Background
The authors write that "climate change is likely to produce more extreme precipitation events," citing Allan and Soden (2008); and they say that "for the Mediterranean basin, several studies indicate a possible amplification of precipitation extremes associated with a decrease of precipitation totals (Gao et al., 2006; Giorgi and Lionello, 2008)," which "could lead to an increased probability of occurrence of events inducing both floods and droughts (Gao et al., 2006)." So what has happened in this regard over the past half-century, in response to the supposedly unprecedented global warming that climate alarmists contend has occurred as a result of steadily rising anthropogenic CO2 emissions?

What was done
In an attempt to answer this question for northern Morocco, Tramblay et al. employed data for ten measuring stations - Casablanca, Rabat, Larache and Tanger (Atlantic coast), Tetouan, Al Hoceima, Nador and Oujda (Mediterranean region), and Fes and Ifrane (Atlas mountainous area) - which they carefully analyzed for signs of the predicted precipitation-related phenomena.

What was learned
Quoting the six scientists who performed the work, "the Mann-Kendall test indicates no significant trends in the data series for all the stations at the 5% significance level," and in like manner they report that "the Deviance test results between stationary generalized extreme value [GEV] models and non-stationary GEV models with time as covariate [also] indicate no evidence of trends in extreme precipitation for all the Moroccan stations."

What it means
Another part of the planet "bites the dust" with respect to providing real-world evidence for model-based predictions of warming-induced increases in precipitation extremes. For the rest of the world, see Weather Extremes (Precipitation) in our Subject Index.

References
Allan, R.P. and Soden, B.J. 2008. Atmospheric warming and the amplification of precipitation extremes. Science 321: 1481-1483.

Gao, X., Pal, J.S. and Giorgi, F. 2006. Projected changes in mean and extreme precipitation over the Mediterranean region from a high resolution double nested RCM simulation. Geophysical Research Letters 33: 10.1029/2005GL024954.

Giorgi, F. and Lionello, P. 2008. Climate change projections for the Mediterranean region. Global and Planetary Change 63: 90-104.