WWF, ‘Living Planet Report’, 2004,
Water is not normally consumed in the same way as food or fuel, as it may be returned after it has been used, although with a reduction in its quality. Therefore withdrawals are measured rather than consumption...
Globally, agriculture accounts for 65% of the total water withdrawal on Earth. Different parts of the world rely on water for agriculture to different extents...
- only 2.5% of the total water volume on Earth is fresh water: the rest is saline. Less than 1% of the world’s water is readily available for direct human uses, for example in agriculture and industry, for drinking and domestic purposes, and for energy generation and transport. Increasing competition for water among such uses is degrading the very natural resources on which we all depend;
- it is estimated that more than 50% of what is readily available is used by humanity;
- some countries have abundant, untapped stores of water to support growth well into the future. But others are already using most of their water, and major increases in supplies will be expensive. Far from plentiful, rural water has to be shared by the growing cities, the burgeoning rural areas, and a thirsty environment. Needed are greater efficiency in the use of water and fair allocation to balance the limited supply with rising demand;
- available freshwater supplies are not distributed evenly around the globe, throughout the seasons, or from year to year. For instance, the Congo River and its tributaries account for about 30% of the entire African continent's annual runoff, but the watershed contains only 10% of Africa's population. Two-thirds of the world's population - around 4 billion people - live in areas receiving only 1/4 of the world's annual rainfall;
- throughout much of the developing world the freshwater supply comes in the form of seasonal rains. Such rains run off too quickly for efficient use, as during the monsoons in Asia. India, for example, gets 90% of its annual rainfall during the summer monsoon season, which lasts from June to September. For the other eight months the country gets barely a drop;
- China has22% of the world's population but only 7% of all freshwater runoff. China's freshwater supplies have been estimated to be capable of supporting 650 million people on a sustainable basis - only half the country's population. Despite periodic flooding, particularly in the southern part of the country, China faces chronic water shortages in the northern part. At the start of the millennium, some 400 of 600 major Chinese cities were suffering from severe water shortages. Of these, 30 cities in northern China, including Beijing, will face long-term shortages severe enough to limit their economic development;
- if withdrawals exceed a threshold, which varies depending on the ecological situation but which experts put in the range of 20-40%, natural ecosystems will be put under stress. Many countries already exceed this threshold, and some countries withdraw more than 100% of their annual renewable resources. This is only possible by withdrawing fossil water from underground aquifers, a resource that can only be used once;
- the consequences of overuse can be seen in large rivers such as the Nile, Yellow, and Colorado rivers, which are often so depleted by withdrawals for irrigation that in dry periods they fail to reach the sea. Wetlands and inland water bodies are drying up and aquifers are being drawn down faster than they replenish;
- pollution of rivers and lakes reduces accessible freshwater supplies. Each year roughly 450 cubic kilometres of wastewater are discharged into rivers, streams and lakes. To dilute and transport this dirty water before it can be used again, another 6,000 cubic kilometres of clean water are needed - an amount equal to about 2/3 of the world's total annual useable fresh water runoff;
- between 1961 and 2001, global water use doubled passing from about 2,000 km3 to about 4,000 km3. An average annual increase of 1.7%; agricultural use grew by 3/4, industrial use more than doubled, and domestic use grew more than four-fold.
- the amount of water used in irrigation has increased 10 times in the past 100 years: 235 million hectares of land are currently irrigated worldwide. Plans are set for further expansions;
- agriculture represents 69% of total water withdrawal in Africa, with the industrial sector accounting for just 5%. In North America, the industrial sector claims 47% of total water use, with 39% going to agriculture;
- large-scale irrigated agriculture supplied by underground waters or by diversions from rivers can be extremely wasteful and have long term environmental impacts. Together, 4 crops - cotton, rice, sugar cane and wheat - account for 58% of the world’s irrigated farmland.
- a WWF book, World Agriculture and the Environment, points out that agriculture wastes 60% or 1,500 trillion litres, of the 2,500 trillion litres of water it uses each year – which is 70% of the world’s accessible water. Many big food producing countries like the US, China, India, Pakistan, Australia and Spain have reached or are close to reaching their renewable water resource limits.