Cities are particularly affected by climate change due to their sealed surfaces, building structure and density. Climate simulation for Austrian cities show that the number of days during heat waves will almost double by the end of the century. The same applies to tropical nights, which is particularly stressful for the human body. Rising temperatures directly and indirectly impact health and increase the vulnerability of society. This affects all populations, but especially those who are more exposed to heat or more physiologically or socio-economically vulnerable.
Climate resilience promises to be an effective means for helping cities to deal with future uncertainties and unexpected impacts. By transforming the city into a system which is able to absorb disturbances, adapt, recover, self-organize and learn, the range for coping with future climate changes is widened.
Nature-based solutions hold the potential to increase climate resilience in cities as plants and water balance the urban microclimate. Shading and evapotranspiration act like a natural air conditioner and unsealed surfaces can retain extreme precipitation events and relieve the sewage system. The positive effects of nature-based solutions (NBS) on the urban climate could be proved in climate simulations for the City of Vienna, where COSMO-CLM runs with and without NBS were calculated. The evaluation of large-scale impacts of greening proves the positive effect of green and unsealed surfaces with respect to heat storage and lower night-time temperatures.
Although NBS show many positive micro-climatic effects, the analysis of the societal implications of urban adaptation to climate change such as gentrification processes is still in its infancy. Therefore, it is necessary to study how a transition to a climate resilient society can be facilitated without neglecting questions of social equality and climate justice. First insights of the SENSUS project, which addresses exactly this issue, will be presented in this paper.