Urban Green Infrastructure as a tool for urban heat mitigation: Survey of research methodologies and findings across different climatic regions

We surveyed the distribution of methodologies employed, spatio-temporal scales considered, type and extent of UGI, climatic variables studied and contribution of UGI to ambient air cooling and enhancement of human comfort. It was found that neither the differences in geographic location or in climate conditions had a significant impact on the choice of research approach. The studies, mostly done on limited spatio-temporal scales, have focused on the rate of air cooling by UGI, and to a lesser extent on its impact on thermal comfort. Maximum observed intensities of park cool island (PCI) effects typically ranged between 1.5 °C-3.5 °C, with no apparent correlation to climatic region. However, there is a tendency seen for larger green sites to induce a stronger PCI, whereas well-shading street trees also have a significant cooling and relieving effect.