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> One of the points that TeMPOraL made above is "and again, trees were a renewable resource too, before the industrial revolution.". The point being that resources that are seemingly infinite when first used can end up being not so unlimited.

It's legitimate to ask what our energy usage might grow to. It's not legitimate to dismiss potential energy sources because we cannot predict the future with perfect accuracy. We will never predict the future perfectly, or even close, and if we have a choice between killing the planet in 1000 years or killing it in 100, we'd still be better off taking the first option.

The "1000 years" comment also assumes we'll double our energy usage every 25 years. If we accept that as true then our only viable strategy is to get off this planet because it assumes that in 1000 years we will literally have extracted all energy from the core. We're doomed if this is our future.

Also, please stop mentioning the trees. This has been addressed multiple times now. The industrial revolution didn't result in trees being cut down. Quite the opposite. The large-scale adoption of fossil fuels resulted in forests rebounding worldwide as we stopped relying on timber as a fuel.

> *The 1,000 year quote is based on historical data, and 800,000 years is based on flat/zero growth. So there appears to be room for discussion, not all of which is 'fear monger'ing.

It's rather generous to say it was based on historical data. It was based on taking the log2() of our current energy usage and eyeballing an energy usage chart to produce a guess at a 25-year doubling rate. Our energy growth is no more a constant than our usage, though, so extrapolating this way is as unrealistic as assuming we'll stay at present-day usage forever.

There is certainly room for discussion. Again, though, I'll point out that a discussion should be about options and not just the worst case for geothermal exhaustion. If we found that we could replace all of our fossil fuel use with geothermal but we'd only get to extract energy for 1000 years safely, that would be a great deal, because the obvious alternative is that we literally burn every bit of fossil fuel we can extract from the Earth.




On the trees numbers, the US now actually has more forest or trees than it did at the start of the twentieth century.

The argument sometimes gets confused, since conservationists are concerned about the loss of old-growth forests, and animal habitats vs. the quantity and area of forests.




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