Heat Island Effect
Welcome to EPA's Urban Heat Island Newsroom. The Newsroom provides current news and links to news releases related to urban heat island impacts, mitigation strategies, and community initiatives. To help keep you up to date, you may also wish to sign up for EPA's Urban Heat Island Newsletter. Older stories can be found in the Newsroom Archive.
- Ninaski Brewing Company in Eugene, Oregon, Installs Green Roof (September 2, 2014) – Ninaski Brewing Company installed a 6,100-square foot green roof that reduces stormwater runoff and moderates runoff water temperature.
- Tree Canopy Project Receives Grant in Catonsville, Maryland (September 3, 2014) – A project to increase the tree canopy in Catonsville, Maryland, by planting 1,000 trees by 2020 received a $10,000 grant from Baltimore Gas and Electric.
- Montana Completes Urban Forest Inventory (September 8, 2014) – The Montana Department of Natural Resources and Conservation has completed an urban forest inventory that assesses tree size, health, species, and location within 39 communities across the state.
- Forest Heights, Maryland, Plants 1,100 Trees, Intends to Plant 500 More (September 8, 2014) – The town of Forest Heights, Maryland, has planted 1,100 trees since 2008, and intends to plant 500 additional trees with the help of 150 University of Maryland students.
- University of Iowa Installs Second Green Roof (September 9, 2014) – The University of Iowa installed its second, 600-square foot green roof on top of the Seamans Center engineering building.
- Los Angeles, California Apartment Buildings Feature Cool Roof Designs (September 9, 2014) – In Los Angeles, California, the Coronado Place and Knob Hill Apartments are built with newly installed cool roof systems intended to increase building energy efficiency for low-income residents.
- Arizona State University Researchers Find that Urban Forest in Phoenix, Arizona Can Mitigate Urban Heat Island Effect (September 23, 2014) – Arizona State University researchers released a study concluding that, for a typical neighborhood in Phoenix, increasing tree canopy cover to 25% from the current level of about 10% could reduce air temperature by 4.3 degrees Fahrenheit. For a bare neighborhood with no vegetation, the researchers found that adding 25% canopy could reduce air temperatures by 7.9 degrees Fahrenheit.
- Lawrence Berkeley National Laboratory Releases Interactive Map on Rooftop Reflectance in California Cities (September 23, 2014) – Researchers at Lawrence Berkeley National Laboratory released an interactive map that uses aerial imagery to provide data on the reflectivity of roofs in Bakersfield, Long Beach, Los Angeles, San Francisco, and San Jose, California.
- Western Illinois University Installs Green Roof (September 29, 2014) – Western Illinois University installed a 9,720-foot green roof composed of seasonal plants.
- Sunnyvale, California, Passes Urban Forest Management Plan (September 24, 2014) – The city of Sunnyvale, California, approved an urban forest management plan that aims to increase the city's tree canopy, maintain street trees, foster community support for maintaining and improving the city's urban forest, and encourage proper tree management on private property.
- Milwaukee Metropolitan Sewer District Announces Partnership to Promote Stormwater Management System (August 5, 2014) – The Milwaukee Metropolitan Sewer District announced a partnership to monitor the performance of a new stormwater management system that combines a blue roof with a green roof to harvest rainwater and control its release. While the project was not designed specifically to reduce heat islands, the green roof provides cooling as a co-benefit.
- Levi’s Stadium in Santa Clara, California, Installs Green Roof (August 8, 2014) – Levi’s Stadium in Santa Clara, California, features a 27,000-square-foot green roof that is planted with grasses and native plants, captures rainwater, and grows herbs for stadium food. Harvested rainwater is used in all toilets and to irrigate the playing field.
- Odette Estate Winery in Napa Valley, California, Installs Green Roof (August 14, 2014) – The Odette Estate Winery in Napa, California, installed an 8,500-square foot green roof that harvest rainwater in an underwater irrigation system to prevent water from evaporating.
- Washington State Department of Natural Resources Announces Urban Forest Restoration at Forest Park In Everest, Washington (August 15, 2014) – The Washington State Department of Natural Resources announced an urban forestry restoration project at Forest Park in Everest, Washington, to remove invasive species and plant new trees.
- Spokane, Washington Begins Tree Planting Initiative (August 15, 2014) – The city of Spokane, Washington, approved the “Forest Spokane” program, which intends to plant 10,000 new trees in the next two years.
- Climate Central Ranks Urban Heat Island Effect in U.S. Cities (August 20, 2014) – Climate Central has released a report that analyzes impacts of the urban heat island effect in 60 of the largest U.S. cities over the past 10 years. The analysis finds that, on average across the 60 cities, the maximum single-day temperature difference between urban and rural areas was 17.5°F, and the three cities with the most intense urban heat island effect are Las Vegas, Albuquerque, and Denver. The study also found that in three quarters (45 of 60) of the cities examined, urbanized areas are warming faster than adjacent rural locations. On average across all 60 cities, urban summer temperatures were 2.4°F hotter than rural temperatures. The difference was more pronounced at night, with average summer overnight temperatures more than 4°F hotter in cities than in surrounding rural areas.
- Fire Station in Deltona, Florida Installs Cool Roof (August 19, 2014) – A fire station in Deltona, Florida is constructed with both a cool roof and a green roof.
- Price of Green Roofs Projected to Decrease by 2017 (August 21, 2014) – Lux Research, an independent research and analysis firm, released a study estimating that the cost of green roofs will decrease from the current price of $38 per square foot to $23 by 2017.
- Minnesota Creates Stormwater Crediting System (August 28, 2014) – Minnesota developed a credit system that incentivizes communities to invest in trees, rather than stormwater pipes. The system gives credit to properly planted trees that reduce stormwater runoff. While the credit system was not designed to address urban heat islands, trees help reduce heat as a co-benefit.
- University of Minnesota Researchers Examine Heat Island Effect (July 2, 2014) - Ongoing University of Minnesota research using 200 temperature sensors placed around the Twin Cities has found that Minneapolis and St. Paul have about a 3-degree temperature difference compared with surrounding areas.
- Yale Researchers Examine Primary Causes of Urban Heat Island Effect (July 9, 2014) - In an analysis of 65 cities across North America, researchers found that variation in how efficiently urban areas release heat back into the lower atmosphere—through the process of convection—is the dominant factor in the daytime UHI effect.
- ASTM International Announces Green Roof Design Document (July 14, 2014) – ASTM International released its “Guide for Vegetative (Green) Roof Systems,” which is intended to serve as a reference for green roof designers.
- Savannah Tree Foundation Study Shows Savannah Tree Canopy Decreasing (July 15, 2014) - Chatham County, GA has lost the equivalent of three football fields of tree canopy every day, on average, over the last 15 years, according to an ongoing analysis commissioned by the Savannah Tree Foundation.
- Study Examines Urban Heat Island’s Effect on Tree Mortality in the Southeast (July 24, 2014) - New research from North Carolina State University shows that urban heat islands are slowly killing red maples in the southeastern United States. One factor is that researchers have found warmer temperatures increase the number of young produced by the gloomy scale insect—a significant tree pest—by 300%, which in turn leads to 200 times more adult gloomy scales on urban trees.
- Milwaukee Public Library Installs Green Roof (July 25, 2014) – A 33,000 square foot green roof on the Milwaukee Public Library has prevented 2.82 million gallons of rainwater from entering the city's storm sewer system since it was installed.
- University of Iowa Deploys Green Roof at Medical Campus (July 28, 2014) - The Pappajohn Biomedical Discovery Building will feature a multi-level green roof totaling 6,440 square feet of plants.
- Charleston, West Virginia Announces Tree Mapping Initiative (July 29, 2014) – Charleston, West Virginia, announced an initiative to undertake a full tree census at the state capitol.
- Ann Arbor City Council Approves Urban Forestry Plan (June 3, 2014) - The city’s first comprehensive plan for managing Ann Arbor’s urban forest has been given approval by the city council.
- Virginia Tech Researchers Examine Benefits of Green Roofs on Stormwater Runoff (June 10, 2014) – The Virginia Tech research team found that the deeper the vegetation, the better the roofs controlled stormwater runoff. Overall, green roofs retained about 50% of the stormwater, compared with about 6% for conventional flat roofs.
- American Council for an Energy-Efficient Economy Releases Urban Heat Island Mitigation Survey (June 17, 2014) - This report profiles the causes, impacts, strategies, and social and institutional context of city action on heat island mitigation in the sampled cities. It found that heat waves and other disasters are motivating cities to implement heat-mitigation strategies.
- Georgia Tech Researcher Finds that Louisville Requires More Trees to Counteract Urban Heat Island Effect (June 18, 2014) – The urban heat island effect in Louisville ranked highest among 50 of the country’s largest metropolitan areas, according to a study by Brian Stone, a professor of city and regional planning at Georgia Tech. The study found that Louisville has room to add about 1.2 million trees.
- Too Hot to Handle (June 23, 2014) - The New York Times’ health correspondent Jane Brody reports on the risks to human health from extreme heat events, both today and under future climate change scenarios.
- Study Finds that Green Roofs Can Reduce Urban Heat Island Effect (June 25, 2014) – Princeton University researchers tested their model on the Baltimore-Washington metropolitan area during a four-day heat wave and found that a reduction of surface temperature of 1 °C could be achieved if 30% of all roofs in the area were green or cool roofs.
- U.S. Department of Agriculture Announces Urban and Community Forestry Challenge Grants (June 26, 2014) - The grants provide funding that will help enhance urban forest stewardship, support new employment opportunities, and help build resilience in the face of a changing climate.
- AC Trees Announces Urban Forestry Grants to 12 Communities (June 30, 2014) - Funding will support local grassroots organizations to plant, maintain, and harvest fruit and nut trees in 12 cities across the country from California to New Hampshire.
- Arizona State University Releases Study on the Impact of Air Conditioners on Urban Heat Island Effect (May 15, 2014) – Arizona State University researchers have found that excess heat from air conditioners running during the night leads to higher outside temperatures, worsening the urban heat island effect and increasing cooling demands.
- Louisville Awards $115,700 Tree Canopy Assessment Contract (May 7, 2014) – Louisville city officials awarded a contract worth $115,700 to a firm to complete a tree canopy assessment by the end of the year. The city will use the assessment to set priorities for tree planting to address urban heat, stormwater management, and other concerns.
- American University Researcher Studies Impact of Green Roofs on Pollution (May 14, 2014) – An American University researcher is studying the ability of green roofs to prevent pollutants from entering the Anacostia and Potomac rivers.
- Butte, Montana Establishes $2 Million Tree Planting Program (May 24, 2014) – A $2 million tree planting project in Butte aims to establish species diversification, stabilize the soil, and prevent soil erosion on Butte Hill, the site of former copper mines.
- University of Maryland Sustainability Fund Awards $50,000 in Green Roof Grants (April 3, 2014) – The University of Maryland Sustainability Fund awarded $50,000 to the university’s facilities management department for projects that either include a green roof or a rainwater harvesting system.
- People Who Have Trees Are More Likely to Participate in a Tree-Planting Program, Study Finds (April 15, 2014) – A new study indicates that homeowners with street trees, and ones living in older homes, are more likely to participate in a tree-planting program.
- White Roofs are More Economic than Green Roofs, Study Finds (April 22, 2014) – A new report from Lawrence Berkeley National Laboratory found that white roofs are three times more effective at countering climate change than green roofs.
- Menomonie, Wisconsin, Urban Forestry Board Announces Urban Forestry Program (April 9, 2014) – The Menomonie Urban Forestry Board announced the Trees for Everyone Everywhere (TREE) initiative, a cost-sharing program for tree planting in the city.
- New York Department of Environmental Conservation Awards $797,437 in Urban Forestry Grants (April 26, 2014) – The New York Department of Environmental Conservation awarded $797,437 in urban forestry grants to 34 cities, towns, villages, and non-profits.
- Survey Finds Green Roof Square Footage Increased 10 Percent from 2012 (April 24, 2014) – Green Roofs for Healthy Cities released its Annual Green Roof Industry Survey, which finds that the North American green roof industry grew by 10 percent in 2013 over 2012.
- Nashville Music City Center Completed with Green Roof (April 23, 2014) – The Nashville Music City Center achieved LEED Gold certification, in part for its 175,000 square foot green roof and 360,000 gallon rainwater harvesting and recycling system.
- New Orleans Sustainable Village Complete, Along with Green Roofing (April 21, 2014) – Global Green USA completed its Holy Cross Project in the Lower Ninth Ward of New Orleans, which contains green roofs and bioswales to reduce the urban heat island effect and improve permeability.
- New York City Offers $6 Million in Green Project Grants (March 4, 2014) – The New York City Department of Environmental Protection is encouraging community groups, non-profits, and property owners to apply for $6 million in new funding for green infrastructure projects.
- Seattle Department of Transportation Plants 500 Trees (March 31, 2014) – The Seattle Department of Transportation planted approximately 500 trees in West Seattle and Rainier Beach.
- TD Bank and Arbor Day Foundation Announce 2014 TD Green Streets Grant Recipients (March 4, 2014) – Ten municipalities were each awarded $20,000 to support innovation in urban forestry.
- New Haven Urban Resources Initiative Receives $30,000 Grant to Promote Benefits of Trees (March 13, 2013) – The Connecticut Department of Energy and Environmental Protection has awarded $30,000 to New Haven’s Urban Forestry Initiative to improve outreach strategies and increase citizen involvement in urban forestry programs that enhance aesthetics and reduce cooling costs.
- Oklahoma Arbor Week Initiative Seeks to Plant Trees to Reduce Urban Pollution (March 20, 2014) – The City of Edmond, Oklahoma celebrated Oklahoma Arbor Week by planting trees throughout the city for enhanced aesthetics and air quality, erosion prevention, and energy savings.
- Austin Creates Urban Forest Master Plan (March 26, 2014) – The City of Austin, Texas adopted an Urban Forest Master Plan with guidelines that city departments should address, including protecting trees during development, creating tree canopy cover goals, and recycling green waste.
- Iowa Museum Installs Green Roof (March 25, 2014) – The Curatorial Center at the Museum of Danish America in Elk Horn, Iowa will install a green roof using a $50,000 grant from the Iowa West Foundation. The roof will be covered in prairie grasses, goldenrod, yellow cornflower, and other plants native to the area.