Core - Chapter 3 - Water Usage and Change Flashcards
The world population has during the last century tripled - how about the water usage?
It had increased sixfold
How has the pattern or water changed?
Half the world’s wetlands have disappeared and today 20% of freshwater species are endangered or extinct. Many important aquifers are being depleted and water tables in many parts of the world are dropping at an alarming rate.
How much is world water use predicted to increase?
By about 50% over the coming 30 years
How many are estimated to live under severe water stress i 2024 and where are these conditions particularly severe?
4 billion people, half the world’s population at that time. Africa, the Middle East and south Asia
How many people currently lack access to safe water, how many are without adequate sanitation, and how many do not have their waste water treated to any degree?
Access to safe water: 1.1 billion people
Without adequate sanitation: 2.6 billion people
Do not have their waste water treated to any degree: 4 billion
What do the water supply depend on?
Rates of rainfall
Evaporation
Transpiration (the use of water by plants)
River and groundwater flows
How much water is considered available for human use on an annual basis and what will be available in 2025?
Currently: 6600m3 per person (12,500km3 in total)
2025: 4800m3 per person
How is the available freshwater distributed around the world?
Three-quarters of annual rainfall occurs in areas containing less than one-third of the worlds population
Two-thirds of the world’s population live in areas receiving only one-quarter of the world’s annual rainfall
When is a country suffering from water stress?
When the per capita water supply is less than 1700m3
How many people currently live under water stress conditions and how many will in 2025?
Currently: 2.3 billion people
2025: 3.5 billion people (48% of the world’s predicted population)
