Some people say it's too late to reverse what we have done to the earth. I think it's also due to human greed and ignorance that we continue exploiting the earth. Ideally everyone should play their part in caring for the environment. But we humans seem to have everything else on our mind that environment is usually given the lowest priority. There might come a point where earth would be so damaged that it would not be able to sustain life anymore, and that's why scientist are looking for substitutes long before that happens. Or are we already quite close to that point?