Why are Parking Lots Bad for the Environment?

There are many environmentally unfriendly aspects to the modern world, including gas-guzzling cars, pollution-spewing industry, and apathetic consumers. Looking beyond the usual suspects, many people would be surprised to find out that something as mundane as a parking lot could also be bad for the environment. Most people know that the cars they drive and park on them can be detrimental to the environment, but few know that the need of some people to sprawl out and “pave paradise” may be contributing to the problem as well.

It turns out that Americans are paving more space than ever, as was shown by a 2005 study by researchers from Purdue University that counted parking spaces in Tippecanoe County in Indiana. In a county of 155,000 residents, there were 355,000 parking spaces, which had paved an area bigger than a thousand football fields. Tippecanoe is reflective of many other counties in the US, where suburban strip malls, schools and businesses are creating the need for more parking lots.

Parking lots can be bad for the environment for many reasons. Increasing need for more parking spaces may indicate that more cars are on the road, which means that more gas is being consumed and more pollutants released into the air. More pavement means less green space, thereby reducing the number of trees and plants that serve as natural “air cleaners” by absorbing carbon dioxide in the air and releasing oxygen. It also means less open soil that can collect rainwater, which helps to replenish natural aquifers. Areas that have less of a natural groundwater supply suffer even more from an overabundance of paved areas.

Cars are dirty pieces of machinery and leak all sorts of toxic liquids. Oil, grease, coolant, and other fluids can collect on the asphalt and sit until rain washes it into storm drains, which may drain to lakes and streams. The runoff is often highly polluted.

Another negative effect of parking lots is called the urban heat island. The asphalt or concrete more readily absorbs and retains the heat from the sun’s rays than the surrounding ground. This in turn raises surrounding temperatures a few degrees, affecting what is called the “urban growing season.”

For those looking for less paving and more open green space, Keweenaw County in Michigan was found to have the most space between paved roads and parking lots. Washington D.C. has the most pavement with the least amount of open green space.

Parking lots exacerbate urban heat islands by replacing natural, permeable surfaces with asphalt or concrete, which absorb and retain heat. This effect increases local temperatures, leading to higher energy consumption for cooling and contributing to the formation of ground-level ozone, a harmful pollutant. The EPA has documented that urban areas can be 1.8–5.4°F warmer than their rural surroundings.

Parking lots significantly increase stormwater runoff due to their impervious nature. Rainwater cannot infiltrate the ground, leading to flash flooding and the swift transportation of pollutants into waterways. The Center for Watershed Protection notes that runoff from paved surfaces can carry heavy metals, oils, and other contaminants that harm aquatic ecosystems and degrade water quality.

Absolutely. Parking lots disrupt local ecosystems by replacing natural habitats with barren surfaces, which can lead to a loss of biodiversity. They create barriers to wildlife movement and can contribute to the death of animals through collisions. Additionally, the heat and pollution associated with parking lots can alter the microclimates necessary for native species to thrive.

Long-term soil consequences of parking lots include compaction and contamination. The weight and construction process compact the soil, making it less able to absorb water and support plant life. Moreover, pollutants from vehicles and asphalt can leach into the soil, degrading its quality and potentially poisoning groundwater, as reported by the United States Geological Survey.

Parking lots contribute to air pollution by facilitating vehicle use, which emits greenhouse gases and other pollutants. Idle vehicles in parking lots also release emissions. According to the Environmental Protection Agency, transportation accounts for 29% of greenhouse gas emissions in the United States, with a significant portion coming from light-duty vehicles that frequent parking lots.

Environmentally friendly alternatives to traditional parking lots include permeable paving materials that allow water to infiltrate the ground, reducing runoff and improving water quality. Green parking lots incorporate vegetation, such as grass or groundcover, which can cool the area and provide habitat for wildlife. Additionally, integrating solar panels can produce renewable energy while shading vehicles.