Http://. Water stress How is demand for water changing? Lesson Objectives: To know why demand for water is increasing To understand.

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Water stressHow is demand for water changing?

Lesson Objectives:To know why demand for water is increasing

To understand water stress and scarcity

Why is water stress increasing?

How are humans altering the water

supply?

Key terms

So far, freshwater is not scarce on a global scale. However, many parts of the word are now experiencing water stress.

Write down what you understand the term “water stress” to mean

Water stress occurs when the demand for water exceeds the amount available during a certain period, or when it is not good enough quality to use.

Physical water scarcity – shortages occur when demand exceeds supply. I.e. There is not enough good quality water available for everyone to have the amount they need

Economic water scarcity – when people cannot afford to extract the water even if it is readily available (Sub-Saharan Africa)

1. Describe the location of water stressed countries in 1995.

2. Describe how this may change in 2025. Why do you think this is?

Why is water stress increasing?

Why is water stress increasing?

Energy Supply

Tourism

Climate change

Industry

Urbanisation

Agriculture

Population Growth

Pressures on water supply: Energy• Storing water in reservoirs (to use for hydro-

electric power) increases the amount of water lost through evapouration, and the risks of water-related diseases.

Pressures on water supply: tourism

• Golf courses and large hotels take up a huge amount of the world’s water resources.

• They are becoming increasingly popular in developing countries.

Pressures on water supply: Climate change

• Affect rainfall, evaporation and water availability.

• Very dry areas in developing countries will be worse hit.

Pressures on water supply: Industry

• Industries such as steel and paper are major water users.

• They also use rivers and seas to get rid of waste.

Pressures on water supply: Urbanisation

• By 2025 nearly 60% of the world’s population will live in urban areas.

• The current water supply and sanitation infrastructure will not be able to cope.

Pressures on water supply: Agriculture

• Rising population increases the demand for food and the water needed for farming.

• The area of irrigated land doubled in the 20th Century.

• Future water shortages could threaten food supplies in many countries.

Pressures on water supply: population growth

• World population grew from 2.5bn to 6.2bn between 1950 and 2000.

• Water supplies per person decreased by one third from 1970-1990.

• 7bn people are likely to have insufficient water by 2050.

Which two of the pressures on water supply are greatest? Explain your choice.

•What is this cartoon telling us about water stress around the world?

Can there be such thing as ‘water stress’ if there are no people?

True or False?

• Freshwater is not scarce globally• Demand for water is even• It is only LEDCs that will suffer from water

stress in 2025• There are two types of water scarcity• Urbanisation is partly responsible for the

decline in water availability