Water Scarcity (SL IB Geography)

• 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 and water quality

• Water quantity depends on several factors:
  • Rates of rainfall
  • Groundwater and river flows 
  • Transpiration
  • Evaporation

Freshwater resources in the world

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

 

• 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

Graph to show increased demand for water 

 

• The world’s population has tripled since 1922
• This has increased the global demand for water

Water use by sector

• 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 

 

Cost of bottled water