Identifying priority heat-risk areas in Granada, Spain, using InVEST and landscape metrics

Abstract

The urban heat island effect and its disproportionate impact on vulnerable groups is a major challenge for cities. The aim of this research is to identify heat-risk areas and to examine the effect of vegetation spatial patterns on heat mitigation. The focus of the study is on Granada, Spain, and its metropolitan area, serving as a relevant case study due to its status as a medium-sized city within the Mediterranean region, a location particularly vulnerable to climate change. We used InVEST for urban heat island modelling and calculated heat vulnerability and exposure indices. We also used Boosted Regression Trees to assess the importance of the spatial composition and configuration of the vegetation in heat mitigation. We identify priority heat-risk areas for intervention highlighting regions where high heat exposure and vulnerability overlap. Our results show that the combination of green cover above 35 % and mean patch size above 200 m2 maximized heat mitigation. However, because most of the priority areas are located in densely populated and built-up areas, the suggested approach could be on creating interconnections between smaller green infrastructures to increase their cooling capacity. We highlight the need for urban planning strategies that prioritize heat-vulnerable populations, while optimizing the spatial configuration of green infrastructure by focusing on Nature-based Solutions.