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353 points dmazin | 2 comments | | HN request time: 0.016s | source
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Biologist123 ◴[] No.44510157[source]
This was a great positive start to the day. Thanks whoever posted that.

One point curious in its omission is whether the growth of renewables outpaces the depletion of our carbon budget. Presumably that’s the critical metric in all of this.

[Edit: I ran this question through ChatGPT and the initial (unvalidated) response wasn’t so exciting. This obviously put a dampener on my mood. And I wondered why people like McKibben only talk about the upside. It can sometimes feel a bit like Kayfabe, playing with the the reader’s emotions. And like my old man says: if someone tells you about pros and cons, they’re an advisor. If someone tells you only about pros, they’re a salesman.]

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alex_duf ◴[] No.44510297[source]
>whether the growth of renewables outpaces the depletion of our carbon budget

I'm not sure I understand. There's no carbon budget, any carbon that we emit is carbon we'll have to re-capture somehow and the longer it stays in the atmosphere the longer it will have a heating effect.

I think renewable have accelerated to the point of matching the electricity growth worldwide: https://ourworldindata.org/grapher/electricity-production-by...

We've also passed the peak of CO2 per capita, but since the population is still growing we are still increasing carbon emitions worldwide. It's going to be a while before we stop emitting anything, and then longer before we start re-absorbing it...

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myrmidon ◴[] No.44510573[source]
I highly doubt that we will have global negative emissions (CO2 capturing) within the next decades-- maybe by the end of the century.

Even very rich nations have a handful of prototype plants for CO2 capture right now at best, and the budget for things like this is the first thing that gets slashed by Doge et al.

If we were on track for lots of CO2 capture by 2050, we would see the beginnings already (massive investments, quickly scaling numbers of capture sites, rapid tech iteration).

Fully agree with the rest of your point though. I consider CO2 emissions as basically "raising the difficulty level" for current and future humans (in a very unethical way, disproportionately affecting poor/arid/coastal nations).

I'm also highly confident that human extinction from climate change is completely off the table (and I think a lot of people delude themselves into believing that scenario for no reason).

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fpoling ◴[] No.44517406[source]
If electricity is sufficiently cheap it can be cheaper to capture carbon from the atmosphere for chemical industry than to use oil or coal there.
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VBprogrammer ◴[] No.44517921[source]
Do you have any source for this extraordinary claim? It's practically a claim of perpetual motion.

Carbon dioxide a tiny fraction of the atmosphere, even in concentrations which are immediately harmful to human life.

At the moment it's 400 parts per million. So in order to extract 1kg of Carbon Dioxide from the atmosphere you have to pump 2500kg of air through the system. This alone makes it unlikely we can do this profitability.

You then need to extract the carbon dioxide using some technique which will probably involve cooling or pressuring that volume of air. Before finally transforming carbon dioxide, a very stable chemical compound, into a reagent which is actually useful (probably carbon monoxide).

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ben_w ◴[] No.44518292[source]
They said "If electricity is sufficiently cheap", which is less a claim and more a tautology.

Will it be that cheap? I think so, given that trees and grass etc. exist and get their carbon from the air.

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HPsquared ◴[] No.44518516[source]
Even with free electricity, the capital (and maintenance, consumables etc) costs of the process could easily be too high.
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ben_w ◴[] No.44518616[source]
I suppose that in principle that is indeed possible; in practice, trees exist and self-seed, so the limit is our own ignorance.
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overfeed ◴[] No.44518946[source]
We are also limited the incentives to that make us cut tree for money, and not develop technologies if they are not profitable within a short time-window. We have the technology to plant more trees right now, but we aren't.
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ben_w ◴[] No.44519049[source]
People plant loads of trees for lumber, but you're right, it's an economics question in the end.

This actually means I'm also worried about something currently impossible: that when we do develop the tech sufficiently to be useful, if it's cheap enough to be profitable, nothing would seem to stop extraction. So CO2 goes down to, what, 300ppm? Pre-industrial? Ice age? Same coin, other side. We want to flip a coin and have it land on the edge.

A single world government could organise to fix this either way, but as all leadership roles come with the risk of the leader being fundamentally bad, this isn't something I'd advocate for either.

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1. myrmidon ◴[] No.44519810[source]
> that when we do develop the tech sufficiently to be useful, if it's cheap enough to be profitable, nothing would seem to stop extraction. So CO2 goes down to, what, 300ppm?

This is an extremely improbable scenario, for several reasons:

1) If you actually use the extracted CO2, then it gets re-emitted on use, and the atmospheric concentration is virtually unaffected.

2) Concentration difference alone makes it very unlikely that we'll ever extract CO2 as cheaply as O2 from ambient air (or carbon from a mine), and CO2 is not really an appealing ressource compared to its components, either (so demand would presumable be pretty low for centuries, even if the price comes down a lot).

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2. ben_w ◴[] No.44520922[source]
> 1) If you actually use the extracted CO2, then it gets re-emitted on use, and the atmospheric concentration is virtually unaffected.

Depends what you use it for, e.g. synthetic diamond windows won't re-emit unless they catch fire.

> 2) Concentration difference alone makes it very unlikely that we'll ever extract CO2 as cheaply as O2 from ambient air (or carbon from a mine), and CO2 is not really an appealing ressource compared to its components, either (so demand would presumable be pretty low for centuries, even if the price comes down a lot).

Underestimating how big an industry would get is the mistake Svante Arrhenius initially made, thinking it would take millennia to emit enough CO2 to cause noticeable global warming.

And remember, with this concern I'm inherently presuming tech (mainly energy) that makes it sufficiently cheap that business and/or governments are willing and able to remove in the order of at least one teratonne of the stuff (but hopefully not two or more teratonnes) — because less than that, it's not solving global warming.