Time is a strange concept, people can never ever agree on it's nature.
Some say it's linear, one way, unable to be changed, past and present. Others believe the past is unchangeable, but the future is what we shape it. It's a problem which has plagued many people since the dawn of conscious thought. Something intangible to most fought over live it was all the riches in the world cumulated into one mound. Man has fought over the true understanding of time. But the truth is something many never expected. Time is something malleable.
The world is sickened, it's waters poisoned, it's land decayed, it's life all extinguished. The world long ago destroyed by the will of one man with disdain over the actions of mankind and their new creations. He created his own race to inherit the earth and not repeat the mistakes of their forefathers.
But with history wiped it was inevitable.
They destroyed one another, the survivors slowly starving as the earth died. One man destroyed ninety-nine percent of the world, he never thought to ask how the one percent would fair.
They destroyed themselves, uncaring of the consequences. Ignorant, violent children who murdered one another until the survivors starve. The earth uninhabitable.
Death decided that wouldn't happen.