causing more property
damage -- in real terms and in dollars -- than ever before. In October 1998, Hurricane Mitch became a real killer in Central America. And in September 1999, Hurricane Floyd prompted the largest peacetime evacuation in United States history.

Earlier that year, new electricity use records were set throughout the
summer as cities broiled in heat waves and citizens died of heat-related stress.

Drought scorched the Eastern Seaboard while above-normal rains drenched the Great Plains. And the previous winter, near-record snowfalls paralyzed entire regions of the country while other regions basked in above-normal temperatures.

But even though they made exciting news, these climatological events
didn't constitute aberrant weather. Instead, they were just weather as usual. To recycle an old line, when it comes to extremes in weather, "There's nothing new under the sun."
 

Weather extremes are normal

The evidence shows that extremes in weather are perfectly "normal", both subjectively and objectively.

So while a Midwestern heat wave may seem abnormal to someone who has moved there from the Pacific Northwest, there's nothing unusual about a Midwestern heat wave in July.

Similarly, there's nothing unusual about months-long periods without rain in Southern California -- with accompanying brush fires -- followed by flooding, cold squalls off the Pacific in wintertime with mudslides. It's just part of the local climate. But they may seem abnormal to someone watching on television from New York City.

And an entire summer of 90-plus degree highs in Dallas doesn't constitute an ecological catastrophe. It just gets hot in central Texas in the summer, although it may seem abnormally hot to a transplant from Michigan.
 

News emphasizes extremes

Daily reporting can make normal weather appear abnormal. For example, weathercasters always will state that a day's high and low temperatures are either above, below or at that day's "normal" -- meaning "average" -- high and low temperatures.

But because they almost always use the word "normal" instead of
"average", their presentation literally implies that a daily high or low at wide variance with the average temperature is abnormal, even though it actually falls within the normal swing of temperatures for that date.

In fact, very rarely will a local high or low temperature exactly hit the “normal” high or low.

Compounding this is weathercasters' sometimes careless use of "wind chill" data and its newer cousin, the "heat index". These terms describe, respectively, the real sensation of the combination of cold air temperatures and wind speed, and hot air temperatures and relative humidity, on exposed human skin.

But indiscriminate use of the wind chill and heat index information on a weathercast can mislead viewers, giving the impression that it's colder or hotter than it really is. Weather maps with wind chill or heat index data usually are broadcast without an identifying legend, further confusing viewers.
 

Weather makes the news

Moreover, in today's supercharged, 24-hour, wall-to-wall news
environment, the media can be hard-pressed to come up with hard news updates on an hourly basis. In that vacuum, the weather substitutes for hard news. In many cities, even a minor snowfall becomes the lead story.

And some "news" isn't really news at all, like a city's ever-increasing
electricity usage records during a heat wave. That's because all things being equal -- given yet another day in a heat wave -- theoretically all it takes is for one additional air conditioner to be purchased and turned on to set a new electricity use record in a service area.

Speculation about the increasing number and power of hurricanes -- and their link to presumed global warming -- is another weather theme which makes easy headlines.

"We had it, or saw it, all: floods, tornadoes, fire and ice storms," wrote Palm Beach [Fla.] Post staff reporter Mary McLachlin in December 1998. "Four hurricanes spinning at once, 10 tropical storms born in little more than a month . . . It even made some of the bah-humbug crowd admit that something really weird, and probably bad, is happening to the weather on planet Earth."

She reflects environmentalists' claim that presumed global warming will lead to more intense hurricanes. "Because tropical storms such as hurricanes derive their energy from the oceans, it is possible that as the seas warm, there could be an increase in the number and intensity of such storms," said the World Resources Institute.

But a new report sponsored by The Greening Earth Society shows such predictions of more intense hurricanes are "overblown", so to speak, despite a slight increase of greenhouse gases in the atmosphere.

In the report, Does Global Warming Threaten U.S. Coastal Regions With Stronger Hurricanes?, Dr. Anthony R. Lupo of the University of Missouri-Columbia cites nine peer-reviewed studies and an online database in support of his contention that such long-range predictions are difficult at best, and fly in the face of a half-century trend toward fewer and less-intense hurricanes making landfall in the United States.

Lupo attributes the recent higher economic losses due to U.S. hurricanes to the greater buildup of costly beachfront real estate in hurricane-prone areas.

And he quotes researchers at Colorado State University's Tropical Meteorology Project who throw cold water on the idea that hurricane activity since 1995 can be related to increased greenhouse gas emissions.

And Hurricane Floyd aside, 1999 was not a bad year for hurricanes. The warm water associated with the "El Nino" upwelling of warm water in the eastern Pacific Ocean may have helped reduce the number of intense hurricanes that formed in the Atlantic.

"One of the consequences of El Nino is less hurricane development in the Atlantic," said Robert M. Wilson of the Marshall Space Flight Center of the National Aeronautics and Space Administration (NASA), in his study, Statistical Aspects of Major (Intense) Hurricanes in the Atlantic Basin During the Past 49 Hurricane Seasons: Implications for the Current Season.

Further evidence that Atlantic storms are decreasing is provided in the newsletter World Climate Review, in which a 1999 study by Boston University's Jeffrey Key and Alan Chan detected significant declines in the number of storms from 1958 to 1997 in the Northern Hemisphere's mid-latitudes in both winter and spring, but found no changes in summer or fall.

"The hoopla over Hurricane Floyd is but the latest outbreak of millennial hyperbole in our weather reports," wrote David Laskin in The Wall Street Journal in September 1999. "The notion that global warming is making our weather worse is a myth that got going in the media a few years back and has taken on a life of its own."
 

Weather extremes are politicized

In addition to the news media, weather extremes also are used to support political agendas.

For example, in August 1999, Vice President Al Gore told fifth graders in Washington, D.C. that 1999's summer heat waves were the result of global warming. "Of course we had heat waves long before there was a threat of global warming," Gore said, "but because the atmosphere of the whole earth is warming up, it's more common now to have these very, very hot days."

And on Sept. 16, 1999, in an environmental address, President Bill
Clinton described global warming-fueled storms. "Unless we change course, most scientists believe the seas will rise so high they will swallow whole islands and coastal areas," Clinton said. "Storms, like hurricanes ... will intensify." 

Clinton and Gore are leading a worldwide effort to reduce carbon dioxide emissions, and thus curtail presumed global atmospheric warming thought to come from increased man-made greenhouse gas emissions.

"Both Cotton Mather and Thomas Jefferson were convinced that the
colonists had changed North America's climate by clearing off the virgin forests: global warming theories circa 1690 and 1770," Laskin wrote. "Notions that the weather is behaving bizarrely because of something we have done to it crop up again and again in our weather history. We don't need global warming to account for what goes on overhead. Our weather is plenty crazy without it."