5.7 Human and Physical Causes of Water Insecurity Flashcards
5.7a patterns of water stress and water scarcity
supply and demand
In 2015, 15% of the world’s population do not have reliable access to safe water.
2.5% of global water supplies is freshwater (97.5% saltwater).
1% of freshwater is easily accessible surface water (30% groundwater and 69% icecaps and glaciers).
5.7a patterns of water stress and water scarcity
‘peak water’
‘Peak water’ is being increasingly used to describe the state of growing constraints on quantity and quality of accessible water.
5.7a patterns of water stress and water scarcity
physical distribution of water supplies
There is a mismatch between where the water supplies are and where the demand is.
Water supplies are spread unevenly across the world: 60% of the world’s supplies are contained in just 10 countries
Location of precipitation belts/temperature and level of development are important for water resources per capita.
66% of the world’s population live in areas receiving 25% of the world’s annual rainfall.
5.7a patterns of water stress and water scarcity
reasons for rising demand
Population growth:
World population growing at 80 million per year but demand for water is increasing twice as fast
Rising standards of living: Growing middle class and affluence leads to higher consumption of water- for agriculture (meat-rich diets) and domestic use (drinking, bathing and cleaning).
Economic growth and industrialisation:
Increases demand for water in all economic sectors (agriculture, industry, energy and services)
particularly the mining of unconventional energy sources, such as fracking, puts increased demands on water.
Where water use is not well regulated, pollution could increase dramatically- with industrial spillage and poor waste management leading to contaminated groundwater and rivers.
Irrigated farming:
The inefficient use of water for crop production is:
- depleting aquifers and reducing river flow
- degrading wildlife habitats
- increasing pesticide and fertiliser pollution s they seep into groundwater
- causing water logging and increased salinity
5.7a patterns of water stress and water scarcity
reasons for dwindling supplies
Groundwater aquifers:
Geology controls the distribution of aquifers (water-bearing rocks) that provide groundwater storage. Climate change-induced drought puts pressure on supplies leading to a falling water table as the groundwater supplies are being extracted faster than they can be replenished (over-abstraction).
Excessive withdrawals lead to land subsidence and intrusion of salt water in costal districts.
Groundwater can no longer be regarded as the unlimited supplement to surface water supplies.
5.7a patterns of water stress and water scarcity
water stress
water stress is when a country’s renewable freshwater supply drops below 1700 cubic metres per person per year
5.7a patterns of water stress and water scarcity
water scarcity
water scarcity is when a country’s renewable freshwater supply drops below 1000 cubic metres per person per year
5.7b physical and human causes of water insecurity
water insecurity
water insecurity is when present and future water supplies cannot be guaranteed
by 2050, 1.5 billion people will be experiencing water scarcity, especially in Middle East and parts of sub-Saharan Africa
5.7b physical and human causes of water insecurity
physical factors- climate variability
At a macro scale, climate determines the global distribution of water supply by means fo annual and seasonal distribution of precipitation. This is affected by ENSO cycles and blocking high pressure zones (STR and mid-latitude blocking anti-cyclones)
On a regional scale topography and distance from the sea have significant impacts on precipitation and surface water storage.
5.7b physical and human causes of water insecurity
physical factors- saltwater encroachment at coast
a
5.7b physical and human causes of water insecurity
human factors- over-abstraction from rivers, lakes and groundwater supplies
Over-abstraction of water supplies is driven by population growth, rising living standards, economic development and industrialisation, and irrigated farming. These factors have driven water demand to unsustainable levels.
5.7b physical and human causes of water insecurity
human factors- water contamination from agriculture
a
5.7b physical and human causes of water insecurity
human factors- industrial water pollution
a
5.7c finite resources and rising demand
causes of rising demand
increasing population:
improving living standards:
industrialisation and agriculture (economic activity):
