The Case For Greenspace :

Locating Suitable Regions For Urban Greenspaces in Alabama

by Elijah T. Johnson

Ecosystem services describes the goods and services provided to humans from the natural environment. These resources include land-area, groundwater, and vegetation. Well-managed ecosystem services can be mutually beneficial for humans and the environment, including unpolluted water, climate stabilization, species biodiversity, and natural hazard mitigation. However, disaster arises, and vulnerability increases when these ecosystems are poorly managed. Land use change, pollution, and greenhouse gas emissions fundamentally change the ecosystems that provide these necessary services and lead to these grand challenges, like climate change.

One substantial alteration to the climate system that people have caused is by changing the Earth’s landscape for various human needs. For example, land use change has impacted the climate in the Southeast US by causing the average temperature to decline in the last approximately 100 years due to the transition from row cropping to a more forestry-dominated industry. However, in the last approximately 40 years, we have seen a rise in average temperatures likely due to rapid regional urbanization. In Alabama, this rapid urbanization can be seen in Montgomery, Jefferson, and Lee counties. This is of particular concern because land-use change to urban landscapes could exacerbate warming caused by a changing climate.

The urban heat island (UHI) effect is a well-studied impact of urbanization where urban areas tend to be warmer than surrounding rural or vegetated areas. Materials that make up roads and buildings tend to absorb more radiation from the sun, which makes them hotter. When these buildings are packed together in a smaller area, there can be more heat generated along with a greater density of other heat-producing machines, like cars. Populations in these dense urban areas are more likely to experience a greater UHI effect. Additionally, research has shown that households with lower income are more likely to experience a greater UHI effect.

The good news is that there may be a solution to help mitigate the effects of UHIs. Incorporating greenspaces in urban settings have potential benefits to the people who live and work there. Greenspaces are vegetated areas that tend to be substituted for hardscapes like sidewalks and blacktop. The vegetation in greenspaces can take up carbon dioxide in the atmosphere while removing heat. Greenspaces have also been shown to lower energy demand for cooling when they are situated near buildings. Having greenspaces around can improve physical health by providing places for physical activity and by lowering the chance of experiencing heat-related morbidities.

The Southeast US is expected to continue to warm along with increased urbanization. Since extreme heat can have direct negative effects on humans, our goal was to determine which areas of Montgomery, Jefferson, and Lee counties in Alabama could benefit the most from installing greenspaces.

Per capita income, population density, and land cover data were used as the criteria for urban greenspace suitability in Alabama cities. Finding suitable regions for greenspaces in Alabama cities was completed using the suitability modeler in ArcGIS PRO 2.7. A suitability model can be used to identify ideal locations for a specific purpose based on certain criteria the scientists define. Lower per capita income was given a higher ranking for suitability since income is inversely related to UHI effect, as well as higher population density. Urban or barren land cover was given a higher ranking while water bodies and forested regions were given a lower ranking. Since this was an exploratory study, the criteria were weighted about equally in the suitability model.

The suitability analysis showed that areas in Jefferson County that were most ideal for greenspaces were Central Park, Bush Hills, Inglenook, Forest Park, and Woodmeadows areas. In Montgomery County, the Old Cloverdale and Woodland Hills areas were most suitable for greenspaces. In Lee County, areas just west of Auburn University’s campus were the most suitable regions for greenspaces.

Suitability modelling can help community members are social geographers identify ideal locations for greenspaces. Several areas in Jefferson, Montgomery, and Lee counties in Alabama make ideal starting locations for greenspaces. Evaluating suitable regions and including socioeconomic factors ensures that the people who need greenspaces most access them.

A very special thanks goes out to Mason Pitre, Dr. Lindsay Maudlin, Dr. Chandana Mitra, and Dr. Karen McNeal.

Acknowledgement: This work was supported by the SouthEast Climate Adaptation Science Center and was carried out in the lab of Dr. Karen McNeal in the department of Geosciences, Auburn University.

This analysis was supported by the Southeast Climate Adaptation Science Center as part of a suite of case studies investigating the application of ecosystem services mapping in support of regional partner needs. More information can be found at ecosystem services case studies. In addition, our project Story Map can be found here.