Background
The authors begin the report of their study by stating that "warmer atmospheric temperatures associated with greenhouse warming are expected to lead to a more variable hydrological cycle, including more extreme rainfall events (IPCC, 1995)," and that "this change is expected to influence the erosive power, or erosivity, of rainfall and, hence, soil erosion rates (Nearing, 2001)."

What was done
As a test of this "expectation," D'Asaro et al. had as their objective "to assess changes in annual and seasonal rainfall erosivity that occurred in Sicily during the twentieth century," which hundred-year period is typically described by climate alarmists as having experienced an increase in global temperature that was unprecedented over the past two millennia (Mann and Jones, 2003; Mann et al., 2003) or more (Hansen et al. 2006). This they did by first generating long-term series (from 1916 to 1999 in most cases) of a storm erosion index based on storm rainfall amounts and intensities, and then applying it at 17 different Sicilian locations (representative of different climatic zones) where the latter two parameters were routinely measured.

What was learned
The three Italian researchers discovered, as they describe it, that "the annual erosivity did not [our italics] increase during the twentieth century." In fact, they report that it actually "decreased at a few locations."

What it means
The finding that contrary to climate-alarmist "expectations," rainfall-induced soil erosion failed to worsen during the twentieth century, and at every single one of the 17 locations examined by D'Asaro et al., does not bode well for the IPCC's basis of future weather prediction, especially in light of the great degree of global warming claimed by the IPCC to have occurred over the period examined in D'Asaro et al.'s study.

References
Hansen, J., Sato, M., Ruedy, R., Lo, K., Lea, D.W. and Medina-Elizade, M. 2006. Global temperature change. Proceedings of the National Academy of Sciences USA 103: 14,288-14,293.

Intergovernmental Panel on Climate Change (IPCC). 1995. Second Assessment Synthesis of Scientific-Technical Information Relevant to Interpreting Article 2 of the U.N. Framework Convention on Climate Change. Intergovernmental Panel on Climate Change, Geneva.

Mann, M., Amman, C., Bradley, R., Briffa, K., Jones, P., Osborn, T., Crowley, T., Hughes, M., Oppenheimer, M., Overpeck, J., Rutherford, S., Trenberth, K. and Wigley, T. 2003. On past temperatures and anomalous late-20th century warmth. EOS, Transactions, American Geophysical Union 84: 256-257.

Mann, M.E. and Jones, P.D. 2003. Global surface temperatures over the past two millennia. Geophysical Research Letters 30: 10.1029/2003GL017814.

Nearing, M.A. 2001. Potential changes in rainfall erosivity in the U.S. with climate change during the 21st century. Journal of Soil and Water Conservation 56: 229-232.