A Sound Method For Forecasting Hurricanes
This year's Atlantic Ocean hurricane season - June through November - was one to remember. In fact, says hurricane climatologist William Gray, ``records back to 1871 show no season like 1994.''
This is not because of some horrible disaster, but because the season was so mild. There was no hurricane activity at all between Aug. 20 and Nov. 5 when, on average, 80 percent of all hurricane activity occurs. Records Dr. Gray cites show only three previous cases of this high-season lull. Moreover, two-thirds of the hurricane action - two storms out of three - occurred in the last month of the season. And that's never been recorded before.
Next year may be rougher. Gray expects above average action with eight hurricanes. (The average is 5.7.) The early forecast from his Colorado State University office in Fort Collins warns that the ``probability of hurricane destruction along the US coastline and within the Caribbean basin is projected to be higher than the mean probability for the last 45 years and distinctly higher than the probabilities for the last four years.''
There's more to this than storm statistics. Gray works with a well-tested, scientifically based methodology. His warning contrasts sharply with the scare-mongering of environmental groups linking disastrous weather with purported man-made global warming. That claim has no scientific basis. Global warming because of pollution by such so-called greenhouse gases as carbon dioxide has yet to show up. There is no theoretical way to link severe weather in recent years to any mild but undetected warming either.
The factors Gray uses for his forecasting scheme, which only works for the North Atlantic, include rainfall in the West African Sahel region (drought inhibits hurricanes) and the presence or absence of conditions that bring the sea-surface warming in the tropical Pacific called El Nino. El Nino also inhibits Atlantic hurricanes.
A year ago, Gray projected slightly above normal Atlantic hurricane activity for 1994 because he thought the three-year-old El Nino then in progress would peter out. However, El Nino persisted far longer than expected. Gray's updated forecasts in June and August were closer to the mark, although the season turned out to be milder than he projected even then. Now the El Nino is fading. That and expected higher rainfall over West Africa, where many prehurricane disturbances originate, foretell a more active 1995 storm season.
Gray's scheme has worked fairly well for over a decade. It's sound science. Earlier this fall, the Greenpeace environmental organization released its well-publicized report ``The Climate Timebomb.'' It listed several hundred severe weather events of the past four years with the claim that only curbs on greenhouse gas emissions will halt their increase. This is the same four years in which Atlantic hurricane activity was unusually quiet.
The Greenpeace report is propaganda for tougher curbs on fossil fuel use. It's unsound science. Unfortunately, some executives in the insurance industry, which has been hit hard by natural disasters, have swallowed the report's spurious logic. Munich Re, the big reinsurance company in Munich, Germany, has said it is ``convinced'' such disasters are on the increase because of global warming. It, too, urges curbs on fossil fuels.
Such companies should think again. Hurricane Andrew, which hit Florida in 1992, caused the biggest storm-related losses in United States history. This was not because such storms were on the increase, but because Andrew hit a highly developed area.
Weather disasters become more severe because of unwise development. Insurers should look at Gray's work. He has warned that the factors that have held down hurricane activity will change to enhance such activity. This will happen under the climate we've had for centuries, nevermind speculation about global warming. The real need is for wiser land use in storm-prone areas. Fossil-fuel restrictions have to be justified on other grounds. @QUOTE = Hurricane scientist William Gray warns of more storms next year. His findings are based on scientific data, not a political agenda to save the environment.