Sound urban planning key to mitigating heat waves

The recent editorial in the Philippine Daily Inquirer titled “Are we ready for ‘global boiling’?” (7/30/23) calls urgent attention to the impacts on people’s health, water supply, food production, and livelihoods of the increasing frequency and intensity of heat waves. While increasing temperature is affecting the whole country, it is particularly making our cities some of the hottest places to be. And the United Nations has predicted that there will be more and more heat waves in the years to come.

People living in cities are at a higher risk of heat waves because city infrastructure—like roads and buildings—absorbs heat and then releases it back into the city, thus creating the “heat island effect” which is the highest temperatures in urban areas during a heat wave. But city dwellers have a major problem in trying to keep cool. Air-conditioning systems use tons of fossil fuels which only makes the problem worse. While houses and offices stay cool, the planet does not.

Local governments, however, can take steps to help residents, infrastructure, and systems reduce their vulnerability to heat, both in response to an extreme heat event and as part of longer-term planning to lessen future risks. The most effective way to reduce the negative impacts of an extreme heat event is to develop a comprehensive heat response plan that combines individual strategies into an integrated approach. Components of such a plan can include forecasting and monitoring, education and awareness, heat wave response, and infrastructure improvements.

Reliable weather forecasts allow city officials to warn citizens and emergency agencies of heat waves in a timely manner and to prepare for responses, similar to that for typhoons, extreme rainfall and flooding. In addition to providing extreme heat warnings, local governments should have a public health outreach program to communicate information about potential risk factors, symptoms of excessive heat exposure, and recommended response and treatment.

During heat waves, local governments can take a number of steps to protect residents and infrastructure, such as establishing hotlines to alert public health officials about high-risk or distressed individuals; ensure proper functioning of energy and water systems; encourage energy conservation to reduce demand on electricity systems; and implement load restrictions for older roads and bridges to reduce traffic on vulnerable transportation infrastructure.

Local governments can also help urban areas adapt to extreme heat in the short-term by improving the resilience of infrastructure. Transportation planners and engineers can protect or modify roads, bridges and other structures, for example, by using materials that are more resilient and heat tolerant, to help these systems withstand higher temperatures and reduce service disruptions. They can also implement energy efficiency and conservation efforts to reduce stress on electricity systems during heat waves and help avoid power outages.

City officials can also incorporate heat island reduction strategies—such as green or cool roofs, cool pavements, or increased vegetation and trees—into long-term planning to help reduce extreme temperatures during future heat waves. For example, local building codes that promote “living walls” and urban agriculture or gardens on roofs can help keep buildings cooler. Cool pavements—which absorb less heat from the sun, and in the case of permeable pavements, absorb more water than concrete or asphalt—can be used for roads and parking lots to help cool areas. These measures also reduce flooding as well as electricity demand, which helps improve the reliability of the electric system, particularly during heat waves.

Sound urban planning that includes measures for adapting to extreme heat in both the short- and long-term is an effective way for cities to respond to the heat island effects while fulfilling their mission to protect and provide vital services to the community.

Nathaniel von Einsiedel, principal urban planner, CONCEP Inc.