Janette K. Monear for the Dallas Morning News
July 31, 2018
This weather is a scorcher, especially in cities like Dallas with lots of concrete and few trees.
Driveways, sidewalks, parking lots, roads and plazas absorb the sun’s heat, getting hot enough to burn the soles of your bare feet or the paws of your furry best friend. These areas, known as urban heat islands, are slow to cool down, especially when temperatures don’t significantly drop during the evening and night.
The Dallas Urban Heat Island Management Study, completed in the fall of 2017 by the Texas Trees Foundation, found that if you live in, or near, an urban heat island, then you’ll experience temperatures that can be 50 to 90 degrees hotter than reported temperatures.
This condition can be lethal. In 2011, there were 52 deaths in Dallas County directly related to heat stroke and heat exhaustion. When temperatures outside are high for prolonged periods of time, the body has trouble regulating its own temperature. The most vulnerable are children up to 4 years of age, people 65 and older, and people who are overweight or have existing medical conditions such as diabetes, heart and kidney disease and lung problems. Anyone of any age can succumb to heat if working or exercising outside during hot weather, especially on or near an urban heat island.
When the weather forecaster says, “Today we will reach 108 degrees,” that doesn’t take into consideration the radiant heat coming off the surface of the ground in the city of Dallas. On July 19 at 3 p.m., the Texas Trees Foundation recorded surface temperatures on the plaza at Dallas City Hall at 142.5 degrees and surface temperatures at Fair Park of 151 degrees.
High surface temperatures don’t know boundaries. Heat radiates out into neighborhoods, making it more costly to cool your home — if you’re lucky enough to have air conditioning. The impact of air conditioning is cooler indoor air but higher energy costs that can affect cash flow, especially for those on fixed and low incomes. This often results in compromised spending. The economic impact of urban heat goes beyond energy costs into health-related costs, which is why Dallas County has had a program to provide air conditioners to at-risk citizens. Real costs are both tangible and intangible.
Brian Stone, author of Cities and the Coming Climate and collaborator for the 2017 Dallas Urban Heat Island Mitigation Report, says “urban heat islands do not cause heat waves, they amplify them.”
Serious consideration needs to be given to planting more trees to shade urban heat islands, and greater attention needs to be given when designing communities. Cities were designed and built for cars, but cars don’t die of heat stroke. It’s time we begin to mitigate the urban heat for people.
A first step, and most cost effective, is to reforest our cities through a strategic tree-planting plan. The 2017 Dallas Heat Mitigation Report found that a minimum of 250,000 trees need to be strategically planted in Dallas, focusing on 32,300 trees in northeast Dallas and 3,700 in downtown Dallas. This would begin the process of reforestation, but if we are to move the needle to get to 35 percent tree canopy overall, we need additional plantings throughout the city and protection of existing trees, especially in southern Dallas. Planting 1 million trees on both public and private lands; protecting trees, especially large groups of trees; and high management of the great Trinity Forest will position Dallas to have one of the best urban forests in the country, if not the world. This would help address the health risks we face from air and water quality, as well as heat.
Through efforts like the Cool Schools and NeighborWoods programs and the redesign of the Southwestern Medical District, the Texas Trees Foundation has begun to mitigate the urban heat island effect and increase the tree canopy in Dallas. With a staggeringly low 7 percent tree canopy in the Southwestern Medical District and on the campuses of our Dallas ISD schools, we need greater investments in one of our most productive natural resources: trees.
There is no upside to urban heat. Mitigation strategies and solutions are necessary and cost effective and have a high return on investment. Plus, it just may save lives. Let’s get busy making our cities greener, cleaner and cool — now.
Janette K. Monear is chief executive of the Texas Trees Foundation. She wrote this column for The Dallas Morning News.