Monday numbers: Mapping urban heat islands to blunt the health risks of climate change

How hot is it on your block?

If you live in an historically Black neighborhood, it’s probably hotter than in whiter, more affluent areas.

As climate change leads to more extreme temperatures, communities of color are more vulnerable to the health risks of the heat. According to federal climate research, within the same city, “some neighborhoods can be up to 20 degrees hotter than others and, due largely to the practice of historic redlining — discriminatory, race-based lending and housing policies in the 1930s — these hot spots are often home to poorer communities of color.”

This summer, volunteers will disperse throughout more than 20 U.S. cities — including Raleigh and Durham — to take their neighborhoods’ temperature. (Disclosure: I’m volunteering for the program.) Using heat sensors mounted on their own cars or bikes, community volunteers, led by a team of local partners in each city, will traverse their neighborhoods morning, afternoon, and evening on one of the hottest days of the year. The sensors will record temperature, humidity, time, and the volunteers’ location every second. NOAA’s National Weather Service will provide forecasts to help the communities plan their campaigns.

The Museum of Life and Science in Durham is the lead community organizer for North Carolina.

The data will help researchers at NOAA’s Climate Program Office and state climate programs to find ways to cool these neighborhoods and the people who live in them. This could mean planting more trees; research has shown communities of color have fewer trees, parks and other environmental amenities than their predominantly white counterparts. These neighborhoods could also be candidates for federal- and state-funded cooling centers and installation or upgrades of home air conditioners.

In North Carolina, climate scientists predict that overall temperatures will increase predominantly at night. This is particularly dangerous for people vulnerable to the heat — those who live in urban heat islands, outdoor workers, the elderly, children and the chronically ill — because their bodies have no recovery time to cool down.

“Communities are taking action to manage dangerous extreme heat that’s impacting their families and neighbors,” said Hunter Jones, Climate and Health project manager with NOAA’s Climate Program Office in a press statement. “As climate change brings worsening heat waves, the information from these campaigns will help bring local and equitable solutions to those facing the greatest threat.”

After the data are collected they will be released in a report with maps, charts and other information. Previous participating cities, such as Fort Lauderdale, Fla., have released their reports.

Here some relevant and sobering numbers relevant to this topic:

421.36 ppm — Global concentration of carbon dioxide in the atmosphere, recorded on April 8, 2021, at Mauna Loa Observatory in Hawaii. It is the highest daily reading in   recorded human history.

274 million — Number of people who live in metropolitan areas in the U.S., equivalent to 85% of the population

80% — Percentage of human-caused greenhouse gas emissions in North America attributed to urban areas

1-5% — Percentage of land in North America that is urban

20 — degrees hotter in some urban neighborhoods, mostly communities of color, than whiter, more affluent urban areas

94% — Percentage of formerly redlined urban areas nationwide, which remain mostly lower income communities of color, that are exposed to higher temperatures than non-redlined, affluent areas

239 — Number of U.S. cities that had federally redlined neighborhoods, as part of the Home Owners’ Loan Corporation in 1930 (this is an underestimate of redlined neighborhoods because the maps were drawn for cities with populations of 40,000 or greater)

5 — Number of N.C. cities in the HOLC maps: Asheville, Charlotte, Durham, Greensboro and Raleigh

1968 — Year redlining was officially outlawed, although the legacy of these racist policies persist in terms of home values, public investment, environmental amenities, proximity to pollution and more

30 — Number of days the heat index exceeded 105 degrees, RDU, 1972-1981

63 — Number of days the heat index exceeded 105 degrees, RDU, 2011-2020

1 — Number of days in the past 70 years when the heat index exceeded 115

2010 — Year that extreme heat index occurred

Sources: NC Climate Office, Mapping Inequality, National Heat Health Integrated System, NOAA