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The impact of direct air carbon capture on climate change

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Re: The impact of direct air carbon capture on climate change

#71

Post by LessDmesg »

pinkfoot wrote: post #69
LessDmesg wrote: post #67

Tell me again, why are we fighting the harmless gas carbon dioxide instead of air pollution (sulphurous, nitrous oxides, lead etc)?

Again: https://www.ipcc.ch/ Go read. Come back when you find errors in the reports.

But that's a biased source of information. The IPCC depends on donations from Western governments for its existence, and Western governments are fatally dependent on inventing reasons for new taxation due to their exorbitant amounts of sovereign debt. Is there any unbiased source on this extraordinary claim that the tiny CO2 emissions humanity makes actually control climate?

Re: The impact of direct air carbon capture on climate change

#72

Post by xbmcuser »

Robotbeat wrote: post #23
jarvist wrote: post #6

I'm not sure if this article hammers home the key point: extracting carbon from the air always takes more energy that was gained by burning the fossil fuel to make that carbon. This is inevitable due to the entropy cost of de-mixing CO2 from the air, and from the limited efficiencies of thermal power generation (~33-40% for a coal power plant, perhaps 20% in an internal combustion engine), and limited efficiency of t…

Not objectively true, as plants and even rocks grab CO2 out of the air pretty efficiently. From a thermodynamics standpoint, you can burn fossil fuels at 50-70% efficient (50% is not uncommon), and the actual theoretical lower bound of CO2 direct air capture is ~20 kJ/mol,[0] or about 1.7MJ/kg of elemental carbon, compared to 33MJ/kg for burning elemental carbon (same as high grade coal). (Burning methane is even bet…

With solar prices hitting negative rates for some periods in a day capturing carbon and converting into burnable fuel will probably start making sense in the next few years.

Re: The impact of direct air carbon capture on climate change

#73

Post by pinkfoot »

LessDmesg wrote: post #71
pinkfoot wrote: post #69

Earlier quoted context omitted.

Again: https://www.ipcc.ch/ Go read. Come back when you find errors in the reports.

But that's a biased source of information. The IPCC depends on donations from Western governments for its existence, and Western governments are fatally dependent on inventing reasons for new taxation due to their exorbitant amounts of sovereign debt. Is there any unbiased source on this extraordinary claim that the tiny CO2 emissions humanity makes actually control climate?

So no reading for you then.

Re: The impact of direct air carbon capture on climate change

#74

Post by vanniv »

aidenn0 wrote: post #16
ForHackernews wrote: post #7

Earlier quoted context omitted.

> Maybe it has a future role (>2050? >2100?) It absolutely must, or else it's basically already too late: https://www.vox.com/2016/10/4/13118594/2-degrees-no-more-fos... > This image should terrify you. It should be on billboards. > As you can see, in either scenario, global emissions must peak and begin declining immediately. For a medium chance to avoid 1.5 degrees, the world has to zero out net carbon emissions by…

My dad sees articles like this and he'll just say that maybe the damage needed to prevent warming is worse than the damage that will be done by the warming.

Your dad is right.

If the wild alarmists are correct that the only way to prevent destructive climate change is to immediately dismantle all human economies and return to a life more like that of the middle ages, maybe we should just forget the whole thing and invest in sunscreen.

Re: The impact of direct air carbon capture on climate change

#75

Post by vanniv »

pfdietz wrote: post #58
WalterBright wrote: post #40

Just plant trees. They're cheap, solar powered, and convert CO2 to building materials.

They use too much land.

That's why you cut them down and build stuff out of them!

But, yes, in time we can probably build something more efficient.

Re: The impact of direct air carbon capture on climate change

#76

Post by killjoywashere »

xbmcuser wrote: post #72
Robotbeat wrote: post #23

Earlier quoted context omitted.

Not objectively true, as plants and even rocks grab CO2 out of the air pretty efficiently. From a thermodynamics standpoint, you can burn fossil fuels at 50-70% efficient (50% is not uncommon), and the actual theoretical lower bound of CO2 direct air capture is ~20 kJ/mol,[0] or about 1.7MJ/kg of elemental carbon, compared to 33MJ/kg for burning elemental carbon (same as high grade coal). (Burning methane is even bet…

With solar prices hitting negative rates for some periods in a day capturing carbon and converting into burnable fuel will probably start making sense in the next few years.

Think we could frack with corn syrup? Inject that carbon back into the ground?

Re: The impact of direct air carbon capture on climate change

#77

Post by dx034 »

pfdietz wrote: post #57
btilly wrote: post #20

I would have liked to see https://projectvesta.org/ commented on in the article. They claim to be able to sequester carbon by scattering olivine rock in an active and warm coast. The cost of the rock is $25/ton now, with the prospect of $10/ton in the future. Plus whatever it costs to break it up and scatter it. That makes it at an interesting price point if it works as advertised. Even more interesting to me is that…

I would worry about nickel and chromium pollution.

Why is that? I couldn't find any reference to that on their homepage. Is it a byproduct of the process?

Re: The impact of direct air carbon capture on climate change

#78

Post by rapnie »

zozbot234 wrote: post #19
gibybo wrote: post #17

Earlier quoted context omitted.

> extracting carbon from the air always takes more energy that was gained by burning the fossil fuel to make that carbon. This sounds true at first glance, but is it always? It seems like it's obviously true for simple reactions like burning methane and converting it back to methane since the energy you get from it is equal to or less than the energy required to turn it back into methane, but might there be some othe…

Yes, there are rocks that will "extract" carbon from the air on their own if crushed into sand. They are even reasonably abundant, so it seems like they would be a feasible tool for carbon capture. It would basically amount to speeding up the natural carbon cycle, which normally keeps carbon dioxide concentrations relatively stable in the very long run.

The rocks are called olivine, and are very common. They indeed look very promising for CO2 absorption.

https://www.betterworldsolutions.eu/is-olivine-the-solution-...

Re: The impact of direct air carbon capture on climate change

#79

Post by adrianN »

dx034 wrote: post #77
pfdietz wrote: post #57

Earlier quoted context omitted.

I would worry about nickel and chromium pollution.

Why is that? I couldn't find any reference to that on their homepage. Is it a byproduct of the process?

Olivine rock usually contains those elements.
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