Exploring socio-ecological inequalities in heat by multiple and composite greenness metrics: a case study in Belfast, UK

In light of pressing environmental and social justice challenges, levels of interest in green infrastructure as a possible solution have increased markedly for reasons related to both climate change adaptation and enhancing quality living environments. This study explores how green infrastructure influences the urban heat island effects experienced by communities across the socio-economic strata found in Belfast. To avoid scale effects and obtain accurate results, we devise multiple and scale-composite greenness metrics to assess the distribution of green infrastructure based on each residential unit. The results indicate that despite widespread recognition that green infrastructure significantly contributes to the mitigation of heat island intensity, socio-economically deprived communities are exposed to greater urban heat. Further examinations identified the close correlations between green infrastructure distribution and socio-economic factors, which relate to two major spatial patterns: that the suburbs are better catered for than the inner city, and that south and east Belfast are better than west and north. Moreover, our findings identified a tendency that communities with higher proportions of female- and ageing- populations have greater greenness and are less exposed to heat, which suggests the distributional and environmental injustice in GI provision and related heat adaptation are driven by the underlying socio-economic dynamics and the vulnerable groups may change based on local context. Overall, we found that there is a need to incorporate and prioritise different types of green infrastructure in plans for heat adaptation and to integrate green infrastructure development with environmental justice in areas that suffer socio-ecological deprivation in mitigating urban heat island effects.