Experts want St. Louis to participate in the work so the region can prepare for intensifying heat extremes, made worse by climate change and urban development.
“We know extreme heat kills,” said Tom Di Liberto, a scientist at the National Oceanic and Atmospheric Administration and a member of its heat risk team. “We know that’s increasing in general across the country but especially in cities.”
Walk on asphalt or lean against a brick wall in summer and you can feel the warmth they release — essentially acres of radiators amplifying the heat. The phenomenon, known as the “urban heat island” effect, is why cities are generally hotter than rural areas surrounding them. But heat doesn’t build uniformly. Parks and shady neighborhoods trend on the cooler side, while parking lots, highways and business districts bake.
Efforts to map those disparities have gained momentum in recent years. This summer, cities in 11 states — Kansas City among them — are working with NOAA to map local heat. Dozens have joined the initiative since 2017.
But not St. Louis.
“We don’t have the urban heat island really well mapped,” said Jayson Gosselin, a local meteorologist for the National Weather Service.
Findings from other cities show how drastically temperatures can vary from one pocket of town to another. The hottest and coolest neighborhoods in Baltimore varied by 17 degrees, according to research conducted through NOAA’s mapping program.
And new evidence suggests that the hotter it gets, the bigger the gaps can grow. On a 90-degree day in Portland, Oregon, temperatures can generally differ by 15 to 20 degrees, said Vivek Shandas, a professor at Portland State University who has worked on heat-mapping research across the U.S. But during the height of this year’s deadly, record-shattering “heat dome” that gripped the Pacific Northwest, the difference in cross-city temperatures grew to about 25 degrees.
“As the temperatures go up, that differential seems to expand,” said Shandas.
Homes cooking
The National Weather Service’s observation stations in the St. Louis region offer a glance at heat disparities. Readings at the Spirit of St. Louis Airport in suburban Chesterfield, for example, are routinely 5 to 10 degrees cooler than at the St. Louis Lambert International Airport, in more a densely developed area. Even at night, Lambert is consistently the warmest spot among those monitored by the NWS.
But the agency does not have stations spread throughout the region’s neighborhoods, making it harder to draw broader comparisons, thanks to factors such as differences in elevation — with Lambert sitting at one of the higher locations in the region. And while some satellite data can track surface temperatures, those might not match air temperatures that people experience.
Still, some work has been done to analyze local heat impact.
The city’s Climate Vulnerability Assessment, from 2018, reports the number of days of “dangerously extreme heat” doubled from 10 to 20 between 1970 and 2015, and will continue to rise, to 46 by 2030, and 63 — more than two months — by 2050. Residents of north St. Louis — neighborhoods that are predominantly Black and often poor — are “more vulnerable to the effects of extreme heat,” the report says.
Catherine Werner, St. Louis’ sustainability director, called extreme heat the No. 1 climate-related concern for local residents.
The city also has some thermal imaging snapshots that show at least a 16-degree difference between streets with and without trees.
Cool Down St. Louis, an energy assistance program that has served area residents for two decades, gets more calls from areas where green space is lacking, and in homes where shade is sparse, said program founder Gentry Trotter. Old housing stock — particularly some of the area’s brick homes — are particularly prone to sweltering conditions, he said.
“Old brick homes cook,” he said. “I tell you, they heat up.”
Extreme heat is a top cause of weather-related deaths, according to government data. The highest rates of heat-related emergency room visits in St. Louis, the city said, were among residents of two north city ZIP codes plus part of downtown.
Handling the heat
Experts are asking cities to improve access to cooling centers. But they’re also pushing for more aggressive action: boosting urban green space, planting trees and even “de-paving” some areas.
St. Louis city officials have dabbled with solutions, including an initiative to outfit some homes with white roofs, which absorb less heat, as well as grant-funded work to plant trees. The city has the potential to boost its urban tree canopy by 33% — or more than 13,000 acres — according to an assessment completed about a decade ago.
Shandas, the Portland State professor, said that the scale and urgency of adapting to extreme heat needs to improve. Many places have “bits and pieces” of heat plans but nothing with “regulatory teeth,” he said.
“We don’t have a heat mitigation plan for any city I know of in the U.S.,” said Shandas. “The physical design of our cities continues to move forward without any consideration of heat.”
But to engineer the best solutions, experts like Shandas say that cities first need to understand how their residents are affected by heat differently.
“It all starts with the science of getting good data and showing differences across a metro region,” said Shandas. From city to city, he hopes those numbers can then help spark conversations about how to handle the heat.
Negative impacts don’t just threaten the most vulnerable. Everyone will confront a hotter future, defined by extremes.
“Even highfalutin people are going to get hot, too,” said Trotter. “Nobody’s safe.”
© 2021 the St. Louis Post-Dispatch. Distributed by Tribune Content Agency, LLC.
