The document discusses several key issues related to environmental degradation and pollution: 1. Pollution and environmental degradation come in many forms and negatively impact land, air, water and human health. 2. The largest polluters are often large-scale industrial operations that tend to cluster together. 3. Exposure to pollution can have varying effects from minor to severe, and sustained pollution usually impacts more people long-term than incidental pollution. 4. Access to clean water is vital for development but water scarcity impacts many people and threatens food supplies, economic growth, and international conflicts.

1. CAMBRIDGEA2
GEOGRAPHYREVISION
ENVIRONMENTALMANAGEMENT
12.3 ENVIRONMENTALDEGRADATION

2. KEYTERMSANDDEFINITIONS
Pollution is contamination of the environment. It can take many forms: air,
water, soil, noise, visual and others.
Environmental degradation is the deterioration of the environment through
depletion of resources such as air, water and soil.
Toxicity is a measure of the degree to which something is poisonous. It is
often expressed as a dose–response relationship.
Externalities are the side effects, positive and negative, of an economic
activity that are experienced beyond its site.
Externality gradient and field is the geographical area within which
externalities are experienced.

4. Industrial pollution is the
contamination of the environment
by businesses, particularly plants
and factories, that dump waste
products into the air and water.

5. KEYTERMSANDDEFINITIONS
Incidental pollution is a one-off pollution incident.
Sustainable pollution is longer-term pollution.
Groundwater is water beneath the surface held in or moving through
saturated layers of soil, sediment or rock.
Aquifer is a water-bearing rock such as chalk or limestone. The aquifer must
occur above a layer that prevents the water seeping away, such as clay.
Water-stressed areas are when water supply is below 1700 m3 per person
per year.
Water-scarce areas are when water supply falls below 1000 m3 per person
per year.

7. KEYTERMSANDDEFINITIONS
Green water is that part of total precipitation that is absorbed by soil and
plants, then released back into the air.
Blue water collects in rivers, lakes, wetlands and groundwater. It is available
for human use before it evaporates or reaches the ocean.
Potable water is water that can be consumed by humans without ill effects.
Evapotranspiration is the combined processes of evaporation, sublimation
and transpiration of the water from the Earth’s surface into the atmosphere.
Physical water scarcity is when physical access to water is limited.
Economic water scarcity is when a population does not have the necessary
monetary means to utilise an adequate source of water.

8. From the perspective of crop production,
rainwater may be split in green, blue and white
components. Green Water is the water
infiltrating into the soil, taken up by roots, used
in photosynthesis and transpired by the crop;
White Water is intercepted and directly
evaporated by the crop canopy and the ground
surface; Blue Water is made up from run-off to
rivers and deep percolation to aquifers that
finds its way to rivers indirectly. From the
perspective of dry land cropping, green water
is the productive component. In addition to
direct input from rain, the amount of green
water may be increased by irrigation and run-
on. Green water applies to dry land farming
and blue water to irrigated farming.

9. KEYTERMSANDDEFINITIONS
Virtual water is the amount of water that is used to produce food or any
other product and is thus essentially embedded in the item.
Agro-industrialisation is the form of modern farming that refers to the
industrialised production of livestock, poultry, fish and crops.
Green revolution is the development of high-yielding varieties of seed for
crops such as wheat and rice in LEDCs that require extensive technology for
planting, irrigation, fertilising, spraying and harvesting.
Newly industrialised countries are where manufacturing industry has
expanded significantly since the 1960s.
Overpopulation is when there are too many people in an area relative to
the resources and the level of technology available.
Urbanisation is the process whereby an increasing proportion of the
population in a geographical area lives in urban settlements.

10. Agro industrialisation in Ghana

11. TOPICSUMMARY
Pollution is the dominant factor in the environmental degradation of land,
air and water and impacts significantly on human health.
The most serious polluters are the large-scale processing industries, which
tend to form agglomerations as they have similar locational requirements.
Exposure to pollution can result in health and environmental effects that
range from fairly minor to severe.
It is important to consider the different impact between one off pollution
incidents (incidental pollution) and longer-term pollution (sustained
pollution).
It is usually the poorest people in a society who are exposed to the risks
from both incidental and sustained pollution.

12. Drought Forces California to Consider Turning Sewage into Drinking

14. TOPICSUMMARY
Sustained pollution, such as that caused by ozone-depleting substances,
usually takes much longer to have a substantial impact on human
populations than incidental pollution, but it is likely to affect many more
people in the long term.
Securing access to clean water is a vital aspect of development. The lack of
clean, safe drinking water is estimated to kill almost 4 500 children per day.
Water scarcity has been presented as the ‘sleeping tiger’ of the world’s
environmental problems, threatening to put world food supplies in
jeopardy, limit economic and social development and create serious
conflicts between neighbouring drainage basin countries.

18. TOPICSUMMARY
Physical water scarcity is when physical access to water is limited. Economic
water scarcity exists when a population does not have the necessary
monetary means to utilise an adequate source of water.
The importance of the concept of virtual water is becoming increasingly
recognised. Virtual water is the amount of water that is used to produce food
or any other product and is thus essentially embedded in the item.
Rural areas all around the world have been degraded at a rapid rate over the
past century. This has been due primarily to population growth and
increasing pressures on the land.

20. TOPICSUMMARY
There has been an increasing reaction to high input farming as more and
more people have become concerned about the use of fertilisers,
pesticides, herbicides and other high investment farming practices that are
having a significant impact on the environment.
Large-scale farming has been expanding geographically into a number of
fragile environments, particularly into areas of rainforest.
Urban areas can impact on the environmental degradation of their rural
surroundings in a number of ways.

21. Away from the small scale family farms towards large, capital intensive, fully mechanised and specialised industrialised farms.

22. TOPICSUMMARY
The degradation of urban environments occurs mainly through
urbanisation, industrial development and inadequate infrastructure.
The relationship between the urban poor and the environment is
somewhat different from that of the rural poor.
There are numerous constraints on improving the quality of degraded
environments.
Environments at risk can be protected in various ways. At the most
extreme, human activity and access can be totally banned such as in
Wilderness Areas.

23. Urban pollution in China

24. ADDITIONALWORK
1. How is water utilised in the country in which you live? Has this changed
to any significant extent over time?
2. Look at the World Resources Institute website (www.wri.org) to examine
in more detail the link between pollution, health and development.
3. Look at Five Past Midnight by Dominique Lapierre and Javier Moro
(Scribner, 2002) or a detailed account of the Bhopal accident.
4. Do you think that government should place environmental taxes on
products that contain a lot of virtual water to make both producers and
consumers think more carefully about these products?
5. Suggest how you could realistically reduce your use of virtual water.

25. SUGGESTEDWEBSITES
www.wri.org
www.fao.org/landandwater
www.thewaterproject.org
www.waterfootprint.org
www.SciAm.com
www.worldbank.org