Water Security

This lesson examines global patterns of water availability, the distinction between physical and economic water scarcity, the concept of virtual water, water conflict, and strategies for improving water security. Water is fundamental to food production, health, energy generation, and ecosystem maintenance, making water security a critical theme in AQA A-Level Geography.

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Defining Water Security

Key Definition: Water security is defined by UN-Water as "the capacity of a population to safeguard sustainable access to adequate quantities of acceptable quality water for sustaining livelihoods, human well-being, and socio-economic development, for ensuring protection against water-borne pollution and water-related disasters, and for preserving ecosystems in a climate of peace and political stability."

Key Statistics

• Approximately 2.2 billion people lack access to safely managed drinking water (WHO/UNICEF, 2023)
• 3.6 billion people lack safely managed sanitation
• 2 billion people live in countries experiencing water stress (UN, 2023)
• Agriculture accounts for approximately 70% of global freshwater withdrawals
• Industry accounts for approximately 19% and domestic use for approximately 11%

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Global Water Distribution

Although 71% of the Earth's surface is covered by water, only 2.5% is freshwater. Of this freshwater:

Source	Percentage of Freshwater	Accessibility
Ice caps and glaciers	68.7%	Largely inaccessible
Groundwater	30.1%	Accessible but often expensive to extract
Surface water (rivers, lakes)	0.3%	Most accessible; most used
Soil moisture, atmosphere, biota	0.9%	Not directly usable

This means that less than 1% of the Earth's total water is readily available freshwater for human use.

Water Stress

Key Definition: Water stress occurs when annual freshwater supply falls below 1,700 m³ per person per year. Water scarcity is defined as below 1,000 m³ per person per year. Absolute water scarcity is below 500 m³ per person per year (Falkenmark Indicator).

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Physical vs Economic Water Scarcity

graph TD
    WS["Water Scarcity"] --> PWS["Physical Water Scarcity"]
    WS --> EWS["Economic Water Scarcity"]
    PWS --> P1["Insufficient natural<br/>water resources to<br/>meet demand"]
    PWS --> P2["Examples: Middle East,<br/>North Africa, parts of<br/>Australia and USA"]
    EWS --> E1["Water exists but<br/>lack of infrastructure,<br/>investment, or governance<br/>to access it"]
    EWS --> E2["Examples: Sub-Saharan<br/>Africa, parts of<br/>South and SE Asia"]

Type	Definition	Characteristics	Examples
Physical water scarcity	Water resources are insufficient to meet all demands, including environmental flows	Arid/semi-arid climate; over-extraction of rivers and aquifers	Saudi Arabia, Libya, Yemen, parts of western USA
Economic water scarcity	Water is physically available but lack of human, institutional, and financial capital prevents access	Abundant rainfall but poor infrastructure; lack of treatment plants, pipes, storage	DRC, Uganda, Madagascar, Myanmar

Exam Tip: This distinction is crucial. Sub-Saharan Africa receives abundant rainfall overall, but poor infrastructure and governance mean millions lack clean water. Presenting all water problems as "not enough rain" is inaccurate — economic water scarcity is the dominant form globally.

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Factors Affecting Water Supply and Demand

Supply-Side Factors

Factor	Effect on Supply
Climate	Determines rainfall, evaporation, and seasonal availability; arid regions naturally water-scarce
Geology	Permeable rocks (e.g., chalk, limestone) store groundwater in aquifers; impermeable rocks (e.g., clay) promote surface runoff
River systems	Major rivers (Nile, Mekong, Indus) are critical water sources but often transboundary
Climate change	Altering precipitation patterns; accelerating glacier melt; increasing drought frequency
Pollution	Contamination reduces available clean water; industrial, agricultural, and sewage pollution

Demand-Side Factors

Factor	Effect on Demand
Population growth	More people = more water needed for drinking, sanitation, food production
Economic development	Industrialisation and urbanisation increase water demand; middle-class diets require more water (meat production is water-intensive)
Agriculture	Irrigation is the largest single use; inefficient flood irrigation wastes water
Lifestyle	Higher-income populations use more water per capita (USA ~300 litres/person/day vs. Mozambique ~4 litres/person/day)

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Virtual Water

Key Definition: Virtual water (concept developed by Tony Allan, 1993) is the total amount of water embedded in the production of goods and services. It includes water used in growing crops, raising livestock, and manufacturing products.

Examples of Virtual Water Content

Product	Virtual Water (litres)
1 kg of beef	~15,400
1 kg of chicken	~4,300
1 kg of rice	~2,500
1 kg of wheat	~1,800
1 pair of jeans	~10,000
1 cup of coffee	~140
1 cotton T-shirt	~2,700

Water Footprint

Key Definition: A water footprint measures the total volume of freshwater used by an individual, community, business, or country. It includes direct use (household) and indirect use (virtual water in consumed goods).

National water footprints (litres/person/day):

• USA: ~7,800
• UK: ~4,600
• China: ~2,900
• India: ~3,000
• Ethiopia: ~1,800

The concept highlights that countries can "import" water by importing water-intensive goods. The UK effectively imports approximately 75% of its water footprint through food and manufactured goods.