Earth may have only one chance!

Here is a sobering thought from www.dieoff.org

Sir Fred Hoyle in 1964 put it bluntly.

It has often been said that, if the human species fails to make a go of it here on the Earth, some other species will take over the running. In the sense of developing intelligence this is not correct. We have or soon will have, exhausted the necessary physical prerequisites so far as this planet is concerned. With coal gone, oil gone, high-grade metallic ores gone, no species however competent can make the long climb from primitive conditions to high-level technology. This is a one-shot affair. If we fail, this planetary system fails so far as intelligence is concerned. The same will be true of other planetary systems. On each of them there will be one chance, and one chance only. (Hoyle, 1964)

I think this is the credible viewpoint, but I don't think absolute pessimism is in order. Given a long enough time scale (hundreds of millions of years) after a demise of human life, the Earth might replentish fossil fuel supplies. We may have created essentially new stores of high grade materials, already concentrated along with some archeology that might well catapult a successor civilization.

But the goal is to spread our memes and our genes, and that means we must get off world, start replicating, remove the single point of failure, find new energy sources, and protect and spread our biosphere.