Part Five, Issue 11

1. Part Five, Issue 11 Global Water Supplies: Are They Sustainable

2. Objectives After reading the assigned chapter and reviewing the materials presented the students will be able to understand: • How much water do people need? • How much water is used in agriculture? • What effect will climate change have on water supplies?

3. Introduction • In 1977, California was in the midst of a powerful drought. Residents were forbidden to water their lawns or wash their cars. • Health officials have shown that cholera, an often deadly bacterial infection can be controlled by a simple and cheap cloth filtration system for drinking water. • One in six of the planet’s 6.4 billion people presently lack access to safe water and at least 2.4 billion do not have access to adequate sanitation. • Water demand is projected to grow by 40% over the next 20 years. If this issue is to be addressed, hundreds of billions of dollars must be invested globally in water infrastructure.

4. The Hydrologic Cycle • The movement of water at the earth’s surface is called the water or hydrologic cycle. • The components of the cycle are evaporation, precipitation, runoff, and infiltration (fig 11-2, page 117). • Water that infiltrates into the soil is called groundwater. • Glaciers and permanent snow have 68.70% of the earth’s freshwater and fresh groundwater has 30.10%. • The earth’s oceans have 97.50% of all water.

5. How Available is Water Globally • Eighty percent of all illness in developing countries are water related, according to the UN. • By UN estimates two-thirds of humanity, or as many as 5 billion people will face shortages of clean freshwater by the year 2025. • Some toxic organisms are already resistant to chlorination, the most widespread technique to purify drinking water.

6. Who collects and distributes the Planet’s Water? • Sizeable investments are required to extract, purify, and distribute water. • The UN estimates that at least US $180 billion will be required globally to expand supplies over the next two decades. • There is a lot of waste due to leaking pipes. • Lack of water will generate refugees, the cost will be borne by other segments of society or other nations. • Governments typically build and operate water distribution systems.

7. Impacts of Contaminated Water • According to the UN, as many as 3 million children die each year from polluted water or water scarcity. • It is one of the major factors driving mass migration, creating increasing number of human refugees. • Humans need 500,000 liters a year to meet minimum human hygiene demands.

8. Water Use in the United States • The United States uses about 400 billion gallons each day. • This figure includes both consumptive use (the water is not put back where it came from) and non consumptive use (the water is put back after use). • About three-fourths of all water used in California, is by agriculture. • Subsidized prices to agribusiness meant massive waste. Most irrigation ditches were made of unlined dirt. • Up to a quarter of the water trickled into the soil before reaching its destination. • Up to 25 % evaporated from the ditches in 100 degree heat.

9. Climate Changes and Water Demand in California • Studies on ancient trees have yielded valuable insight into climatic variability in California. • Such studies confirm that California’s climate over the past millennium have been extremely variable, with severe drought conditions persisting for decades to centuries. • Incorporating this data into computer forecasts, shows that California’s climate is going to become more extreme than in the recent past. • This will force agonizing choices for providing water consumed by industrial agriculture, commerce, and municipalities.

10. Water and Development: The People’s Republic of China • Over half the population must use drinking water that fails to meet minimum drinking water quality standards in China. • Three reasons account for China’s degraded water: • 1. Rapid and unregulated expansion of industry. • 2. Failure to invest in infrastructure to meet growing need. • 3. Reliance on sewage effluent to irrigate crops.

11. Water and Geopolitics: Israeli/Palestinian Water Conflict • Water is one of the major areas of disagreement between the Israelis and Palestinians. • Future water needs cannot be met by increasing supply from existing sources. • Thus conservation, new supplies, or a combination of both will be needed, along with measures to address population growth.

12. Summary • One in six of the planet’s 6.4 billion people presently lack access to safe water and at least 2.4 billion do not have access to adequate sanitation. • Water demand is projected to grow by 40% over the next 20 years. If this issue is to be addressed, hundreds of billions of dollars must be invested globally in water infrastructure. • The movement of water at the earth’s surface is called the water or hydrologic cycle. The components of the cycle are evaporation, precipitation, runoff, and infiltration . Water that infiltrates into the soil is called groundwater. • Eighty percent of all illness in developing countries are water related, according to the UN. • By UN estimates two-thirds of humanity, or as many as 5 billion people will face shortages of clean freshwater by the year 2025. • The UN estimates that at least US $180 billion will be required globally to expand supplies over the next two decades. • Humans need 500,000 liters a year to meet minimum human hygiene demands. • Studies on ancient trees have yielded valuable insight into climatic variability in California.

13. Home Work •  1. What are the components of the water or hydrological cycle? • 2. What percentage of all illness in developing countries are water related, according to the UN? • 3. What is the minimum human hygiene demand for water?