Climate like any other physical phenomenon is not static but rather a dynamic kind of things. In greater or lesser degree it is even changing. In every part of the world one year, one decade or one century differs from other. Till recently, the concept of climate change was considered only of academic importance but only during the past few decades’ scientists began to recognize the variability of climate.
The scientists have also reconstructed the past climates from indirect evidences based on the findings of geology, geomorphology, zoology, meteorology, oceanography, botany etc.
Recent fourth assessment report of the Inter Governmental Panel on Climate Change set up under the United Nations, published in Paris in
February 2nd, 2007 indicates that something serious is happening and man is in part responsible. Report also pointed out that warming seems to be accelerating and eleven out of the dozen years from 1995-2006 wee among the 12 hottest years since 1850.
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The report also estimated that the average increase in global temperature for the past century which the third assessment report put at 0.6°c has now risen to 0.74°c and sea level rose on average by 1.8 mm a year from 1961 to 2003. All long lived greenhouse gases- carbon dioxide, methane and nitrous oxide-have increased markedly as a result of human activities since 1750. This impact of climate change and global warming will be felt by sectors. Such as:
i. Agriculture:
Climate change will affect agricultural yield directly because of the alteration in temperature and rainfall and indirectly through changes in soil quality, pests and diseases. The yield of cereals is also expected to decline in India, Africa and the Middle East. In the higher latitudes (in the northern countries) agriculture will benefit with the rise in temperature as the winter season will be shorter and the growing season longer.
Weather: A warmer climate will change rainfall and snowfall patterns, lead to droughts and floods, because melting of glaciers, polar ice sheets and ultimately results in accelerated sea level rise. The rising temperature will also lead to an increase in the level of evaporation of surface water, the air will expand and this will increase its capacity to hold moisture. This in turn will affect water resources, forests and other natural ecosystems.
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ii. Health and Diseases:
It is anticipated that there will be an increase in the number of deaths due to greater frequency and severity of heat waves and extreme weather events. An extreme rise in temperature will also affect people living in urban areas as these are developing into heat islands due to concrete constructions, paved roads etc.
Changes in weather pattern will also lead to ecological disturbances, food production levels, increase in Malaria and other vector borne diseases. Depletion of stratospheric ozone will result in higher exposure to ultraviolet rays of the sun, leading to an increase in the incidents of skin cancer. It could also lead to an increase in eye diseases such as cataract among people,
iii. Marine Life:
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As ocean water in the tropics became warmer, the damage to the coral reefs seems to be increasing. The corals which are known as the tropical forest of the ocean and sustain diverse life forms would be in danger. These corals are very sensitive to changes in water temperature would face problems of bleaching. Study has also shown that large stretches of Great Barrier Reef in Australia have been damaged by bleaching.