When life began on earth 3 billion years ago, its atmosphere contained gases, most of which would be poisonous to much of the present life form. Whatever life form evolved on the earth in the initial phase could thus survive only under water.
The advent of photosynthesis led to the release of oxygen, which diffused into the atmosphere about 2 billion years ago. As oxygen built-up, it generated O3 -which started screening out UV rays, and thus life could move to surface of the earth & on land. The moment vegetation moved to the surface, it started growing rapidly, consuming more carbon dioxide and releasing more oxygen in the atmosphere, in turn building up the protective ozone layer further. This created the atmosphere in which more life forms could develop & more vegetation could grow. Life on earth, thus, nurtured life on earth.
When the forests die and the green cover disappears from the face of the earth, earth's atmosphere will become like that of other planets. When the green cover & the host of fauna it supports vanish, the earth will not support any life form -including human.
By a grand design of nature, everything in nature is linked to each other in many complex ways - of which man has little or no knowledge. If you damage one strand of this web, it can have the effect of damaging or weakening the entire web. And since we are a major part of this web, it is in our interest to ensure that we do not damage this web.
Like mentioned, BPCL considers it a corporate duty to share information on the importance of these issues. Knowing that plenty of informative material is available on the net on the subject, we have instead provided you with web link assistance to surf through some content that would facilitate your clarity on the same