This page provides a comprehensive introduction to water scarcity. It provides detailed worksheets, reading material and interactive activities on water scarcity. It begins with a map from memory activity on global patterns, leading to a comprehensive explanation of the causes of droughts. Students complete the lesson by exploring the social, economic and environmental impacts of drought.
Lesson Time: 1 hour
- To describe water stress and water scarcity including physical and economic water scarcity
- To explain the causes of water scarcity, both natural and human-made
- To describe the consequences of drought
Map from memory the following water scarcity map with a partner
Source: World Development Report 4
Read the following text and complete the gap-fill on your worksheetWater stress: When the demand for water exceeds the supply of water and shortages exist.
Physical Water Scarcity: When the supply of rainfall is lower than the demand of water.
Economic Water Scarcity: When water supplies exist, but the local population can not access them because of pollution, lack of technology, etc.
Water scarcity is both a natural and a human-made phenomenon. There is enough freshwater on the planet for the human population but it is distributed unevenly and too much of it is wasted, polluted and unsustainably managed.
Hydrologists typically assess scarcity by looking at the population-water equation. An area is experiencing water stress when annual water supplies drop below 1,700 m3 per person. When annual water supplies drop below 1,000 m3 per person, the population faces water scarcity, and below 500 cubic metres "absolute scarcity"
Click on the map to go to 'Interactive growing Blue Tool'. Navigate the map to identify different reason for water scarcity. Complete your table with 5 different places
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Watch the following video and answer the question on your worksheet
Work with the card sort to
- Match the image with the text
- Classify into physical scarcity and economic scarcity
Read the following text and answer following questions:
- Sort the the different causes of drought into global and regional/continental scale
- How does sinking air create dry conditions?
- Can you think of any human causes of drought?
Drought can affect nearly every place on the planet, even places like the British Isles, which has a Temperate Maritime climate experiences droughts as part of anticyclonic weather systems. These systems are caused by the slow sinking of cooler air creating areas of high pressure. As air sinks it warms and relative humidity falls. This process in turn, locks moisture in, creating dry calm conditions. It is possible for these condition to be prolonged when these high pressure systems get anchored to one place for an extended period of time.
This process of sinking cool air follows a distinct spatial pattern at the global scale. This can be seen in the global atmospheric circulation presented in the tricellular model. High pressure is experienced at 30 degrees and at the poles creating the warm and cold desert belts. In places like the Sahel in Africa, droughts are a natural part of their Tropical Dry/Wet climate. However with climate change droughts seems to be increasing in both frequency and extremity. Another global system that causes drought is El Nino. This several of Pacific Ocean currents, which brings drought to South East Asia seems to be increasing in frequency.
Other places experience drought conditions as part of their geographical positioning in relation to rain shadows of mountain ranges. As air sinks downwards on the leeward side of ranges, the air warms and relative humidity falls locking moisture in. A good example of this is found in the Atacama Desert region of South America.
Continentality is also a factor that causes droughts. Air movement over large land masses such as Asia and Australia becomes moderated by the dry conditions of the land. This distance from large bodies of water means the air id dry and little rain forms. This can be seen in the image below of Australia.
Complete the worksheet by identifying the social, economic and environmental impacts of droughts