Raleigh's hottest neighborhoods

Nearly a quarter of Raleigh residents live in neighborhoods where summer temperatures climb much higher than the city's average due to what's called the urban heat island effect.

Why it matters: Heat islands — wherein heat is trapped by heat-absorbing surfaces and structures — can make cities less livable and increase the risk of heat-related health complications, Axios' Alex Fitzpatrick writes.

• They can also amplify the effects of already-dangerous heat waves.

Driving the news: Around 200,000 people in the Raleigh metro area live in census tracts where temperatures increase more than 8 degrees because of the heat island effect, according to a new study from the nonprofit climate science research organization Climate Central.

Between the lines: Low-income neighborhoods tend to be more vulnerable to heat islands, making this a key climate equity issue — especially as local cities have a history of planting more shade-giving trees in richer neighborhoods.

• Heat islands can also lead to increased energy usage and costs as residents keep cool with air conditioning.

State of play: In the Raleigh metro — data was not available for Durham — census tracts in the downtown core were hotter than most tracts along the city's outer edges.

• Of the 10 hottest census tracts, seven were inside of Raleigh's beltline, its most urban area.
• A census tract in Research Triangle Park, around Page Road and home to many suburban office parks, also experienced a high urban heat island effect.

Of note: Two of the hottest census tracts actually contained parts of Falls Lake.

• That's because water has a low albedo, meaning it absorbs more sunlight rather than reflecting it, Jen Brady, a senior data analyst at Climate Central, said in an email.
• "Albedo is a large contributor to heat and is highly weighted in the equation we used to estimate temperatures," she said.

Zoom out: 41 million Americans live in urban areas where heat islands raise local temperatures by 8 degrees or more, per Climate Central's analysis of 44 U.S. cities.

• Raleigh's urban heat island effect was relatively less than many other metro areas — ranking 42 out of 44.

What's next: Cities across the country are increasingly experimenting with new ways to reduce heat islands, Axios' Jennifer A. Kingson reports.

• One popular innovation: special paint designed to reflect the sun's heat back into the atmosphere, rather than absorb it.
• Some large cities are adding a role called a "chief heat officer" to coordinate citywide responses to heat waves.

But simply planting more trees can have the biggest impact.

• Both Raleigh and Durham have city programs that try to plant thousands of trees in public right-of-ways every year.
• Durham's program is prioritizing many Black-majority neighborhoods that the city neglected in previous planting cycles, INDY Week reported.