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Comment by immibis | Hacker News Reader

The answer to the headline question ultimately doesn't matter. Either the answer is "yes", or we figure out how to make the answer "yes", or we all die.

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Even if the answer were "we'll still need 50% from fossil fuels" it still cuts CO2 in half. If the answer were "we still need 10% for unusual cases", it still means that fossil fuels stop being the problem, at least for that one country.

This isn't insurmountable. It doesn't have to be perfect. Even a real but incomplete effort makes a genuine difference.

The problem, unfortunately, remains the US, who has a large and powerful minority who is convinced it's all a hoax. The solution doesn't have to be complete but it does have to be something. With many millions of people actively making it worse, even 100% in the UK doesn't come anywhere near close.

There are other options... nuclear power is more expensive but if cost wasn't the issue (e.g. running out of land was) is an option.

If cost is the issue there are still risky moonshots like "throw tons of money at fusion" (attacking the cost of nuclear) and "throw tons of money at high temperature superconductor research" (attacking the amount of energy we need), and "geoengineering" (risking screwing it up worse). Not guaranteed to work, but you know, better than rolling over and dying. Also has the side benefit that a lot of the moonshots are worth trying anyways.

Hard reliance on nuclear power is one of the "we all die" options. Didn't we learn our lesson about building a whole civilization on consuming a limited resource dug out of the ground?

Sure, at least with regards to fission, but it plausibly extends the timeline out so that the moonshots are no longer quite so difficult.

Is it not the case that Uranium and Thorium are not just more abundant than existing fuels, but also about a million times more energy dense? I find it hard to believe running out is a chance we'll face soon.

Million times more energy dense, yes.

More abundant? Depends. There's a lot in the sea, which isn't currently recoverable. There's a lot we could do (but actually don't) with breeder reactors to make more fuel.

This means the answer to the question "how long could we last on just nuclear fuel alone?" varies from 5.7 years[0][1] to 4.3 billion years[1].

[0] https://globalwarming-sowhat.com/renewables

[1] https://whatisnuclear.com/nuclear-sustainability.html

Don't forget about induced demand.

Not like the sun is renewable either. Everything is finite if you use enough of it. The problem is that the old "limited consumable resource dug out of the ground" changes our natural habitat as a side effect of creating energy, assuming we continue to use it as we do today.

(By that last bit, I mean: powering EVs from coal plants with carbon capture at exhausts might be different, idk, but probably not cheaper than just not polluting in the first place.)

"Renewable" isn't the best word for wind and solar, better would be "use-it-or-lose-it", either you harvest it or it dissipates into useless low grade heat. Using more of it doesn't deplete the supply of it.

Solar energy (and thus wind assuming otherwise constant environmental conditions) is only going to get more plentiful for next 5 billion years...

The Earth becomes uninhabitable in about a billion years due to solar brightening, but your point certainly applies to far future civilizations in solar orbit.

I think nuclear is a red herring in most of the world (too expensive and SMRs are too far away to matter), but the idea that we’ll run out of fuel for them is a nonsense.

We haven’t looked very hard at all for uranium. Nor have we tried very hard to use the uranium we already have efficiently. Nor have we tried very hard to use thorium as an alternative. Some combination of these would stretch out the supply of uranium we have essentially indefinitely.

The problem with nuclear is that their is so much FUD around it that it becomes not just expensive but very difficult to build.

Mainly due to new regulations meaning projects have to re-engineer themselves before they are even complete. Leading to delays and cost overruns.

The problem with nuclear is that it’s slow and expensive to build and there is FUD that it is not.

But it's slow and expensive to build because of ReGuLaTioNS. If we just remove all the rEGUlaTiONS it could be fast and cheap. What's a Chernobyl?

We are all going to die! But nuclear power is to expensive, so let's sit in the roads and block traffic and subsidize Teslas for rich people.

Either we are under an existential threat, in which case nuclear power is an amazingly cheap way to save 8+ billion people, or there is some other agenda at play.

The primary constraint limiting the speed at which we move away from fossil fuels is cost. Investing in more expensive alternatives like nuclear increases the risk of the threat becoming existential, and the damage it does if it doesn't become existential, compared to investing in cheaper alternatives like solar and wind.

It is not a case of "we should do everything" because we can't afford to do everything. If we could afford to do everything we could easily do a small subset of everything and solve the problem.

Hard disagree, the primary limitation is availability of energy. There is no path to 100% solar + wind + storage without mass deindustrialization.

Nuclear would stop being expensive if it was committed to. Building 1 bespoke plant avery few decades is not a good approach.

The article is literally about showing that there is in fact enough solar and wind energy available to fulfill expected (not artificially constrained or "deindustrialized") demand.

The article doesn't have a plan for storage, and relies on a plurality of energy from floating offshore wind, which has never been relied on at any scale. There are 4 windfarms in the world generating just 193MW. You are going to bet humanity on that?

https://en.wikipedia.org/wiki/Floating_wind_turbine

Superconductors are probably a red herring. It's technically possible to make a 1 Ω global power grid for only a few hundred billion in raw materials, a superconductor isn't going to help much with anything except the material cost, including but not limited to the cost of actually installing that cabling, the geopolitics of where to put it, conflicts involving it.

A superconducting cable probably also makes attempts to damage the thing easier — to get 40,000 km of aluminium down to 1 Ω, it needs to have a cross section of 1 m^2, which is kinda hard to damage, though also you don't really want a single cable because that, with current global electrical demand and reasonable (i.e. currently in use) choices for the voltage, would be in the order of 1.5 mega-amperes and match Earth's geomagnetic field at a distance of about 11 km.

My understanding is that that if they have nice properties they'll enable substantially more efficient motors/generators thanks to strong magnetic fields. I can't say I'm that confident in that knowledge though.

Very true, but extremely unpopular to say. The downvotes are as expected as they are cause for despair.

No, it is not very true - even if you look at the worst case "do nothing" scenarios in the IPCC report, they are very bad, but very, very far from "we all die".

Using such hyperbole is counterproductive and makes people discount the actual risks. If we're talking about, for example, a billion people being displaced due to climate change disrupting food production or flooding areas which are currently densely populated, and many millions dying in that process, that is bad enough by itself to justify taking action, and there is no need to resort to ridiculous unjustified exaggerations implying that we're all going to die.

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