Urban Heat Island Effect

If you have ever noticed that it was hotter in a heavily developed area compared to a mostly natural, nearby area, then you have experienced the “heat island effect”.

The heat island effect mostly occurs in cities, where the built environment absorbs sunlight and radiates heat back into the environment, creating pockets of higher temperatures. Since cities have significantly more buildings, roadways, and man-made structures than rural areas, they hold on to more heat than rural areas over a longer period.

Extreme heat can harm the public's health, causing issues such as heat stroke, heat exhaustion and heat cramps, among other health impacts. The City is working to address the heat island effect through the Urban Heat Island Ordinance. To learn more, click on the Urban Heat Island Ordinance dropdown below.

Miami Beach Temperatures

Weather describes the conditions in the atmosphere in an area over a short time. The weather can fluctuate from day to day and minute to minute. On the other hand, climate is the long-term pattern of weather in a region. A change in climate requires persistent changes in weather conditions over a long period.

Over the past few years, Miami Beach has experienced several summer seasons with record-breaking high temperatures and this trend is expected to continue if current conditions persist.

The National Aeronautics and Space Administration (NASA) has released data explaining how temperature and rainfall patterns could change throughout the world through the year 2100 due to mounting levels of greenhouse gases being emitted in the Earth’s atmosphere. Summers in the majority of the United States are now warmer than they were in the 1970s.

The greenhouse effect has a vital role in regulating the temperature on Earth’s surface but higher levels of greenhouse gas emissions are absorbing more heat and causing higher temperatures throughout the planet. Since Miami Beach is an urban city, the higher temperatures may feel even hotter due to the heat island effect.

There is scientific consensus that human activities are causing greater temperature increases than have historically naturally occurred. Population growth has led to a global increase in energy consumption which has released growing levels of greenhouse gas emissions into the atmosphere exacerbating the greenhouse effect.

Reducing Urban Heat Island Effect

Increasing the urban canopy is a great way to reduce the urban heat island effect. The City of Miami Beach aims to increase the urban canopy from 17% to 22% tree canopy cover city-wide by 2040.

Planting trees, shrubs, and ground cover can contribute to lowering temperatures in an urban area by providing shade and helping to reduce the amount of heat absorbed by the asphalt and concrete from roadways and buildings. These trees and plants also contribute to stormwater management, absorb carbon dioxide, and provide habitat to nearby species.

Another method for reducing the heat island effect is to choose lighter-colored building materials or those that have a higher albedo. For example, a white roof absorbs less sunlight than a dark roof. This allows the building and surrounding area to remain cooler. Similarly, sustainable roofing systems such as green roofs and blue roofs are great options to reduce the heat island effect. For more information on sustainable roofing systems, click on the Urban Heat Island Ordinance dropdown below.

Urban Heat Island Ordinance

In March 2019, the City of Miami Beach adopted the Urban Heat Island Ordinance (2019-4252) which requires new construction to install a sustainable roofing system. Sustainable roofing systems can be solar roofs, blue roofs, cool roofs, green roofs, and other roofing systems that will reduce the heat island effect, allow reuse or retention of stormwater or reduce greenhouse gases.

The Ordinance also waives public hearing fees for the installation of sustainable roofing systems, solar carports, porous pavement, and cool pavement and provides a height exception for solar roof installations.

Per the Ordinance, solar roof installations shall not exceed 25 feet above the height of the roofline of the main structure for all districts except single-family residential districts, which shall not exceed 5 feet.

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