D. Tsaknias, Statistical comparison of extreme observed temperature and rainfall with outputs of climate models, Diploma thesis, 128 pages, Department of Water Resources and Environmental Engineering – National Technical University of Athens, Athens, 2011.
During the last decades, it has been a common belief that climate change is man-made, due to the increasing amounts of CO2 emissions. This belief is also consolidated by climate model outputs, whose projections have widely been used to support decision making for social and financial policies, with special focus on extreme events. Moreover, it is a general perception that extreme events will be more frequent in the future. To evaluate whether climate models provide a credible basis for predictions of extremes, we study their ability to reproduce annual extreme values of daily temperature and precipitation, as well as a series of climate indices which are used in order to investigate the occurrence of droughts, heat waves and floods. Furthermore, we fit probability distributions which describe the extreme events in both cases. The results from climate models are compared to observed data from stations in the Mediterranean, which is one of the most vulnerable areas to climate change. The statistical comparison indicated that the observed time series cannot be simulated satisfactorily. Therefore, serious concerns are risen about the use of climate models to hydrological applications.