5.7

• Water security – the capacity of a population to safeguard sustainable access to adequate quantities of acceptable quality water for sustaining livelihoods, human wellbeing and socio-economic development, for ensuring protection against water borne pollution, disease and water related disasters, and for preserving ecosystems in a climate of peace and political stability
• Water insecurity – occurs when these economic, social and environmental criteria are not met or are partially met.

  
  

  Renewable water resources – the long term annual average total of internal and external renewable water resources. Internal resources include river discharge and aquifer recharge generated by precipitation. External resources are generated outside of a country e.g. inflows from rivers or lakes
• Water stress – if renewable water resources are between 1000-1700m3 per capita. Symptoms are widespread and include frequent and serious restrictions on water use, growing tension and conflict between users, harvest failure and food insecurity.

  
  

  Water scarcity - if renewable water resources are between 500-1000m3 per capita. Symptoms include unsatisfied demand, open tension and conflict, over extraction of groundwater, insufficient flows to the natural environment.

  
  

  Absolute water scarcity - if renewable water resources are below 500m3 per capita
• Physical causes of water insecurity

  Climate variability – precipitation levels vary between humid areas and arid areas, but also varies seasonally between wet and dry seasons. Climate change will increase the variability in precipitation patterns. Warmer climates will lead to less effective precipitation

  Saltwater encroachment – global sea level rise and localised abstraction of groundwater are allowing saltwater to encroach into some coastal areas. Abstraction of groundwater lowers the water table and allows saltwater to move into the soils and aquifers. 
• Human causes of water insecurity

  Over-abstraction – removal of water faster than it can be replaced. Agriculture accounts for 70% of water consumption globally. Groundwater plays a substantial role in water supply. 2.5 billion people rely on groundwater as their sole source of water and so it is estimated that over 20% of the World’s aquifers are over exploited.

  Contamination – water availability is affected by pollution. e.g agriculture (chemical fertilisers, pesticides), industrial production (waste), urban runoff, power stations (hot water encourages bacterial activity)
• Demand for water is increasing:

  • Population growth
  • GDP has risen – greater wealth comes greater water consumption
  • Industrialisation – requires more water
  • Commercial agriculture – more food is needed and so more water is used to produce it.
  • Urbanisation – growing cities demand water for building and water supply

  The UN predicts that by 2050 demand for water will have risen by 55% and that if we continue with the “business as usual” approach then the world will face a global deficit leading many areas to face a state of water stress