Due to ever increasing human activities are vitiating the earth's bio-sphere on an alrming scale. These can be traced from the following available datas :
1) The carbon dioxide content of the atmosphere has grown up by 25% in the last 200 years, with about half the increase having been accrued since 1950. The sources are internal combustion engines, furnaces. This results in global warming and Greenhouse Effect.
2)Nitrogen cycle is being disturbed. Increased use of nitrate fertiliser is at the root of this evil. Since nitrate is readily leached from the soil by water, the increased use of nitrogen fertiliser has caused nitrogen pollution in the lakes, rivers, streams, and ground water.
3)Human beings now use (take or transform) an estimated 25% of the net photosynthetic product (NPP) i.e. the plant mass fixed by photosynthesis. As human beings consume more of the primary productivity of the earth for themselves, less is left for other species.
4)The withdrawal of water from natural circulation has increased 35 times since the 17th. century. Now this is annually about 3,600 cubic km. per year. This is a grave concern for the watersphere of the earth.
5)Since the development of agriculture, deforestation is wildly rampant. It is about 8 million sq. km., an area almost equal to the continental United States. The exitinct of forest-cover on this scale has caused alarming change in the bio-sphere.