. . .

Eventually we ran out of local flora and fauna. Eventually we ran out of new regions of flora and fauna. Eventually we ran out of arable land. Eventually (soon) we will run out of resources. Eventually (later) we will run out of a capacity to transform energy.

We are never free of the universe’s limits. We are never free of the limits of energy transformation in this universe.

We have only one medium term problem in mankind. The malthusian population of the underclass.

We have only one medium-long term in mankind: The malthusian population of the middle and upper classes.

We have only one long term problem in mankind: eventually we will hit the malthusian limit of energy transformation.