World Wetlands Day 1998 fact sheet
World Wetlands Day 1998
About this fact sheet:
This fact sheet has been produced as a contribution to World Wetlands Day 1998, which this year focuses on the theme of water and wetlands. It has been compiled by Doug Hulyer, a Director of the Wildfowl & Wetlands Trust, U.K., and Coordinator of the Wetlands International Education and Public Awareness Specialist Group, on behalf of the Ramsar Bureau.
Its purpose is to provide, in easily digestible form, key points of information to all involved in the education and communications fields within wetland conservation. The information has been drawn from a number of sources including publications by the Worldwatch Institute, the World Resources Institute, WWF, IUCN and the Ramsar Bureau. No responsibility is taken for the accuracy of the information nor for its subsequent use by readers.
If you would like to amend or add to any of the information supplied, or have ideas on how we could develop this approach for future World Wetland Days, please contact Doug Hulyer directly (Doug.Hulyer@wwt.co.uk) or the Ramsar Bureau (firstname.lastname@example.org).
Water, wetlands and us - whats the link?
Life needs water
The water we need comes from wetlands.
This is the simple message of World Wetlands Day 1998.
1. Why do we need water?
The human machine and water - basic survival
Like most animals, about 70% of our body weight is water and were losing it all the time. On average, a 70Kg adult needs to take in about 2.5 litres of water a day just to survive (drinking 2.2 litres and taking in the other 0.3 litres in the food we eat). People living in a mild climate (and without exerting themselves too much ) lose this 2.5 litres each day through excretion and respiration . . . if they live in a hot climate, and work in the sun all day, they can lose up to 10 litres (all of which, of course, must be replaced).
On average the amount of water a human turns over each day is equivalent to about 5% of his or her body weight; a person can lose up to half his or her body weight through starvation and survive, but if 12% of weight is lost through dehydration, death is almost inevitable.
We use water for many things other than our basic biological survival for washing and cooking, to irrigate our crops, for manufacturing virtually any goods. Five litres a day per person is regarded as the minimum for survival; to sustain a reasonable standard of living requires about 80 litres per day. The amount we each use varies remarkably depending upon where we live and the lifestyle we follow; for instance, each person in Madagascar uses an average of 5 litres per day for basic needs around the home, whilst their counterpart in Australia uses about 325 litres, and some U.S. A. citizens use up to 650!
Of the total water people use globally, about 65% is used to irrigate our crops, 25% is used by industry and the remaining 10% for domestic and municipal use.
Table 1. Some examples of the amount of water needed to manufacture various products (in litres)
|A tonne of wheat||1,000,000|
|An average car||450,000|
|A tonne of synthetic material||140,000|
|A tonne of paper||54,000|
|A bag of cement||180|
|500g coffee powder||55|
|A pair of leather shoes||53|
|A litre of petrol||15|
|A pint of beer||4|
|A small bar of chocolate||1|
|A page of this fact sheet||half a litre!|
2. How much water is there?
Planet Earth is wrongly named . . . it should be Planet Water! Over 70% of the Earths surface is covered by this remarkable molecule. When viewed from space, the globe can be divided into two hemispheres if viewed from above the Pacific Ocean, 90% of the surface would be water, whilst if we looked at the world from a satellite stationary over West Africa only 50% would be covered by land.
There is, in total, about 1.41 billion cubic kilometres of water on the surface which, if spread evenly over the surface of the Earth would cover it to a depth of between 2,500 and 3,000 metres. This sounds a lot but that water covering is proportionately no more than that of a thin film of moisture on a soccer ball.
Of all the water on Earth, 97% is salty and is found in the seas and oceans. The remaining 3% freshwater is unevenly distributed with very little available for our use, because most of it is locked up in the ice caps of the Arctic and Antarctic (80%). Of the tiny amount remaining, only about 3% is on the surface or in the atmosphere (the rest is locked up in underground aquifers or the soil).
To graphically illustrate this to students or an audience, try the following demonstration:
Take a litre container of water. Pour off 30 ml into a beaker (put salt in the remainder to simulate the seas/oceans). Pour off 6ml of the 30ml (and put the remaining 24 ml into a freezer to simulate the ice caps). Use an eyedropper to pick up one drop of the remaining water . . . and drop it onto your open hand (this represents the precious drop of water that is non-polluted available freshwater; the rest is locked up underground).
Nevertheless, this seemingly small amount of water actually represents an enormous body of water, equivalent to 8.4 million litres of water for every man, woman and child on Earth, which is more than a person in the developed world would use in their lifetime!
The actual quantity of useable freshwater available to us in rivers, lakes and other wetlands amounts to about 129 cubic kilometres at any given moment. This available water is not evenly distributed geographically:
Table 2. Distribution of available freshwater on Earth (cubic kilometres)
The Water Cycle
Water on Earth is constantly recycled through the actions of evaporation, condensation, precipitation and flow the great Water Cycle.
Every day about 800,000 million megawatt hours of solar energy is used to evaporate the equivalent of 5 million Olympic-sized swimming pools of water from the surface of the sea and land (the total output of all our power stations is about 20 million megawatt hours).
About 300 cubic kilometres of water falls as rain or snow, enough to supply 31,000 litres to every person. The mean daily rainfall across the whole globe is only about 3mm, but this is unevenly spread between the extremes of 30mm per day (in Mt.Waialeale, Hawaii, and Cherrapunji, Assam ) to zero (in parts of the Atacama Desert in Chile, there is no record of rain falling at all!)
On average, the water in rivers is replenished every 18-20 days, but a single molecule of water may take up to a year to complete the whole water cycle.
Water in underground reservoirs takes much longer to renew several hundred years, in fact and fossil water (stored deep underground for millennia) can never be renewed once extracted.
River basins, fed mostly by precipitation, occupy about 60% of the Earths land surface and of this, 25-30% of the rivers are fed by snow melt waters (mainly in the Russian Federation, Scandinavia, Canada and Alaska).
Water is the life force of wetlands and wetlands are a vital link in the water cycle.
3. Whats a wetland?
Wetlands are areas where water is the primary factor controlling the environment and the associated plant and animal life. They occur where the water tables are at or near the surface of the land, or where the land is covered by shallow water.
The Convention on Wetlands (Ramsar, Iran, 1971) defines a wetland in broad terms as:
"areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres." (Article 1.1)
The Convention text also stipulates that wetlands:
"may incorporate riparian and coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six metres at low tide lying within the wetlands." (Article 2.1)
So, in simple terms, if its wet, even temporarily, and its not too deep, its a wetland!
Five major types of wetland are generally recognised:
* marine (coastal wetlands including coastal lagoons, rocky shores and coral reefs);
* estuarine (including deltas, tidal marshes and mangrove swamps);
* lacustrine (wetlands associated with lakes);
* riverine (wetlands along rivers and streams); and
* palustrine (meaning marshy a marshes, swamps and bogs)
In addition there are many human-made wetlands such as fish and shrimp ponds, farm ponds, irrigated agricultural land, salt pans, reservoirs, extraction pits (for example, gravel and brick pits), sewage farms and canals.
4. Water, Wetlands and us
1.4.1. Early beginnings we owe it all to wetlands!
Bathed in shallow water, and often saturated with nutrients, wetlands make up some of the most productive natural systems on Earth, and they also provide an ideal medium for moving both people and goods. It is no surprise that wetland areas were the birthplace for the agricultural revolutions that heralded our earliest civilisations. From the Nile to the Indus and from the Yangtse to the Tigris/Euphrates and to Tenochtitlán (now Mexico City) nearly all the great ancient states were founded by wetland peoples.
1.4.2. Living in the wetland zones
Our close relationship with wetlands continues to the present day with the majority of us living in wetland regions (for many city dwellers, particularly in the developed world, one needs to search hard for these wetland roots in the drained, canalised, conduited and tunnelled remains of former rivers, streams, swamps and marshes).
- The river basins, including their estuaries, support over 90% of the worlds population.
- 66%of the worlds population live on lands adjacent to the coast, some 3.6 billion people; within three decades, 75% (6.4 million) will live in the coastal zone.
- Of the ten largest conurbations in the world, seven border upon estuaries accounting for over 50 million people (New York, London, Shanghai, Tokyo, Osaka, Buenos Aires, Los Angeles).
- Inland wetland areas also support large populations, e.g. the inland Niger Delta supports over half a million people who graze cattle, grow rice and harvest fish in this seasonally inundated wetland region.
- Many of the natural river flows and the floodplains upon which we live have been regulated and controlled through major engineering works, particularly in the developed world:
- in the USA only 2% of the countrys 5.1 million km of river remain free flowing and undeveloped; more than 85% of inland waters are artificially controlled; half of the original freshwater wetlands have been drained.
- the Rhine runs for over 1,300 km from the Alps to the North Sea, and 20% of the worlds chemicals are produced along its banks; the river is now cut off from its original floodplain for 90% of its length, and the fast flowing constricted channel is digging a deeper and still faster channel on its way to the Low Countries. People along its banks have experienced 10 major floods in the past 20 years, including the flood of 1995 which caused the evacuation of 250,000 people in the Netherlands and cost an estimated $1 billion in damage.
- along the Mississippi River, almost 1,600 levees and channels have been constructed to control the flow of this river, allowing extensive farming on the floodplain; nearly half of the rivers 3,782 km length flows through artificial channels. Some 6.9 million hectares of wetlands have been drained as a result wetlands which normally act as a natural absorption and slow-release mechanism for floodwaters. The great flood of 1993 is thought to have been the most destructive in US history with over 1,000 levees being ineffective.
Pressure on these areas has resulted in substantial loss of wetlands. Consider these further facts:
- Countries having destroyed over half their wetlands by the 1980s include: the USA, New Zealand, Australia, Pakistan, Thailand, Niger, Chad, Tanzania, India, Vietnam and Italy.
- Only half of the original area of mangrove remains (only 240,000 sq km) in the world; e.g., in Indonesia 10,000 sq km have been converted to brackish water ponds for the cultivation of fish and prawns.
- Of the 600,000 sq km of coral reef, only 30% are in stable condition (of the 109 countries with significant coral, 93 are damaging them - in over 50 countries coral is being smothered by sediments and in 70 coral is affected by land reclamation and dredging)
1.4.3. Clean water for all
Many people do not benefit from clean supplies of water, nor are served by adequate sanitation. These two factors combine to produce the greatest threat to human health on Earth.
Worldwide, 250 million cases of water-related diseases result in 10 million deaths a year; every hour 1,000 children die of diarrhoeal-related diseases; dirty water is believed to be the transmission agent for 80% of the diseases which affect people in developing countries
In more than half of developing countries, less than half of the population has a source of potable water. In the North, 9 out of 10 people have clean piped water and mains sanitation; in the South, only 4 out of every 10 have access to safe water and 2-3 out of 10 to proper sanitation. Nearly 1,200 million people do not have access to clean water and 1,800 million to sanitation.
The UN Water Decade ran from 1981-90. Its aim was to provide clean water and adequate sanitation to all. By the end of the decade access to safe water had been provided to an extra 1,200 million people and sanitation to an extra 700 million, at a cost of $134 billion. Unfortunately, due to the rate of population increase and the slow pace of social development over the same period, the number requiring these services had risen still more, leaving 1.2 billion still short of clean water and 1.8 billion unserved by sanitation. To supply this growing population adequately requires an investment of $30-60 billion a year; this is equivalent to $80 million per day (compared with the $250 million spent on cigarettes worldwide).
A wide range of water-borne diseases affects humans including cholera, schistosomiasis and malaria; the costs for treating these diseases or, better still, preventing them are relatively minor:
Schistosomiasis is transmitted by a water snail and occurs in 76 countries; it kills 200,000 people each year and debilitates a further 200 million. Treatment with praziquantel costs around $1 per person. Over 30 million infected people live in Nigeria, Malawi, Kenya and Zambia, and the costs of treatment at this level of demand could amount to as much as the whole national health budgets of those countries.
Cholera, caused by the Vibrio cholera organism, can be controlled by the use of chlorine tablets; the supply of these costs between 25 cents and $2 per family per year. Within its first 10 weeks, a cholera epidemic in Peru during 1991 cost the country an estimated $1,000 million (estimated by the World Bank on the basis of loss of agricultural exports and tourism) this is three times the amount it would have cost to invest in proper sanitation and water supply services in the 1980s.
1.4.4. Waste disposal - poisoned chalice
Wetlands and water courses are often used as vehicles for human waste, both domestic and industrial. Wetlands can absorb pollutants, but only to a degree. Overload causes loss of the natural systems that can help regulate pollution and inevitably causes a major threat to public health.
- In 1980 it was estimated that people generated around 1,900 cu km of waste water each year; this figure was expected to double by the end of the century.
- It has been estimated that less than 2% of urban sewage flows in Latin America receive treatment (UN Economic Commission for Latin America and Caribbean 1989).
- Results of contamination by faecal coliform bacteria of 24 rivers surveyed in Central and South America suggest that the situation in this region is worse than anywhere in the world (safe drinking water should have zero counts; over half the rivers sampled had counts in excess of 1,000 per 100 ml and 8% had up to 100,000/ml!)
- In the Mediterranean region, the population in the tourist season is upwards of 200 million people, 50% of whom are not served by a sewage treatment system; 80% of the effluents from large cities is discharged into the sea untreated.
- Caspian Sea: the rivers flowing into the sea drain an area from Leningrad in the north to land south of Teheran; a major source of contamination of the sea is the Volga River, with the sea forced to accommodate nearly 25% of all the wastewater produced by Russia. As a result the fisheries in the sea have collapsed: catches of pike and perch have dropped by 96% in the last 30 years; the Caspian used to produce nearly 90% of the worlds sturgeon/caviar, but now 90% of the sturgeon are killed before they reach maturity.
1.4.5. Water for food the irrigation boom (and bust?)
We need water to grow our food; as our population increases, the already inadequate global harvest will need to grow but this will require even greater inputs of water.
- 16% of the worlds cultivated land is irrigated, but this area accounts for 40% of the total harvest (irrigated land can be harvested two or three times a year).
- In 1950 the total irrigated land area was 94 million hectares by 1995 this had risen to 206 million hectares. For the past five years, there has been little growth in the total amount of land irrigated; this is due to the depletion of water reserves and the impact of loss of cultivable land following increased salinisation, countering any gains of newly irrigated land.
- 25 million hectares, more than 10% of the worlds irrigated land, is subject to salinisation; the total amount is increasing by 2 million hectares each year.
- The extraction of water from coastal wells is a cause for concern in Israel. Some estimates suggest that 20% of all such sources in the country will need to be closed due to salt water incursion in the next few years.
- Taking the world as a whole, each person would consume directly or indirectly 300Kg of grain a year if consumption were distributed evenly. Growing enough food for the 90 million additional people born every year requires an additional 27 billion cubic metres of water. This is equivalent to about half the total flow of the Yellow River. If population should grow at the same rate as today, the additional requirement by 2025 will be 780 billion cubic metres, more than nine times the annual flow of the River Nile.
- Major rivers are drying up due to over abstraction for irrigation and prolonged periods of drought in Africa, including the Limpopo in southern Africa and the Save/Sabi (flowing through Zimbabwe and Mozambique); there are indications that the Chari/Logona (flowing to Lake Chad), the Nile and Zambezi are also decreasing.
- Some globally important wetlands under threat from over abstraction include the Everglades and Mono Lake (USA), the Coto Doñana (Spain), Sudd swamps (Sudan), Okavango basin (Botswana).
1.4.6. Water power Dammed or damned?
The power of water can be harnessed to supply the energy needed for development without recourse to other more polluting forms of generation. Hydro-power brings benefits, but it also causes great environmental damage including lowering of river flows downstream, disruption to natural patterns of soil fertility, displacement of peoples, increased health risks, destruction of habitat both upstream and downstream, and the potential for major conflict over international property rights. Thus, the negative environmental effects may far outweigh any social or economic benefits. Nevertheless there are in place or planned over 38,000 large dams in the world and countless smaller ones over half of these large dams are in China, including the recently-begun Three Gorges complex on the Yangtse.
- The Aswan Dam supplies half of Egypts total energy needs and has brought freedom from seasonal flooding; but at a cost . . .
100 million tonnes of silt, clay and sand are now filling Lake Nasser. This silt would formerly have fertilised fields in the floodplain, so vast amounts of fertiliser are imported to counter the loss;
Offshore sardine fisheries have been hit hard there has been a drop of 83% in annual harvest in the eastern Mediterranean caused by lack of nutrients and effects of low flows, etc. on breeding grounds; of the 47 species of fish formerly harvested, only 17 were harvestable a decade after completion of the dam.
The Nile Delta is in retreat and soil salinity and waterlogging has increased (the FAO reckon that 35% of Egypts cultivated land is affected by salinisation and 90% by waterlogging); recent research indicates that Egypt could lose 19% of its habitable land within 60 years, displacing 16% of its population.
The incidence of schistosomiasis has exploded among people living around Lake Nasser.
- Laos is to build 23 dams by the year 2010 in order to supply cheap electricity to the tiger economy of Thailand; such a major taming of the Mekong and its tributaries could have a serious effect upon flows in both Laos and Vietnam.
- The great flooded forest region of the Amazon is threatened by low flows caused by upriver damming projects and direct habitat destruction. It is estimated that in the lower Amazon only 15-20% of previously flooded forest remains. The 6,500 km length of the Amazon contains one-fifth of all the worlds freshwater discharge into the oceans; during half the year portions up to 20km from the river are flooded to a depth of several metres covering an area of 150,000 sq km (total of the Amazonian rainforest = 5 million sq km)
- The flow of the Colorado is impeded by 10 major dams. Unless there is extremely high rainfall, the river does not reach the Sea of Cortez; as a result the fisheries in the sea have collapsed and coastal communities devastated.
- 21 million people in India have been dislocated as a result of dam projects in the last 40 years.
1.4.7. Water demand when will we run out?
Since 1950 the worlds population has doubled our demand for water has tripled over the same time period. Water use is now exceeding the sustainable yield of the aquifers in many parts of the world: even at current rates of abstraction, water tables are falling in the south-western and Great Plains regions of the United States, several states in India (including the breadbasket state of Punjab), much of northern China, across North Africa, southern Europe and the Middle East.
In 1990, 26 countries, with a total population of around 300 million people, faced water scarcity. Regions of water scarcity are defined as those with more than 600 people for every million cubic metres (MCM) of available freshwater. By 2025, it is estimated, 65 countries, with a total combined population of 3 billion people, will be water short, including Nigeria, India, Korea, Peru and Poland.
Fossil waters are being depleted at an alarming rate; e.g., the Ogallala aquifer underlies the Great Plains region of the USA and the irrigated land in the shallow southern end of the aquifer has declined by 11% in the last decade.
The effects of global climate change will affect global water supplies with the likelihood of extended periods of drought; chronic water shortages already affect 80 countries from time to time (holding 40% of the worlds population).
Mexico City: built upon what was once a huge lake, abstraction is outstripping the natural recharge by 50-80%; additional water is now brought in at great expense (over $50 million annually). Water is wasted through breakages in the system; in fact, what the Mexico City loses through breakages could supply the whole of Rome!
On the Arabian peninsula abstraction rates are three times that of the natural recharge. Saudi Arabia depends upon non-renewable groundwater for about 75% of its water and at current rates of abstraction, all groundwater reserves will have been used by the middle of the 21st century.
In China the water table under parts of Beijing has dropped by over 35 metres in 40 years; in northern China, 1.5 million hectares of land is affected by abstraction rates being higher than recharge.
Due to abstraction upriver the Ganges no longer reaches its natural outlet in dry season, causing a rapid advance in salinity in the western portion of the river delta in Bangladesh.
Hydro-power schemes, river diversions and irrigation projects have all contributed to the environmental disaster which is the Aral Sea. Prior to 1960 the Amu Darya and Syr Darya poured 55 billion cu m of water into Aral, but between 1981 and 1990 their combined flow dropped to 7 billion cu m. As a result of this the wetland areas have shrunk by 85%, the number of nesting bird species in Syr Darya declined from 173 to 38, and in the Aral Sea itself 20 of the 24 species of fish have disappeared. A fish catch which totalled 44,000 tons/year in the 1950s and supported 60,000 jobs has dropped to zero; each year the winds pick up 40-150 million tons of toxic dust-salt mix and dump it onto farmland, killing crops.
1.4.8. The potential for conflict
Many countries share river flows and underground aquifers; in areas where water is at a premium now, or likely to be so in the future, the potential for international conflict over the shared resource is high.
At least 214 of the worlds major rivers run through more than one country from their source to their end.
Potential hot spots for conflict include the rivers Ganges, Nile, Jordan, Tigris-Euphrates and the Amu Darya/Syr Darya.
Countries that depend upon imported surface water include:
Source: Water in Crisis: A guide to the worlds fresh water resources - Peter H Gleick (OUP, 1993)
86% of the Niles total flow is controlled by Ethiopia; an estimated 3.7 million ha of land in that country is potentially irrigable. To irrigate half this area would reduce flows by 9 billion cu m/yr, which is equivalent to 16% of Egypts annual Nile supply.