Humans as Biological Creatures

The human capacity for innovation is truly remarkable, and has allowed us to completely escape the limits of natural selection that we were once subject to, particularly in more privileged countries like our own. However, some might argue that the extent of our innovations has become a burden on our planet. Many of these creations are responsible for improved public health, longer life spans, larger populations, and luxuries that were, up until recently, unimaginable. So, why would anyone doubt the remarkable and vast creations of "man"? What could warrant a person's disapproval when from such innovativeness stems rapid transport, modern medicine and advanced agriculture?
I would like to introduce the concept of a carrying capacity. Carrying capacity is, in essence, the population size of a given species that an ecosystem can support indefinitely without the said population or ecosystem being destroyed. The carrying capacity  for a population is determined by the food and water availability, as well as any other necessary resources provided by the ecosystem in question. In nature, population sizes often level off at their designated carrying capacity, fluctuating slightly above and below the line over time. If a population at any point exceeds its' carrying capacity, it may damage its' resource availability permanently, effectively lowering the carrying capacity. Below is are two figures illustrating the various approaches of a population towards its' carrying capacity. The first figure depicts, in yellow, a population approaching, and not exceeding, its' carrying capacity; and, in blue, a population approaching, exceeding, and fluctuating about its' carrying capacity. The second figure illustrates what can often happen to a population if it overshoots its carrying capacity too intensely for its' ecosystem to recover: a permanently lowered carrying capacity.

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Although the global human carrying capacity is not yet known, some scientists speculate that we humans have already exceeded (or far, far exceeded) our own carrying capacity. If this is the case, humans may already be depleting their resources at a rate faster than they can recover. In his paper "Ecological Footprints and Appropriated Carrying Capacity: What Urban Economics Leaves Out," William Rees explains that while many of us believe our species has escaped natural checks and balances with our advancing technology and "assumed mastery" of nature, we are still a biological species just like any other, and can be affected by changes in our ecosphere.
So, what resources might humans already be damaging irrevocably? What global changes are we as a species causing or exacerbating? How might the damage and change we cause impact the wellbeing of our own species, not to mention countless others? In the following entries, I will answer these questions and provide a number of examples as supporting evidence.