Global Water Crisis

Peter Rogers, Professor of City and Regional Planning at Harvard University has written an impressive article entitled Facing Freshwater Crisis in the August 2008 issue of the monthly Scientific American which I read regularly because it puts all facets of science in popular language for easy one’s understanding.

The article starts with the condition of freshwater availability at New Delhi, the capital of India.

It induced more interest for me to go through the article.

Water is shared by human beings and agricultural crops, which are turn required as food for humans.

Scarcity of freshwater by mid-century has been forecasted by the United Nations.

As the human activities increase because of intensive industrialization, pollution of environment results in.

Even the available water is contaminated causing health hazards to human beings and animals.

Water is again not equally distributed.

In some regions we have plenty of water due to good rains whereas other regions are drought affected.

Water supplies in the whole world vary considerably.

Much of the Americas and northern Eurasia enjoy abundant water supplies.

Other areas, Central Africa, part of Indian sub-continent and Southeast Asia suffer with water scarcity.

That was one of the reasons, the Consultative Group on International Agricultural Research (CGIAR) established ICRISAT (International Crops Research Institute for Semi-Arid Tropics) at Hyderabad, India to research on semi-arid crops of Africa and Asia.

In fact, the quantity of water used by cities and industries from the total precipitation is only 0.1%.

What happens to the rest of the 99.9%?

Major quantity flows through lands and rest ends up in oceans.

It appears, each person on earth needs a minimum of 1000 cubic meters of water per year for drinking, hygiene and growing food for sustenance.

Scientists have calculated the amount of water used to produce a kilogram of wheat is about 1000 litre of water and when a country is exporting millions of tons of wheat, one can imagine how much water has been used to produce that much of grains.

It is a huge quantity of water, crop production requires every season for every crop farmer grow.

Many steps have been taken to conserve water and minimize the water requirement of crops.

Water management, one of the important branches of Agronomy, is developing technologies to conserve moisture in the soil.

Sprinkler and drip irrigations instead of surface irrigation help a great deal to save irrigation water.

Mulching is another technology for preventing the evaporation of moisture from soil.

Crops and crop varieties that require less water to produce unit mass of dry matter are being tried.

We see large quantity of water in the sea around our land area, but the water is salty; not a drop to drink!

How to desalinize such vast quantity of water available free to us?

Desalinization technology such as membrane reverse-osmosis systems will secure new source of potable water.

During reverse osmosis, salty water flows into the first of two chambers that are separated by a semi-permeable (water-passing) membrane.

The second chamber contains freshwater.

Then a substantial amount of pressure is applied to the chamber with the salt solution in it.

Over time the pressure forces the water molecules through the membrane to the fresh-water side.

Large-scale desalination plants using the new more economical technology have been built in Singapore and Tampa Bay, Florida, USA.

Scientists are now working on reverse osmosis filters composed of carbon nanotubes that offer better separation efficiencies and the potential of lowering desalination costs by an additional 30 percent.

More attempts are needed to research and to get more water for the growing population all over the world.

At the same time everyone on the planet earth is trying to do something to reduce, reuse and recycle the precious water, which is essential for our livelihood.