We are the most selfish species on our planet. For every opportunity to choose the betterment of the world, we chose what would make the most money instead. We took and took. Our greed far outweighed any attempts at giving back. Humanity had become a parasitic infestation, that ravaged Earth. No consideration for our future. For the children to come or the animals that became captives and that were eventually murdered by our desire to expand and grow.
To nurture a planet means creating a cycle of give-and-take. The apex species is responsible for reasonable development and ensuring that other species have the ability can live without outside interference. This respect creates prosperity and abundance. If nurtured, that relationship creates a sustainable equilibrium that grows better with time. The catch here is that it takes work, planning, and the ability to compromise in ways that are not always in humanity's favor.
We ruined that though. The only legacy for the following generations was avarice. The unrelenting desire for more even to others' detriment and eventual destruction. Eons later, humanity hit a wall. The quality of people soon became the commodity to have. Perfection outwards and inwards became desirable in the extreme. The Flawed were put down or used for the better of all. The best of what made us human, eroded or torn away.
And, our planet became a reflection of that. Beautiful blue skies turned yellow, the oceans withered, and the soil deteriorated into dust. The plants and animals desperately tried to survive, only to be pushed further and further into smaller and smaller niches to make way for "civilization." Eventually, we upturned every rock, hollowed out our planet, and murdered innumerable creatures in our pursuit for more. There was nothing left to be taken.
It was our selfishness that ultimately doomed us all. It is only now, looking back, that I wonder if we could even still be considered human anymore, or are we monsters clad in human skin? After all, everything that made us human was gone.