Have you ever driven through the rural roads of Florida with your windows down and noticed it becomes hotter as you drive into the city? You weren’t imagining things; this phenomenon is called the urban heat island effect, where urban areas are hotter relative to outlying rural areas.
What’s going on?
The urban heat island effect is caused by paved areas like roads, sidewalks, and parking lots. These areas are made of materials like concrete that trap heat and release it slowly rather than reflecting it back. Because concrete cools down slowly, temperatures are also typically hotter at night in urban heat islands. These areas also provide less shade and moisture than natural landscapes with more plants. Rural areas also have more plants, which release water vapor into the air as a result of transpiration, cooling the surrounding area.
Why it matters.
Heat islands can affect a community’s environment and quality of life in a variety of ways. Hotter temperatures can lead to increased energy consumption, emissions of air pollutants and greenhouse gases, and public health concerns. Heat islands raise demand for air conditioning to cool buildings, which can quickly overwhelm utility systems and lead to blackouts. Additionally, these utility systems are usually powered by fossil fuels that contribute to air pollution and greenhouse gas emissions. Heat islands also compromise human health: excessive heat conditions increase the frequency of heat-related deaths and illnesses such as dehydration, heat stroke, heat cramps, and heat exhaustion.
What you can do.
- Contact your city officials to build greenscapes into the city infrastructure.
- Plant trees and other plants. As more plants grow in the same area, the increased transpiration will cool the surrounding areas.
- Build rooftop gardens. They improve air quality and reduce the heat island effect. Some cities even have green roof tax credit programs.
- Paint pavements and roofs white. Darker colors absorb heat, whereas lighter colors reflect heat.
Information from the Environmental Protection Agency, NASA Climate Kids, UF/IFAS Extension Orange County, and WUSF.