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Water Resources
1. Over the last 300 years, world population has increased sevenfold, but water use has increased by 35 times. Since 1950, the amount of annually renewable fresh water available per human being has fallen by more than half. Although 70% of the Earth is covered by seawater and a further 3% by ice, neither of these is easily transformed into usable water. Less than 1% of the Earth’s total water resources is usable for drinking, farming or industry.
2. The quality of water needed for domestic use is much higher than that needed for industry or farming. As a general rule, 80 litres of water per person per day are enough for a reasonable quality of life, but the regional differences are considerable. An American uses 400 litres of water, while an inhabitant of Burundi can survive on 10 litres.
3. Consumption is much higher where pipelines are laid than in regions where water has to be carried from a well. Thus, the provision of piped water services – while highly desirable from a health point of view – greatly increases water use, putting a further strain on scarce resources. It is difficult to establish precise figures for access to safe drinking water, but it is thought that 1.3 billion people worldwide do not have this basic service.
Ответьте на вопрос:
What percentage of the Earth’s surface is covered with water?
Eighty per cent.
Thirty-five per cent.
Seventy per cent.
Seventy-three per cent.