Is the Earth overpopulated? How do we decide?

Alright, **Valteron **, lets use the Socratic method.

You asked, “Is the Earth overpopulated?”. What is the difference between the Earth being overpopulated and a country being overpopulated? A country is an open system; people can come from outside of a country to inside of another country. The Earth is a closed system.

So now we have the concepts of an open system and a closed system. The next concepts are long term and short term. Using the two sets of concepts, I have divided the question into four parts:
Can a closed system be overpopulated in the short term?
Can a closed system be overpopulated in the long term?

Can an open system be overpopulated in the short term?
Can an open system be overpopulated in the long term?

Based on this, overpopulation has actually eased since 1850 or so, before which nobody had clean water (by modern standards).

As I said “most objective”. Surely this is the *most *objective and scientific way of measuring our impact on the planets ecology.

It is a good thing that some European countries are decreasing their footprint. At the same time, however, other European countries are increasing theirs. Across the planet there is increasing population and increasing consumption of resources (e.g. China and India) which swamp out this effect.

Is it possible to borrow against the ecology without a permanent impact? Maybe it is if this in the short term, but I suspect that long term overpopulation will have a lasting effect on ecology. There would be a lag time where ecosystems would need to regenarate in response to the payback of ‘debt’ via reduction of footprint. I don’t think using monetary debt as an analogy quite works.

Surely? How do we know this? It may, indeed, be the best tool we currently have, but that does not make it optimal, in and of itself. The astrolabe was the best tool available for taking celestial readings prior to the invention of the sextant, but it is a pretty poor tool in retrospect.

However, the question of the OP is whether we have already reached a point of overpopulation. Unless it can be proven that we have far outstripped our resources (and the current lack of natural famines argues against that claim), then the footprint/biocapacity algorithm does not establish that point as fact. It may, indeed, be true that we have already passed the point beyond which only a calamitous reduction of humans can save some remnant, but that remains speculation, not an established fact.

Lest my position be mistaken: I am not arguing some neo-con version of a Pollyanna approach to the world in which we face no obstacles or challenges to survival. I think the possibility of humans rendering the Earth unfit for humans is a real possibility. However, the question of the OP was whether we had reached some point (rather vaguely identified as “overpopulation”) already. Nothing in the footprint model identifies that as an established fact. To take one example from the footprint site to which you linked: a huge deficit that enlarges the “footprint” immensely is the reliance of Europe, North America, Russia, and China on fossil fuels. However, that calculation is based on an assumption that we already know the limits of fossil fuels (which we do not) and that our current reliance of fossil fuels will not be modified. There are a lot of possible changes to that schema, including the discovery of oil where we have not yet looked, the development of technologies that will reduce the dependence on such fuels, the development of technologies that will make coal a worthwhile replacement for petroleum in the production of plastic (and the possibility that ethanol is only the first step in creating many more renewable fuels), the putting to rest of the Three-Mile-Island-Chernobyl fears in the U.S., leading to an increase in the development of nuclear applications in the world’s largest energy consumer, the (potential) development of fusion technology, and a host of other events that could turn every current projection into nothing more than a waste of (renewable) wood pulp.

I am not taking the position that we should not strive to control ourselves. I think it would be foolish to assume that some magical discovery will save our asses. However, the actual question asked was whether we had already gone too far and I do not find the evidence for that claim to be compelling.