What was done
The authors analyzed 14 instrumental precipitation series, stretching back in time some 300 years, which had been recovered from six sub-areas of the Western Mediterranean basin, i.e., Portugal, Northern and Southern Spain, Southern France, and Northern and Southern Italy.

What was learned
Camuffo et al. report that all of the regional series, and the Western Mediterranean series itself, "are characterized by repeated swings between rainy and dry periods, as already noted by Piervitali and Colacino (2001), Xoplaki et al. (2004), Tildes-Gomes (2005), De Lima et al. (2010) and IPCC 2007 (Le Treut et al., 2007)." And they also state that "the regional series in the most recent decades don't show any homogeneous tendency," noting that "some tend toward dryness and some toward increasing rain," and that "the same can be said for the most recent decades."

What it means
Even in spite of what climate alarmists typically refer to as the unprecedented warming of the globe over the past century or so, there has been no concomitant change in precipitation over the Western Mediterranean basin.

References
De Lima, M.I.P., Carvalho, S.C.P., de Lima, J.L.M.P. and Coelho, M.F.E.S. 2010. Trends in precipitation: analysis of long annual and monthly time series from mainland Portugal. Advances in Geosciences 25: 155-160.

Le Treut, H., Somerville, R., Cubasch, U., Ding, Y., Mauritzen, C., Mokssit, A., Peterson, T. and Prather, M. 2007. Historical overview of climate change. In: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor, M. and Miller, H.L. (Eds.). Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom.

Piervitali, E. and Colacino, M. 2001. Evidence of drought in Western Sicily during the period 1565-1915 from liturgical offices. Climatic Change 49: 225-238.

Tildes-Gomes, P. 2005. Modos de variabilidade da precipitacao na Peninsula Iberica. Teleconexoes atmosfericas e oceanicas. PhD. Thesis, University of Lisbon, Lisbon, Portugal.

Xoplaki, E., Gonzalez-Rouco, J.F., Luterbacher, J. and Wanner, H. 2004. Wet season Mediterranean precipitation variability: influence of large-scale dynamics and trends. Climate Dynamics 23: 63-78.