Urban Heat and What Cities Can Do To Keep Cool
Urban areas are especially vulnerable. Since buildings and roads absorb heat, cities can be up to 7°F warmer than natural areas. This adds to the heat island effect, which poses risks to human health and environment. It discourages physical activity, requires greater energy use for air conditioning, and elevates risks for heat-related illnesses.
Reducing heat’s impact on health starts with identifying the physical and social contributors.
Heat vulnerability is a function of three factors. They are: 1) exposure to heat at specific locations, 2) sensitivity characteristics of the population such as age and health status, and 3) adaptive capacity (ability to mitigate the stress).
Heat resilience tactics are diverse. Solutions include adding tree canopy, indoor cooling, shade structures, asphalt reduction, cooling centers, green infrastructure, and green roofs.
But finding the most effective mitigation options is difficult. Even more so when viewing all the costs and benefits for each. Triple-bottom-line and lifecycle cost assessments are two decision-support tools that help compare project outcomes. We analyze social, environmental, and economic impacts over the lifetime of a project.
A stand-alone framework for heat vulnerability mitigation would be costly. A better path is to include many benefits within a project. Examples include encompassing categories for greenhouse gas emissions, changes in abutting property value, stormwater management, and human health.