TCS Daily

Insurance Scam

By George Taylor - March 15, 2004 12:00 AM

Perhaps you read the recent Reuters news item:

"The world's second-largest reinsurer, Swiss Re, warned on Wednesday that the costs of natural disasters, aggravated by global warming, threatened to spiral out of control, forcing the human race into a catastrophe of its own making."

"There is a danger that human intervention will accelerate and intensify natural climate changes to such a point that it will become impossible to adapt our socio-economic systems in time," Swiss Re said in the report. "The human race can lead itself into this climatic catastrophe -- or it can avert it."

The report went on to say that "Scientists expect global warming to trigger increasingly frequent and violent storms, heat waves, flooding, tornadoes, and cyclones while other areas slip into cold or drought. Sea levels will continue to rise, glaciers retreat and snow cover decline."

Let's take a look at the facts.

First, it is clear that insurance claims for weather-related losses HAVE increased dramatically, and there is no reason to assume that will change in the future. But is climate change the culprit? Not according to Kunkel et al. (1999), who concluded "increasing losses are primarily due to increasing vulnerability arising from a variety of societal changes, including a growing population in higher risk coastal areas and large cities, more property subject to damage, and lifestyle and demographic changes subjecting lives and property to greater exposure." Climate change is not a major factor because "trends in most related weather and climate extremes do not show comparable increases with time."

Also, they found "increasing property losses due to thunderstorm-related phenomena (winds, hail, tornadoes) are explained entirely by changes in societal factors," and that when hurricane losses are adjusted for societal changes such as population, inflation, and wealth there is a downward trend. Finally, they saw "no apparent trend in climatic drought frequency" and "no evidence of changes in the frequency of intense heat or cold."

This is consistent with the results of van der Vink et al. (1998), who say "we are becoming more vulnerable to natural disasters because of the trends of our society rather than those of nature." Changnon et al. (2000) say much the same: "Population growth and demographic shifts are the major factors behind the increasing losses from weather-climate extremes." They also conclude "it is reasonable to predict ever-increasing losses even without any detrimental climate changes."

But since the news release came out of Geneva, let's look at trends in Switzerland. Dapples et al. (2003) studied landslide events in the Eastern and Western Swiss Alps during the Holocene. The three most recent and best documented periods of landslide activity were 300-750, 1150-1770 and 2100-3500 years before present. These "can be related to a significant deterioration of the climatic conditions," associated with "periods of more cold and humid conditions." Among these were the well-known Little Ice Age, Dark Ages Cold Period, and the cold period just before the Roman Warm Period. As for the intervening warm periods, there was relatively low activity.

In nearby Italy, Moonen, et al. (2002) report "extremely cold temperature events have decreased and extremely warm temperature events have remained unchanged." This is especially good news for agriculture, since "the number of frost days per year has decreased significantly resulting in a decrease in risk of crop damage." Regarding precipitation, extremely high rainfall events seem not to have changed over the period of their study; but there was an increase in very low rainfall events. They also concluded that "no increased drought risk is to be expected."

Starkel (2002) analyzed the correspondence between extreme weather events and climate in Europe since the last ice age. The author concluded that more extreme fluvial activity (high river levels) was associated with cooler climates, not warmer ones. Starkel identified "flood phases," which were "periods of very unstable weather and frequent extremes of various kinds. Further, "most of the phases of high frequency of extreme events during the Holocene coincide with the periods of declined solar activity."

Hisdal, et al. (2001) performed statistical analyses on streamflow records from more than 600 measurement stations in Europe. They examined the severity, duration and frequency of drought over the following four time periods: 1962-1990, 1962-1995, 1930-1995, and 1911-1995. They found "no clear indication that streamflow drought conditions in Europe have generally become more severe or frequent in the time periods studied." Further, they state "overall, the number of negative significant trends pointing towards decreasing drought deficit volumes or fewer drought events exceeded the number of positive significant trends (increasing drought deficit volumes or more drought events)."

Turning our focus back to North America, we hear from Kunkel (2003), who said, "there has been no discernible trend in the frequency of the most extreme events in Canada." In the United States, Kunkel sees "a sizable increase in their frequency since the 1920s/1930s." On the other hand, older data show that "frequencies in the late 1800s/early 1900s were about as high as in the 1980s/1990s." Thus, "frequencies of extreme events were about as high around the turn of the 20th century as they were at the end of the 20th century," and "this early episode of high frequencies occurred at a time when anthropogenic forcing of the climate system was very small." This would indicate "that natural variability in the frequency of precipitation extremes is quite large on decadal time scales and cannot be discounted as the cause or one of the causes of the recent increases."

Regarding that most destructive of tropical storms, Atlantic hurricanes, Elsner et al. (2000) reported fewer storms in the Caribbean in the last half of the 20th century than in all five of the preceding 50-year periods. During the Little Ice Age (1701-1850), for example, the frequency of major hurricane occurrence was 2.8 times greater than it was from 1951 to 1998; and from 1851 to 1950 it was 2.2 times greater.

Easterling et al. (2000) state that "the number of intense and landfalling Atlantic hurricanes has declined." This is echoed by Parisi and Lund (2000) over the interval 1935-1998. And for the period 1944-1996, Landsea et al. (1999) found decreasing trends for the total number of hurricanes and the maximum observed wind speeds. They also claim that the total number of Atlantic hurricanes striking the United States decreased over the period from 1899 to 1996, and that normalized hurricane damages in the U.S. between 1925 and 1996 decreased by 728 million dollars per decade.

These are just a few of many, many journal articles on this subject, and the consensus appears to be "extreme climate events are not becoming more common." Rather, the opposite is often reported. If you would like to read more discussions and reviews, I suggest visiting, selecting Subject Index, and choosing Weather Extremes.

And while you can expect to pay more for your insurance premiums, don't blame climate change for the increase!

George H. Taylor is the State Climatologist for Oregon and a faculty member at Oregon State University's College of Oceanic and Atmospheric Sciences.


Changnon, S.A., Pielke Jr., R.A., Changnon, D., Sylves, R.T. and Pulwarty, R. 2000. Human factors explain the increased losses from weather and climate extremes. Bulletin of the American Meteorological Society 81: 437-442.

Dapples, F., Oswald, D., Raetzo, H., Lardelli, T. and Zwahlen, P. 2003. New records of Holocene landslide activity in the Western and Eastern Swiss Alps: Implication of climate and vegetation changes. Eclogae geologicae Helvetiae 96: 1-9.

Easterling, D.R., Evans, J.L., Groisman, P.Ya., Karl, T.R., Kunkel, K.E., and Ambenje, P. 2000. Observed variability and trends in extreme climate events: A brief review. Bulletin of the American Meteorological Society 81: 417-425.

Hisdal, H., Stahl, K., Tallaksen, L.M. and Demuth, S. 2001. Have streamflow droughts in Europe become more severe or frequent? International Journal of Climatology 21: 317-333.

Kunkel, K.E. 2003. North American trends in extreme precipitation. Natural Hazards 29: 291-305.

Kunkel, K.E., Pielke Jr., R.A. and Changnon, S.A. 1999. Temporal fluctuations in weather and climate extremes that cause economic and human health impacts: A review. Bulletin of the American Meteorological Society 80: 1077-1098.

Landsea, C.N., Pielke Jr., R.A., Mestas-Nunez, A.M. and Knaff, J.A. 1999. Atlantic basin hurricanes: Indices of climatic changes. Climatic Change 42: 89-129.

Manrique, E. and Fernandez-Cancio, A. 2000. Extreme climatic events in dendroclimatic reconstructions from Spain. Climatic Change 44: 123-138.

Moonen, A.C., Ercoli, L., Mariotti, M. and Masoni, A. 2002. Climate change in Italy indicated by agrometeorological indices over 122 years. Agricultural and Forest Meteorology 111: 13-27.

Starkel, L. 2002. Change in the frequency of extreme events as the indicator of climatic change in the Holocene (in fluvial systems). Quaternary International 91: 25-32.

van der Vink, G., Allen, R.M., Chapin, J., Crooks, M., Fraley, W., Krantz, J., Lavigne, A.M., LeCuyer, A., MacColl, E.K., Morgan, W.J., Ries, B., Robinson, E., Rodriquez, K., Smith, M. and Sponberg, K. 1998. Why the United States is becoming more vulnerable to natural disasters. EOS, Transactions, American Geophysical Union 79: 533, 537.


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