landfalling hurricanes

Post image for No Long-Term Trend in Frequency, Strength of Landfalling Hurricanes

Numerous politicians, pundits, and activists, and even some scientists blame fossil-fuel emissions for the death and devastation wrought by Hurricane Sandy. Such allegations are ideological, not scientific.

As noted previously on this blog, when hurricane damages are adjusted (“normalized”) to account for changes in population, per capita income, and the consumer price index, there is no long-term trend such as might indicate an increase in hurricane frequency or power related to global climate change.

Moreover, 370 years of tropical cyclone data from the Lesser Antilles (the eastern Caribbean island chain that bisects the main development region for landfalling U.S. hurricanes) show no long-term trend in either power or frequency but a 50- to 70-year wave pattern associated with the Atlantic Multidecadal Oscillation, a mode of natural climate variability. 

A new study by Jessica Weinkle (University of Colorado), Ryan Maue (Naval Research Laboratory), and Roger Pielke, Jr. (University of Colorado) dumps more cold water on claims that global warming significantly (detectably) influences hurricane behavior.

The researchers examined data on the number and power of hurricanes making landfall in the five main hurricane basins: North Atlantic, northeastern Pacific, western North Pacific, northern Indian Ocean, and Southern Hemisphere. The data extend back to 1944 for the North Atlantic, to 1950 for the northeastern Pacific, and to 1970 for the other basins. The data for all basins is current through 2010.

Here’s what Weinkle, Maue, and Pielke, Jr. found:  

We have identified considerable interannual variability in the frequency of global hurricane landfalls; but within the resolution of the available data, our evidence does not support the presence of significant long-period global or individual basin linear trends for minor, major, or total hurricanes within the period(s) covered by the available quality data. Therefore, our long-period analysis does not support claims that increasing TC [tropical cyclone] landfall frequency or landfall intensity has contributed to concomitantly increasing economic losses.

Figure explanation: Red bars indicate the number of major (category 3-5) hurricanes, blue bars indicate the number of minor (category 1-2) hurricanes. [click to continue…]