Source: Janette Monear and Ed Heffernan, “Commentary: It’s not your imagination, Dallas is getting hotter — and here’s why,” The Dallas Morning News; Brandon Loomis, “In Dallas as in Phoenix, people look to trees for relief from urban heat islands,” AZCentral
Dallas, TX (January 5, 2018) – Among cities with a population greater than 1 million, excluding Phoenix, Dallas is heating up faster than every other city in the country. A 2017 Dallas Urban Heat Island Management Study from the Texas Trees Foundation provides reasons why the city needs to rethink how it handles growth, and build a better balance between the gray and green infrastructures.
The research, funded by Alliance Data and considered one of the most comprehensive urban heat studies in the country, found that more than one-third of Dallas is covered in concrete and commercial and residential buildings. Together, these impervious surfaces form urban heat islands, areas that absorb and then very slowly release the heat from the sun.
This study shows that these urban heat islands, especially in the downtown core of Dallas and along Interstate 35, can be 15 degrees hotter than our rural neighbors, with average temperatures of 101 degrees over the 150-day warm season. Average low temperatures for the same period are pushing 80 degrees, making it difficult to regulate body temperatures or building temperatures effectively.
According to heat island study partner Brian Stone, professor with the School of City and Regional Planning at the Georgia Institute of Technology and author of The City and the Coming Climate — Climate Change in the Places We Live, “Cities do not cause heat waves — they amplify them.” Stone notes that, accounting for both land surface changes and emissions of greenhouse gases, human activities at the city and regional scale may have twice the impact as that of greenhouse gases alone on climate.
The economic impact of the urban heat burden is reflected in higher costs for businesses, a major consideration in a region that has been a magnet for corporate relocations and expansions. Increased temperatures translate to increased energy demand and infrastructure repair costs, and those costs are passed to taxpayers.
Equally important, public health issues increase with higher temperatures, especially for children. The No. 1 reason for emergency room visits at Children’s Medical Center in Dallas is acute asthma and respiratory-related illnesses, which spike during heat-induced poor air quality days and can be life-threatening.
According to Children’s Health, annual economic costs to Dallas, including costs to families and medical care facilities across the community for respiratory-related illnesses, is estimated to be a staggering $60 million. Texas Trees’ study reveals that during the 2011 heat wave in Dallas, there were 112 heat-related deaths, 52 of those directly related to the urban heat island effect.
What’s the solution? Adaptation strategies and public policies that include requirements for municipalities to plan and use trees and green infrastructure in development, combined with the use of reflective roofs (both commercial and residential), are a good start. Shade trees and green infrastructure are cost-effective solutions for the mitigation of heat.
The study provides the data and framework for a citywide urban forestry program to protect, plant and maintain the more than 14.7 million existing trees in Dallas and the strategic planting of 600,000 additional trees to increase the city’s tree canopy from 29 percent to 35 percent — a reasonable and achievable goal for Dallas.
But one nonprofit can’t do it alone. Public and private partnerships are extremely important. Businesses and local governments have an important role as change agents working toward a solution. In addition to committing financial support for these efforts, companies must continue reducing their carbon footprints, while at the same time balancing the gray with the green when building or expanding facilities on their corporate campus sites. And they should involve and educate employees, who can serve as powerful advocates to encourage their city leaders to take action in investing in our communities.
Together, corporations, nonprofits and cities can support a strategic plan to make our cities greener, cleaner and cooler, creating an environment that is healthy for our children and future generations.