Climate change and built environment - the role of urban greenery as a mitigation strategy in Greek urban areas

Abstract Extreme thermal conditions and heat waves, as a result of global warming, have increased in recent years. Especially in the Mediterranean area, cities face higher temperatures during summer months which severely affect thermal comfort and citizens’ well-being. In this context, this study aims to evaluate the role of urban greenery as a mitigation strategy and focuses on its effect towards the improvement of the urban microclimate and thermal comfort under extreme summer conditions. To this aim, a typical square, located in Athens, Greece, has been chosen as a case study. The microclimatic conditions are evaluated for its present state and after an increase of 20% of soil surface and 30% of trees, while both current (i.e., 2020) and future summer climatic conditions (for the year 2060) are examined. It was also proposed that all the soil surfaces would be covered in grass. The potential air temperature, mean radiant temperature and surface temperature are analysed by simulation means, using the ENVI-met microclimate simulation tool. The results of this study showed that increasing the vegetation ratio inside the study area contributes to considerably lower surface temperatures, while a significant reduction on mean radiant and air temperature at the pedestrian level is also achieved, forming better microclimate conditions. Urban greenery is an important factor for healthy and resilient cities. Its presence can provide lower temperatures in the pedestrian level during summer months, reforming the microclimate. The outcomes of this study can be used by urban planners and stakeholders to improve environmentally urban areas, mitigate the results of climate change, and create resilient cities.