Human response to climate change - The Global Climate System: Patterns, Processes, and Teleconnections - page 279

insurance. The crop-weather insurance program was modified, but it required
multiple agricultural disasters to bring about more effective legislation and a
more stable crop insurance program. After being benign for about 20 years,
the climate had become more variable again with conditions more typical of
the nation's long-term climate. The enormity of the losses caused by this
array of climate anomalies since 1975 is an important part of the story of
society's vulnerability to climate.
Societal factors
The 1990s experienced a record number of damaging storms, including 72
storms each with damage exceeding $100 million during 1990-6, whereas
only 142 such storms occurred in the preceding 40 years. Trends in insured
loss statistics since 1960 display sharp regional differences. On the West
Coast, the Arizona-NewMexico-Colorado-Texas area, and the southeastern
coastal states, the number of property catastrophes exceeding $100 million
in losses during 1990-7 was double the number in the preceding 40 years
(Changnon 1999a ). Elsewhere in the nation, these costly storms had increased
by only 10 to 20 percent. Events with losses exceeding $100 million averaged
$551 million in loss per event since 1990, just $12 million more than the
average of the 142 events of the prior 40 years. This reveals no increase in
storm intensity.
Many climate extreme losses, after careful adjustment for societal and
insurance factors, did not display upward trends over time. Comparison of
this information with the upward trends in actual dollar losses, and inspection
of areas where losses had grown most (Southeast, South, and West) revealed
that a major cause of the upward loss trends was societal factors (Changnon
2003 ). Over time, the nation's society and infrastructure had become more
susceptible to climate anomalies. The ever-growing population, with its
concomitant demands for food, water, energy, and other climate-influenced
resources, became more vulnerable to extremes that reduced these resources.
In addition to the increased population, or target at risk, there are other
reasons for this increased vulnerability to climate extremes.
Increased wealth with more valuable property at risk.
Increased density of property.
Demographic shifts to coastal areas and to storm-prone large expanding urban
areas.
Aging infrastructure, structures built below standards, and inadequate building
codes.
Interdependency of businesses and product development.
Thus, the results from extensive recent assessment studies show a marked
increase in the nation's vulnerability to weather and climate extremes.