EQ3: How does water insecurity occur, and why is it becoming such a global issue for the 21st century? Flashcards
The growing mismatch between water supply and demand had led to what?
A global pattern of water stress (below 1,700m³ per person) and water scarcity (below 1,000m³ per person)
Below 1,000m³ per person gives way to what?
Water scarcity
Below 1,700m³ per person gives way to what?
Water stress
Examples of countries experiencing absolute scarcity
Saudi Arabia, Algeria and Syria
(less than 500m³ per person)
Examples of countries experiencing water stress
Much of east Africa, and India
What does the growing mismatch between water supply and demand lead to?
The distribution of freshwater resources (water availability) and the distribution of the demand for water.
What does the United Nations define water security as?
The capacity of a population to safeguard sustainable access to adequate quantities of acceptable water for sustaining livelihoods, human wellbeing and socio-economic development, for ensuring protection against water-borne pollution and water-related disasters, and for preserving ecosystems in a climate of peace and political stability.
When does water insecurity occur? (according to UN definition)
When these economic, social, and environmental criteria are not met, or only partially met.
According to UN water, how much has water use been growing by?
Growing at more than twice the rate of population increase in the last century
By 2025, how many people will be living in countries with absolute water scarcity?
1.8 billion
How much of the world could be living under water stress conditions by 2025?
Two thirds
Water stress
When the demand for water exceeds the available amount during a certain period. Countries experience water stress if renewable water resources are between 1,000 and 1,700m³ per capita.
Water scarcity
When renewable water resources are low, between 500 and 1,000m³ per capita. Imbalance between demand and supply.
Symptoms of water stress
Symptoms are widespread and include frequent and serious restrictions on water use, growing tension and conflict between users and competition for water, declining standards of reliability and service, and harvest failures and food insecurity
Symptoms of water scarcity
Unsatisfied demand, open tension and conflict between users, competition for water, over-extraction of groundwater and insufficient flows to the natural environment.
Physical water scarcity
Where water availability does not meet water demand in a particular area. Arid regions often face this, such as southern Spain.
Occurs when more than 75% of a country’s or region’s blue water flows are being used. Applies to about 25% of the world’s population, most countries in the Middle East and North Africa, and regions such as North China and Western USA.
Economic water scarcity
Occurs due to lack of investment in infrastructure so people cannot get access to water, or the price of it is at a point where the population cannot afford the amount they need.
Water insecurity
When a country has inadequate quantities of acceptable water quality for livelihoods, wellbeing and development.
Absolute water scarcity
Countries experience this if their renewable water resources very low, less than 500m³ per capita. Leads to widespread restrictions on water use and rationing.
Renewable water resources
The long-term annual average of internal and external renewable water resources.
What are internal renewable water sources?
The discharges of rivers and the recharge of aquifers, generated from precipitation.
What are external renewable water sources?
Those generated outside a country including inflows from upstream countries and parts of a water body (lake or river) divided by a border.
Summarise reasons for rising demand of water
Population growth
Rising standard of living
Economic growth
Irrigation - intensive agriculture
By 2025, what will the total annual water withdrawal be? (km³)
5235km³
Why are water supplies diminishing?
Human activity is the most significant cause of diminishing supplies - mainly related to over-abstraction of groundwater supplies for irrigation. In many countries, groundwater is no longer regarded as an unlimited supplement for surface water supplies.
Why else are water supplies diminishing?
Cheap technology used to pump water
Few/minimal legislation to regulate pumping
Threats of climate change - induced drought
Water pressure points Venn diagram
Diminishing supply?
Impact of climate change
Deteriorating quality from air pollution
Impact of competing users upstream vs downstream
Water pressure points Venn diagram
Rising demands?
Population growth
Economic development
Water pressure points Venn diagram
Competing demands from users?
Internal conflicts in a basin
International issues - upstream and downstream, HEP vs irrigation
Water pressure points Venn diagram
Section right in the middle
PRESSURE POINT - need for management
According to the International Water Management Institute global water stress in increasing, how many people face some sort of water scarcity?
1/3 of all people
(Named example) Physical water scarcity in Australia
Diversion 1/4 of all water away from Murray Darling Basin for agriculture
Physical water scarcity in Egypt
Egypt imports less than 50% of its food because of physical scarcity
Physical water scarcity in China
Severe water scarcity in North China, leading to the South-North transfer scheme
Aral Sea approaching physical water scarcity
Aral Sea faces environmental catastrophe although recent attempts to reduce attempts to reduce impacts of river diversions for cotton production.
Physical water scarcity: West coast of USA: California
Ogallala aquifer provides 1/3 of all US irrigation water, but is seriously depleted: the water table is dropping by about 1m per year. As a “fossil” reserve, formed from past glacial meltwater flows, it is effectively a finite resource.
Economic water scarcity: Sub Saharan Africa
Much of Sub-Saharan Africa (1 billion people) suffers from economic scarcity from poverty but also lack of infrastructural development.
India - River Ganges
Physical stress from pollution and over abstraction
List 6 physical causes of water insecurity
Climate change - changing weather patterns
Changes in glacial snowmelt
Less precipitation
No groundwater store (fossil water) - could be due to humans
ENSO
Flooding - pollution of water
List 7 human causes of water insecurity
Climate change - changing weather patterns
Pollution making water sources unusable (industrial, fertiliser, domestic)
Deforestation - changed transpiration
Economic development - over abstraction
For irrigation - intensive agriculture
Dams and reservoirs - issues with upstream vs downstream
Population increase (natural increase, migration)
The United Nations World Water Development Report 2015 projected an increase in global water demand of _____ by 2050.
55%
Mainly due to a growing demand from secondary industries, thermal electricity generation and domestic use - increasing urbanisation in developing countries.
Significant problems related to water insecurity in Asia and the Pacific?
Salinity and arsenic (from industrial pollution) affect 60% of the groundwater supplies across the Indo-Gangetic Basin
Withdrawals in West Asia exceed natural replacement
1 billion gallons of raw sewage us demurred into the Ganges each day
Significant problems related to water insecurity in Europe and Central Asia?
Increasing water consumption, with half of Europe’s cities over-exploiting their groundwater reserves
Significant problems related to water insecurity in North America?
Aquifer depletion is increasing due to both population and urban growth, and expansion of irrigation and industry
Significant problems related to water insecurity in Africa ?
Predicted that 25 African countries will face either water stress or water scarcity by 2025
Lack of groundwater protection from agricultural uses (which make up 80% of total water use)
Lack of preparedness and mitigation
Significant problems due to water insecurity in Latin America and the Caribbean?
Poor sanitation - only 2% if the sewage in Latin America is treated
Economic scarcity, with conflict over access to - and use of - water.
What is leading to direct and indirect effects on the whole of the hydrological cycle?
Increasing variability in precipitation patterns, with changes in runoff and aquifer recharge and in water quality.
What does the warmer climate mean for water insecurity?
Increased rates of evaporation and transpiration, leading to less effective precipitation (the amount of precipitation that is added and stored in the soil after losses.
Higher water temperatures of a warmer climate and localised industrial discharges of warm waste water increase many forms of pollution. Warmer waters encourage the growth of bacteria and other organisms that are harmful to human health and possibly ecosystems.
What is saltwater encroachment?
The movement of saltwater into underground sources (aquifers) of freshwater.
What happens to the natural pump during saltwater encroachment?
Starts to produce saline water, so it’s closed off.
Describe natural process of saltwater encroachment.
Under natural conditions, the seaward movement of freshwater reduces saltwater encroachment in coastal zones, and soil moisture and groundwater remain fresh.
Two factors that increase saltwater encroachment?
Localised abstraction of groundwater
Sea level rise (result of climate change)
How do human processes e.g localised abstraction of groundwater and sea level rise increase the risk of saltwater encroachment?
Extensive groundwater pumping for freshwater wells lowers the water table, and allows saltwater to move into soils and aquifers.
Thermal expansion of the sea, along with melting ice sheets and glaciers - a result of global warming - are enabling saltwater to intrude further inland, threatening farming and natural ecosystems e.g Sundarbans in Bangladesh.
Synoptic link with saltwater encroachment?
Saltwater encroachment will occur in coastal areas due to sea level rise associated with global climate change, but further than this, all coastal processes will change, with stronger storm events and associated storm surges, increased coastal erosion, and flooding of low-lying land.
This will put pressure on people and whole countries, and superpowers may have to help developing countries to relocate their people or provide mitigation and adaptation measures.
Main physical causes of water availability/insecurity
- CLIMATE VARIABILITY
- SALT WATER ENCROACHMENT AT THE COAST
- climate - annual precipitation - the water is then moved and distributed by the drainage network
- evaporation and evapotranspiration
- discharge into the sea
- saltwater encroachment at the coast
Human causes of water insecurity
- OVER ABSTRACTION FROM RIVERS, LAKES AND GROUNDWATER AQUIFERS
- WATER CONTAMINATION FROM AGRICULTURE
- INDUSTRIAL WATER POLLUTION
- contamination of water by agricultural, industrial and domestic pollution
- over-abstraction from rivers, lakes and groundwater aquifers and the acute need to replenish these dwindling stores
What are physical and human causes of water insecurity exacerbated by?
Global warming and climate change.
What is rising demand from a growing population, industry and agriculture leading to?
Serious implications in some locations and increasing the risk of water insecurity.
What has generated ever increasing demands for freshwater resources?
Population growth, urbanisation and industrialisation, as well as increases in production and consumption
What has led to sharp, and perhaps unsustainable increases in water use?
Strong income growth and rising living standards (a rising middle class).
What has led to sharp, and perhaps unsustainable increases in water use?
Strong income growth and rising living standards (a rising middle class), especially where supplies are vulnerable or scarce and where the distribution, price, consumption and management of water are poorly regulated.
What are some changing consumption patterns that typically involve increased water use?
- Rising demand for meat (water is needed for fodder crops as well as for the animals).
- For larger homes (water is used in concrete manufacture).
- Increased use of motor vehicles.
- Increased use of appliances and energy consuming devices (needing HEP and cooling water for power stations).
What is the human activity with the largest use of water?
Agriculture. Excessive water withdrawals for agriculture have created problems from California to India.