Can the world support 72 billion people ?

Professor Jared Diamond publishes an essay on the NY Times op-ed page summing up the current view about excess consumerism.
He says

The estimated one billion people who live in developed countries have a relative per capita consumption rate of 32. Most of the world’s other 5.5 billion people constitute the developing world, with relative per capita consumption rates below 32, mostly down toward 1....
China’s catching up alone would roughly double world consumption rates. Oil consumption would increase by 106 percent, for instance, and world metal consumption by 94 percent. If India as well as China were to catch up, world consumption rates would triple. If the whole developing world were suddenly to catch up, world rates would increase elevenfold. It would be as if the world population ballooned to 72 billion people (retaining present consumption rates). Some optimists claim that we could support a world with nine billion people. But I haven’t met anyone crazy enough to claim that we could support 72 billion. Yet we often promise developing countries that if they will only adopt good policies — for example, institute honest government and a free-market economy — they, too, will be able to enjoy a first-world lifestyle. This promise is impossible, a cruel hoax: we are having difficulty supporting a first-world lifestyle even now for only one billion people.

Sounds convincing, doesn't it ? Can the earth support 72 billion people ?

The answer is - we don't know. The earth and mankind are too huge for us to fully grasp and predict their development over time.

Doomsday predictions are not new. The most famous is perhaps Thomas Robert Malthus, who published An Essay on the Principle of Population, in 1798 and predicted the world will not be able to support much more than the about 1 billion people alive then (at a infinitely lower level of consumption). Other such publications include Paul Ehrlich's "The Populations Bomb" published in 1968 predicted "in the 1970s and 1980s hundreds of millions of people will starve to death".
The Club of Rome raised much attention with its report Limits to Growth, which has sold 30 million copies, it predicted that economic growth could not continue indefinitely because of the limited availability of natural resources, particularly oil.

The one who best refuted these doomsday scenarios was economist Julian Simon. "His 1981 book The Ultimate Resource is a criticism of the conventional wisdom on population growth, raw-material scarcity and resource consumption. Simon argues that our notions of increasing resource-scarcity ignore the long-term declines in wage-adjusted raw material prices. Viewed economically, he argues, increasing wealth and technology make more resources available; although supplies may be limited physically they may be viewed as economically indefinite as old resources are recycled and new alternatives are developed by the market."

The fact is that, so far, the doomsday prophets have been proven terribly wrong. The world is too big and complicated, by far, for us to make predictions.

Jared Diamond concludes his essay with the weasel words:

The world has serious consumption problems, but we can solve them if we choose to do so.

They are weasel words because he refrains from stating his recommendation for the "we can solve" part. What he means is that government must impose consumption limits by mandate on people. Lefties have a universal solution to all problems - government forcing people to do as they, the lefties, think advisable. Because all people are dumb and greedy, and don't know what is good for them, only the lefties know, and their superior wisdom must be imposed by force, else the world ends.

Let the world and it's people develop in a natural, free way. No one is wise enough to impose his views on all people by force. Attempts at totalitarian rule have proven catastrophic, on a gigantic scale. Let's not try it again.

To the question "can the world support 72 billion people" - my answer is - I don't know. It is possible that it can't. In this case people will not reach these levels of population and consumption. They will not consume what isn't available, of this I'm sure. In the natural course of development some equilibrium will emerge between the number of people, their consumption and the resources available. No one can predict what it will be, and no one can manage world growth by decree. We don't need any totalitarian "solutions". Just let things run their natural, free, course. We can't improve on that.