Carbon Dioxide and Earth's Future Pursuing the ... - Magazooms

3. More Frequent and Severe Hurricanes
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The claim: CO2-induced global warming will increase the frequency, intensity and duration of
hurricanes.
How do hurricanes respond to global warming? A popular book and award-winning film (Gore,
2006) suggest that global warming is leading to “an increased frequency of hurricanes,” and
that rising temperatures are also linked to “a significant increase in both the duration and
intensity of hurricanes.”
This view of the subject received significant early support in the scientific literature, especially
within the climate modeling community. Free et al. (2004), for example, wrote that “increases
in hurricane intensity are expected to result from increases in sea surface temperature and
decreases in tropopause-level temperature accompanying greenhouse warming (Emanuel,
1987; Henderson-Sellers et al., 1998; Knutson et al., 1998).” In fact, Knutson and Tuleya (2004)
stated that “nearly all combinations of climate model boundary conditions and hurricane model
convection schemes show a CO2-induced increase in both storm intensity and near-storm
precipitation rates.”
To test this climate-model-based hypothesis, we examine the pertinent scientific literature to
determine how much more frequent, powerful and longer-lasting hurricanes may -- or may not
-- have become over the course of earth’s recovery from the cooler temperatures of the Little
Ice Age, or how hurricanes of the Medieval Warm Period may have differed from those of the
Little Ice Age. An analysis of this subject was presented by Idso and Singer (2009) in Climate
Change Reconsidered: The Report of the Nongovernmental International Panel on Climate
Change (NIPCC), where in examining the peer-reviewed scientific literature up through 2007
they found “little or no support for these predictions and considerable evidence to support an
opposite prediction.” Therefore, we confine ourselves here to an analysis of scientific papers
published after 2007, in order to see if Idso and Singer’s conclusion still holds.
With respect to hurricanes occurring over the Atlantic Ocean, we begin with the study of
Chylek and Lesins (2008), who applied simple statistical methods to the NOAA HURDAT record
of storm activity in the North Atlantic basin between 1851 and 2007 in order to investigate a
possible linear trend, periodicity and other features of interest. Using what they describe as “a
hurricane activity index that integrates over hurricane numbers, durations, and strengths,” the
two researchers reported discovering “a quasi-periodic behavior with a period around 60 years
superimposed upon a linearly increasing background.” However, they noted that “the linearly
increasing background [was] significantly reduced or removed when various corrections were
applied for hurricane undercounting in the early portion of the record.” And further noting that
“the last minimum in hurricane activity occurred around 1980,” they stated that in comparing
the two 28-year-long periods on either side of this date, they found “a modest increase of
minor hurricanes, no change in the number of major hurricanes, and a decrease in cases of
rapid hurricane intensification.”
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