SAERC GGS 12 Mr. R. Allen Global Water Resources: Half Full or Half Empty? Essential for life, water is the most important natural resource in the world today. As with all resources, however, it is distributed unevenly. Some countries have an abundance of fresh water, while others the majority have limited access to this vital commodity. The following activity will explore some basic facts about the global water situation, and will then look at the effect of water on agriculture in three very different locations. You ll also examine the relationship between water and the disturbing trend toward desertification, especially in Africa. The final part of the activity challenges you to decide whether or not countries with apparently abundant water reserves, such as Canada, should be sharing their water wealth with countries in dire need. Part 1: Basic Water Facts Before you go any further, it s important that you gain a better understanding of water and its importance to the Earth. The first question is Where are all of the Earth s water resources located? Take a look at the table titled Distribution of the Earth s Water on page 129 of the Atlas and answer the following questions. 1. Where is most of the water on Earth located? 2. Which source of water listed is least abundant? 3. Identify which resources are suitable and accessible sources of fresh water for human consumption. 4. In general, how does the volume of available freshwater resources compare with the volume of salt water and inaccessible water resources? 5. Use the Freshwater resources map on page 141 of the Atlas to complete the chart on the next page. If a region includes a variety of resource levels, use compass directions to describe the differences. The first one is done for you. 6. Why is a country like Madagascar in southern Africa unable to provide all of its population with access to fresh water despite having abundant resources? Use the Physical map of Africa on pages 108 109 of the Atlas and the Distribution of the Earth s water table on Atlas page 129 to help with your answer.
Region North America Description of Freshwater Resources Generally abundant, but the amount decreases as you move south and closer to the Equator. Percentage of Population with Access to a Water Source (estimate) All citizens in Canada and the United States have access to a water source, while 86% of those in Mexico do. South America Europe Asia Africa Oceania
Water and Agriculture What does all this water get used for? Many of us only think of personal uses of water such as brushing our teeth, watering the garden, bathing, or drinking. But domestic use accounts for only a small percentage of total water consumption. Some is used by industry, especially for power generation, but by far the largest volume of the world s water resources is used in agriculture. In the last 100 or so years, agricultural use has increased more than sevenfold. In places like Africa and Asia, an amazing 85 90 per cent of freshwater use is for agriculture. 7. Why do you think the use of fresh water for agricultural purposes has grown so much over the past century? Irrigation can be defined as the process of supplying crops with fresh water through channels, streams, pipes, or other human-induced solutions. The amount of irrigated land around the world for agricultural purposes is rising. In many countries, this creates a strain on freshwater supplies. Let s compare the water resources and levels of irrigation on two continents: Africa and Asia. Use the maps on Atlas pages 129 (Water surplus or deficiency) and 141 (Irrigated land) to answer the following questions. 8. Describe the pattern of water resources you observe across these continents. 9. We can observe that Asia generally uses more of its water resources for irrigation purposes. What reasons can you hypothesize to explain why Africa does not irrigate more of its land to increase its agricultural output? 10. Predict what future impacts the continued use of fresh water for irrigation in Asia may have.
Part 2: Comparing Three Cities We have learned from Part 1 that many parts of the world have a severe deficiency in water resources. You have also seen that the most significant use of global water resources is for agriculture. The following exercise will examine current water availability and the resulting agricultural practises. Let s take a closer look at the situation at three climate stations in different parts of the world: La Paz, Bolivia; Montréal, Canada; and Tamanrasset, Algeria. 11. Complete the chart on the next page using maps and information found on Atlas pages 126, 129, 132 133 and 140 141 as well as in the Gazetteer. 12. Look at the annual precipitation figures for the La Paz area. How do you reconcile the amount of rainfall with the fact that this location has a water deficiency? Why does it have so little arable land? 13. Why does the Montréal area have such a low percentage of irrigated land? 14. In which of these three locations is lack of precipitation most likely to be a major problem? 15. How do the Montréal area s precipitation patterns give it an advantage over the other two locations for agriculture? 16. Which location in your opinion has the least potential for agriculture? Why?
La Paz, Bolivia Montréal, Canada Tamanrasset, Algeria Latitude Metres above sea level Annual precipitation Climate region Natural vegetation region Types of agriculture Arable land (hectares per capita) Irrigated land Water surplus or deficiency
Part 3: Desertification and Groundwater We ve looked at who has water and who doesn t, and considered some of the ways that water can affect agriculture in a region. Now let s look at what severe water shortages can do to an area that is already under stress. An unwelcome environmental trend that is occurring around the globe is desertification. Desertification is the process by which arable land is being degraded (made unsuitable for agriculture) and changed into desert as a result of poor land use, population pressures, or climate change. Compare the map on the bottom of Atlas page 130 with the map of Freshwater resources on Atlas page 141. Many of the areas at risk of desertification are areas close to desert areas that receive little precipitation. If left alone, these areas would probably not be at risk of becoming desert. But with human interference, the land becomes severely distressed because it cannot sustain the practices we put to it. A dry but natural savannah can support natural plant species and wildlife. It cannot support herds of cattle or other forms of agriculture without deteriorating into useless desert. Irrigation is one way to address this problem, but irrigation requires adequate freshwater resources and the infrastructure as well as the means to pay for transporting the water. Let s take a closer look at the situation facing Northern Africa. 17. a) Using the data on pages 105 107 and 140 141 of the Atlas, write a brief report explaining how the water situation in the Sahel region of Africa may affect the process of desertification. Make sure to include the following topics: rainfall patterns from 1950 to 2005 in the Sahel average annual precipitation temperature ranges freshwater resources irrigated land natural vegetation types of agriculture employment in agriculture b) In your report, predict how the loss of arable land is likely to affect its economy.
The Sahel region of Northern Africa is certainly facing a water crisis. But is continuing desertification of these lands inevitable? Not necessarily. Parts of this dry and arid region contain groundwater resources that could be used to supply more of the water needs of the people who live there. Groundwater can be defined as the fresh water that seeps into the ground through the natural processes of the hydrologic cycle and is stored in aquifers beneath the Earth s surface. In humid regions, these freshwater reserves are sometimes just below the surface, while in arid regions the water table may be hundreds of metres underground. The Sahara Desert region in Northern Africa has a huge underground supply of water in a natural groundwater reservoir. One of the world s most ambitious engineering projects to date, the Great Man- Made River Project, is currently harvesting these water resources and transporting the water to cities along the coast of the Mediterranean in countries such as Libya in Northern Africa. 18. Using the Internet, gather information regarding the Great Man-Made River Project and answer the following questions. What is the location of the reservoir? What is the geological background of the area? Who are the main beneficiaries of the project? Why is the water being transported out of the desert to coastal regions, instead of being used in the Sahara? What is the long-term sustainability of this source of water?
Part 4: At Issue Water as a Commodity Throughout this activity, we have been focusing on regions of the world that face water deficiencies. But some countries have a surplus of freshwater resources. While Canada contains a surplus of fresh water, not all of it is easily accessible. According to Environment Canada, Canadians are the world s biggest water wasters. We use an average of 330 L per day for personal domestic use, while most people in water-scarce regions use less than 10 L per day. Yet the amount of water we have is finite. The hydrologic cycle does have a natural ability to purify water, but it cannot sustain itself against the current assault. Some Canadian communities dump raw or minimally processed sewage into rivers, and contamination from chemical and agricultural pollution adds significantly to our water woes. Intensive development, increasing demand from industry and growing cities, and even increased bottled water sales, all reduce the quality and quantity of our water supply. After we consider that we must share our water with millions of other plant and animal species, any idea you might have that Canada has an abundance of fresh water should quickly fade. Water is so essential to everyday life that we could not survive without it. Because of this, some people claim that it is a human right to have access to fresh, clean water. More than 1 billion people in the world do not have this access. Canadians are indeed fortunate to live in a part of the world with a water surplus. Recently, however, there have been some changes. The demand for bottled water has risen sharply because many people are concerned about the quality of tap water. A number of corporations have begun to turn water into a commodity that can be privatized (taken out of the hands of government control), so that they can suck up our water and sell it back to us. The World Bank estimates the global water market is worth a trillion dollars. No wonder water has become known as blue gold. So who owns Canada s water? Who has the right to extract it, divert it, or sell it? Does Canada have an obligation to sell its water resources to those regions in need? Or should we conserve this valuable resource for future generations and needs within Canada? Opinions are sharply divided. The following CBC Web site will give you an overview of the arguments on both sides of the issue: <www.cbc.ca/news/background/water/>. 19. What is your opinion regarding the selling of Canada s water resources? Prepare a one- to two-page report outlining your position on the topic. Your analysis should use supporting evidence not only from your research but also from the knowledge you have gained about water throughout this activity.