| It is impossible to exceed the carrying capacity of the earth. Let me explain why. Every human being alive is made up of biomass, which means that the meat that people are made up of was once animals and plants, also eating, also drinking water. So the idea that food and water shortages are caused by increase in human population is simply not possible. It is not possible for there to be more people than there are resources to create them in the first place. The only real difference is that human beings consume industrial goods and excess consumption caused by increase in standard of living (for example flushing toilets, something animals and plants do not do). But even considering these things, they're due to an increase in standard of living which can only come from an increase in production. In aggregate, humans cannot consume more than we can produce. So it follows that an increase in population that causes resource shortages can only lead to a reduction in living standards, and only down to the living standards of a subsistence agrarian society. Overconsumption of resources then is a self correcting problem. Now, suppose human beings could exceed the earth's carrying capacity, which I have just showed you is not possible. This would cause many human beings to die from starvation, as the decrease in living standards would take us below the standard of living of subsistence agriculture in this hypothetical scenario. Even in this extreme case, it is still a self correcting problem. There is no need to artificially correct it. Any and all problems that appear to stem from overpopulation are actually resource allocation problems, inefficiencies in resource distribution. The problem with China is not that the resources cannot be produced to support the population, the problem is that the resources are inefficiently distributed, in part because a centrally controlled economy cannot possibly distribute resources more efficiently than a distributed (or free market) economy, but that is a different discussion. |
People can have different daily-intake requirements as children versus adults, plus a growing populations consummation can temporarily exceed food production by burning trough food stores. Also, local food production can vary, place to place, season to season - what's sustainable during a good year, might not be during a bad one.
Plants and animals can eat and drink things humans can't; e.g. a plant is fine with muddy, faeces-contaminated water, it would even thrive on it. Livestock may happily eat grass/straw long-term.
The killing of one cow won't feed a human for the rest of their lives - multiple cows are needed to provide constant food, and the cow population may as such increase along with the human population.
When the rate at which the cows are eating grass is faster than the rate at which the grass grows, your population is unsustainable, and you will eventually not be able to feed everyone. The only sense in which it's "impossible to exceed the carrying capacity of the earth" is that when you do, people will die.