There is one concept in biology that everyone should be aware of, the concept of Ecosystem Carrying Capacity. ECC is the ultimate limit of resources that are theoretically available within a closed system. Lets start with something manageable to understand this. Think of an isolated island in the ocean. There is only so much land area on this island for plants to grow and for water to be naturally filtered through geological processes.
Any population of animals will naturally fluctuate; in relation to individual species as well as in total, until the upper limit of resources it reached. Now in practice, most islands are capable of supporting a larger population than can be supported purely based on terrestrial vegetation due to the ocean's natural resource abundance. This can be seen as even tiny rocks can hold amazing numbers of birds nesting in colonies. Magnitudes larger in fact than the ECC of the land alone.
The point is, a strict accounting is still taking place. Resources can be tracked back to their sources definitively.
Now imagine the earth as an island. We humans have found all sorts of inventive ways to extract resources from what is ultimately a limited system with a single energy source. But unlike our tiny island, we are not solely limited by surface area with the ocean making up the debt for us. We have no such extra capacity to draw on. We are limited to the confines of our hunk of rock orbiting our star and the thin smear of habitable area clinging to it.
According to William Rees the simple math of global arable land suitable for food production in relation to population, paints a rather striking image. If for example we all lived at the resource consumption level of a sub-Saharan African, the ECC of our earth is around 15 billion people. At the other end of scale, the level of consumption of the average American places the ECC of the entire earth at about 1.5 billion people.
So where does that leave us today? With the world population recently crossing seven billion people, we have to find a resource consumption level that is sustainable for over seven billion people. Currently we rely on disproportionate resource distribution to maintain the luxurious American lifestyle. But that implies that we will have to increase the number of people we disenfranchise in order to maintain the standard of living for our growing population.
This inherent inequality isn't just exported either. At home we are becoming an increasingly stratified society, with resources being hoarded at the top and wages stagnating at the bottom (with the effect of lowering the standard of living for millions of Americans). True the agricultural revolution did have the effect of greatly increasing our ECC, but assuming another technocratic solution will expand our resources; to cover the quickly growing gap as other countries strive to reach western standards of living, ignores basic principals of physics and biology. Agricultural productivity does not advance like Moore's Law for farmers.
Water resource consumption is another important part of the equation as well. Again technocratic solutions, like desalination, are resource consumptive them selves and are realistically only stop-gaps and band-aids to and ever growing problem.
The only real path forward is to personally limit resource consumption. This needs to be a comprehensive process, with top down policy measures as well as bottom up personal accountability. The attitude of many Americans who feel completely entitled to an unsustainable standard of living is a luxury the human race can no longer afford. In effect that attitude is committing genocide on a large segment of the future population of earth.
We can soften the blow right now, by being proactive and working towards finding the balance or we can wait and hope that resource competition doesn't become violent in our lifetimes.