Thermoman, you expose an interesting paradox when you say, “Please try to see the big picture. 25,000 people a day are dying of starvation.”

The assumption, if I read you correctly, is that those deaths are unnecessary and a direct result of too many folks competing for too few resources, and it follows that we should be concerned and upset about the fact so many are dying of starvation. And you might be right; it can readily be demonstrated that food supplies are a limiting factor.

But isn’t that what is supposed to happen? Is anyone surprised? In fact, wouldn’t those folks who are seriously concerned about a planet presently hosting 6 billion, and who recommend a global population ceiling of 2.5 billion, say that given the predictions of rapid resource depletion, a death rate of 25k per day is perhaps far too low?

But, in order to reach the desired population level, who will volunteer to apply limits to population distribution and abundance? Who will determine optimum numbers? Based on what measure? Birth rate? Death rate? On military needs? On available water supplies? On locally grown food supplies? On available land mass? On the rate of technological change? The evolution of a proactive political will that will introduce serious economic incentives or legislations, suggested by eclipse, that are aimed at encouraging smaller families in order to reach the optimum number, is extremely unlikely. It's my guess that the reason we haven't seen the evolution of proactive political will, in democratic societies, is that the voters will not elect a politician that suggests placing community values above those of the individual because it means individuals, especially those with large families, will have to suffer and sacrifice personal gain, and that’s not an easy concept to corral.

Pericles,
I have already responded to you — but you cannot be bothered engaging arguments that do not suit your case. Instead, you avoid my many source documents and ecological authorities and try to appeal to a sense of vagueness about the current situation.

You said: “Neither you nor I can determine, from any genuine statistics, whether this point has been reached.” Your statement that there are “no statistics” by which to judge this issue is exactly correct but also entirely misleading!

• It is correct because the upper population limit is determined by vagaries such as exactly what kind of lifestyle we are prepared to put up with, how much energy we can harness in a post-oil world to facilitate agriculture, water, and the many other resources we need to survive, and how much damage we are prepared to inflict on natural eco-systems by the sheer size of our agricultural requirements. We already harness 36% of the land surface of the earth for agriculture. Jared Diamond has estimated that we use 70% of all available {{{arable land}}} in what he calls the “photosynthesis ceiling” — and that includes all the rainforests on earth! Do you really want to clear the Amazon to grow crops?

It is precisely because of the vagaries of the upper limit that we must practice caution. Part of that is beginning a public debate, which we are doing here. The fact that there are uncertainties is the very reason for this important debate, and yet you try to scold us over this fact!

The dangers of overpopulation are so great that we must practice the “Precautionary principle” or risk testing Liebig’s Law on multiple fronts simultaneously. As Pulitzer-prize winner Jared Diamond has indicated in his book, “Collapse”, civilizations implode when their ecological foundations are eroded beyond repair.

Your statement correctly confirms the need for a public campaign based on this formula because you have just demonstrated its truth. As Xist demonstrates, there are many complex variables within the equation, but as Xist also believes, the need for an effective policy has never been more urgent.

Xist, are you really suggesting that voters will not elect politicians who see the problems stemming from ever-increasing population? That would be based on a wild and poorly tested assumption.
Currently for Australian voters, no choice is available.
In Victoria, at next Federal election, the Labor Party will be offering the population-boosting Bill Shorten. It wasn't because every mumma's little baby in that electoral branch of the party loved how Shorten was bred. The safe labor electorate was dictated to.
And the good burghers of the safest of Liberal seats in Sydney did not have a better go of things when their current representative, no-shinking-violet Turnbull, squashed his opposition under a steamroller of cash.
Voters mightn't really want the show to be run by Tony Abbott with his religious-cyclops vision, Peter Costello of fast-breeder fame, or others of similar persuasion. They have no choice when it comes to population (or any other ) growth. Sure, they weren't too keen when offered Bomber Beazley as captain - he having decreed that Australia's population should match Java's, pronto!
And so it is for much of the rest of the world where population is increasing. Visiting medical practitioners to southern Pacific communities tell of women walking miles over mountains to their clinics on the possibility of accessing contraceptives. In China fifty years ago, stories are told of women denuding the countryside of tadpoles following the rumor that swallowing them live prevented pregnancy.
More than ten years ago it was recognised that women of the world needed education and choice in the matter of their own fertility. A glimmer of opportunity; then, largely, denial. Responsibility for such denial lies heavily on the shoulders of the Vatican, the Bush administration's liasion with US Christian fundamentalists, and the likes of Australia's Tony Abbott.
Xist, you infer coercion in the matter of human fertility. It does indeed have a most unappealing presence - the opposite to what have inferred.

I have raised the idea in the other 'population growth' thread, that there is a strong link between the farming of livestock and water usage.

Here are some facts that should speak for themselves:

- Human population of Australia: 20 million
- Number of humans that can be fed by the grain and soybeans eaten by Australian livestock: 93 million
- Percentage of corn grown in Australia eaten by livestock: 75%
- Percentage of corn eaten by humans: 15%
- Percentage of oats and wheat grown in Australia eaten by livestock: 85%
- Percentage of protein wasted by cycling grain through livestock: 90%
- Percentage of carbohydrate wasted by cycling grain through livestock: 99%
- Percentage of dietry fibre wasted by cycling grain through livestock: 100%
- How frequently a child dies of starvation: Every 2 seconds
- Amount of potatoes that can be grown on 1 hectare: 12000 Kilos
- Amount of beef that can be grown on 1 hectare: 85 kilos
- Percentage of Australian agricultural land used to produce beef: 49%
- Amount of grain and soybeans needed to produce 1 kilogram of beef: 7.1 kg
- Amount of protein fed to chickens to produce 1 kilogram of protein as chicken flesh: 2.3 kilos
- Amount of protein fed to pigs to produce 1 kilogram of protein as pig flesh: 3.4 kg
- Number of children who starve to death every day: 40,000
- Number of pure vegetarians who can be fed on the amount of land needed to feed 1 person consuming meat-based diet: 20
- Number of people who will starve to death this year: 60000000
- Number of people who could be adequately fed by the grain saved if Australians reduced their intake of meat by 10%: 60000000

Perseus,
Your arrogance knows no bounds "green/lefties should not reproduce" maybe if the opponents of green lefties did not reproduce the problem may have already been solved.

The article suggests a move North? I live in Townsville, North Queensland, there is no stock up here, Brisbane is in short supply, and our national government with $17 billion in the bank has done nothing. Maybe it is the old adage, if you do nothing, you can't make mistakes theory, if the AWB scandal is anything to go by.

• Part 2 to Pericles: your statement
“Neither you nor I can determine, from any genuine statistics, whether this point has been reached” is also entirely misleading because it avoids engaging the many credible sources I have quoted that are now raising the alarm over our population trajectory. I will repeat the references here.

Professor of ecology David Pimentel:-
2 billion = high lifestyle
12 billion = poor lifestyle with much starvation.
http://en.wikipedia.org/wiki/Overpopulation
http://www.utne.com/web_special/web_specials_archives/articles/799-1.html

Warning to Humanity
“The earth is finite. It’s ability to provide for growing numbers of people is finite. Current economic practices which damage the environment, in both developed and underdeveloped nations, cannot be continued without the risk that vital global systems will be damaged beyond repair. Pressures resulting from unrestrained population growth put demands on the natural world that can overwhelm any effort to achieve a sustainable future.”
—From World Scientists’ Warning to Humanity, the Union of Concerned Scientists (UCS), written and signed in 1993 by more than 600 of the world’s most distinguished scientists, including a majority of the living Nobel laureates in the sciences.
http://www.ucsusa.org/

The exact upper limit is vague, but it is better to be safe than sorry!

The more people we have, the more changes we will have to make.
Tubley has posted that we could all become vegetarians to cram more people in. While I agree with limiting meat intake and changing grazing practices, the fact is I have spoken to people who would like to be vegetarian but just medically cannot absorb enough iron on a vegetarian diet. (Tubley do you have any sources for those statistics?)

The greater problem is… where do we find enough fresh water for all these people, how do we give them homes, what energy will they require, what is their first world footprint going to be, how much Co2 per person would be released, etc?

It’s not just food — it’s also the broader resource constraints that make the following equation so pertinent.

“All things being equal, Resources / Population = Lifestyle.
Pericles, it’s just plain true! Deal with it!