Cool Ideas for Reducing Urban Heat-Island Effect

More U.S. cities are or will be at risk of extreme heat because of climate change and increased urban development.

More U.S. cities are or will be at risk of extreme heat because of climate change and increased urban development.

By ecoRI News staff

The impact that rising temperatures and excessive heat are having on urban development, and strategies to mitigate urban heat-island effects are explored in a new report published by the Urban Land Institute.

Scorched: Extreme Heat and Real Estate explores how extreme heat is emerging as a growing risk factor and planning consideration across the United States. The 76-page report also examines how the real-estate industry is responding with design approaches, technologies, and new policies to mitigate the impacts and help protect pubic health.

According to the Urban Land Institute (ULI), a global organization dedicated to responsible land use, the real-estate sector can improve resilience to extreme heat through mitigation strategies that reduce temperatures and adaptation tactics to help people and businesses cope with extreme heat.

The report noted that:

More cities in the United States are or will be at risk of extreme heat because of climate change and increased urban development.

Extreme heat is a pressing health risk, particularly for low-income and elderly communities.

Without intervention, the current and potential future impacts of extremely high temperatures — on real-estate developments, infrastructure, and the economy — could be substantial.

The widespread adoption of mitigation strategies could help reduce the urban warming trend, leaving cities to contend with a more manageable 1- to 2-degree Fahrenheit increase, rather than the 5- to 10-degree increase currently projected for some cities.

The report provides a snapshot of the urban warming issue, with several statistics documenting the impact of extreme heat, and offers potential strategies to address the problem:

$1 billion: the amount saved on electricity costs if all commercial buildings in the United States switched from dark to light roofs.

30-40 degrees Fahrenheit: the amount by which green roofs can be cooler than conventional rooftops.

2 years: the average payback time for installing a green roof on commercial buildings.

35 degrees Fahrenheit: the maximum amount that trees reduce surface temperatures. Trees also reduce summer air temperatures by 2-9 degrees Fahrenheit.

10 percent: the decrease in office worker productivity in thermally uncomfortable and poorly ventilated environments.

Cool design strategies, combined with public health and emergency responses, can help offset heat-related mortalities.

Increase shading with the use of built and/or natural canopies.

Use “heat aware” building envelopes and heating, ventilation, and air conditioning choices that stabilize indoor temperatures even during power outages.

Investments in extreme heat mitigation technology and approaches can lead to a host of benefits, according to ULI, such as improved tenant experience, reduced operating costs, and enhanced branding.

For instance, the report noted that being “heat-resilient” can potentially reduce the likelihood of construction delays caused by extreme heat; increase support from investors, public officials, and other stakeholders; and reduce stress on public infrastructure.

“As extreme heat becomes increasingly prevalent because of the urban heat island effect and climate change, designing for heat and ensuring users’ comfort is likely to become a mainstream concern,” according to the report. “This translates into different design and development decisions for buildings, which may need enhanced cooling capacity, and for public spaces and outdoor retail environments that are likely to be used differently in hot weather.”