CAMBRIDGEA2GEOGRAPHYREVISION

ENVIRONMENTALMANAGEMENT12.3 ENVIRONMENTALDEGRADATION

KEYTERMSANDDEFINITIONSPollution 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.

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

KEYTERMSANDDEFINITIONSIncidental 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.

KEYTERMSANDDEFINITIONSGreen 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.

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.

KEYTERMSANDDEFINITIONSVirtual 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.

Agro industrialisation in Ghana

TOPICSUMMARYPollution 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.

Drought Forces California to Consider Turning Sewage into Drinking

TOPICSUMMARYSustained 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.

TOPICSUMMARYPhysical 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.

TOPICSUMMARYThere 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.

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

TOPICSUMMARYThe 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.

Urban pollution in China

ADDITIONALWORK1. 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.

SUGGESTEDWEBSITESwww.wri.orgwww.fao.org/landandwaterwww.thewaterproject.orgwww.waterfootprint.orgwww.SciAm.comwww.worldbank.org