Public Release: 

New Findings Blame Jump In Hurricane Toll On Coastal Growth, Not Climate Change

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BOULDER--In the past eight years, three U.S. hurricanes--Andrew (1992), Hugo (1989), and Opal (1995)--have wreaked a total of over $40 billion in damage. However, according to a new study, this number does not reflect any unusual increase in hurricane strength or frequency. Instead, it indicates that more and more Americans have put themselves and their property at risk by flocking to vulnerable coastal locations. The population shift could spell further trouble if hurricanes again make landfall as often as they did in the 1940s or 1960s.

"Normalized Hurricane Damages in the United States: 1925-1995" was presented by Roger Pielke (National Center for Atmospheric Research, or NCAR, Boulder, Colorado) and Christopher Landsea (National Oceanic and Atmospheric Administration/Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida) on May 22 in Fort Collins, Colorado, at the 22nd Conference on Hurricanes and Tropical Meteorology, sponsored by the American Meteorological Society. NCAR is operated by the University Corporation for Atmospheric Research under sponsorship of the National Science Foundation.

Pielke and Landsea note that a variety of sources from the U.S. Senate to Newsweek magazine have linked global warming to the past decade's rise in hurricane damages. Yet most of the Atlantic hurricane seasons since 1970 have seen tropical cyclones occurring at a less frequent rate than the century-long average. Only in 1995 and 1996 (the two busiest consecutive seasons on record) did the pace pick up significantly. Some climatologists now believe that a natural multidecadal cycle will inevitably return to a period of increased Atlantic hurricane activity similar to the 1940s-1960s.

How might that affect today's society? Pielke and Landsea examined landfalling U.S. hurricanes since 1925 and normalized their effects to 1995 values, taking into account three factors: (1) inflation; (2) a disproportionate increase over time in the number of Americans living near the Atlantic and Gulf Coasts; and (3) increase in material wealth held by the average household (families own more possessions than ever before).

Through this analysis, Pielke and Landsea estimate that the 1926 Miami hurricane--which passed just north of Andrew's track across south Florida, then struck the Mobile, Alabama/Pensacola, Florida region--would inflict some $72 billion in damages if it struck today. That storm was a category 4, one notch below the strongest ranking on the Saffir-Simpson scale, the hurricane rating system used by U.S. meteorologists.

The analysis also shows that seven hurricane seasons between 1940 and 1969 would have produced damages of more than $10 billion each had they occurred in 1995, while only three seasons since 1970 would have done the same. (See graphs on back page.)

"The normalized data indicate clearly that the United States has been fortunate in recent decades with regard to storm losses. The data also refute recent claims that the rapid increase in nonnormalized damages is due to climatic changes," says Pielke. According to Landsea, "The normalized damages suggest that the nation should expect about $5 billion in damages per year, and substantially more than that if we are entering a regime of more active hurricane conditions."

If the normalization methodology is any indication, Pielke adds, "It is only a matter of time before the nation experiences a $50 billion or greater storm, with multibillion-dollar losses becoming increasingly frequent. Climate fluctuations which return the Atlantic basin to a period of more frequent storms will enhance the chances that this time occurs sooner, rather than later."

Writer: Bob Henson


A draft of the referenced paper will be available on the Web after May 22 at http://www.dir.ucar.edu/esig/hp_roger/hurr_norm.html Reporters are free to quote from this version of the paper.

This press release is available on the World Wide Web at http://www.ucar.edu/ucargen/press/hurricane.html

CAPTION:
Although U.S. hurricane damage tolls have soared in recent years (left), a new study puts these figures in perspective by adjusting them for increases in coastal population and wealth during this century. The normalized values (right) show that landfalling hurricanes in 1926 would have produced over $74 billion of damage if they struck today. Several other hurricane seasons in the 1940s, 1950s, and 1960s would have topped $10 billion in damage. (Illustrations courtesy Roger Pielke, Jr., and Christopher Landsea.)

IMAGES:
Figure 1: Time series of United States hurricane-related losses.
http://www.dir.ucar.edu/esig/HP_roger/rpbook1.gif

Figure 4: Time series of United States hurricane related losses from 1925 to 1995 in normalized 1995 damage amounts.
http://www.dir.ucar.edu/esig/HP_roger/rpclhur.gif

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