On the impact of climate change on urban microclimate, thermal comfort, and human health: Multiscale numerical simulations

Climate change is expected to aggravate urban microclimatic conditions and have adverse effects on human morbidity and mortality. However, there is limited knowledge on the impact of climate change on urban microclimate and human health for actual urban areas. In this study, we investigate the impact of climate change on urban microclimate and pedestrian thermal comfort within a complex district in Nicosia, Cyprus. Two climatic scenarios are considered: (i) current scenario based on meteorological conditions derived from field measurements performed in 2010, and (ii) future scenario for which meteorological conditions of 2050 are based on downscaled Regional Climate Models (RCMs). URANS CFD simulations are performed for the period of 9-10 July with a 1-h time-step. The results show that by 2050, the maximum air temperature at the pedestrian height of the case study area can increase by 2.3 degrees C which can increase heat-related mortality by more than 240 %. The UTCI is expected to significantly increase especially in the afternoon hours with up to a 4.3 degrees C increase at 20:00. The "very strong heat stress" conditions (UTCI: 38-46 degrees C) are expected to prevail for a longer period during the day, increasing from 3.3 to 6.6 h. In addition, the "extreme heat stress" conditions (UTCI: >46 degrees C) are expected to apply in parts of the area. This prolonged exposure to heat stress can incite additional health risks.