G C Flashcards
Sustainability
Social, economic and environmental use of resources in a way that allows future generations to maintain their standard of living.
Arid and semi-arid areas
arid areas receive less than 250mm rainfall per year whereas semi-arid areas receive between 250mm and 500mm per annum
infertility
a lack of nutrients or bases in soils, cause by low weathering rates, a lack of biomass; insufficient nutrients to support arable farming.
periglacial
snow and ice cover on the fringe of glaciated areas (peri = edge) usually associated with permafrost or ground that remains frozen for at least two years. These regions include high mountain and tundra areas of northern Eurasia and North America.
permafrost
permanently frozen subsurface. TO be classified as a permafrost the land must have been frozen for at least two years.
Weathering and erosion
weathering is the breakdown (denudation) of the Earth’s surface in situ (on the spot, that is, without a moving force) whereas erosion is the breakdown of the Earth’s surface by a moving force, for example glaciers, rivers, wind.)
Desertification
the spread of desert or desert-like conditions
Indigenous people
People native to an area and who have been there for many generations.
Resource nationalism
The use of a country’s resources to benefit that country rather than allowing a TNC or another country to benefit from the resources.
polar environments are located? what belt of environments do they have
towards the north pole and the south pole where levels of insolation (solar radiation) are very low)/. in the northern hemisphere there is a belt of periglacial environments, other cold environments are associated with high mountains.
where are desert and semi-arid environments located?
around the tropics and are associated with permanent high-pressure systems which limit the potential rain formation
what are the main factors determining the location of the world’s main deserts?
- high-pressure conditions, for example Sahara and the great Australian deserts
- Continentality - large distance from the sea
- Rain-shadow effects, as in Patagonia in South America and the Gobi desert in central Asia.
- Cold upwelling currents which limit the amount of moisture held in the air.
Disadvantages of mountain areas
difficult areas to build on, they act as barriers to transport, soil are often thin and suffer from high rates of overland run-off and erosion.
periglacial areas - or tundra regions advantages
low temperature produce low rates of evaporation and soils are frequently waterlogged but the growing season is short. Some periglacial areas support large numbers of people and there may be important settlements adjacent to some high-altitude environments
features of desert and semi-arid environments
in areas close to the gulf of aden or the red sea, the lack of water acts as a major constraint for developments. Temperatures are high and in the absence of fresh water the farming is almost impossible. The annual rainfall varies between 250mm and 500mm. Deseret areas may be characterized by a mixture of steep slopes, flat areas, seasonal streams and flash floods.
extreme environments are characterized by
low population densities. for example, three people per square km in central Australia, Iceland and northern Canada. (insufficient heat) Two people per square km in Namibia, and one people per square km in western Sahara. (insufficient water)
indigenous people coping with periglacial environments
indigenous people have turned to river and the oceans since fishing is extremely important in periglacial environments. (Nenets of the Yamal Peninsula in SIbera e.g.)
building on permafrost
engineers rise building above the ground on steel frame so that cold air can flow under them and stop the permafrost from thawing, or thaw the ground first so the structure keeps the ground from freezing.
rainfall in the arid environment
areaas with less than 250 mm rainfall has annual variability of about 50%, flash floods may occur in deserts due to dry surfaces these result in sheet flow (water flowing over large surface areas rather than in distinct channels) and lead to erosion and severe disruption of economic activities
sheet flow
in arid areas where water flowing over large surface areas rather than in distinct channels and lead to erosion and severe disruption of economic activities
when more snow falls (accumulates\an input) than melts (ablates\an output)
the glacier advances
an input - snow falls another from a glacier word
accumulates
an output - snow melts of a glacier another word
ablation
when less snow falls (accumulates\an input) and more melts (ablates\an output)
the glacier retreats
when same amount of snow falls (accumulates\an input) and melts (ablates\an output)
the glacier is steady
the glacier is steady when
accumulation=ablation
glacier retreats when (negative regime)
accumulation<ablation
glacier advances when (positive regime)
accumulation > ablation
pluvials
rainy periods
desertification
due to annual and decadal (in 10 years) variations in rainfall can cause deserts to expand and at other times contract