306 The Environmental Debate
cap and trade system of setting limits on power plant emissions and permitting companies
whose emissions are below the set allowance to sell the excess emissions to other power
plants.
carbon sink forest, deep ocean, or geological reservoir where carbon dioxide can be absorbed
or sequestered away from the atmosphere.
channelization the deepening and straightening of streams and rivers to alter their flow and
control flooding.
chlorofluorocarbons (CFCs) organic compounds, such as Freons, that contain chlorine, fluo-
rine, and carbon atoms and, if they are gases, cause a depletion of atmospheric ozone when
they are released into the air.
clear-cutting cutting all the trees within a segment of a forest.
climate change change in temperature or weather patterns (such as amount of rainfall) induced
by human activity.
climatology study of weather conditions over a long period of time.
commons resources that do not belong to any individual or nation, such as clean air, migratory
birds, and noncoastal ocean resources, as well as property held in common by a community
or nation, such as park land, communal grazing lands, and community dump sites.
conservation natural resource management to prevent resource destruction, exploitation, and
neglect.
DDT dichlorodiphenyltrichloroethane, a chlorinated hydrocarbon (hydrogen-carbon com-
pound) once widely used as a pesticide.
desalination removal of dissolved salts from brackish or salty water to make the water usable
for drinking or agriculture.
dioxin any of several synthetic heterocyclic hydrocarbon compounds that are very toxic and have
frequently been used in making herbicides (weed killers).
drift net large fishing net designed to drift near the surface of the water and used by fishermen
to trap fish or other marine animals.
ecology the study of the relationships among living things and between living things and their
nonliving environment.
ecosphere segment of the universe inhabited by living things and where there is interaction
among living things and between organisms and nonliving things.
ecosystem ecological community of organisms and their environment that functions as a unit.
endangered species species of wild flora or fauna whose numbers have been so reduced that it
is in danger of becoming extinct.
energy usable power (such as heat or electricity) or the resources to produce usable power (such
as coal, water, or sunlight).
entropy the increasing degradation of a society or system.
environment totality of biotic, chemical, and physical elements (including air, climate, living
things, and nonliving things) that affect an organism or a community.