A parched waterworld

Not just humans, nature also needs water

 
Last Updated: Sunday 28 June 2015

A parched waterworld

The doomsday predictions of wars being fought over water indicate the world's precarious position with regard to water. Though 70 per cent of the planet is covered by water, only 2.5 per cent of water is freshwater. Of this, nearly 70 per cent is frozen in the ice caps of Antarctica and Greenland. The rest is present as soil moisture and in deep underground aquifers. As a result, only a minuscule 0.007 per cent of water on the planet is readily available for human consumption.

If the world's total river flow is divided by the world's population in 1995, the average is 7,300 cubic metres of water per person per year. This is a drop of 37 per cent since 1970. It must be noted that water distribution in the world is very uneven. While the Amazon carries 16 per cent of the global run off, the arid and semi-arid zones of the world that constitute 40 per cent of the land mass receive only two per cent of the global run off.

With a projected increase of 50 per cent in population in the next 50 years and the expected increase in demand as a result of economic growth and changes in lifestyles, the future does not look very bright, unless there is proper planning and management of water. Agriculture, industry and basic human needs, such as drinking and sanitation, make up for the most important uses of freshwater. Of late, the ecosystem is also being viewed as a user of water. And in all probability, the most important user of water.

"The severity of the recent floods in Europe and in North America indicate that run off water has been denied access to the natural absorbing or sponging areas such as wetlands and marshes," said Janet Abramovitz of the Worldwatch Institute, Washington, dc . "By ignoring nature as a rightful shareholder in water resources, present development trends can lead to worsening of the situation, like the proposed irrigation plans in the Mekong valley, which will directly affect over 50 million people, besides the natural system," she adds.

According to Comprehensive Assessment of the Freshwater Resources of the World , a 1997 report prepared by the World Meteorological Organisation ( wmo ) on behalf of a host of un agencies: "Water needed to be left in rivers to maintain healthy ecosystems." This reflects the acknowledgement of the ecosystem, hitherto taken for granted, as an equal partner in the use of water. If one goes by the above-mentioned projections whereby all the usable water would be consumed by humanity in the coming 50 years, the ecosystem would be starved of substantial replenishment.

Global withdrawals of water have grown by a factor of over six between 1900 and 1995 -- more than double the rate of population growth. This is attributed to increasing water requirement for agriculture, industrialisation as well as greater human usage in urban centres. According to the wmo report, about 460 million people -- more than 8 per cent of the world's population -- live in countries that can be considered to be highly water stressed. It adds that another quarter of the world's population lives in countries where the consumption of freshwater is so high that they are likely to move into situations of serious water stress.

Agriculture takes about 70 per cent of the water withdrawals, often rising to 90 per sent in dry tropics. Water withdrawals for irrigation has increased by over 60 per cent since 1960, which has coincided with the green revolution. High-yielding crop varieties need a lot of water. While this has led to an increase in the world's agricultural produce to a stste of surplus, it has also increased production costs, essentially due to high costs of inputs. It is estimated that despite the high agricultural production, around 840 million people do not have access to sufficient food. Yet water withdrawals are so high that water bodies, such as lakes and rivers, have shrunk in size. A direct impact of this has been on the levels of groundwater.

Increasing usage of groundwater has pushed the "water table" lower, making its extraction more expensive than before. This can have serious effects on the flow of rivers, especially during dry periods, which is so vital for the aquatic ecosystem. It can also lead to land subsidence. Along the coasts, increasing groundwater withdrawals have led to the ingress of saline water into groundwater. Pollution is another major factor that is reducing water quality and thereby the availability of clean water. The amounts and types of wastes discharged have outstripped nature's ability to break down pollutants into less harmful elements. In the case of the river Yamuna in India, over-extraction of freshwater has denied the river of the minimum flow it requires to actually "cleanse" itself.

Human health is directly linked with the quality of water, as the health of the ecosystem is linked with the quality and quantity of water. About 20 per cent of the world's population lacks access to safe drinking water, while 50 per cent lacks access to adequate sanitation. Most of these people are in developing countries, where governments lack resources to make necessary investments in water supplies and sanitation.

At any given time, it is estimated that half the people in the developing world suffer from water- or food-associated diseases, or from diseases that find their source in water (malaria, for instance). Chemical contaminants and heavy metals in water also result in illnesses such as cancer, nervous system disorders, and birth defects. While the Minamata disaster in Japan has been by far the most extreme case for humankind, similar defects have been noted among birds and other creatures in the wild in North America. However, global concern for freshwater was first expressed two decades ago.

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