The hoopla over Hurricane Floyd is but the latest outbreak of millennial hyperbole in our weather reports. How many storms of the century have we weathered in the past few years? Amid the drumroll of recent meteorological disasters--punishing heat and drought in the East this summer, an F-5 tornado (the highest category on the Fujita wind damage scale) hitting Oklahoma City last May, record rains last winter in the Pacific Northwest, the floods and fires attending the severe El Niño of 1997-98--there invariably sounds the bugle call of global warming. It is now received wisdom, cited by Vice President Albert Gore among others, that as greenhouse gases warm the planet, we will suffer more weather disasters on the order of Floyd--more "superstorms," more intense and more frequent hurricanes, more nor'easters, more floods and droughts.
But it this true? 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. This is not to say that global warming isn't happening (it clearly is, for whatever reason) or that it won't intensify as concentrations of greenhouse gases increase (the verdict is still out). But putting aside the global-warming debate, the simple truth is that America has always experienced weather disasters of one kind or another and that global warming is not making them worse (or better). Catastrophe is the norm.
Take hurricanes. In a recent study, Christopher Landsea, a research meteorologist with the National Oceanic and Atmospheric Administration's Hurricane Research Division, and Roger Pielke Jr., a scientist with the National Center for Atmospheric Research in Boulder, Colo., found that the much-touted tropical storms of the last few years actually look rather tepid once you adjust for inflation, population and wealth. For example, an unnamed hurricane that caused $105 million in damage when it struck Miami in 1926 would cost an unimaginable $77.5 billion if it followed the same track today, primarily because of the huge increase in the population of Dade County. Messrs. Landsea and Pielke's assessment of the major hurricanes of the century revealed that nine of the 10 most damaging storms struck before 1970. Hurricane Andrew, which cost $26.5 billion in 1992, accounts for the majority of the hurricane damage of the past 50 years; damage assessments for Floyd have not yet been calculated.
This is not to dismiss the severity or increasing frequency of hurricanes in the 1990s. But, according to William Gray, a professor of atmospheric sciences at Colorado State University, the reason for the recent upswing in tropical activity is not global warming but rather a strengthening in a naturally occurring long-term cycle known as the "Atlantic Ocean thermohaline," a sort of conveyor belt. When the conveyor accelerates, as it seems to have done starting in 1994, hurricanes increase in number and become more likely to make landfall. The resulting hurricanes are likely to be more damaging because of the vast increase--much of it directly or indirectly subsidied by the government--in the number of people living along the shoreline. Thus imprudent property development--not global warming--is to blame for the resulting catastrophes.
And it's not just coastlines that are in danger. Thanks to a confluence of geography, ocean currents and global atmospheric circulation patterns, the U.S. is blessed and cursed with the greatest variety of extreme weather in the world. Practically every region of the country has its meteorological disaster specialty. Three-quarters of the world's twisters touch down on our soil, most of them in the vast flatlands of Tornado Alley. There is a higher concentration of lightning strikes along the Front Range of the Rockies than anyplace else on the planet. Blizzards plague the Plains states, droughts and floods alternate on the West Coast, nor'easters regularly whack New England in the winter.
Our recorded history, brief as it is, abounds in epic weather disasters, and archeologists and climatologists have discovered ancient evidence of even more cataclysmic climatic upheavals in Indian ruins, fossilized pollen, tree rings and ice cores. So why are we so aghast at every major "weather event," so convinced that something especially weird is happening to the weather now, and so quick to blame ourselves for causing it by spewing carbon dioxide into the air?
Part of the reason, I believe, is that our history is so short: we're relative newcomers to the weather of this continent and we're still getting acclimated. The Western European and West African peoples who displaced North America's natives brought with them memories of tamer or at least less varied climates and were unprepared for the spectacular violence of North American weather. Words like "blizzard" and "hurricane" had to be invented or imported into the language to account for atmospheric phenomena outside the experience of most colonists.
As we trekked westward into stranger, drier and more erratic climatic zones, we zealously altered the face of the continent, only to speculate anxiously about the atmospheric consequences. 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. 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. Hurricane Floyd is neither a freak superstorm fueled by idling combustion engines nor an ominous symbol of the impending millennium. It's a natural signal that another summer is coming to an end.
David Laskin is author of "Braving the Elements: The Stormy History of American Weather" (Anchor, 1997) and the forthcoming "Partisans: Marriage, Politics and Betrayal Among the New York Intellectuals" (Simon & Schuster).
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