[wnkrshm]

Use of fusion as an energy source removes a lot of threats our civilizations are facing but it also comes with some caveats rooted in human behavior.

Human energy consumption has always gone up when the supply got more efficient, from coal to oil to fission. While here, the power generation itself won't have such a drastic impact (unless humanity overdoes it, though, we seem to always do that) but maybe more power means more consumption and demand for other goods that get used up while using things that consume power. And with enough power you can think about making things that consume more or even build more things that consume more power. Lots of processes that were considered too wasteful suddenly become feasible.

Just like with digital documents, when people predicted that paper wouldn't be needed in the modern economy and the demand for paper would decline, it has actually skyrocketed - because a paper document isn't important anymore. You throw it away and print a new one when it has a crease.

Historically, we've been very bad at predicting such side effects. So I won't buy in a 'fusion solves everything' mindset. Fusion power can be a boon for humanity on a global scale but it could also make some problems worse.

[blake1]

Your first point is not supported by the data. The US Energy Information Agency keeps track of this[1], and the per capita energy use peaked around 2000.

And we are much better at running an energy-efficient economy: energy use/real $ GDP has halved in the last century.

The trend may not continue. People might start to do much more air travel (which would require massive runway building). Global warming might increase the need for AC. But my intuition is that there is some limit to the amount of energy one person can consume.

[1] https://www.eia.gov/totalenergy/data/annual/pdf/sec1_13.pdf

[wnkrshm]

It is good to see that the per capita trend has reversed, maybe if the global population would not increase steadily we may actually not increase energy consumption steadily.

Edit: I found an interesting nature article[0] that looks at different correlations of population and consumption to identify if there is an anthropocene epoch. There are pretty clear-cut trends but who knows, maybe Earth's population will actually reach a kind of steady state.

[0] https://www.nature.com/articles/s43247-020-00029-y.pdf

[eru]

Global population is expected to plateau soonish.

[pfdietz]

> the per capita energy use peaked around 2000.

1980, actually.

[neutronicus]

Yeah, capital-E Energy is mostly for capital-W Work and thermodynamics. Once you refrigerate your living space and don't walk anywhere and everything you want is brought to your door what else are you going to do?

[Someone]

I’m not sure whether you’re serious, but:

Bigger cars? Supersonic city trips to the other side of the world? Weekends in Antarctica? A week in one of SpaceX’s hotels? High-resolution screens on every wall of your home, plus the AC needed to keep your house cool? Reshape a mountain to improve your view? Transform lead into gold? Mine bitcoin?

If energy were free, I foresee accelerated destruction of nature. At best, the world would become a gigantic park.

[TeMPOraL]

> If energy were free, I foresee accelerated destruction of nature.

Perhaps the reverse, eventually. If costs of space travel dropped enough, we could push polluting industry out into orbit and further, and start repairing Earth. It's impossible now, but if there were little difference on the margin for the businesses between working on the surface and upwell, then businesses would hesitantly say "ah, what the hell, we'll do our stuff up there, you go ahead with your silly environmental programs if that floats your boat". Social progress happens when the market stops caring about it, and doesn't resist it anymore.

[Someone]

In a world where energy is free, I don’t see polluting industry as a problem. What pollution is there that can’t be prevented if you can spend as much energy as you want in recycling stuff? If you try hard enough, about everything can be taken apart into its chemical elements.

The problem would be the demand for resources. Yes, there’s the asteroid belt, but it is far away. Would we get there before we would have dug up the earth? Maybe.

[eru]

The market is very much an engine for social progress. See eg https://www.econlib.org/jim-crow-more-racist-than-the-railro...

> Jim Crow laws established apartheid, that is, legally enforced segregation. Railroad companies provide an interesting historical example of business incentives. These private companies were often willing, against the political correctness of the times, to sell tickets to both blacks and whites and to not segregate their customers in different cars or compartments. Poor whites and poor blacks purchased second-class tickets, while rich whites and occasionally rich blacks rode in first-class cars. The situation was far from perfect, and violence sometimes erupted, but it was better than the segregationist state-enforced laws that followed.

> A historian of populism observes:

>> More than any other institution, train cars and railroad stations exemplified the modern dilemma of the racial order. They were places where mobile, unsupervised, anonymous travelers met in close quarters. Making the situation more explosive, those whites, including most farmers, who could not afford a first-class ticket met blacks on equal terms. In contrast to the workplace where blacks served white employers, or in the supply store where blacks owed debts to white merchants, in a railroad car blacks and whites paid the same fare for the same right to a seat. Accordingly, whites made the railroads a primary target of the new segregation laws. Reform-minded southerners considered these laws a mark of modern and progressive race relations. (Charles Postel, The Populist Vision, Oxford University Press, 2007, p. 178)

[wnkrshm]

But, didn't the market trade the same people as property? How is the market an engine for social progress there? Isn't that a bit cherry picked?

[wnkrshm]

This is an interesting read as to the possible caveats of fusion power [0]. It's interesting, whether one reaches the same conclusion as the plasma physicist who wrote the article or not.

[0] https://thebulletin.org/2017/04/fusion-reactors-not-what-the...

[jeffparsons]

> Lots of processes that were considered too wasteful suddenly become feasible.

I worry about this, too, but couldn't there be some positive effects here, too? E.g. what if it made desalination a lot cheaper?

[eru]

Why do you even worry?

[jeffparsons]

Because the secondary effects of something becoming more efficient can be harmful, in counterintuitive ways.

E.g. if some process in steel manufacturing is improved to require less power, you might think, yay, there's less power needed so less CO2 released. Good for mitigating global warming. But what might actually happen instead is that it becomes feasible to make more things out of steel because it is cheaper than before, so more energy is used on steel production in total, even though per unit it is more efficient.

The same thing could happen with fusion energy, but in ways we can barely imagine now. What high-power workloads are not even considered now that would be cheap enough with fusion power?

[eru]

Yes, I understand that. But if you run your high-power workload with fusion, you won't be releasing any CO2.

Your explanation reminds of the common example that increased car safety leads to more speeding. And somehow arguing that increased safety is futile.

But people like having more steel and like being able to go faster at the same level of safety.

[eru]

> While here, the power generation itself won't have such a drastic impact (unless humanity overdoes it, though, we seem to always do that) but maybe more power means more consumption and demand for other goods that get used up while using things that consume power.

Eh, we are sitting on a giant ball of matter. Not much worry about using stuff up.

(We might use up any one particular thing. But there are substitutes.)