Fragile Environments Flashcards
What is a Fragile Environment?
A fragile environment is one which can be easily damaged, as it is unable to adapt to variations that may arise as a result of human and physical impacts.
3 processes that have increased fragility
- Desertification
- Deforestation
- Climate Change
Human causes of environmental disturbance
Pesticides and Herbicides
Deforestation
Dam building
Monoculture
Mining
Road and residential building
Pollution
War
Poaching and smuggling
Physical causes of environmental disturbance
Drought
Volcanic activity
Tropical storms
Deforestation
Definition of Sustainability
Meeting the needs of the present without compromising the ability of future generations to meet their own needs.
Measuring Sustainability
It is the amount of the environment necessary to produce enough water, food, energy, raw materials and waste disposal to support a particular lifestyle.
Ecological deficit
We take more than what Earth can regenerate each year. It now takes the Earth one year and six months to regenerate what we use in a year.
Ecological footprint
The link between ecological footprint and sustainability is that the footprint informs us about just how sustainable (or not) we are being.
A large ecological footprint means that…
*Undeveloped land is harder to find so pressure increases on what remains.
*Protecting biodiversity is more difficult: we try to conserve, but then we promote these areas as ‘must see destinations’ – ecotourism?
*The desert fringes are becoming deserts through overgrazing and the removal of trees/shrubs which give rise to soil erosion, and the decreasing rainfall all combine to turn productive farmland into useless scrub.
Ecological footprint patterns
Developed countries have a higher ecological footprint (1) as they consume more resources (1) use more fossil fuels (1)
The Northern Hemisphere has higher ecological footprints than the South (1) this could be due to higher levels of wealth (1)
Countries like Australia have higher ecological footprints (1) as they use many resources due to extreme weather (1)
Describe the global distribution of areas at risk of forest loss.
Areas at risk of forest loss are concentrated through Asia, Africa and South America. (1) There is a linear pattern to areas of forest loss in Eurasia (1) There is a scattered pattern of forest loss in Asia. Significant area of forest loss in South America/Amazon/Brazil (1) Significant area of forest loss in Indonesia (1) There is little forest loss in North America (1) There is little forest loss in Europe (1)
Causes of desertification
Population Pressure
Degradation (area of land being degraded)
Migration
Overcultivation (crops grown on farmland too many times)
Overgrazing
Soil erosion
Human causes
Natural causes
What is desertification?
The process of desert conditions spreading into what were previously semi-arid areas, as the quality of soil and its fertility decline over time
Soil erosion and Desertification
*Vegetation biodiversity degraded or lost
*Soil erosion increased as bare soil exposed to wind (no protection)
*Soil salt content increases
*Soil becomes less stable
*Loose sand increases.
*Absence of surface water
*Dried up rivers and ponds
*Water table lowered (the level below ground which is saturated with water
Social Impacts of Desertification
*People are forced to migrate, with many people - young men in particular, leaving to work in cities and towns. This puts pressure on already limited urban resources.
*Disputes occur over land between herdsmen and farmers.
*Food shortages lead to malnutrition and famine, e.g. in Ethiopia. This also results- in increased movement to refugee camps.
Economic impacts of Desertification
As the land becomes unproductive, farm income falls.
*This leads to widespread poverty and an increased reliance on overseas aid.
*Increased dependency on government grants.
Environmental impacts of desertification
*As vegetation is removed the roots cannot bind the soil together and the soil becomes vulnerable to wind erosion.
*The fertile topsoil is easily blown away and becomes less productive
*The land becomes infertile, turning to desert, e.g. the expansion of the Sahara desert.
*Degraded land reduces the soil’s ability to absorb carbon.
*Habitats are lost to various plants, insects and animals.
*Increased frequency of sand and dust storms.
Case study: Sahel, Africa
Semi-arid, it is always hot and has long dry seasons. Globally, 24% of the land is degrading. About 1.5 billion people directly depend on these degrading areas. The Sahel lands receive between 100mm -200mm of rainfall in the north to 600mm on rainfall in the south. Lands are under pressure due to population growth, conflict, overgrazing and removal of trees for firewood.
This region is very important for Africa as it provides food and cash crops such as millet and cotton. Since the 1970s, the Sahel has experienced drought conditions on a regular basis. This is down to physical and human factors.
Why is the Sahel Desert threatened?
Changing weather patterns - less rainfall leads to drier grounds - soil easily eroded.
Climate change - hotter temperature increase speed of desertification.
Population increase - need to farm more land.
Poor farming techniques - monoculture and cannot afford fertilisers to keep soil fertile.
Sahel - social impacts
Mali, Burkina Faso and Niger experience lots of insecurity with sate authorities withdrawing to cities and armed groups spreading through some rural areas.
A lack of clean drinking water - increases diseases (cholera).
Land is unable to support people, so they are forced to migrate.
Sahel - Economic impacts
As land becomes unproductive, farm income falls.
increased reliance on overseas aid.
With less food being grown and an increase in demand, food prices increase.
Sahel, Environmental impacts
Increased soil erosion.
Reduction in groundwater reserves.
Fewer plant and animal species.
