Dear EarthTalk: The term "sustainable communities" gets bantered around quite a bit today. Could you define it for me? -- Holly Parker, Mechanicsburg, Pa.

Kaid Benfield, sustainable communities program director at the Natural Resources Defense Council, uses the term "sustainable communities" to describe places "where use of resources and emissions of greenhouse gases and other pollutants are going down, not up; where the air and waterways are accessible and clean; where land is used efficiently and shared parks and public spaces are plentiful and easily visited; where people of different ages, income levels and cultural backgrounds share equally in environmental, social and cultural benefits; where many needs of daily life can be met within a 20-minute walk and all may be met within a 20-minute transit ride; where industry and economic opportunity emphasize healthy, environmentally sound practices."

In his March 2011 NRDC "Switchboard" blog post titled "A Trip to Sustainaville," Benfield described his vision for what a model of sustainable communities could look like, with neighborhoods sporting healthy amounts of green space and shared vegetable gardens; mass transit, biking and walking replacing the majority of automobile traffic; and mixed use communities where schools, residences and commercial spaces are near each other and are powered by solar panels, geothermal heat pumps or windmills.

According to the Vermont-based Institute for Sustainable Communities, sustainable communities are "economically, environmentally and socially healthy and resilient" and meet "challenges through integrated solutions rather than through fragmented approaches." And perhaps more important: Sustainable communities take a long-term perspective, focusing on "both the present and future, well beyond the next budget or election cycle" so that the needs of the current as well as future generations are met with adequate resources. ISC adds that the success of a community's efforts to be sustainable depends on its members' commitment and involvement as well as leadership that is inspiring, effective and responsive.

Some of the ways ISC has worked to further its goals include helping teach leaders from low income U.S. communities along the Gulf of Mexico how energy efficiency and ecological restoration can revitalize their otherwise struggling economies; developing community sustainability initiatives throughout war-ravaged parts of Kosovo, Serbia and Macedonia; installing green roofs on residences in the Chinese city of Shenzen as a pilot project to show how such "technologies" can yield significant carbon sequestration and other environmental benefits, and many more.

Key to any consideration of what makes a community sustainable is the acknowledgement that there is no such thing as perfection. "Sustainability is a process of continuous improvement so communities constantly evolve and make changes to accomplish their goals," reported Sustainable Communities Online, a web-based information and networking clearinghouse started in the 1990s by a broad coalition of sustainability-oriented organizations and managed by the Washington, D.C.-based nonprofit CONCERN Inc. Those looking to learn more about sustainable communities and what makes them tick should be sure to check out, Sustainable Communities Online's information-packed website.

Contacts: NRDC Sustainable Communities,; Institute for Sustainable Communities,; Sustainable Communities Online,

Dear EarthTalk: I understand the Environmental Protection Agency recently took steps to limit pollution from power plants. What are the details? -- Maddie Samberg, via e-mail

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In March 2012 the U.S. Environmental Protection Agency (EPA) proposed the first nationwide emission standards to limit carbon dioxide emissions from new coal- and gas-burning power plants. And while the operative word here is "new" -- the standards would not apply to plants currently in operation or those that begin construction over the next year -- they would effectively cut carbon emissions in half over the lifetime of a new power plant. According to the EPA, the standards reflect the ongoing trend in the power sector toward cleaner plants deploying the latest in American-made pollution minimizing technologies.

"The nation's electricity comes from diverse and largely domestic energy sources, including fossil fuels, nuclear, hydro and, increasingly, renewable energy sources," reported the EPA. "The proposed standard would not change this fact, and EPA put a focus on ensuring this standard provides a pathway forward for a range of important domestic resources, including coal with technologies that reduce carbon emissions."

New plants could still choose to burn any fossil fuel to generate electricity as long as modern carbon reduction technologies are employed.

Environmentalists are cheering the EPA's move given that power plants are the largest individual sources of carbon pollution in the U.S., responsible for some 40 percent of our overall greenhouse gas emissions. Despite this huge pollution burden, currently there are no uniform national limits on the amount of carbon pollution that future power plants will be able to emit.

"The Supreme Court has found in two landmark cases, Massachusetts v. EPA and American Electric Power v. Connecticut, that it is the EPA's job under the Clean Air Act to protect the American people from dangerous carbon pollution, including the carbon pollution from the nation's fleet of new and existing power plants," reported David Doniger of the Natural Resources Defense Council, another leading environmental nonprofit backing stronger pollution standards. "EPA's `new source performance standard' for new power plants ... is a critical step towards providing that protection."

Greens are optimistic that the proposal will become a rule. In concert with clean car standards the EPA announced in 2010 -- mobile sources contribute some 30 percent to our overall carbon emissions -- the new power plant standards should help take a significant bite out of U.S. greenhouse gas pollution.

"These standards will help further the progress we are making towards a cleaner, more secure future for energy in America," said Fred Krupp, president of the nonprofit Environmental Defense Fund. "We will use our nation' electricity resources more efficiently to cut energy costs for families and businesses, mobilize `Made in the USA' technologies and fuels for cleaner energy generation, and ensure that America will lead the global race to a clean energy economy."

Contacts: EPA "Carbon Pollution Standard for Power Plants,"; NRDC,; EDF,

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