Nashville will see an increase in 100° heat index days

Virtually all of Tennessee is in the midst of a climb that will see the number of extremely hot days skyrocket over the next 30 years, according to new research.

• Davidson County could ultimately spend a month-and-a-half of each year with a heat index of more than 100°.

By the numbers: Researchers estimate Nashville will experience about 26 days that feel like more than 100° next year. That tally could grow to 45 days by 2053, according to new, hyperlocal data from the First Street Foundation.

• The number of extremely hot days is expected to grow even more rapidly in Memphis and West Tennessee.

Why it matters: The data put the systemic impact of climate change and the emerging "extreme heat belt" that includes Nashville into brutal, real-life terms.

State of play: It's already really hot. This year marked one of the hottest summers ever in Nashville, according to the National Weather Service.

• NWS meteorologist John Cohen tells Axios that the meteorological summer in 2022, which runs from June-August, was the city's seventh hottest on record, with an average temperature of 81.4°.

Between the lines: Climate change is causing heat waves to be more intense, longer-lasting and more frequent. Studies in recent years have shown that some extreme heat events likely would not have occurred in the absence of human-caused climate change.

What's next: Nashville participated in a heat-mapping project on Aug. 14 to determine what parts of the city get the hottest.

• Kendra Abkowitz, the city's chief sustainability and resilience officer, told Axios last month that the final results should be available this fall.

Zoom in: Cities are typically hotter than their surroundings, in part because of the prevalence of dark surfaces that absorb heat like pavement and rooftops. The "urban heat island" effect can disproportionately harm low-income neighborhoods, Axios' Jennifer A. Kingson reports.

• But experts say mitigation measures could dramatically improve conditions.

Abkowitz said the local heat-mapping data would help guide Nashville's mitigation strategy.

• Options could include expanding the tree canopy, using different materials for roofing and roads, and creating hydration centers.