Bulletin of the American Meteorological Society (in press)
http://sciencepolicy.colorado.edu/admin/publication_files/resourse-1766-2005.36.pdf

Hurricanes and Global Warming
Pielke, Jr., R. A., C. Landsea, M. Mayfield, J. Laver and R. Pasch, in press, 2005.
December. Hurricanes and global warming, Bulletin of the American Meteorological
Society.

Abstract
This paper reviews recent research on tropical cyclones and climate change from the
perspective of event risk - the physical behavior of storms, vulnerability - the
characteristics of a system that create the potential for impacts, but independent of event
risk, and also outcome risk - the integration of considerations of vulnerability with event
risk to characterize an event that causes losses. The paper concludes that with no trend
identified in various metrics of hurricane damage over the 20th century, it is exceedingly
unlikely that scientists will identify large changes in historical storm behavior that have
significant societal implications, though scientists may identify discernible changes in
storm behavior. Looking to the future, until scientists conclude (a) that there will be
changes to storms that are significantly larger than observed in the past, (b) that such
changes are correlated to measures of societal impact, and (c) that the effects of such
changes are significant in the context of inexorable growth in population and property at
risk, then it is reasonable to conclude that the significance of any connection of humancaused
climate change to hurricane impacts necessarily has been and will continue to be
exceedingly small.

Hurricanes and Global Warming

Debate over climate change frequently conflates issues of science and politics.
Because of their significant and visceral impacts, discussion of extreme events is a
frequent locus of such conflation. Linda Mearns, of the National Center for Atmospheric
Research (NCAR), aptly characterizes this context, "There's a push on climatologists to
say something about extremes, because they are so important. But that can be very
dangerous if we really don't know the answer" (Henson, 2005). In this essay we focus
on a particular type of extreme event, the tropical cyclone in the context of global
warming (tropical cyclones are better known in the United States as hurricanes, i.e.,
tropical cyclones that form in the waters of the Atlantic and Eastern Pacific oceans with
maximum 1-min average surface winds that exceed 32 m/sec).

In our discussion we follow distinctions between event risk and outcome risk
presented by Sarewitz et al. 2003. "Event risk" refers to the occurrence of a particular
phenomenon and in the context of hurricanes we focus on trends and projections of storm
frequencies and intensities. "Vulnerability" refers to "the inherent characteristics of a
system that create the potential for harm" but which are independent from event risk. In
the context of the economic impacts of tropical cyclones vulnerability has been
characterized in terms of trends in population and wealth that set the stage for storms to
cause damage. "Outcome risk" integrates considerations of vulnerability with event risk
to characterize an event that causes losses. An example of outcome risk is the potential
for a $100 billion hurricane in the United States. To calculate such a probability requires
consideration of both vulnerability and event risk. This essay discusses hurricanes and
global warming from both of these perspectives.

FULL PAPER at: http://sciencepolicy.colorado.edu/admin/publication_files/resourse-1766-2005.36.pdf

© Copyright 2005 American Meteorological Society (AMS)