THE residents of North and South Carolina and Virginia in the US, currently picking up the pieces in the wake of hurricane Fran, will take little comfort from the fact that, compared to many of its predecessors over the years, the storm was unremarkable in terms of human casualties.
Fran's death toll of 17 compares with the 26 people killed by hurricane Andrew in August 1992, and the 200 casualties in the wake of hurricane Gilbert in September, 1988. Going further back, the Galveston hurricane of September 8th, 1900, killed 6,000 people, about a sixth of the population. It was the worst natural disaster ever to strike the North American continent.
But if Atlantic hurricanes nowadays tend to cause less loss of life, it is mainly because better tracking and forecasting techniques allow vulnerable areas to be evacuated in good time. It is certainly not because there are fewer or less vigorous hurricanes. Indeed, many are afraid that the opposite may be the case.
Moreover, houses and other fixtures cannot be removed to safety and, as the vulnerable coastal regions of the United States experience a steady increase in population, the financial consequences of such disasters become greater year by year.
However, at $600 million, tile estimated damage caused by Fran was modest compared to Andrew's $28 billion a few years ago. But the occurrence will be an unwelcome reminder to the world's major insurance companies of their vulnerability to a changing climate.
Their fears are closely related to the current debate on global warming. For many of us, the prospect of a gradual rise in global temperatures is a matter of somewhat academic interest, but for insurers the possibility that warming might lead to more frequent and more vicious hurricanes is frightening.
It could result in a dramatic escalation in insurance claims, with financial implications that are potentially catastrophic.
Insurers' concerns have a scientific basis. Hurricanes and other tropical storms develop over warm ocean waters near the equator. Vast amounts of solar energy are consumed in these parts in evaporating sea water, but the energy is not lost. It is stored in the atmosphere in the form of latent heat" and subsequently released through the reverse process of condensation, as clouds and rain form in a developing storm.
It is this renascent energy that provides the great reservoir of energy required to fuel a fully developed hurricane. Hurricane Fran was typical of its ilk, forming in the sub-tropical regions of the North Atlantic late last month and skirting westwards past the Caribbean Islands before veering north across the Carolina coast last Friday morning.
The fear is that higher temperatures associated with a warmer world may enhance evaporation, and thus provide even more energy to fuel violent storms like hurricane Fran. Moreover, hurricanes are known to form only over waters whose temperature exceeds about 26 C so, in a warmer world, the area where hurricanes form would be significantly increased.
Such storms would be delivered, perhaps, in regions hitherto unaffected and might travel along tracks quite different from those to which we are now accustomed. The combined result, it is feared, might be more vicious, more frequent and more widespread hurricanes.
These theoretical concerns on the part of insurance underwriters have been exacerbated by events of recent years. Their fears were first awakened by Gilbert in 1988, which was the strongest hurricane to hit the Caribbean. Then in 1989 came hurricane Hugo, which cost the industry an unprecedented $6 billion.
In 1991, Cyclone Ofa broke all records in the Pacific, only to be bettered less than a year later by Cyclone Val which completely devastated Western Samoa. August, 1992, brought hurricane Andrew and it was followed a few weeks later by Cyclone Iniki, the strongest cyclone ever to cross the islands of Hawaii.
There have been a few relatively quiet years since then, although pessimists are quick to note that the lull coincided with the tendency for global temperatures to stabilise after the 1991 eruption of Mount Pinatubo in the Philippines.
Then last year, the warmest year on record, while not marked by particularly violent hurricanes, brought more of them than had occurred in a single season for more than half a century.
There were 19 Caribbean tropical storms or hurricanes in 1995, a figure that has been exceeded only once (in 1933, when there were 21) since these events began to be recorded in 1871. Moreover, on a spectacular day in August last year no fewer than three hurricanes were in simultaneous existence in the North Atlantic, a very rare occurrence that did nothing to reassure the worried underwriters.
Meteorologists are careful to point out that you cannot prove a theory from a few exceptional occurrences like these over a relatively short period. They allow that these happenings are "consistent" with possible global warming due to the greenhouse effect, but rightly maintain that there is as yet no unambiguous causal" link between the greenhouse hypothesis and any unusual weather events of recent times.
But in the insurance world they observe the hurricanes, the devastating floods of recent years and the summer heat waves of the northern hemisphere in 1995, and they fear that these indicate a trend. The underwriters see their future shrouded in uncertainty, they envisage a scenario in which the risks are massive and in which their current actuarial calculations may be all but useless.