Large and small numbers: options for quantifying the costs of extremes on transport now and in 40 years

The past 15 years has been characterized by a high density of record-breaking weather extremes in Europe. These include the extratropical cyclones Lothar, Kyrill and Xynthia across western and mid Europe; the major floods in the UK, Germany and eastern Europe; the heat waves in 2003 and 2007 and, after a long period of mild winters, the heavy winter seasons in 2009/2010 and 2010/2011. Inspired by the rising trends in weather-related damages worldwide and the studies on the topic carried out in overseas, the EC funded the sister projects such as Weather Extremes-Assessing the Impacts on Transport and Hazards for European Regions (WEATHER), EWENT and ECCONET to determine the magnitude of current and future risks to the European transport sector and to assess suitable adaptation strategies. This paper presents the assessment framework of the WEATHER project and the results of weather-inflicted damage costs now and in 2040-2050. Total annual damages are found to be around a,not sign2.5 billion, which largely attribute to road traffic. However, broken down to passenger and ton kilometers the highest risk is borne by rail traffic due to its expensive infrastructures and its comparably complex operating structure. This indication even amplifies when looking four decades ahead: while average road transport costs will only raise by 7 % due to milder winters, rail traffic costs may increase by up to 80 % due to more floods and less predictable winter periods. A comparison with the results of the EWENT study uncovers a high range of uncertainty concerning methodological approaches and data treatment. Thus, the final figures might even be much higher.