[f0e4c2f7]

Ctrl+f fusion.

> "Fusion is therefore a complicated and not particularly cheap way to generate electricity. Meanwhile, we are not running terribly short on renewable ways to produce electricity: solar; wind; hydroelectric; geother- mal; tidal."

Fusion is the key to long term success for humanity. It paves the way to essentially unlimited cheap burstable power.

In the even longer term plasma fusion offers a way to create the heavier elements that we are running out of here on earth. Forged in a manmade nuclear furnace.

These pesky climate problems can be solved. We just have to mine ideas out of nature now instead of minerals.

If you're trying to think about humanity's long term prospects fusion should be the crown jewel, not an after thought you handwave away. I believe today we spend somewhere on the order of 1% of what we should be spending on fusion research.

[philipkglass]

In the even longer term plasma fusion offers a way to create the heavier elements that we are running out of here on earth. Forged in a manmade nuclear furnace.

The only heavy element that we actually "use up" to any significant degree is uranium, which is consumed for energy, but if we had cheap fusion energy uranium consumption would plummet. Even if we could make artificial uranium it would be a net-energy-losing process to make artificial uranium with fusion power instead of using fusion power directly.

[adamsmith143]

>The only heavy element that we actually "use up" to any significant degree is uranium

Helium would like a word with you.

[philipkglass]

The only heavy element. Helium is the second lightest of all elements. I didn't think that the post I responded to meant helium because it said heavy elements (plural) and it referred to the far future, after mastering fusion as an energy source.

[ttiurani]

> These pesky climate problems can be solved.

The thing is, it's not just climate that's the problem. The "pesky" problem is that we've crossed or are soon crossing most planetary boundaries[1] at the same time.

Fusion doesn't stop and reverse biodiversity loss, chemical pollutants, land-system change, biochemical flows, ocean plastic buildup and ocean acidification.

To stop the ecological collapse, the necessary condition is that the global North drastically reduces material flows and energy consumption. With less energy use, fusion also becomes less critical.

[1] https://en.m.wikipedia.org/wiki/Planetary_boundaries

[bsedlm]

disagree essentially because I believe we'd get into a situation where the problem becomes heat dissipation.

the problem is the human psique, not technological capabilities.

[stouset]

If we find a cheap new way to generate orders of magnitude more energy, we'll use orders of magnitude more energy.

And you're right. We're only a bit over two hundred years away at 2.3% annualized growth in energy use from noticeably raising Earth's surface temperatures just from a thermodynamic perspective. And that's completely ignoring the effects of greenhouse gases.

[saiya-jin]

You and parent project this in some theoretical universe where these effects would be ignored. Why on earth do you think so? With semi-unlimited energy at our palms, we can do serious geoengineering. We can put these furnaces into high orbits, or moon and beam down just raw output energy with lasers. Or whatever, even the sky isn't a proverbial limit.

[stouset]

Unlimited energy doesn't free us from the consequences of thermodynamics. Geoengineering doesn't help us. Where we generate the energy doesn't change anything if it's used here on this planet.

There are literal physical limits here that can't just be handwaved away by space magic. Higher energy use in a finite spherical volume fundamentally results in increased temperatures when your only way of getting rid of that heat is radiation (and not convection or conduction). And we can't just beam that heat away with space magic either thanks to entropy.

Thermodynamics gives us no tools to deal with this problem outside of increasing the spherical volume of Earth (and therefore its surface area).

[root_axis]

Fusion isn't magic, more energy doesn't suddenly obviate the burden of practical engineering constraints, we won't be "geoengineering" our way out of climate change for the foreseeable future.

[willis936]

A world where energy consumption increases by a factor of 10,000 is a far fetched fantasy. If we're starting with such premises, should they not be followed?

[stouset]

A world where energy consumption increases by a factor of 10,000 would already be a world where the surface is lava thanks to basic thermodynamics. Earth can only radiate so much heat into space, and its ability to do so will not outpace energy production for much longer.

A world where energy consumption increases fiftyfold is a century and a half away and would be brushing up against the point where we are noticeably increasing the equilibrium temperature of Earth sans any greenhouse gases. Hitting the thermodynamic limits of Earth's ability to radiate heat into space isn't a far-fetched fantasy, it's terrifyingly close.

[willis936]

That is an overwhelmingly good problem to have. We would have truly mastered the planet for that to be a concern. As it stands, keeping society above water for the next hundred years seems like the grand challenge to accomplish. Do not assume victory is given. Nothing is a given. We are always on the edge.

[wilkommen]

I agree. I don't think humanity is happier given more resources, above a certain relatively small amount. But humanity's desires are limitless. If we are able to invent a free energy machine we'll just use it so much that it causes new problems.

[deltaonefour]

It's still sort of a gamble.