The debate regarding which individual factor, among the three key factors producing the environmental crisis, causes more damage - the size of the human population on the planet, excessive consumption of resources or unequal/ unjust distribution of resources among countries [the wealthier countries consume much more resources than poorer countries] - is like a debate about which contributes more to a triangle, the base or the ribs of the triangle. You can not separate the three factors. If we analyze the numbers over a relatively longer time interval, we will conclude that the size of the population has a bigger impact than consumption. On the other hand, consumption and unequal distribution are also important aspects. If we do not change these three factors all at the same time, the quality of our life will change dramatically. Today humanity is delivering a serious blow to nature, but it is clear that nature will deliver the final blow.

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.

The ecological crisis, in short, is the population crisis. Cut the population by 90% and there aren't enough people left to do a great deal of ecological damage.

In the last few decades, it has become increasingly clear that humanity is facing a crisis of unprecedented proportions. Modern science has developed effective measures that could solve most of the urgent problems in today's world--combat the majority of diseases, eliminate hunger and poverty, reduce the amount of industrial waste, and replace destructive fossil fuels by renewable sources of clean energy. The problems that stand in the way are not of economical or technological nature. The deepest sources of the global crisis lie inside the human personality and reflect the level of consciousness evolution of our species.

The ecological crisis we find ourselves in is in fact a crisis of human relations, with each other and with the entire planet. It is a crisis created by a set of false assumptions about reality, the same assumptions that drive all systems of oppression. That greed and domination are the inherent driving forces of human existence and, therefore, that warfare, conquest, enslavement, exploitation, the looting of other people and of the entire ecosystem are natural and inevitable, and therefore must be okay.

The world's problems are pressing in on us all. The scale and impact of human activities now affects a great portion of the global resources important to human welfare. These activities are putting growing, often destructive pressure on the global environment, pressure that appears likely to increase as human numbers swell toward the doubling of the world's population that evidently lies ahead. These pressures can spawn or aggravate conflict that. in a world with so much destructive weaponry, generates important national security problems. Great changes are necessary to help ensure a humane future for the generations to come. Most of the world's scientific community and many people in the environmental movement are aware of the gravity of the problems. Yet despite sober warnings from these and other groups, in both the industrial and the developing world, re- medial efforts frequently appear powerless and ineffectual. The scientific community has not taken a sustained, powerful role in the public arena where this great cluster of issues is debated and where the problems must be resolved. There is much more that our community can contribute to assessment, warning, and proposals for new patterns of behavior.

At the beginning of the last two decades of our century, we find ourselves in a state of profound, world-wide crisis. It is a complex, multi-dimensional crisis whose facets touch every aspect of our lives – our health and livelihood, the quality of our environment and our social relationships, our economy, technology, and politics. It is a crisis of intellectual, moral, and spiritual dimensions; a crisis of a scale and urgency unprecedented in recorded human history. For the first time we have to face the very real threat of extinction of the human race and of all life on this planet.

Honesty requires that we each recognize the need to limit procreation, consumption, and waste, but equally we must radically reduce our expectations that machines will do our work for us or that therapists can make us learned or healthy. The only solution to the environmental crisis is the shared insight of people that they would be happier if they could work together and
care for each other. Such an inversion of the current world view requires intellectual courage for it exposes us to the unenlightened yet painful criticism of being not only anti-people and against economic progress, but equally against liberal education and scientific and technological advance. We must face the fact that the imbalance between man and the environment is just one of several mutually reinforcing stresses, each distorting the balance of life in a different dimension. In this view, overpopulation is the result of a distortion in the balance of learning, dependence on affluence is the result of a radical monopoly of institutional over personal values, and faulty technology is inexorably consequent upon a transformation of means into ends

One of the central issues in the world population crisis is poverty.

When people tell me population is the number one environmental problem we face today, I always respond that population is by no means primary. It’s not even secondary or tertiary. First, there’s the question of resource consumption […]. Second is the failure to accept limits, of which overpopulation and overconsumption are merely two linked symptoms.

Humanity is moving ever deeper into a crisis which has no precedent. It is a crisis brought about by evolution being intent on completely integrating differently colored, differently cultured, and intercommunicating humanity, and by evolution being intent on making integrated humanity able to live sustainedly at a higher standard of living for all than has ever been experienced by any. Probably ninety-nine percent of humanity does not know that we have the option to make it ; we do. It can only be accomplished, however, through a Design Science Revolution. Those in supreme power, politically and economically, aren't yet convinced that our Planet Earth has anywhere nearly enough life support for all humanity. They assume it has to be either you or me, that there is not enough for both. Those with financial advantage reason that selfishness is necessary and fortify themselves even further.

More and more, men are beginning to understand the severity of the problems which face them today. On all fronts — political, economic and social — these problems multiply and cause much heartache and sad shaking of heads. Add to these the environmental problems which man’s cavalier attitude to nature and its resources has engendered, and the future for mankind looks bleaker still. The realization is dawning that mankind’s life is in crisis and that something radical must be done before it is too late.

I was born into a world of just under two billion people today there are nearly seven billion of us. Whenever I hear those numbers I can honestly say I find it incredible, triple the number of human beings in what seems like the blink of an eye and the world transformed utterly. Human population density is a factor in every environmental problem I have ever encountered, from urban sprawl to urban overcrowding; disappearing tropical forests to ugly sinks of plastic waste, and now the relentless increase of atmospheric pollution. I've spent much of the last 50 years seeking wilderness filming animals in their natural habitat and, to some extent, avoiding humans. But, over the years, true wilderness has become harder to find. m1s58-m3s03

A crisis is taking place in the contemporary world in a variety of forms, cutting across the realms of culture, ethics, politics, and so forth. At the ground of these problems is the fact that the essence of being human has turned into a question mark for humanity itself.