[aidenn0]

The sun will burn out at a fixed time regardless of how much or little energy we harvest from it.

Assuming energy demand growth of 5% per year, we have enough land-based actinates for less than a century of energy usage in fast breeder reactors (if you prefer 2% annual demand growth, it's enough for about 2 centuries).

Seawater uranium buys you more time, depending on how you extract it, but hundreds of years and the sun burning out are two very different timelines.

[DennisP]

Seawater uranium goes well beyond "hundreds of years." The oceans hold four billion tons of uranium, which in fast breeders would last many millions of years. On top of that, it's in equilibrium; as more is removed, more will dissolve from rocks. It really is at a timescale similar to the sun burning out.

[adrianN]

A hundred years would give us plenty of time to develop alternative energy sources (fusion?). The fossil fuel age also last(s/ed) for about that long.

[mlonkibjuyhv]

And how long will it take us to boil of the oceans (as in fusion) assuming 5% year over year increase?

How has energy consumption behaved before around the time of paradigm shifts and plentiful "free" energy?

[adrianN]

Currently energy use is about 0.01% of energy that the sun sends us (if my googling is right). If energy use increases 5% per year, it doubles every 15 years or so, so after a hundred years we still use so little energy that it doesn't matter compared to solar heating. I think the oceans are safe.

[aidenn0]

And I'm all in favor of fission as a bridge-fuel to something more sustainable, but many people act as though it will last indefinitely, when it seems clear to me that it won't.