Abstract
Urban areas are increasingly affected by severe heat waves due to climate change, threatening people’s health, and posing enormous challenges to human society. Nature-based solutions (NbS) are an effective way to mitigate heat, but the influence of urban green spaces (UGS) characteristics remains insufficiently understood. This study aims to evaluate the UGS potential across European urban areas by (1) quantifying UGS characteristics (percentage, size, canopy cover) and population proximity to UGS, (2) assessing the relative influence of UGS characteristics on urban heat mitigation under 27 scenarios and across four biogeographical regions by simulating cooling effects in a virtual setting, and (3) identifying groups of urban areas with differing potential of enhancing UGS for improving heat mitigation. Our results reveal spatial heterogeneity of UGS characteristics (median percentage 10.3%, median size 10,657 m², median canopy cover 9.4%) and contrasting patterns of population proximity to UGS across Europe, emphasizing the need to expand UGS and to address environmental justice issues. Simulations show that increasing UGS percentage from 6.2% to 17.2% and enlarging canopy cover within UGS from 1.7% to 44.6% in the virtual city significantly reduced the average city-wide temperature, ranging from -0.44 °C in the Mediterranean region to -0.16 °C in the Boreal region. Our findings suggest that people living in southern and eastern European urban areas, where UGS are scarcer, will mostly benefit from an expansion of UGS and more even UGS distribution, thereby improving accessibility. In northern regions, there is potential to increase cooling effects by increasing canopy cover. However, these findings require validation against empirical temperature data before being applied to specific urban areas.