Once the ocean teamed with life, Svetz thought. Now the continental shelf is as dead as the moon: nothing but bubble cities. Once this whole continen… - Larry Niven

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Once the ocean teamed with life, Svetz thought. Now the continental shelf is as dead as the moon: nothing but bubble cities. Once this whole continent was all forest and living desert and fresh water. We cut down the trees and shot the animals and poisoned to the rivers and irrigated the deserts so that even the desert life died; and now there’s nothing left but the food yeast and us.
We’ve forgotten so much about the past that we can’t separate legend from fact. We’ve wiped out most of the forms of life on earth in the last fifteen hundred years, and changed the composition of the air to the extent that we’d be afraid to change it back.
I fear the unknown beasts of the past. I cannot breathe the air. I do not know the edible plants. I could not kill the animals for food. I do not know which would kill me.
The earth’s past is as alien to me as another planet.