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Extreme Hydrologic Events in Southern Italy
Reference
Clarke, M.L. and Rendell, H.M. 2006. Hindcasting extreme events: The occurrence and expression of damaging floods and landslides in southern Italy. Land Degradation & Development 17: 365-380.

What was done
The authors analyzed 50 years of rainfall records (1951-2000) from the eastern Basilicata region of southern Italy, concentrating on characterizing trends in extreme rainfall events, as well as resultant flood events and landslide events.

What was learned
Working with the data plotted in the figure below, which we have adapted from their paper, Clarke and Rendell determined that "the frequency of extreme rainfall events in this area declined by more than 50% in the 1990s compared to the 1950s." In addition, they report that "impact frequency also decreased, with landslide-event frequency changing from 1.6/year in the period 1955-1962 to 0.3/year from 1985 to 2005, while flood frequency peaked at 1.0/year in the late 1970s before declining to less than 0.2/year from 1990."

What it means
The world's climate alarmists continue to claim that global warming will lead to large increases in various types of extreme weather events, based on model-derived IPCC storylines. Some of them additionally claim that the planet's near-surface air temperature is now at a level that is less than 1C below the maximum temperature of the past million years (Hansen et al., 2006), which would suggest that extreme weather events must have risen dramatically almost everywhere over the last quarter-century. However, Clarke and Rendell's results differ radically from this scenario; and they conclude from their analyses of real-world data that if the climate-driven changes they observed over the latter part of the 20th century continue, "the landscape of southern Italy and the west-central Mediterranean will become increasingly stable," or as they say in their concluding paragraph, "increased land-surface stability will be the result."

Reference
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.

Reviewed 17 January 2007