Nature is NEVER kind when it resets a population density.
If y'all hate the idea of "oil wars", just wait for the resultant "water wars" as we continue pollute and salinate an ever decreasing ratio of "drinkable water vs. population." The amount of available, drinkable water decreases every year while we continue to consume more every year. The earth is doing its part to recycle the water in a fresh form. However, we are using and poisoning it faster than it can be recycled by the earth
This is just one of the aspects of our having already exceeded the capacity of the earth to support our population density.
Drought, famine, and the resultant diseases that can run rampant in a weakened and overcrowded population are nature's main tools to reset a population density. For the earth to be able to sustain us in perpetuity, our population would have to be reduced to >2 billion! That equates to <5 billion dead from drought, famine, disease, and war. . . . . and that would be the "good" outcome.
If the remaining population was too thinly disbursed to breed at replacement levels or inhereted a genetic weakness, we may just go the way of the saber-tooth.
Peace,
dave