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| Freshwater facts and key issues |
Facts | Key issues
Facts
Why does freshwater matter?- All organisms on the planet need water to survive. Living cells are approximately 75 per cent water.
- People need water. A major study of ecosystem services has shown that freshwater ecosystems provide the greatest contribution to human welfare per unit area, and that the total global value of all freshwater ecosystem services is 85 per cent greater than the global gross national product 1
- Wildlife needs water. Freshwater ecosystems harbour an extraordinary concentration of species. For instance, approximately 10,000 of the world's 25,000 known fish species are freshwater animals, and an average of 300 new freshwater fish species are described every year2. Wetlands around the world provide goods and services to people worth an estimated $70 billion a year 3 .
How much water is there in the world?
- Less than 2.5 per cent of the Earth's water is fresh, equivalent to approximately 35,000,000 km34 However, with most of this locked up in the polar ice caps, less than 33 per cent of fresh water is liquid, and less than 1.7 per cent of liquid water runs in streams5.
How does human activity put pressure on water and wetlands?
Pollution:- In developing countries, an estimated 90 per cent of wastewater is discharged directly into rivers and streams without treatment6.
- Diffuse agricultural run-off overloads surface and groundwater with nutrients and pesticides. This renders an increasing number of sources useless for drinking, and adversely affects aquatic ecosystems. In the USA, for example, 22 per cent of wells in agricultural areas contain nitrate levels in excess of the federal safety limit7.
Physical modification:- Fragmentation of river systems due to dams is the single greatest threat to the maintenance of ecosystem integrity. The total number of dams worldwide is estimated at 800,000, including some 1,000 mega-dams over 100m high 8.
- Since 1950, the number of large dams (over 15m in height) has increased from 5,700 to 41,000 worldwide, creating extensive habitat fragmentation in nearly 60 per cent of major river basins9. It is estimated that 40-80 million people have been displaced by dams worldwide, with the poor and other vulnerable groups and future generations bearing a disproportionate share of the social and environmental costs 10.
Abstraction:- Humans currently expropriate some 54 per cent of the planet's "blue water" (water that flows through rivers, lakes, groundwater etc). Estimates suggest that this may increase to 70 per cent by 202511.
- The three largest water users in global terms are agriculture (67 per cent), industry (19 per cent) and municipal/residential (nine per cent)12.
How does this impact on people?- Approximately 2.3 billion people live in river basins under water stress, where annual per capita water availability is below 1,700m3. If current consumption patterns continue, at least 3.5 billion people will live in water-stressed river basins in 2025 - around 48 per cent of the world's projected population.
- Contamination denies as many as 3.3 billion people access to clean water supplies13. Drinking water contaminated with human or animal excreta is the main source of water-related disease. The World Health Organisation estimates that there are about 250 million cases of water-related diseases, with roughly 5-10 million deaths annually.
How does this impact on nature?- WWF's Living Planet Index (2002) has shown that the decline in freshwater species has been more serious than that in either marine or forest biomes. Between 1970 and 1999, the Freshwater Species Population Index (which comprises populations of 195 species of birds, mammals, reptiles, amphibians, and fish from lakes, rivers, and wetland ecosystems) fell by about 50 per cent.
- Of 93 lakes for which there is data from the 1960s onwards, 55 are in worse condition, 35 have exhibited little or no change and just three are in better condition14
- Of the 10,000 species of freshwater fish that have been described, 20 per cent are threatened, endangered or have become extinct in the recent decades15.
Key issues
Population growth and urbanisation- Human population growth is the fundamental pressure underlying all others, and it is the primary driver for rising water use. Any increase in global population will mean that we use more water for drinking, washing and cooking, as well as placing more pressure on the other functions that freshwater ecosystems perform.
- Cities put pressure on freshwater ecosystems due to the large inputs of natural resources required by urban populations and because of the pollution that they generate. It is estimated that by 2025, 56 per cent of the global population will live in citiies, with the highest rates of urban growth in developing countries, which are least able to ameliorate its impact on the environment16.
Agriculture
- Agriculture is responsible for the pollution of waterways with phosphates, nitrates, suspended solids and pesticides. In the UK, phosphate contamination of rivers from agricultural sources doubled between 1931 and 199117
- In some areas of Europe, agriculture is estimated to be responsible for up to 80 per cent of the nitrogen loading and 20 to 40 per cent of the phosphorus loading of surface water18.
- Agriculture is responsible for 70 per cent of global water withdrawals.
- To provide 2,700 calories a day requires 4300 litres (equivalent to more than seven bathtubs) of agricultural water use. The variation is considerable, however: to provide 500 calories in the form of maize requires 130 litres of water, while the same number of calories produced as beef requires 4,900 litres19.
- Between 1997/99 and 2030, annual meat consumption in developing countries is projected to increase from 25.5 to 37 kg per person, compared with an increase from 88 to 100 kg in industrial countries20.
- Compared with conventional or furrow irrigation, drip methods often reduce the volume of water applied to fields by 30-70 per cent and increase crop yields by 20-90 per cent. In combination this can mean a doubling or tripling of water productivity. Use of drip and micro-irrigation ranges from 90 per cent share of total irrigated area in Cyprus, through 17 per cent in Spain and South Africa to 4 per cent in the US and less than 1 per cent in China and India21.
Knowledge, attitudes and values
- Once revered for its life-giving properties, water is now too often taken for granted and routinely exploited. To reverse the downward spiral of environmental degradation, people must first understand and appreciate the wealth that healthy, functioning ecosystems represent and the range of goods and services they deliver to mankind22. Awareness of ecosystem benefits and of the consequences of human-induced changes is the essential first step for making water use sustainable.
- Increasing public and governmental awareness, private sector responsibility and the commitment of local groups will be fundamental to achieving WWF's Living Waters vision.
Governance- Despite decades of effort to improve water management, little progress has been made as a result of the lack of a common will and commitment. This is partly due to the fact that many direct effects of water degradation are beyond the common political time horizon of three to five years. A critical step will be the creation of political will and commitment at all levels to protect and manage freshwater ecosystems sustainably23.
- Good water governance exists where government bodies responsible for water establish an effective policy and legal framework to allocate and manage water in ways responsive to social and economic needs, and to the long-term sustainability of the resource base24.
Economic and Social Forces- Market economics that do not take into account ecosystem functions constitute a major driver of ecosystem degradation and water scarcity. In conventional market economies, marketable functions such as water extraction, food harvesting or recreation are overused and depleted at the expense of all or most other functions of the ecosystem.
- If water is free, subsidised or provided at artificially low prices, then society will continue to use it carelessly, whether they be individuals, farmers or factory workers.
- Poverty is also at the root of many water crises. Social and economic insecurity results in a focus on immediate survival strategies, often to the neglect of long-term environmental security.
Climate change
- There is little doubt that climate change will alter the globe's hydrological cycle in a variety of ways. For example, the Intergovernmental Panel of Climate Change (IPCC) predicts that warmer temperatures will lead to a more vigorous hydrological cycle, with more severe droughts and floods in some places and less severe events in others.
- Climate change is predicted to have a whole range of impacts on water resources25. Water resources are becoming even more vulnerable, and the likelihood is that flooding will become a more significant risk in many temperate and humid regions, which is likely to affect infrastructures and safety.
- Systems that are currently stressed by drought or flooding - especially in developing countries - are highly vulnerable to climate change.
Footnotes
1. Costanza, R, d'Arge, R , de Groot, R, Farber, S, Grasso, M, Hannon, B, Limburg, K, Naeem, S, O'Neill, RV, Paruelo, J, Raskin, RG, Sutton, P and van den Belt, M, 1997. The value of the world's ecosystem services and natural capital, Nature, 387: 253-260.
2. Groombridge, B and Jenkins, M, 1998. Freshwater biodiversity: a preliminary global assessment, WCMC, Cambridge.
3. Economic value of wetlands, WWF 2004.
4. Groombridge, B and Jenkins, M, 1998. Freshwater biodiversity: a preliminary global assessment, WCMC, Cambridge.
5. World Commission on Dams, 2000. Dams and development: a new framework for decision-making, Earthscan, London.
6. Johnson, N, Revenga, C and Echeverria, J, 2001. Managing water for people and nature, Science, 292.
7. IUCN, 2000. Vision for water and nature: a world strategy for conservation and sustainable management of water resources in the 21st century, IUCN, Gland, Switzerland.
8. WWF, 2001. Dams and development: WWF's response to the report of the World Commission on Dams.
9. Johnson, N, Revenga, C and Echeverria, J, 2001. Managing water for people and nature, Science, 292.
10. World Commission on Dams, 2000. Dams and development: a new framework for decision-making, Earthscan, London.
11. Postel, SL, Daily, GC and Ehrlich, P, 1996. Human appropriation of renewable freshwater, Science, 192: 785-788.
12. World Commission on Dams, 2000. Dams and development: a new framework for decision-making, Earthscan, London.
13. Johnson, N, Revenga, C and Echeverria, J, 2001. Managing water for people and nature, Science, 292.
14. Groombridge, B and Jenkins, M, 1998. Freshwater biodiversity: a preliminary global assessment, WCMC, Cambridge.
15. WRI, 2000. World resources 2000-2001: people and ecosystems, the fraying web of life, Elsevier Science, Amsterdam.
16. IUCN, 2000. Vision for water and nature: a world strategy for conservation and sustainable management of water resources in the 21st century, IUCN, Gland, Switzerland.
17. The Government's Strategic Review of diffuse water pollution from agriculture in England: Agriculture and Water: A Diffuse Pollution Review June 2002 Department for Environment, Food and Rural Affairs.
18. European Environment Agency, 2003, Europe's Environment: The Third Assessment.
19. Source: D. Renault and W. W. Wallender, 'Nutritional Water Productivity and Diets', Agricultural Water Management, August 2000,
pp. 275-96.
20. United Nations Food and Agriculture Organisation, 2003, World Agriculture Towards 2015/2030: An FAO perspective.
21. Source: Postel, Pillar of Sand, Worldwatch Institute, State of the World 2004.
22. IUCN, 2000. Vision for water and nature: a world strategy for conservation and sustainable management of water resources in the 21st century, IUCN, Gland, Switzerland.
23. IUCN, 2000. Vision for water and nature: a world strategy for conservation and sustainable management of water resources in the 21st century, IUCN, Gland, Switzerland.
24. Global Water Partnership, 2000. Towards water security: a framework for action. Global Water Partnership, Stockholm.
25. van Deursen, 2000. |
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WWF-UK > Research > Issues > Freshwater > Facts and key issues
