IB Environmental systems and societies Topic 4.2B Water Supply Revision Notes (SL/HL)

IB Environmental systems and societies Topic 4.2B Water Supply Revision Notes (SL/HL) | RevisionDojo

Written by official IB examiners

Water demand is rising as populations and economies grow

Every person needs water for basic domestic needs like drinking, cooking, cleaning, and sanitation.
The World Health Organization (WHO) estimates each person needs 50-100 litres per day to meet these needs.
As population grows, total demand rises with it, especially in fast-growing regions of Africa and South Asia.
Urbanisation pushes demand higher because cities need large supply networks, sewage treatment, and expanding infrastructure.

Note

Freshwater is spread very unevenly across the planet.
The Amazon Basin holds about 20% of global runoff but supports fewer than 10 million people.

Economic development raises how much water each person uses

High-income countries use large amounts for domestic comfort such as gardens, car washing, and pools.
Middle-income countries show the fastest rise in demand as industry and mechanised farming expand.
Low-income countries use water mainly for farming but struggle with access and sanitation.

Example

The average North American uses about 3 m³ of water per day, compared with 1.4 m³ in Asia and 1.1 m³ in Africa.

Water is used mainly by farming, then industry, then homes

Domestic use grows sharply as living standards rise

Domestic use covers drinking, cooking, washing, cleaning, and sanitation.
Urban homes often use more because of piped supplies, washing machines, and gardens.
In many developing countries, families spend hours each day collecting water from unsafe sources.

Example

In sub-Saharan Africa, over 300 million people live where water scarcity limits domestic supply, with women and children often walking hours to collect it.

Agriculture is the largest water user at about 70%

Farming accounts for about 70% of all water withdrawals.
Irrigation raises crop yields but also drives water depletion.
Livestock farming uses even more water than crops because of animal drinking, feed, and cleaning.

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Note

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Tip

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IB Environmental systems and societies 4.2B Water Supply Notes

Water demand is rising as populations and economies grow

Economic development raises how much water each person uses

Water is used mainly by farming, then industry, then homes

Domestic use grows sharply as living standards rise

Agriculture is the largest water user at about 70%

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

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Water demand is rising as populations and economies grow

Economic development raises how much water each person uses

Water is used mainly by farming, then industry, then homes

Domestic use grows sharply as living standards rise

Agriculture is the largest water user at about 70%

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

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Topic 1: Foundation 3 subtopics

Topic 2: Ecology5 subtopics

Topic 3: Conservation and biodiversity3 subtopics

Topic 4: Water4 subtopics

Topic 5: Land2 subtopics

Topic 6: Atmosphere and climate change4 subtopics

Topic 7: Natural resources3 subtopics

Topic 8: Human populations and urban systems3 subtopics

HL lenses 3 subtopics

IB Environmental systems and societies 4.2B Water Supply Notes

Topic 1: Foundation 3 subtopics

Topic 2: Ecology5 subtopics

Topic 3: Conservation and biodiversity3 subtopics

Topic 4: Water4 subtopics

Topic 5: Land2 subtopics

Topic 6: Atmosphere and climate change4 subtopics

Topic 7: Natural resources3 subtopics

Topic 8: Human populations and urban systems3 subtopics

HL lenses 3 subtopics

Water demand is rising as populations and economies grow

Economic development raises how much water each person uses

Water is used mainly by farming, then industry, then homes

Domestic use grows sharply as living standards rise

Agriculture is the largest water user at about 70%

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Water demand is rising as populations and economies grow

Economic development raises how much water each person uses

Water is used mainly by farming, then industry, then homes

Domestic use grows sharply as living standards rise

Agriculture is the largest water user at about 70%

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account