Everybody was saying we must have more leisure. Now they are complaining they are unemployed. - Prince Philip, Duke of Edinburgh

I don't claim to have any special interest in natural history, but as a boy I was made aware of the annual fluctuations in the number of game animals and the need to adjust the "cull" to the size of the surplus population.
It took about three and a half billion years for life on earth to reach the state of complexity and diversity that our ancestors knew as recently as 200 years ago. It has only taken industrial and scientific man those 200 years to put at risk the whole of the world's natural system. It has been estimated that by the year 2000, some 300,000 species of plants and animals will have become extinct, and that the natural economy, upon which all life depends, will have been seriously disrupted.
The paradox is that this will have been achieved with the best possible intentions. The human population must be properly fed, human life must be preserved and human existence must be made safer and more comfortable. All these things are obviously highly desirable, but if their achievement means putting the survival of future generations at risk, then there is a pressing obligation on present generations to apply some measure of self-restraint.
What has been described as the «balance of nature» is simply nature's system of self-limitation. Fertility and breeding success create the surpluses after allowing for the replacement of the losses. Predation, climatic variation, disease, starvation--and in the case of the inappropriately named Homo sapiens, wars and terrorism--are the principal means by which population numbers are kept under some sort of control.
Viewed dispassionately, it must be obvious that the world's human population has grown to such a size that it is threatening its own habitat; and it has already succeeded in causing the extinction of large numbers of wild plant and animal species. Some have simply been killed off. Others have quietly disappeared, as their habitats have been taken over or disturbed by human activities.

Is it made with Liffey water?

A new criterion has been added, the conservation of the environment so that in the long run life, including human life, can continue. This new consideration must be taken into account at all levels and in all departments of government and in the boardrooms of every industrial enterprise. It is no longer sufficient simply to quantify the elements of existence as in old-fashioned material economics; conservation means taking notice of the quality of existence as well... The problem is of course to give some value to that quality and perhaps the only way to do this is to try and work out the cost in terms of loss of amenities, loss of holiday and recreation facilities, loss of property values, loss of contact with nature, loss of health standards and loss of food resources, if proper conservation methods are not used. Looked at in that light it may well turn out that money spent on proper pollution control, urban and rural planning and the control of exploitation of wild stocks of plants or animals on land and in the sea, is the less expensive alternative in the long run... The conservation of nature, the proper care for the human environment and a general concern for the long-term future of the whole of our planet are absolutely vital if future generations are to have a chance to enjoy their existence on this earth.