Page 722 - Environment: The Science Behind the Stories

economy A social system that converts re- electron A negatively charged particle that energy The capacity to change the position,
sources into goods and services. moves around the nucleus of an atom. physical composition, or temperature of mat-
ter; a force that can accomplish work.
ecosystem All organisms and nonliving entities element A fundamental type of matter; a chem-
that occur and interact in a particular area at ical substance with a given set of properties, energy conservation The practice of reducing
the same time. which cannot be broken down into substances energy use as a way of extending the lifetime of
with other properties. Chemists currently rec- our fossil fuel supplies, of being less wasteful,
ecosystem-based management The at-
tempt to manage the harvesting of resources ognize 92 elements that occur in nature, as well and of reducing our impact on the environment.
in ways that minimize impact on the ecosys- as more than 20 others that have been artifi- Conservation can result from behavioral deci-
tems and ecological processes that provide cially created. sions or from technologies that demonstrate
the resources. El Niño The exceptionally strong warming of energy efficiency.
the eastern Pacific Ocean that occurs every 2 energy conversion efficiency The ratio of
ecosystem diversity The number and variety
of ecosystems in a particular area. One way to to 7 years and depresses local fish and bird the useful output of energy to the amount
express biodiversity. Related concepts consider populations by altering the marine food web that needs to be input. See also EROI and net
the geographic arrangement of habitats, com- in the area. Originally, the name that Spanish- energy.
munities, or ecosystems at the landscape level, speaking fishermen gave to an unusually warm energy efficiency The ability to obtain a given
including the sizes, shapes, and interconnected- surface current that sometimes arrived near the result or amount of output while using less
ness of patches of these entities. Pacific coast of South America around Christ- energy input. Technologies permitting greater
mas time. Compare La Niña.
ecosystem ecology The study of how the liv- energy efficiency are one main route to energy
ing and nonliving components of ecosystems El Niño–Southern Oscillation (ENSO) A sys- conservation.
interact. tematic shift in atmospheric pressure, sea sur- energy returned on investment See EROI.
face temperature, and ocean circulation in the
ecosystem service An essential service an eco- tropical Pacific Ocean. ENSO cycles give rise enhanced geothermal systems (EGS) A new
system provides that supports life and makes to El Niño and La Niña conditions. approach whereby engineers drill deeply into
economic activity possible. For example, eco- rock, fracture it, pump in water, and then pump
systems naturally purify air and water, cycle emergent property A characteristic that is not it out once it is heated below ground. This ap-
nutrients, provide for plants to be pollinated evident in a system’s components. proach would enable us to obtain geothermal
by animals, and receive and recycle the waste emergent tree An especially tall tree that energy in many locations.
we generate. protrudes above the canopy of a tropical rain-
forest. environment The sum total of our surround-
ecotone A transitional zone where ecosystems ings, including all of the living things and non-
meet. Emerson, Ralph Waldo (1803–1882) Amer- living things with which we interact.
ican author, poet, and philosopher who es-
ecotourism Visitation of natural areas for environmental economics A developing
tourism and recreation. Most often involves poused transcendentalism. school of economics that modifies the principles
tourism by more-affluent people, which may emigration The departure of individuals from of neoclassical economics to address environ-
generate economic benefits for less-affluent a population. mental challenges. Most environmental econo-
communities near natural areas and thus pro- eminent domain A policy in which a govern- mists believe that we can attain sustainability
vide economic incentives for conservation of ment pays landowners for their land at market within our current economic systems. Whereas
natural areas. ecological economists call for revolution, envi-
rates and the landowners have no recourse to
ED (effective dose–50%) The amount of a refuse. In eminent domain, courts set aside pri- ronmental economists call for reform. Compare
50
toxicant it takes to affect 50% of a population vate property rights to make way for projects ecological economics; neoclassical economics.
of test animals. Compare threshold dose; LD . judged to be for the public good.
50 environmental ethics The application of ethi-
edge effect An impact on organisms, popu- emissions trading system A permit trading cal standards to environmental questions.
lations, or communities that results because system for emissions in which a government environmental health The study of environ-
conditions along the edge of a habitat fragment issues marketable emissions permits to con- mental factors that influence human health
differ from conditions in the interior. duct environmentally harmful activities. Under and quality of life and the health of ecological
a cap-and-trade system, the government deter-
electricity A secondary form of energy that can systems essential to environmental quality and
be transferred over long distances and applied mines an acceptable level of pollution and then long-term human well-being.
issues permits to pollute. A company receives
for a variety of uses. environmental history The study of the his-
credit for amounts it does not emit and can then
electrolysis A process in which electrical cur- sell this credit to other companies. Compare tory of environmental change and the history
rent is passed through a compound to release cap-and-trade. of human interactions with the environment.
ions. Electrolysis offers one way to produce Includes the study of how people influence
hydrogen for use as fuel: Electrical current is Endangered Species Act (ESA) The primary their environments over time and how nature
passed through water, splitting the water mol- legislation, enacted in 1973, for protecting influences human culture and society.
ecules into hydrogen and oxygen atoms. biodiversity in the United States. It forbids the
government and private citizens from taking environmental impact statement (EIS) A
electronic waste (e-waste) Discarded elec- actions (such as developing land) that would report of results from detailed studies that as-
tronic products such as computers, monitors, destroy endangered species or their habitats, sess the potential effects on the environment
printers, televisions, DVD players, cell phones, and it prohibits trade in products made from that would likely result from development pro-
and other devices. Heavy metals in these prod- endangered species. jects or other actions undertaken by the gov-
ucts mean that this waste may be judged haz- ernment.
ardous. endemic Native or restricted to a particular GLOSS ARY
geographic region. An endemic species occurs environmental justice The fair and equitable
Ekman drift Wind-driven currents in the in one area and nowhere else on Earth. treatment of all people with respect to environ-
ocean’s upper layers. These currents are named endocrine disruptor A toxicant that interferes mental policy and practice, regardless of their
for scientist Walfrid Ekman, who first modeled income, race, or ethnicity. Responds to the per-
them in the early 20th century. Compare geos- with the endocrine (hormone) system. ception that minorities and the poor suffer more
trophic currents. endocrine system The body’s hormone system. pollution than whites and the rich. G-7

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