Monday, 16 May 2011

Water : A Boon or Curse?

Life on earth depends primarily on water. May it be for human beings, or for ecosystems like forests and other organisms in all forms of life. The change in climate will dramatically affect the world’s fresh water supply which comes in form of rain and snow. Rainfall will increase in some places, bringing floods and will decrease in others, possibly bringing droughts. It could potentially affect to such an extent where conflicts between nations would be inevitable, over water resources. Some areas of the world would suffer from too much water, whereas others would face the scarcity. Thus change in world’s water balance would be a matter of universal concern.
Climate change will bring about imbalance in both, quality and quantity of water. The pace of water cycle will speed up, making evaporation more rapid, leading to intense storms and floods. It will also affect the timing of rainfall, the dry spells in between as well as quantity of down pour, thus profoundly affecting humans and other life forms. On one hand wildlife behaviour will change to adapt to the changing habitat and on the other, crop pattern and crop yield will be affected. Scarcity of water will lead to disputes among groups such as farmers, industries and household users. This secondary effect of climate change would as well have a great impact as much as its direct effect.
As it is a fundamental source to all economic activities, from agriculture to tourism, the pressure will be felt by people world over, which will be experienced in different ways depending upon regional situation. Scientists are working on different models to understand where changes are most likely to occur. According to the study, increased rainfall and flooding will be seen across northern Europe, Canada, Alaska and northern Asia. Whereas countries like Indonesia and others in southern parts will grow drier. With increasing drought situation the top soil, which nourishes the plants, would go drier and get blown away, permanently damaging the land. According to one report China has lost around 3.5 million acres of forest and cropland being turned into desert within last half century alone. Increase in infectious diseases such as malaria and dengue fever would be at rise in tropical regions with rise in temperature and increase in rainfall, both of them being a favourable condition for mosquitoes to thrive. It will not only affect human beings but the cattle population as well, which is a source of livelihood to many. Increased temperature in fresh as well as salt water stimulates growth of harmful algae where bacteria thrive which can cause health problems.
Ecosystems thus have been pushed out of balance. In the Himalayas snow melting fills dozens of lakes, which is a source of fresh water to villages in Nepal, Bhutan and Tibet. With average annual temperature gradually rising each year since last two decade, these lakes are getting increased amount of water with more and more glaciers melting. Adding to this the water is being tapped to get the supply of water to the hydroelectric plants which have been built over the rivers flowing from these glacial lakes. With snow melting fast, these lakes are getting overfilled, posing threat of bursting their banks. United Nations Environment Programme has identified over two dozen of such lakes in Nepal and an equal number in Bhutan that are in immediate danger of bursting. The other forces which may cause such damage is disasters like earthquakes, avalanches and landslides. Landslides are more destructive in mountainous regions and specially deforested areas, where the plants no longer hold the soil in place. Once a slope is weakened it becomes vulnerable to any natural calamites. The worst reported case of landslide disaster was in Venezuela, where within a span of five years since year 2000 with just two landslide incidences over 20000 people were killed and over 5 lakh people were left homeless.

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