Did the incidence of high precipitation levels increase? Statistical evidence for the Netherlands

One of the possible consequences of global warming is that there will be more precipitation days throughout the year, and also that the level of precipitation will be higher. In this paper we provide a detailed statistical analysis of a century of daily precipitation levels for the Netherlands. We show that the often-considered gamma distribution does not fit well to the data. We argue that its incorrect use can lead to spuriously high probabilities of extreme precipitation levels. Relying on advanced nonparametric techniques, we first find that there is indeed more precipitation in the Netherlands, but that this involves only low levels, and second, that the probability of extremely high levels has not changed over time.