Lesson 2 Flashcards
(40 cards)
Thomas Malthus
Thomas Malthus, an eighteenth-century British economist, argued that food supplies grew arithmetically (1, 2, 3 …) while population grew geometrically (1, 2, 4, 8 …). He stated that this imbalance would result in famine unless population growth was restrained. While Malthus’s fears were not realized for the world as a whole, this line of thinking continues to exist in environmental debates. Neo-Mathusians generally argue that population has or will exceed the planet’s ability to support it.
Population Density
A type of demographic measurement that is particularly of interest to geographers is population density. The number of people per unit area (acres, square miles, square kilometers) tells much about a society. Three variants of population density include:
arithmetic: number of people divided by total land area
physiologic: number of people divided by amount of arable land
agricultural: number of farmers divided by amount of arable land
Push and Pull Factors
Why do people move? People respond to appealing and unappealing aspects of places in determining where to live.
Push factors are negative influences that prompt people to leave a place. Examples of push factors include: war, famine, environmental hazard, crime, discrimination, government oppression.
Pull factors are positive influences that attract people to a place. Examples include: economic opportunity, civil liberties, medical care, an appealing climate, and cultural sites. In some ways, the absence of push factors in a place can be seen as a pull factor.
Emigration and Immigration
When people leave a country, they emigrate. Upon entering a new country, they immigrate. Note the similar spellings.
Migration
When people decide to leave their normal location and move permanently a considerable distance from home, they migrate. Migration occurs for a variety of reasons and in a number of specific ways:
Forced: This is involuntary—perhaps a group of people are being expelled from a country or are fleeing genocide.
Voluntary: The migrant acts of their own choice.
Chain: The first migrants to a place report favorably to family and friends in their home town, and additional migrants leave that place to join the initial group. A steady flow of migrants then follows.
Circular: Migrants leave home for a destination, perhaps for work like harvesting crops. When the harvest season ends, the migrants either move to another region where the harvest is later, or return home. The process continues on a predictable basis, from home to temporary destination to home.
Transhumance: Pastoral nomads in economically developing countries move their livestock from pastures in higher elevations to lower elevations as the season changes, and return to particular destinations in a seasonal or yearly cycle.
Step: The migrant stops temporarily at one or more intervening opportunities before reaching their ultimate destination.
Rural-to-urban: Declining economic opportunities in rural locations or other push factors prompt people to leave the countryside and head for cities. This process occurs around the world but most notably in economically developing countries.
Return/counter: The conditions that prompted a migration may change substantially, prompting people to reverse the normal direction of migration. With the rise of the Internet, people who previously moved to cities for job opportunities are instead leaving cities for the rural locations.
Refugee
A migrant who flees a location due to war, famine, persecution, or other great threat.
Internally Displaced Person (IDP)
A migrant who must leave their home area but do not leave their home country.
Asylum Seeker
A migrant who leaves their home country and seeks shelter in another country due to threat of punishment or death at the hands of their government; political asylum is sometimes granted to migrants who fear their home country’s government.
Guest Worker
A migrant who is permitted to immigrate temporarily in order to satisfy a labor shortage; the term is strongly associated with people from Yugoslavia and Turkey moving to West Germany after World War II, but is used for other countries.
Repatriation
Occurs when migrants are returned, sometimes against their will, to their home countries. This may be due to deportation of illegal immigrants or as part of a diplomatically arranged resettlement of refugees after a conflict ends.
Diaspora
The term for when a people are dispersed or scattered due to migration. Jews, Palestinians, Chinese, and South Koreans have been described as being in diaspora due to the large numbers of people who live outside the country where their culture is concentrated.
Brain Drain
Describes the emigration of skilled professionals such as doctors, engineers, and lawyers from their home countries. This migration reflects the individual awareness that greater opportunities exist for them elsewhere. This commonly results in economically developing countries losing vital workers to economically developed countries.
Cultural Ecology
The study of how a society (culture group) interacts with the natural environment in which the society lives.
Environmental Determinism and Environmental Possibilism
The influence of the natural environment upon humans is undeniable, but the degree of and result of that influence has been debated by humans. During parts of the nineteenth and twentieth centuries, scholars, including some geographers, argued that the natural environment determined the social world. The limited economic development of areas in the tropics was interpreted as evidence of this relationship. This interpretation is termed environmental determinism and is seen today as racist and flawed. Instead, environmental possibilism acknowledges that the natural environment has a significant influence upon society but it does not absolutely determine social development.
Natural Resources
Naturally occurring substances that have utility for a culture group are considered to be natural resources. An important consideration in thinking about natural resources is whether they are naturally replenished during human lifetimes or whether they only reoccur over geologic time.
Renewable Resources
Renewable resources such as trees and fish are continually available provided that consumption does not exceed the maximum sustained yield.
Carrying Capacity
The ability of an environment to support a human population.
Global Warming
In recent decades the world has gradually become more aware of the human impact upon the natural environment, particularly the atmosphere. As humans burn more carbon-based fuels like petroleum and coal, the resulting carbon dioxide gas has changed the mix of gases that make the greenhouse effect sustainable. Adding gases like carbon dioxide and methane to the atmosphere results in more long-wave radiation than normal being trapped by the atmosphere. The average temperature of the atmosphere has increased, leading to global climate change (GCC) (or its more popularly known name of global warming).
Non-Renewable Resources
Non-renewable resources, like petroleum, coal, iron ore, and precious metals, only regenerate over millions of years.
The Greenhouse Effect
Life on Earth is possible because the planet possesses an atmosphere that warms the surface. Incoming radiation (light) has a short enough wavelength that it mostly passes through the mix of gases in the atmosphere. Upon striking the surface of the Earth, incoming light is absorbed and radiated upwards as long-wave radiation. Some of that long-wave radiation cannot pass back through the atmosphere, resulting in a warming of the atmosphere. This difference in behavior between incoming short-wave radiation and outgoing long-wave radiation is called the greenhouse effect, since that is how such a facility can grow plants during the colder months of the year.
Acid Precipitation
Another type of environmental impact resulting from air pollution is acid precipitation. Coal burning power plants release sulfur dioxide into the air. This gas mixes with moisture so that when rain or snow falls, the resulting acid precipitation damages stone structures like buildings and gravestones, acidifies water bodies, and kills vegetation.
Ozone Layer
Related to the process of global climate change is the increasing hole in the ozone layer. The various layers of the atmosphere have different mixes of gases. One of the uppermost layers, the ozone layer, prevents harmful types of light from entering the atmosphere. Release of certain industrial chemicals such as those used in refrigeration break down the ozone layer, making all living organisms including humans at risk for illness or injury.
El Niño
The atmosphere is subject to periodic changes in temperature and moisture. A phenomenon called El Niño results in changing temperatures in the eastern Pacific Ocean that alter normal temperature and precipitation patterns across the world. Flooding and drought disrupt life during the El Niño years.
Deforestation
Other types of human impacts on the environment include the removal of large amounts of vegetation. Deforestation occurs when humans clear land for agriculture or to build structures. Vegetation provides important benefits to the environment, like taking in carbon and releasing oxygen, holding soil in place and thus preventing erosion, and providing habitat for wildlife.
