Water Scarcity (DP IB Geography)
Revision Note
Physical & Economic Water Scarcity
Water scarcity is when the supply is below 1000m3 a year per person
There are two types of water scarcity:
Physical water scarcity
This affects about 20% of the world’s population (1.2 billion)
Economic water scarcity
This affects about 25% of the world’s population (1.6 billion)
Physical water scarcity depends on a variety of factors, including:
Level of precipitation
Population growth
Water availability
Water demand
Economic water scarcity is the result of:
Poor management of water resources
Lack of water infrastructure
Drought
Drought is an extended period of dry weather that leads to extreme dryness:
Absolute drought
Partial drought
Drought is caused by:
Changes in atmospheric circulation, such as a shift in the position of the Inter-tropical Convergence Zone (ITCZ) or El Niño, lead to:
A lack of precipitation as a result of short-term changes or longer-term trends
The lack of rainfall is often combined with high temperatures, which increases evaporation
The severity of droughts depends on the length of the drought and the extent of the shortage
Impacts of drought
The impacts of droughts include:
Increase in animal mortality:
Over half a million livestock (cattle, goats) were affected by drought in Somalia in 2022
Increase in forest fires as the vegetation is dry and catches fire easily
Bans on hose pipes for watering gardens in higher-income countries
Potential for conflicts over water supply, particularly where countries share a river basin
Children in rural areas in low-income countries often miss out on school as they are responsible for collecting water (may have to walk miles to the nearest water source)
Lack of food due to:
Lower crop yields because the plants cannot be irrigated
Livestock deaths due to a lack of water
Damaged ecosystems and loss of habitats
Reduced economic development as water is not available for industry
Water Quantity & Water Quality
Water quantity and water quality
Water quantity depends on several factors:
Rates of rainfall
Groundwater and river flows
Transpiration
Evaporation
Freshwater resources in the world
Globally, around 12,500 cubic kilometres of water are available for human use on an annual basis
There are 6600 cubic metres per person per year available for individual human use
If current trends continue, there will only be around 4800 cubic metres available per person in 2025
The world’s available freshwater supply is not distributed evenly around the globe:
75% of annual rainfall occurs in areas containing less than two-thirds of the population
Map to show water stress
Water stress occurs when water supply is less than 1700 cubic metres per year
Water stress can cause problems for food production and further economic development
UNICEF claim that nearly four billion people will be affected by water stress in 2025
Water use
The world’s population has tripled since 1922
This has increased the global demand for water
Globally, agriculture is the largest user of water
Disputes over water scarcity may lead to more armed conflicts
The World Health Organisation claim that 3.6 billion people do not have access to safely managed sanitation in their home
Rural areas are the worst affected, 8 out of 10 people who continue to lack access to safe drinking water
Water quality
In 2022, at least 1.7 billion people in the world drank water that had been contaminated with faeces
Microbiologically contaminated water can transmit diseases such as cholera
One million people are estimated to die each year from diarrhoea due to unsafe drinking water, sanitation and hand hygiene
Water quality may be affected by:
Use of fertilisers and pesticides from agriculture
Sewage water
Industrial processes
Access to safe water may be limited by availability, infrastructure and cost
Urban areas have better access to clean water than rural areas
The cost of water when connected to water mains is less expensive than when customers have to pay
Cost of bottled water
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