By Parag Ranjan Dutta
It took millions of years for the first sign of life to be formed in the form of a droplet of protoplasm. It is believed that life evolved in water. The irony today is that millions of lives might end up in water, either with less, excess or qualitative changes in water bodies.
The availability of fresh water resource is extremely limited and it is threatening the very existence of life. A study by the World Bank revealed that 97 per cent of the earth’s water is saline. Approximately about 2 per cent of the fresh water is trapped in the form of glaciers and polar ice. Only a meager 1 per cent is available for drinking and other domestic purposes.
It is believed that a gaseous envelope of ammonia, methane, water vapour and hydrogen surrounded the primeval earth. Atmosphere had undergone changes gradually and came to stay with nitrogen, oxygen and carbon dioxide as major constituents. It is a known fact that carbon dioxide regulates and maintains the global temperature balance between the solar energy received by the earth and the outgoing terrestrial radiation (known as Heat Budget).
Carbon dioxide is the best known Green House gas, but other Green House gases like methane, nitrous oxide, CFC’s, ozone and water vapour are all heat trappers and have given rise to the phenomenon of Green House Effect and consequent global warming.
Recent studies of air trapped in bubbles inside ice cores in Greenland and Russian station Vostok in Antarctica have revealed a distinct relationship between these variations and air temperature.
From prior to the days of Industrial Revolution till the present, there was a substantial rise in the concentration of carbon dioxide in the atmosphere. According to one estimate more than 18 billion tonnes of carbon dioxide is injected into to the troposphere (layer of the atmosphere closest to the earth) annually.
There are enough geological evidences to prove that the climate of the world changed several times during the past 350 million years.
The presence of coal in the mid-latitude countries, are a testimony to the fact that these regions were hot and humid in the coniferous period (350 million years ago) and were endowed with wealth of vegetation.
On the other hand tropical regions of the continents of the Southern Hemisphere (Gondwanaland) witnessed large scale glaciations in the past. This suggests that continents have undertaken long journeys from their actual positions.
This theory was propounded by the German climatologist and botanist Alfred Wegener. According to him the Gondwanaland started breaking away from Antarctica in the Mesozoic era. This north bound journey of the southern continents was poetically described by Wegener as’ Polflutch’, or flight from the poles. In the evening of April 21, 2008, a disturbing news was aired by CNN, which said that Greenland had started melting. The Arctic was already bustling with activity never seen before. Melting of icebergs in the Arctic had probably opened up a new route for ocean transport. A NASA report of 2002 showed an alarming report that the North Pole would be free of ice by the turn of the century.
Oil boom in Alaska had opened up a new horizon of economic activity in the region. But unfortunately very few of us could realise the long-term implications of these misadventures. Marine pollution by oil slicks is a major international concern because of its devastating effect on marine ecosystem. Oil slicks could inhibit the growth of planktons and photosynthetic activities of other plants. The infamous oil slick from the super tanker Exxon Valdez near Alaska in March 24, 1989, leaked about 20 lakh tonnes of oil into the sea.
If the global warming continues at the pace of today, the day is not far off, when the Tundra Biome (large terrestrial communities of plants and animals) would be lost from the surface of the earth. This will lead to the disappearance of an already fragile food chain in the arctic.
The wonderful world of seals, walruses, polar bears, and a number of flowering plants and Reindeer moss shall not adorn the Tundra anymore. Northbound flights of thousands of birds of different species that hatch and breed in the very brief Arctic summer camps would come to a halt.
(The author is former Head of the Department of Environmental Science, St. Edmund’s College)
(To be continued)
