In constructing and occupying buildings, we expend vast quantities of  the earth’s resources and generate
a signifi cant portion of the earth’s  environmental pollution: The U.S.

Green Building Council reported in  2008 that buildings account for 30 to 40 percent of the world’s energy  use and associated greenhouse gas emissions. Construction and operation of buildings in the United States  accounted for more than one-third of this country’s total energy use and the consumption of more than two-
thirds of its electricity, 30 percent of its raw materials, a quarter of its harvested wood, and 12 percent of
its fresh water. Building construction and operation is responsible for nearly half of this country’s total greenhouse gas emissions and close to a third of its solid waste stream. Buildings are also
signifi  cant emitters of particulates and other air pollutants. In short, building construction and operation cause many forms of environmental degradation that place an increasing burden on the earth’s resources and jeopardize the future of the building industry and societal health and welfare.

Sustainability may be defined  as meeting the needs of the present generation without compromising the ability of future generations to meet their needs. By consuming irreplaceable fossil fuels and other nonrenewable resources, by building in sprawling urban patterns that cover extensive areas of prime agricultural land, by using destructive forestry practices that degrade natural ecosystems, by allowing topsoil to be eroded by wind and water, and by generating substances that pollute water, soil, and air, we have been building in a manner that will make it increasingly diffi cult for our children and grandchildren to meet their needs for communities, buildings, and healthy lives.

On the other hand, if we reduce building energy usage and utilize sunlight and wind as energy sources for our buildings, we reduce depletion of fossil fuels. If we reuse existing buildings imaginatively and arrange our new buildings in compact patterns on land of marginal value, we minimize the waste of valuable, productive land. If we harvest wood from forests that are managed in such a way that they can supply wood at a sustained level for the foreseeable future, we maintain wood construction as a viable option for centuries to come and protect the ecosystems that these forests support. If we protect soil and water through sound design and construction practices, we retain these resources for our successors. If we systematically reduce the various forms of pollution emitted in the processes of constructing and operating buildings, we keep the future environment cleaner. And as the industry becomes more experienced and committed to designing and building sustainably, it becomes increasingly possible to do these things with little or no increase in construction cost while creating buildings that are less expensive to operate and more healthful for their
occupants for decades to come.

Realization of these goals is dependent on our awareness of the environmental problems created by
building activities, knowledge of how to overcome these problems, and skill in designing and constructing buildings that harness this knowledge.

While the practice of sustainable design and construction, also called  green building, remains a relatively recent development in the design and construction industry, its acceptance and support continue to broaden among public agencies, private developers, building operators and users, architectural and engineering fi  rms, contractors, and materials producers.

With each passing year, green building techniques are becoming less a design specialty and more a part of mainstream practice.

The Building Life Cycle   Sustainability must be addressed on a life-cycle basis, from the origins of the materials for a building, through the manufacture and installation of these materials and their useful lifetime in the building, to their eventual disposal when the building’s life is...

Assessing Green Buildings   In the United States, the most widely adopted method for rating the environmental sustainability of a building’s design and construction is the  U.S. Green Building Council’s Leadership in Energy and Environmental Design, or  LEED™...

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