POTENTIAL INCREASE IN HEAT STRESS IN SWEDISH CITIES DUE TO CLIMATE CHANGE: THE IMPACT OF BUILT STRUCTURE ON THERMAL

The mean air temperature in Sweden is expected to rise 2 to 5°C by 2100. Heat waves will become more frequent, intense and longer, resulting with an increase in heat-related illnesses and deaths. Urban centres are particularly vulnerable areas. Climate-sensitive planning is acknowledged to play an important role in primary prevention of heat stress in cities. In this paper, simulations of today’s and future heat stress in Göteborg, Sweden are presented. Spatial variations of the mean radiant temperature are simulated using the SOLWEIG model. Yearly, monthly and daily heat stress maps are produced and aerial means for different built structures are calculated in order to analyse the interaction between urban geometry and the thermal environment – knowledge that can be used to mitigate heat stress in urban areas. Today, extreme heat stress occurs on 2-3 days in summer in Göteborg. In the 2 and 5°C warming scenarios heat stress is expected to occur on 6 and 17 days, respectively. The study also shows that the higher built density the less daytime thermal stress at street level due to less incoming solar radiation. The opposite applies for night time. Key words: climate change, heat stress, built structures 1