Fortune MagazineWhy Weather is Getting Deadlier—and Costlier- its time to take global warming more serious
To New Orleans residents, Hurricane Katrina must seem like an incredibly bad piece of meteorological luck that could only happen once in a lifetime. But to many climate researchers, it looks like a harbinger of things to come—with catastrophic regularity—as the world's atmosphere heats up.
In fact, less than a month before Katrina hit the Gulf Coast, Massachusetts Institute of Technology researcher Kerry Emanuel published a portentous paper in the journal Nature that illustrated how hurricanes' destructive potential has risen dramatically over the past few decades, in tandem with global warming. And a few weeks before Emanuel's paper, the Association of British Insurers issued an equally ominous report on the growing financial risks posed by extreme weather events due to global warming. It predicted that the U.S. may suffer insured losses from single hurricanes of up to $150 billion in 2004 dollars. (To put that in perspective, Hurricane Andrew racked up insured losses of about $20 billion, in 2004 dollars, when it slammed Florida and Louisiana in 1992.)
While the great majority of climate researchers believe that global warming is real (and also that it is partly caused by human emissions of greenhouse gases such as carbon dioxide from burning fossil fuels), no one says Katrina sprang directly from the warming—that would be like arguing that a particular stock's plunge was caused by the onset of a bear market a year ago. But Emanuel and other experts have warned for over a decade that global warming may be creating an environment prone to more violent storms, droughts and other weather extremes, just as a bear market can pave the way for an outsized drop in a particular company's stock price. Emanuel found that since 1949, the average peak wind speeds of hurricanes over the North Atlantic and the western and eastern North Pacific has increased by a whopping 50%. Such increases have huge consequences, Emanuel notes, since even a small increase in wind speed can produce dramatic increases in damage—a 50% rise in a hurricane's wind speed more than triples its destructive potential. Meanwhile the duration of the storms, in terms of the total number of days they lasted on an annual basis, rose by roughly 60%. Almost wildly understating his work's implications, Emanuel concluded that global warming and increasing coastal population "may lead to…a substantial increase in hurricane-related losses." The British insurance association report, titled "Financial Risks of Climate Change," reported:
* Each year since 1990, there have been at least 20 weather events categorized as significant natural catastrophes.
There were only three years that bad among the 20 years preceding 1990.
* Four hurricanes that hit the U.S. last year racked up a record $56 billion in total losses over a period of just a few weeks, setting an annual record for such losses.
* Last year 10 typhoons hit Japan, four more than the previous record, making it the costliest year ever for typhoon damage there.
* In 2003, Europe suffered the hottest summer of the past 500 years, causing 22,000 premature heat-related deaths. Accompanying wildfires caused $15 billion of losses.
Changes in the weather appear to have already doubled the chance of such hot summers.
* The number of severe winter storms in Britain has doubled over the last 50 years.
