Bex shrugged. “You think anybody’s going to listen to a bunch of scientists? No offense. But nobody has so far.” - Stephen Baxter

I know the military. The sooner they can kick a problem upstairs the happier they will be.

On the longest of timescales, over millions of years, the workings of chance defied human intuition. Humans were equipped with a subjective consciousness of risk and improbability suitable for creatures with a lifespan of less than a century or so. Event that came much less frequently than that—such as asteroid impacts—were place, in human minds, in the category not of rare, but of never. But the impacts happened even so, and to a creature with a lifespan of, say, ten million years, would not have seemed so improbable at all.
Given enough time even such unlikely events as ocean crossings from Africa to South America would inevitably occur, over and again, and would shape the destiny of life.

We'd carve a place out of the wilderness—"
"But there is no wilderness, Mane said. "Even without war, even if you found a space not already cultivated, you would be forced to occupy a region, delineated in space, time, and energy flow, already exploited by another portion of the ecology."
It took some time for Emma to figure that out. "Yes," she said. "There is bound to be some environmental impact. But—"
"Other species would find reduced living space. Diversity would fall. And so it would go on. Soon the world would be covered from pole to pole by humans, fighting over the diminishing resources.