More climate extremes, or simply global warming ?

In the paper on the heat wave in Paris (mentioned here) I discussed changes in the distribution of temperature (and autocorrelation of the time series). During the workshop on Statistical Methods for Meteorology and Climate Change today (here) I observed that it was still an important question: is climate change affecting only averages, or does it have an impact on extremes ? And since I've seen nice slides to illustrate that question, I decided to play again with my dataset to see what could..