The relationship between population growth, poverty and environmental degradation is complex and not, as is often suggested, a simple equation involving the terms 'high population" plus "poverty" equals "environmental degradation". The three can go together, and in some countries or regions of the world do go together, but this apparent 'obvious truth' is often used by those in the rich North to displace their responsibility onto the poor South. Two examples will allow us to illustrate this.
The old East European communist bloc had an appalling environmental record from which its successor countries are still suffering. Its factories were some of the worst polluters the worlds has ever seen. Its waterways were grossly polluted and its air quality was extremely poor. Leakages of pollutants into the environment were both frequent and significant. However, in the main, these were countries that were not over-populated and they were certainly not 'poor' countries as we understand the term. Rather, they had a very bad environmental record because they did not put in place any of the available policy and technical solutions to environmental improvement.
The second example is none other than our old friend the United States of America. Certainly not poor and certainly not overpopulated, but the country has in many respects a very bad environmental record. The United States is the world's greatest user of energy. A child born in India twenty five years ago will, by the time she or he dies have used one-fiftieth (thats a mere 2%) of the energy that a child born at the same time in the US will have used by the time of their death. That's fifty times as much air pollution and 50 times as much of a contribution to global warming. The same sort of logic can be applied to other aspects of the environment.
Essentially, the message from both examples is the same. There is no necessary correlation between poverty, population and environmental degradation. Taking care of the environment is much more about a culture 's (and the people within it) attitude to need as opposed to greed, combined with a good legislative and regulatory framework, and it is also about being secure in one's position. The last of these is where poverty comes in. Removing poverty leads to greater security and a better likelihood of children surviving past their fifth birthday. This removes the need to have big families and for those families to struggle for day-to-day survival. If the rich countries, and especially the rich within those rich countries (and believe me they are grossly rich and they pollute far more than the poorest of the poor), were to help alleviate the worst excesses of poverty throughout the world, then population growth would be diminished, poverty would decline significantly, and environmental degradation would be significantly ameliorated.