Future megacity-regions and heatwave exposure

Projections for urbanization and the impacts of climate change suggest increased size and number of cities and increased variability in climate, with the latter bringing risks to the former. This chapter presents a range in projections for the emergence of megacity-regions and for resident exposure to one climate impact: very warm (> 42°C) 15-day heatwaves. Results suggest that by 2100, even under low urban growth pathways and the least climate changes in temperatures, up to 1 billion megacity-region urban dwellers, or 72 per cent of the megacity-regions’ population will be exposed to very warm heatwaves. Under the highest urban growth scenarios and greater climate change, between 1.5 and 2 billion urban megacity-regions dwellers will be exposed, or over 80 per cent of the giant city urban population, by the end of the century. These findings point to the need for planning and policy strategies for cooling our very large urban areas.