adaptation
a potential human response to environmental change, involving either an adjustment to the change, or a blocking of the impact on a valued environmental system.
 

anticipatory adaptation
an adaptive response to environmental change that aims to improve the ability of social systems to withstand such change.
 

biodiversity
the variety and variability of life forms on earth, both wild and domesticated; derived from the words biological diversity.

biosphere
the parts of the earth’s lithosphere, atmosphere, pedosphere, cryosphere, and hydrosphere in which all living organisms exist and interact; the zonal space extending from the immediate subsurface of the earth to the upper atmosphere.

climate
the accumulation of daily and seasonal weather events over a long period of time.

climate change
a change of climate that is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is, in addition to natural climate variability, observed over comparable time periods (from the United Nations Convention on Climate Change).

driving forces
societal forces that bring about global environmental change, including population, economy, technology, ideology, and social organizations.

ecosystem
self-regulating natural community of plants and animals interacting with one another and with their non-living environment.

enhanced greenhouse effect
the increase in the strength of the natural greenhouse effect, resulting from human activities that release additional quantities of greenhouse gases into the atmosphere.

evapotranspiration
the combined water loss to the atmosphere from (1) ground and water surfaces through evaporation and (2) plants through transpiration.
 
 
Geographic Information Systems (GIS)
computer-based systems that are designed to accept, organize, analyze, and display diverse types of spatial information.

greenhouse effect
the trapping of heat in the earth’s atmosphere.  Incoming short-wave solar radiation penetrates the atmosphere, but long-wave outgoing radiation is absorbed by the greenhouse gases in the atmosphere and is re-radiated to the earth, causing a rise in atmospheric temperature.

greenhouse gases
gases present in the earth’s atmosphere, including water vapor, carbon dioxide (CO₂), methane (CH₄), nitrous oxide (NO₂), and chlorofluorocarbons (CFCs), that cause the greenhouse effect.

global annual mean temperature
the average surface temperature per year for the entire planet.
 

global circulation models (GCMs)
complex computer models of the earth’s climate system designed to help scientists learn about the interactions among the atmosphere, the oceans, the lithosphere, and the biosphere.

gross national product (GNP)
total market value of all goods and services produced per year in a country.
 

IPAT
equation (I = P x A x T) developed by Paul Ehrlich and John Holdren in 1972 to describe the variables that interact to produce environmental change;  impact (I) or magnitude of environmental change is a function of the interaction among population size (P), affluence (A), and technology (T).

isoline
a line that connects points of equal value on a map.

isotherm
a line that connects points of equal temperature on a map.

land cover
the physical state of the land, including the quantity and type of surface vegetation, water, and earth materials.

land use
the human employment of land; includes settlements, cultivation, pasture, rangeland, and recreation, among others.

land-cover change
a change from one class of land cover to another (conversion), such as from grassland to cropland, or a change of condition within a land cover category (modification), such as the thinning of a forest.

land-use change
shift to a different land use or an intensification of an existing one.

mitigation
any actions that prevent, limit, delay, or slow the rate of undesired impacts by acting on either the environmental system, the human proximate forces, or the human systems that drive environmental change.

non-proximate forces of change
forces of change that underlie, at various levels, the proximate forces of change.
 

positive feedback
flow of energy or information into a system that causes the system to change continuously in the same direction; as a result, the system can go out of control.

proximate forces of change
human actions that directly alter the physical environment.
 

remote sensing
the measurement or acquisition of information of some property of an object of phenomenon, by a recording device that is not in physical contact with the object under study (i.e., the use of satellites to gather information about the earth’s land cover).

terrestrial ecosystem
a land-based ecosystem, such as forests, deserts, grasslands, or croplands, among others.

terrestrial change
a type of environmental change resulting in the alteration of terrestrial ecosystems; includes land-use change and land-cover change.

scatterplot
graph used to display the relationship between two quantitative variables.

vulnerability
in terms of environmental change, the potential (susceptibility) for loss or the capacity to suffer harm from such change(s).

weather
the conditions of the atmosphere at any particular time and location.