The risk of a hothouse Earth trajectory • Hacker News Board

Re: The risk of a hothouse Earth trajectory

#391

Post by myrmidon » Thu, Feb 12, 2026, 1:56 PM UTC

ben_w wrote: post #389

baq wrote: post #369

Earlier quoted context omitted.

AI which helps us design a commerciallizable fusion reactor might buy us a century.

I don't expect fusion to make a difference in either direction. For big reactors: At current aluminium prices, the bill of materials for a global power grid with 1 Ω resistance the long way round is only about 10x the cost ITER (the organisation) expects ITER (the reactor) to be. Plug in your own numbers for target resistance as desired, halve resistance needs double the material. With such a grid, you can put the PV…

Completely agree with the outlook ("fusion power irrelevant for climate change in every realistic scenario").

But where did you take those grid cost numbers from? Iter costs are <100bn AFAIC; and Germany alone (!!) projects more than that (top end) for grid expansion/operation within 2040 (mainly north/south and offshore connectivity).

Re: The risk of a hothouse Earth trajectory

#392

Post by myrmidon » Thu, Feb 12, 2026, 2:11 PM UTC

matthewdgreen wrote: post #299

timschmidt wrote: post #274

Earlier quoted context omitted.

That's lovely, but it's not what I described. Bottles aren't just taxed. They have a refundable deposit. This ensures they don't end up in a landfill.

Exactly. The point of this sort of tax should not be to collect revenue, it should be to ensure that non-biodegradable bags are being disposed of correctly. To the extent that this is not happening, any bag tax is malfunctioning. Such a tax is either insufficient or poorly-designed. (Our city just banned chain stores from giving out plastic bags under 4 mils thick, and stores now give out paper and sell re-usable bag…

Hard disagree on this.

Even if that state is just straight up burning all the tax income from single-use plastic bags, by taxing them you incentivize consumers and distributors towards untaxed, ideally more sustainable alternatives, like single use paper bags or robust multi-use bags.

> Our city just banned chain stores from giving out plastic bags under 4 mils thick, and stores now give out paper and sell re-usable bags

I don't see how this is not a massive win? Paper bags are significantly more sustainable, and multi-use bags are more durable and thrown aways less simply from being more expensive alone.

People are much more wasteful with things they didn't pay for, regardless of "inherent" value.

Re: The risk of a hothouse Earth trajectory

#393

Post by timschmidt » Thu, Feb 12, 2026, 2:33 PM UTC

M95D wrote: post #385

timschmidt wrote: post #269

Earlier quoted context omitted.

I think the externalities of plastic recycling must be internalized economically by requiring all manufacturers of items to pre-pay for the recycling of said items up front, as part of the manufacturing cost. Similar to how bottle returns are managed, which has been very successful. Items which are provably biodegradable or designed to facilitate repair may be exempt.

That ain't working. A plastic bag discarded in a ditch by the side of the road, or blown by the wind from the landfill, is still going to end up into the ocean. No amount of prepay recycling is going to take back that plastic from the ocean.

Read 'em and weap:

https://www.researchgate.net/figure/Comparative-Table-of-Rec...

https://www.researchgate.net/figure/Comparative-Analysis-of-...

Re: The risk of a hothouse Earth trajectory

#394

Post by ben_w » Thu, Feb 12, 2026, 3:01 PM UTC

myrmidon wrote: post #391

ben_w wrote: post #389

Earlier quoted context omitted.

I don't expect fusion to make a difference in either direction. For big reactors: At current aluminium prices, the bill of materials for a global power grid with 1 Ω resistance the long way round is only about 10x the cost ITER (the organisation) expects ITER (the reactor) to be. Plug in your own numbers for target resistance as desired, halve resistance needs double the material. With such a grid, you can put the PV…

Completely agree with the outlook ("fusion power irrelevant for climate change in every realistic scenario"). But where did you take those grid cost numbers from? Iter costs are <100bn AFAIC; and Germany alone (!!) projects more than that (top end) for grid expansion/operation within 2040 (mainly north/south and offshore connectivity).

Putting this note first, because it's probably the main point of confusion/surprise: I did say "bill of materials"; the estimated full cost for European and US grid upgrades that we need anyway for other reasons, with far less material, is order-of a trillion or so for US, half a trillion for EU.

For the material cost, just applied maths. By sheer coincidence, 1Ω of aluminium around the world is very close to 1m^2 cross section: https://www.wolframalpha.com/input?i=40000km+*+resistance+al...

This is almost exactly 1e8 (100 million) tons: https://www.wolframalpha.com/input?i=40000km+*+1m%5E2+*+dens...

This is $223bn at current prices: https://www.wolframalpha.com/input?i=40000km+*+1m%5E2+*+dens...

For scale, this is about what China makes in 2 years; if this is rolled out over 30, which would be optimistic but plausible, it's within the realm of just how much China increased production between 2023 and 2025, being spent every year.

To get to 10x ITER's own estimate for ITER, the wikipedia page says the organisation estimates the reactor will cost about €18-22bn: https://en.wikipedia.org/wiki/ITER

There are a lot of reasons not to do this as a single big 1m^2 "wire", amongst them being that the surface magnetic field is strong enough to be dangerous to approach with ferrous materials.

Re: The risk of a hothouse Earth trajectory

#395

Post by tastyfreeze » Thu, Feb 12, 2026, 3:15 PM UTC

fc417fc802 wrote: post #99

tastyfreeze wrote: post #76

Earlier quoted context omitted.

I make lots of compost for my own use. Composting is at best delaying carbon release. As soon as you stop recycling materials the carbon will be released to the atmosphere. In permaculture circles the goal is to close open loops of waste/resources. If you want to permanently lock carbon in your soil, and improve fertility, make biochar. Throwing charcoal in your compost is the easiest way to make it into biochar. It…

None of the loops are open in the sense that it's all within the earth system as a whole. The issue is extracting carbon from geological deposits. Stuff about farming and methane is temporary and short term. I don't mean to suggest we shouldn't compost or recycle things. Just that such measures are only indirectly related to carbon emissions. We either stop extracting hydrocarbons from deep within the crust or else t…

In that sense even hydrocarbons are closed loop. Earth made the oil deposits so we aren't adding anything that wasn't already here. The carbon we pump into the atmosphere will eventually become oil again.

Re: The risk of a hothouse Earth trajectory

#396

Post by padjo » Thu, Feb 12, 2026, 3:24 PM UTC

TrackerFF wrote: post #378

One massive mistake scientists made, was to market it as "global warming". Every climate-denier I've ever met, has pulled out the "If the earth is getting warmer, why are our winters still so cold? Check mate" card. I live in a colder climate area, and every. single. time. we get some cold weather, these people will come crawling out of the woodwork to point out that "global warming is hoax!" And, unfortunately, due…

Yes scientists made a mistake by calling something what it us. Definitely not the morons who don't understand the difference between weather and climate.

Re: The risk of a hothouse Earth trajectory

#397

Post by belorn » Thu, Feb 12, 2026, 3:28 PM UTC

smartmic wrote: post #18

It is important to keep reminding ourselves that climate change is a real problem for humanity and that each and every one of us contributes to its intensification or mitigation through our decisions. It is a problem that requires solutions, but implementing these solutions involves so much inertia that it can sometimes be painful. And let's contrast that with the AI hype. It's more the opposite, a kind of solution t…

The major road blocks for solutions has been unchanged for the last decades. The same strategy talked about at the beginning of the 21st century still has the same problems, and while more people are aware of climate change, we are only further away from creating and implementing solutions.

Taking Europe as an example, the main strategy is still to use the combination of natural gas, biofuels created from farming corn, and renewables to enable electrification. This strategy lacks both scientific and political consensus among the people who believe in climate change. The result is that as strong one side of the same movement are pushing for it, the other side is also pushing against it. We see the exact same thing with the other major strategies involving tree planting and changes to the culture (diet).

Re: The risk of a hothouse Earth trajectory

#398

Post by myrmidon » Thu, Feb 12, 2026, 3:38 PM UTC

ben_w wrote: post #394

myrmidon wrote: post #391

Earlier quoted context omitted.

Completely agree with the outlook ("fusion power irrelevant for climate change in every realistic scenario"). But where did you take those grid cost numbers from? Iter costs are <100bn AFAIC; and Germany alone (!!) projects more than that (top end) for grid expansion/operation within 2040 (mainly north/south and offshore connectivity).

Putting this note first, because it's probably the main point of confusion/surprise: I did say "bill of materials"; the estimated full cost for European and US grid upgrades that we need anyway for other reasons, with far less material, is order-of a trillion or so for US, half a trillion for EU. For the material cost, just applied maths. By sheer coincidence, 1Ω of aluminium around the world is very close to 1m^2 cr…

The "square meter of aluminium" is an interesting take. Not sure how much power you'd get over that thing; extrapolating from existing HVDC systems (Inga-Shaba is 1GW over 2x520mm²), I'd expect around 1TW, so twice the US demand?

But because Nimbys have no appreciation for beautiful pylons, projects in that direction are doomed for now anyway and everything needs to be buried underground at extra cost :(

Re: The risk of a hothouse Earth trajectory

#399

Post by matthewdgreen » Thu, Feb 12, 2026, 4:03 PM UTC

myrmidon wrote: post #392

matthewdgreen wrote: post #299

Earlier quoted context omitted.

Exactly. The point of this sort of tax should not be to collect revenue, it should be to ensure that non-biodegradable bags are being disposed of correctly. To the extent that this is not happening, any bag tax is malfunctioning. Such a tax is either insufficient or poorly-designed. (Our city just banned chain stores from giving out plastic bags under 4 mils thick, and stores now give out paper and sell re-usable bag…

Hard disagree on this. Even if that state is just straight up burning all the tax income from single-use plastic bags, by taxing them you incentivize consumers and distributors towards untaxed, ideally more sustainable alternatives, like single use paper bags or robust multi-use bags. > Our city just banned chain stores from giving out plastic bags under 4 mils thick, and stores now give out paper and sell re-usable…

We’re not disagreeing. I’m saying that the tax should be set high enough that it creates the desired behavior, which is to disincentivize the widespread use of polluting plastic bags AND/OR ensure that they’re recycled and don’t wind up in the environment. If you’re charging $.05 per bag and people are just eating the tax and the bags are winding up in wetlands in similar amounts, that means your tax regime isn’t effective. You should either increase the tax or improve the system. My city’s absolute ban is equivalent to setting the tax to infinity, which is one solution that seems to work well.

Re: The risk of a hothouse Earth trajectory

#400

Post by ben_w » Thu, Feb 12, 2026, 4:07 PM UTC

myrmidon wrote: post #398

ben_w wrote: post #394

Earlier quoted context omitted.

Putting this note first, because it's probably the main point of confusion/surprise: I did say "bill of materials"; the estimated full cost for European and US grid upgrades that we need anyway for other reasons, with far less material, is order-of a trillion or so for US, half a trillion for EU. For the material cost, just applied maths. By sheer coincidence, 1Ω of aluminium around the world is very close to 1m^2 cr…

The "square meter of aluminium" is an interesting take. Not sure how much power you'd get over that thing; extrapolating from existing HVDC systems (Inga-Shaba is 1GW over 2x520mm²), I'd expect around 1TW, so twice the US demand? But because Nimbys have no appreciation for beautiful pylons, projects in that direction are doomed for now anyway and everything needs to be buried underground at extra cost :(

Losses are I^2 R, which has the annoying consequence that % loss depends on how much juice you put through it, it isn't a constant percentage.

Pylons… eh. Doing this realistically rather than my napkin-maths, it would be a mix of many different solutions in different parts of the world, from competing environmental issues. Some would be pylons, some underground cables. Is the Sahara dry enough to run it on the ground, or in a concrete trench? I have no idea.

As a side note, every so often I keep being surprised on here by Americans who can't rely on the grid in winter because snow disables it, and some Californian forest fires are attributed to unmaintained pylons failing, dropping live wires onto the forest where they spark and light up the dry wood. These could both be resolved by burying more cables. Likewise within urban areas: here in Europe it's rather rare to see overhead lines in urban or suburban areas, unless they're over a tram/railway line.

IMO the real killer of any project like this, is geopolitics, not local politics. EU doesn't trust China, the US, or Russia; the current US administration doesn't trust or doesn't like basically everyone; Russia kinda gets along with China but few else; China would like to sell stuff to everyone but also have border disputes and other friction with many of their neighbours.