2007 is a crucial year: 50% of the population is living in urban areas. Furthermore, it has been forecasted that this number will double in the next 30 years. This increase rate corresponds to a new city of 1 million people every week during the next 40 years. This exponential curve is enough to imagine that cities become more vulnerable: issues we will have to face dealing with risk management become more complex. Moreover, this quick urbanization comes with climate change uncertainties. Climate change, coupled with people and asset concentration in cities, is the worst combination to set up a sustainable natural hazard management plan. As an example, floods are considered the major natural hazard in the EU in terms of risk to people and assets. Currently, more than 40 bn € per year are spent on flood mitigation and recovery in the EU. More than 75 % of the damage caused by floods is occurring in urban areas. Climate change and concentration of population and assets in urban areas are main trends likely to affect these numbers in the near future. Global warming is expected to lead to more severe storm and rainfall events as well as to increasing river discharges and sea level rise. This means that flood risk is likely to increase significantly. At least, urban systems contain assets of high value and complex and interdependent infrastructure networks (i.e. power supplies, communications, water, transport etc.). The infrastructure networks are critical for the continuity of economic activities as well as for the people’s basic living needs. Their availability is also required for fast and effective recovery after disasters (floods, hurricanes, earthquakes, landslides...). The severity of damage therefore largely depends on the degree that both high value assets and critical urban infrastructure are affected, either directly or indirectly.

In this context, we obtain a urban society:
• more and more menaced by a lot of natural hazards
• more and more vulnerable due to increasing issues and complex urban system relations;
• less and less resilient.

This session aims at discussing how researchers, practitioners and professionals are integrating the resilient concept to set up new risk management approaches and to design more resilient and flexible cities to face all types of natural hazards. Indeed, a lot of projects in the EU are now trying to use the concept of resilience to mitigate different types of risks in urban areas. This session represents a great opportunity to exchange on resilient cities and to build up a resilience framework. We are attending presentations combining different disciplines, bringing conceptual elements on resilience but also tangible applications. All methods, frameworks, tools (GIS) designed to reduce risks in cities and integrating the resilience concept are welcome in this session.

After this session, a special issue of NHESS journal will be produced gathering 2010 and 2011 resilient city session papers.