5.7

• Economic scarcity occurs when there is water available but the infrastructure is not available to access the water
○ About 1.6 billion people face economic water scarcity
○ Physical scarcity occurs when there is greater demand for water than there is supply
§ An estimated four billion people face severe water scarcity for

• Physical - variation in climate, salt water encroachment
• Human - over-abstraction, water contamination, industrial pollution

• Climate variation can lead to drought this reduces the amount of water available
• Salt water encroachment occurs due to sea level rise when freshwater sources are contaminated by seawater and so become saline
• Saltwater encroachment is an issue for coastal communities, particular island communities
○ Tuvalu has experienced damaged crops and a loss of income; further encroachment could affect deep-rooted crops such as coconut and taro
○ Saltwater encroachment in the Maldives threatens drinking water supplies and has also damaged crops

• Over-abstraction occurs when more water is taken than is naturally replaced by precipitation
• Over-abstraction affects many countries worldwide:
○ Jakarta and Beijing are sinking as a result of past over-abstraction of groundwater, which is causing subsidence
• Over-abstraction from lakes and rivers is also an issue
○ Increased abstraction of water from the Nile by Ethiopia is decreasing the availability of water for Sudan and Egypt

• Over 2.4 billion people live without sanitation
○ A lack of sanitation is one of the leading causes of water contamination
○ In developing countries 90% of sewage flows untreated into water sources
○ Agriculture discharges large quantities of agrochemicals, organic matter, drug residues and sediment into water sources
○ As the world population increases so does the amount of agriculture, further increasing the agricultural pollution
§ In the EU almost 40% of water sources are impacted by agricultural pollution
§ Increased nitrates from fertiliser use leads to eutrophication
§ Cattle meat production has doubled since 1961; this leads to increased manure
§ Increased use of antibiotics and growth hormones move through animals into waste and then water systems

• Every year 300-400 megatonnes of waste is discharged by industry into the water system
• In many countries factory waste is discharged into water sources untreated due to a lack of regulations and a failure to challenge industries
○ It is estimated that 80% of China's groundwater is polluted
○ This has led 70% of rivers and lakes to be unsafe for human use
○ In India the Upper Doab region has been severely affected by industrial pollution
§ Heavy metals such as arsenic, mercury, lead, zinc, phosphate, sulphide, cadmium, iron, nickel and manganese were found in the water. These are linked with cancer, bone deformity, and stomach-related diseases
§ Oil refineries along the Gulf Coast in California have been found to be releasing pollutants which are contaminating nearby water sources

population growth and economic development

there are now over 8 billion people
• Each person requires about 2 litres of clean drinking water a day to remain in good health
• In addition 18 litres per person is needed for things like sanitation and cooking
• As well as an increase in domestic water demand, population growth also increases the use of water for:
○ Energy production
○ Agriculture
○ Industry

as countries develop, the demand for water increases because
• People have more items which use water, such as dishwashers, toilets and showers
• Industry increases and factories use large quantities of water
• Intensive agriculture is needed as people eat more food, and irrigation systems use large quantities of water
• As more people move to urban areas, the demand for water for drinking and sanitation increases

• The UN predicts that 5 billion people or two-thirds of the world population, will face at least one month a year of water shortages
• The future shortages will be the result of:
○ Climate change
○ Increased demand
○ Pollution
○ By 2040 Chile, Estonia, Namibia, and Botswana could face a significant increase in water stress
§ In Chile the decrease in water availability is the result of rising temperatures and changing patterns in precipitation
§ Almost half of the most likely water-stressed countries are in the Middle East
§ In the southwestern US water stress could increase between 40 and 70% by 2040
§ The UN report expresses concerns regarding conflicts resulting from water shortages