Green infrastructure substantially advances Mayor Bloomberg’s PlaNYC, a multi-pronged sustainability effort that will reduce the urban heat island effect, enhance recreational opportunities, improve quality-of-life, restore ecosystems, improve air quality, save energy, and mitigate and adapt to climate change. These goals, as well as improved water quality, are substantially advanced by green infrastructure in ways that traditional grey infrastructure cannot match.
Reduced Urban Heat Island Effect
The urban heat island (UHI) effect occurs when built-up urban areas become warmer than nearby areas because of changes in surface coverage over time. The UHI effect can be detected throughout the year, but it is of particular concern during the summer, when higher surface air temperature is associated with increases in electricity demand for air conditioning, air pollution, and heat stress–related mortality and illness. Green infrastructure can mitigate the UHI effect through added shade and evapotranspiration in areas otherwise covered by buildings, streets and sidewalks, and other paved surfaces.
Energy Conservation and Climate Change Offsets
Green infrastructure reduces the energy needed for
heating and cooling, and eliminates carbon dioxide emissions through direct
removal from the air and avoided emissions from power plants. The shading and
climate effects of New York City’s street trees already provide approximately
$27.8 million in energy actual savings per year and reduce atmospheric carbon
dioxide by 113,016 tons according to the New York Municipal
Forest Resource Analysis (MFRA). Similarly, a
publication titled Cool and Green Roofing Manual 2007
by the Department of Design & Construction
calculated an energy benefit of at least $82 million a year for every reduction
of 1°F. Learn
Improved Air Quality
Green infrastructure offsets air pollution by directly removing pollutants from the air, reducing power plant emissions, and reducing the high temperatures and sunlight that contributes to ozone formation. Existing New York City street trees are estimated to remove or avoid 129 tons of ozone, 63 tons of particulate matter, and 193 tons of nitrous dioxide every year according to the MFRA.
Higher Property Values, Enhanced Recreation, and Improved Quality of Life
The aesthetic benefits provided by green infrastructure
can enhance the livability of New York City neighborhoods. For example, real
estate advertisements in Staten Island cite proximity to the Bluebelts as a
selling point. A useful proxy to demonstrate this benefit is provided by New
York City parks and community gardens, which increase adjacent property value by
8% to 30% as found in a 2008 study entitled The Effect of Community Gardens
on Neighboring Property Values
Green infrastructure can provide valuable habitat. The Bluebelt program is a leading example of using ecosystem services to manage stormwater and improve wildlife habitat. On a smaller scale, street trees and green roofs can provide nesting, migratory, and feeding habitat for a variety of birds, butterflies, bees, and other insects.
Operational Benefits of Reduced Flow
Encouraging prudent water use provides benefits to DEP’s water supply and wastewater treatment system by reducing wear on infrastructure, chemical costs at our water supply and wastewater treatment plants, and energy costs for pumping and treating flow.