The impact of green areas on mitigating urban heat island effect: A review

Urban Heat Island (UHI) is one of the major problems in the 21st century as a consequence of urbanisation and industrialisation of human civilisation. The main source of UHI is the considerable amount of heat produced from urban structures, as they absorb and re-radiate solar radiations. Therefore, urban heat islands develop in areas with a high percentage of non-reflective, water-resistant surfaces and a low percentage of vegetation. Specifically, a lack of vegetation reduces heat lost due to evapotranspiration. Vegetation, particularly in the presence of high moisture levels, plays a vital role in the regulation of surface temperatures, even more than may nonreflective or low-albedo surfaces. There are different ways of reducing the effects of UHI. However, a common measure to mitigate urban heat island is to increase urban green spaces such as parks, street trees and green roofs. This paper discusses the current literature and knowledge about the impacts of green spaces on mitigating UHI. Studies conducted on the influence of greenery on mitigating UHI have indicated that all green spaces help urban areas adapt to the impact of UHI regardless of whether they are parks, street trees or green roofs.