Physical & Human Causes of Water Insecurity (Edexcel A Level Geography)

There is an increasing mismatch between water supply and demand leading to:

• Water stress (below 1,700m³ per person)
• Water scarcity (below 1000m³ per person)

Global water scarcity

• Water scarcity can be economic or physical:
  • 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 at least one month a year
• It is estimated by the UN that by 2025 over 65% of the world's population could be living with water stress
• The World Economic Forum rates water crises as one of the greatest global threats
• An estimated 30% of groundwater systems are being depleted

Water withdrawals as a share of available water

• The causes of water scarcity are both physical and human:
  • Physical - variation in climate, salt water encroachment
  • Human - over-abstraction, water contamination, industrial pollution

Physical 

• 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

• 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

Human

• Over-abstraction occurs when more water is taken than is naturally replaced by precipitation
• Many countries around the world are affected by over-abstraction:
  • Jakarta and Beijing are sinking as a result of past over-abstraction of groundwater which is causing subsidence

World's largest aquifers

• 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

Water contamination

• 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

Industrial pollution

• 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, sulfide, 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

• The finite water resource faces increasing pressure 

Global freshwater use

• Water use increases more rapidly than population - it is estimated that water demand will increase between 20-30% by 2050
• Population growth: 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
• Economic development: 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 future and water stress

• 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 40-70% by 2040
• The UN report expresses concerns regarding conflicts resulting from water shortages