Benefits of Managing the Heat Island Effect
Urban areas, where structures are highly concentrated and greenery is limited, become Heat Islands of higher temperatures relative to outlying areas.
Heat islands form under a variety of conditions, during the day or night, in small or large cities, in suburban areas, in northern or southern climates, and in any season.
Efforts to reduce the heat island effect, mitigate climate change, and adapt to climate change impacts often interact with each other in complex ways.
What are Heat Islands?
Urban structures such as buildings, roads, and other infrastructure absorb and re-emit the sun’s heat more than natural landscapes such as forests and water bodies.
Most efforts to cool urban heat islands produce many benefits, including lower temperatures, electricity demand, air pollution, greenhouse gases, and harmful health impacts. Efforts to reduce the heat island effect thus also help to address climate change and improve air quality. In addition, these same measures can help communities become more resilient to many of the damaging impacts of climate change.
- Planting shade trees or installing green or cool roofs can lower surface and air temperatures while reducing the amount of energy needed to cool buildings, resulting in improved reliability of the electric system, particularly during extreme weather events.
- Green roofs and some types of cool pavements can diminish heat islands while also reducing stormwater runoff, and limiting flooding risks during heavy rainstorms. In the same way, increasing the tree canopy helps protect against high winds, erosion, and flooding.
- Smart growth can cool urban areas, while also decreasing the need for fossil fuel-powered transportation and improving access to cooling centers.
In some cases, climate change adaptation or mitigation strategies might conflict with heat island reduction efforts. For example, any adaptation effort that results in replacement of vegetative cover with impermeable surfaces, such as hardening coastal infrastructure to protect against rising sea levels, could increase the heat island effect. However, communities can help minimize such negative outcomes by incorporating cooling strategies into overall climate action planning (mitigation and adaptation).