Overview - Background
Background
Topics:
What
is Sustainability?
Climate
Change and Global Warming
Greenhouse
Gases
Global
Warming versus Ozone Depletion
The
Carbon Footprint
Carbon
Offsetting and Emissions Trading
What is Sustainability?
The first formal definitions of sustainability
came from the 1987 Brundtland report, originating from a commission within
the United Nations. Sustainability is "meeting
the needs of the present without compromising the ability of future generations
to meet their own needs." The Brundtland
report introduced the concepts of environmental sustainability, economic
sustainability, and social sustainability as separate frameworks for consideration.
- Environmental
sustainability deals with the maintenance of natural resources.
- Economic
sustainability deals with the maintenance of capital.
- Social
Sustainability deals with the maintenance of communities and societies
through cooperation rather than competition.
A fourth concept was later identified
for consideration: Human sustainability deals with the maintenance
of individual health and life.
Climate
Change and Global Warming
Climate change refers to the
variation in the Earth's global climate or in regional climates over time.
These changes can be caused by processes internal to the Earth, external
forces (e.g. variations in sunlight intensity) or, more recently, human
activities. Climate change can include global cooling as well
as global warming. In
terms of popular usage, global warming often refers to temperature
increases which are primarily caused by human action.
Greenhouse
Gases
Greenhouse
gases are components of the atmosphere that contribute to the greenhouse
effect. These gases
can come from natural sources or from human activity.
In
the order of relative abundance, Earth's atmospheric greenhouse
gases include water vapor, carbon dioxide, methane, nitrous oxide, and
ozone.
Global
Warming versus Ozone Depletion
Global
warming comes from release of certain gases which enhance the natural
greenhouse effect. These gases trap solar heat much as a greenhouse or
blanket would, and cause temperature of the lower atmosphere to rise.
The
ozone layer in the lower stratosphere protects Earth by shielding it from
the sun’s ultraviolet radiation. Halocarbons act as catalysts to
kick off a chain reaction that destroys ozone. A thinning ozone layer
means more ultraviolet radiation, which can harm living things (for example,
by causing skin cancer in humans).
Global
warming and ozone depletion are related because the halocarbons which
destroy the ozone layer are also potent greenhouse gases.
The
Carbon Footprint
A carbon footprint measures the impact that humans, organizations, or
other entities have on the environment in terms of the amount of greenhouse
gases produced, measured in units of carbon dioxide. The
carbon footprint is similar to a greenhouse gas emissions inventory.
However, the carbon footprint measures emissions over the lifetime of
an entity, whereas the emissions inventory is measured at increments (usually
on an annual basis). The
carbon footprint is calculated using the Life Cycle Assessment (LCA) method.
Carbon
Offsetting
and Emissions Trading
Carbon offsetting is voluntary mitigation of greenhouse gas emissions.
The
most popular offset methods include the use of renewable energy, funding
energy conservation, methane capture, and tree planting.
Emissions
trading is the idea of paying for emission reductions elsewhere instead
of reducing one's own emissions.
Controversies
exist regarding carbon offsetting and emissions trading. These practices
do not necessarily encourage conservation and there exists a lack of transparency
in these industries. An entity should reduce its own emissions as much
as possible before resorting to carbon offsets or emissions trading.
The
information on this page is gathered from various sources. You
can learn more about the topics listed on this page by viewing these web
sites:
The
World Commission on Environment and Development
U.S.
Environmental Protection Agency
The Natural Resource Defense
Council
The University Corporation
for Atmospheric Research
CarbonFund.org
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