UofL, TreesLouisville release updated Louisville urban heat mitigation study

As another heat wave hits the local region this week, the University of Louisville Christina Lee Brown Envirome Institute, in partnership with TreesLouisville, has released results and recommendations in this 2026 follow-up study that analyzes Louisville’s tree canopy and urban heat island. 

Residents are well acquainted with the challenges caused by urban heat, such as higher utility bills and serious health problems that disproportionately affect disadvantaged communities and residents with pre-existing health conditions. The initial foundational study commissioned in 2016 and co-authored by Brian Stone, a professor and director of the Urban Climate Lab at Georgia Institute of Technology, identified Louisville as having the fastest-growing urban heat island in the United States at that time. 

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As part of Envirome’s Greenprint initiative, Stone re-visited Louisville in June 2026 to present the newest findings to Louisville Mayor Craig Greenberg, environmental researchers and community members. Louisville is the first city in the nation to have commissioned a follow-up study.

Aruni Bhatnagar, director of the Christina Lee Brown Envirome Institute, highlighted the organization’s mission and commitment to community-centered health research.

"We need to do things that matter in people's lives,” he said. “This study is one example of how our work can have a direct impact on the health of our community."

Stone shared results from the 2016 and 2026 urban heat risk assessments and proposed a series of short-to-medium term strategies to enhance the city’s affordability, mobility and economic stability as a product of continuing investments in climate-adaptive infrastructure.

The research results yielded valuable information about Louisville and future planning, including:

• Between 2016 and 2024, hot afternoon temperatures increased in about two-thirds of all neighborhoods in Louisville, with some neighborhoods experiencing a rise in temperatures exceeding 10°F.
• In August of 2024, some neighborhoods were 20°F hotter on a typical hot day than other, more well-canopied neighborhoods.
•  If trees were added to 50% of the available spaces for tree planting in each neighborhood, high afternoon temperatures would fall by an average of 1.8°F, with some neighborhoods cooling by as much as 7°F.

The project, which used advanced climate models to generate highly detailed, hourly temperature maps for June, July and August 2024, offers an unparalleled view of where heat is most intense across Louisville's urban core. The study highlights areas where residents are most vulnerable to heat-related illnesses and where targeted urban forestry and greenspace strategies are most urgently needed to improve public health outcomes. 

These insights will help guide tree planting initiatives by TreesLouisville and other partners, ensuring that efforts maximize cooling benefits. 

Stone said Louisville is an ideal city to embrace adaptive urbanism, a strategy where climate-resilient investments like tree planting are integrated with broader municipal goals such as affordable housing, utility cost reduction, land use efficiency, multi-modal transit and reducing auto dependency. 

Once ranked among the most rapidly warming U.S. cities, Stone said Louisville holds the potential to emerge as a global model for climate resiliency. 

"If you want to create a city that is both economically resilient and environmentally resilient, I think you've already done the hardest part, and that is saving these kinds of spaces that are scaled to humans, that are endlessly adaptive to all kinds of different uses over time, and that are just inspiring to the people who move through them and live in them,” Stone said, referring to Louisville’s wealth of historical architecture.

For more detailed information on the study, visit the StoryMap that illustrates key findings.