Nero fiddled while roman burn. Not much has changed. Recent report of the U.N. panel on climate change and the global warming on account of human activities has spread the message like never before. We are facing a global crisis; if we continue to generate green house gases, we will sink without a trace. The report makes it clear that the days of passing the buck and pussyfooting are over. It says that emissions of carbon dioxide must start declining by 2015 to prevent the world’s temperatures from rising more than 2c over reindustrialized temperatures to stave off disaster. To that end, the emissions of carbon dioxide in particular have to drop between 50 to 85 per cent by 2020.
The result of the melting of most of the Himalayan glaciers by 2030, as predicted by the U.N. panel on climate change, could be truly catastrophic for India and its neigh hours. The Himalayan glaciers are the largest store of water outside the polar ice caps and feed seven grates once the perennial rivers turn into seasonal ones. As these river-flows fall, agriculture, water supplies on which millions of people depend, and power generation and cultivation will be badly affected.
The ultimate objective of the United Nations framework convention on climate change (UNFCCC) is to achieve stabilization of green-house gases (GHG) concentration in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time-frame sufficient to allow decoys systems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.
SERIOUS CHANGES IN CLIMATE IN THE PAST
Evidence of climate change ranges from differing geological strata to the study of pollen grains and tree rings.
The early climate history of the world is not well understood but it is known that during the last 55 million years the earth has been cooling and that during the last million years there has been alternating of glacial and interglacial episodes.
External causes of climate change may include: changes in solar output; changes in the number of sunspots which seem to vary in an 11 year cycle, changes in the elasticity of the earth’s year cycle,. Changes in the elasticity of the earth’s orbit, which roughly follow a 1, 00,000-year cycle and changes in the earth’s axis of rotation, which after the season of perihelion and which follows and approximately 1,00,000 year cycle.
Internal causes include valcanicity, which canincrase the density of atmospheric nuclei in the atmosphere, variations between the distribution of land and sea, continental drift and changes in the atmosphere-surface-ocean system. Recent research suggests the human agency in altering the climate.
Evidences gathered in the northern hemisphere concerning the past 10,00,000 years have revealed that the climate had minor fluctuations of short duration. The worldwide nature of these climatic changes and the simultaneous begi9nning and ending of glaciations in all parts of the world, indicate a general excuse for the advance and recession of glaciers. Variations in solar radiation, which have been monitored, might be a satisfactory general cause, but there are no accurate records to prove their existence. Another possible cause is a variation in the tide-generating forces, as a result of changes in the distance of the moon and the sun over a period of about 1700 years. Thus a maximum tidal force computed 1433 A.D. thus a maximum tidal force computed quantities of ice in the polar seas, thus increasing the among of drift ice.
The great storms and excessive rainfall of 12th to 14th centuries in Europe were supposed to have been caused by the increase of tidal forces at that been caused by the increase of tidal forces at that time. Solar activity, however, may have been an equally important factor.
The most notable climate events in modern times were the dry periods of the 16th century, the great increase in mountain glaciers; the dry period in western Europe in the first half of the 18th century; and the worldwide rise of temperatures, alone with the recession of mountain glaciers, since 1850 till at least 1940.