It is now apparent that the ecological pragmatism of the so-called pagan religions, such as that of the American Indians, the Polynesians, and the Au… - Prince Philip, Duke of Edinburgh

If we are to exercise our responsibilities so that all life can continue on earth, they must have a moral and philosophical basis. Simple self-interest, economic profit and absolute materialism are no longer enough... It has been made perfectly clear that a concern for any part of life on this planet — human, plant or animal, wild or tame — is a concern for all life. A threat to any part of the environment is a threat to the whole environment, but we must have a basis of assessment of these threats, not so that we can establish a priority of fears, but so that we can make a positive contribution to improvement and ultimate survival.

We talk about over- and underdeveloped countries; I think a more exact division might be between underdeveloped and overpopulated. The more people there are, the more industry and more waste and the more sewage there is, and therefore the more pollution.

I do believe ... that human population pressure--the sheer number of people on this planet--is the single most important cause of the degradation of the natural environment, of the progressive extinction of wild species of plants and animals, and of the destabilization of the world's climatic and atmospheric systems.
The simple fact is that the human population of the world is consuming natural renewable resources faster than it can regenerate, and the process of exploitation is causing even further damage. If this is already happening with a population of 4 billion, I ask you to imagine what things will be like when the population reaches six and then 10 billion.... All this has been made possible by the industrial revolution and the scientific explosion and it is spread around the world by the new economic religion of development.