Something I'd do if the theme is Pollution as I imagine
2020: Scientists announced the failure of all climate change prevention efforts. It is now too late to save humanity. No matter what we do now, the damage is irreversible. Earth's climate will slowly plummet into chaos, until it reach the point where no life can survive.
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2070: Despite the death penalty, scientists herald of the end was a relief. Humanity's final restrain was broken.
No longer do we need to care about, what, "recycle, reduce, reuse".
No longer do we have to prevent car's exhaust releasing toxic into the air.
The Earth would be dead soon anyway, why would we care?
Complete freedom pushed the boundary of nature's last defense, and it collapsed. Hundreds of years sooner than even the smartest of us would've expected.
We have imaged a thousand ways humanity would end, we were only trying to dismiss the truth we all knew: humanity will die by its own hand.
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2080: 99% of life was eliminated. Humanity's collaborate effort built one single spaceship, big enough to bring (not you) some last thousands of humanity's populace into space.
It would be our last bet to search for another sustainable planet to destroy, or face extinction in darkness.