How hot? Initiative measures, maps extreme temps, risk

Charlotte is one of 14 cities selected by the National Oceanic and Atmospheric Administration to identify areas where people are most at risk during extreme heat waves, the top weather-related cause of death in the United States over the last three decades.

Low-income communities in Sunbelt cities like Charlotte are typically most vulnerable to heat-related health emergencies. How hot are Charlotte’s heat islands? A coalition of community groups, nonprofits, and government agencies will spend the summer mapping temperature variations across the city. The collaboration, called Charlotte Heat Mappers, will be led by UNC Charlotte’s Department of Earth, Environmental and Geographical Sciences.

Charlotte is one of 14 U.S. cities selected by the National Oceanic and Atmospheric Administration to identify areas where people are most at risk during extreme heat waves, which according to the federal agency is the top weather-related cause of death in the country over the last three decades.

Community-driven Effort

“This is truly a community-driven effort,” UNCC urban planning researcher and Charlotte Heat Mappers leader Katherine Idziorek told the school’s news website. “Our partners are hungry to learn more about the distribution of urban heat across our city. We are very excited about the potential of this data to empower Charlotte communities and to help them advocate for solutions that will improve their health and wellbeing.”

Urban Heat Islands

Urban heat islands, defined as communities with little tree cover and more pavement and concrete that absorbs heat, can be up to 20 degrees hotter than neighborhoods with more trees, grass, and less asphalt. The health risk burden associated with extreme heat is not distributed equitably and disproportionately affects vulnerable populations such as low-income communities and communities of color.

Local environmental factors such as humidity and air pollution can further compound health risks. Climate change has a disproportionate impact on vulnerable communities that lack the economic scale or flexibility to mitigate health-related hazards.

Disproportionate Impact

According to a study by Princeton University researchers, “people of color are found to be particularly more vulnerable to heatwaves, extreme weather events, environmental degradation, and subsequent labor market dislocations.” Extreme heat – a summer staple in Sunbelt cities like Charlotte – takes a greater toll on Black people than other ethnic groups.

According to data from the Killer Heat Report authored by the Cambridge, Massachusetts-based nonprofit Union of Concerned Scientists, the average number of days with a heat index above 105 degrees Fahrenheit is higher in counties where Black people make up at least 25% of the population (about twice the national average) compared to those that aren’t.

Addressing the Issue

With federal legislation on environmental sustainability stalled in a politically divided Congress, state and local governments are stepping up. Mecklenburg County commissioners in 2022 approved $50 million to buy land for parks, greenways, and nature preserves in fiscal year – $30 million more than the previous fiscal year.

Mecklenburg has developed more than 60 miles of greenways – about a fifth of Mecklenburg’s goal of a 308-mile network. Charlotte has made infrastructure inroads by building dedicated bike lanes to encourage less dependence on fossil fuel transportation in addition to light rail.

Justice40 Initiative

Heat island mapping is part of the Biden administration’s Justice40 initiative in which federal agencies work with states and local communities to deliver 40% of benefits from federal investment in climate and clean energy to underinvested communities. Volunteers will use specially designed sensors mounted on their cars and drive along predetermined routes to record ambient temperatures and humidity in the morning, afternoon, and evening on one of the hottest days – likely in mid-July.

NOAA’s science consultant will compile the information into area-wide maps and a report that will help local decision-makers, planners, and health organizations take action to reduce health impacts.

Past Initiatives

Access to heat islands data from previously mapped cities, including Raleigh and Durham’s 2021 campaign is open to the public and available on the federal website HEAT.gov. Charlotte’s community scientists will be recruited in May and June by Charlotte Heat Mappers volunteers.

Cities involved in previous heat mapping initiatives have used their data and maps to implement tree planting strategies, direct neighbors to the location of cooling shelters, develop heat action plans, and direct new research.