Evaluation of Nature-Based Solutions to Improve the Urban Microclimate in Mediterranean Climate Conditions: A Case Study of Izmir-Karsıyaka

Abstract

Today, rapid urbanization and increasing human activities have affected the climate at macro and micro scales in cities and caused unfavorable conditions in terms of human thermal comfort, especially in outdoor spaces. In this context, new solutions need to be researched, developed, tested, and updated to improve thermal comfort in cities. Using ENVI-met 5.1 software, this study investigated the effects of different NBS combinations on the urban microclimate and human bioclimatic comfort in Izmir (Turkey). The current situation, the scenarios where some nature-based solutions (NBS) are applied within the scope of the European Union’s HORIZON 2020 “URBAN GreenUP” project, and two other scenarios planned within the scope of the study were evaluated. The findings of the study showed that both the NBS scenarios created within the scope of the EU project and the NBS scenarios with large deciduous trees had the most positive impacts on improving thermal comfort conditions in all three study zones and achieved temperature reductions of up to 2.5 °C in urban temperatures. In terms of thermal comfort, the most significant differences were calculated between the minimum PMV values and were close to 1 °C. In addition, the simulation results showed positive changes in psychological stress levels.