World water resources
Diving in
Availability
- World oceans cover about three-quarters of earth’s surface
- According to UN estimates, the total amount of water on earth is about 1,400 million km3
- However, fresh water constitutes a very small proportion of this enormous quantity
- About 2.7% of the total water available on the earth is fresh water of which about 75.2% lies frozen in polar regions and another 22.6% is present as ground water
Distribution
- The rest, 0.06% of the total water, is available in lakes, rivers, atmosphere, moisture, soil, and vegetation
- What is effectively available for consumption and other uses is a small proportion of the quantity available in rivers, lakes, and ground water
- Crisis about water resources development and management arises firstly, because most of the water is not available for use and secondly, it is characterised by its highly uneven spatial distribution
Consumption
- Drinking and sanitation require approximately 10 % of the fresh water supplies
- Industry, recreation, and other uses comprise about 20 %
- Irrigation, which accounts for 70 % of all the water extracted from rivers, lakes, and aquifers, is by far the most intensive use of the world’s fresh water resources
Population
- We have on earth 4.2 births every second
- If we take away from that the number of deaths - 1.7 every second. We then have an increase 2.5 people every second on this planet
- This is equal to 250 people every minute
- Now if we take it every hour, this means that the world’s population increases by 9000 people every hour
- Therefore, there are an extra 80 million people every year who need water for drinking, sanitation and agriculture
Demand
- Across the globe, demand for water has been growing on average six times faster than the increase in population
- Pressure on water resources has been coming not so much from people’s need for water in their homes but from the big increase in industrial production and above all from agriculture.
- Large parts of the world now live in areas of water stress, defined as having an annual per capita availability of less than 1700 cubic meter.
- In parts of Africa and the Middle East, per capita availability is well below 200 cubic meter. Population of 600 Millions within 40 years in ME alone