A cost–benefit analysis of implementing urban heat island adaptation measures in small- and medium-sized cities in Austria

Urban heat islands are an increasing concern even in small- to medium-sized cities, although these areas are still understudied especially in terms of the economic feasibility of adaptation options. This paper uses adaptation scenarios produced by an urban climate model as inputs to a social cost–benefit analysis in three small- to medium-sized cities in Austria: Mödling, Klagenfurt, and Salzburg. The adaptation scenarios, which consider measures such as increasing the reflectivity of different sealed surfaces (referred to as the White City scenario) as well as greening measures (i.e. the Green City scenario), show decreases in the number of hot days (T max ≥30°C) when implemented. Benefits include reductions in heat-related mortality, which are modeled based on trends of daily mortality and climate data, reduced morbidity, productivity loss, and numerous urban ecosystem services. The results demonstrate favorable benefit–cost ratios of a combination of measures (White and Green City) of 1.27, 1.36, and 2.68 for Mödling, Klagenfurt, and Salzburg, respectively, indicating positive economic grounds for supporting policies in line with the adaptation scenarios. Furthermore, results of the Green City vs. White City showed higher benefits for the combined and Green City scenarios despite higher costs for each of the cities.