Silvio Schmidt and colleagues have a
new paper in press that replicates our hurricane loss normalization work in Pielke et al. 2008 (
PDF). Here is a comparison of the two normalizations over the Schmidt et al. period of record (which begins in 1950, ours dates to 1900), which should give additional confidence in the fidelity of our work, as Schmidt et al. use a different dataset for losses (Munich Re NatCat) and a different approach to normalization. As you can see, over the period of record the differences are minimal (in fact the statistical analysis in Schmidt et al. turns out identically if you use the results from Pielke et al.).
After a detailed look at the data they conclude quite properly:
There is no evidence yet of any trend in tropical cyclone losses that can be attributed directly to anthropogenic climate change.
They do speculate about a link based on the conclusion of IPCC 2007:
The IPCC states that humans have, “more likely than not”, contributed to the trend towards intense tropical cyclone activity since the 1970s. Therefore, any increase in losses could, more likely than not, be partly related to anthropogenic climate change. . . we advance the premise that if losses are affected by natural climate fluctuations, they are also likely to be affected by additional global warming due to anthropogenic climate change. This premise is supported by indications that the intensity of tropical cyclones is affected by anthropogenic climate change.
This is a valuable paper not just because it replicates our work (but of course that is nice to see). The authors also do a nice job clearly distinguishing what can be shown with available data versus what remains in the area of speculation.
After a detailed look at the data they conclude quite properly: