Thursday, May 08, 2008

This has been another simple answer to a simple question

Air capture is the Nigerian scam letter of climate policy and about the last thing to invest anything but the buck you buy the odd lottery ticket with. Anyone who understands about entropy knows that you want to extract CO2 from places where it is a lot more concentrated. Just about nothing else would cost so much and do so little, so the bunnies have asked Eli why Roger and the Breakers are doubling down

CO2 capture at the source (fossil fuel power plants, cement kilns) imposes a cost on the fossil fuel industry. Air capture is another Treasury Raid (as well as silly, work out the energy and materials cost). It also holds out hope that we don't have to do anything now, but that in 50-100 years air capture will save the world.

This has been another simple answer to a simple question

SORT OF AN UPDATE: It's even worse. If you don the air capture true believer togs, then air capture makes even less sense because you could do better with less by picking off all the CO2 coming out of fossil fuel power plants and other fixed installations which, by itself would go a huge way, if not all the way to solving the problem.


Anonymous said...

I agree that ambient air capture is a stupid idea.

But fossil fuel plants account for only about 40% of emissions, so even capture at the source would not solve the problem.

One would have to have source capture AND a zero emission transportation sector AND a zero emission heating (eg homes) sector and zero emission whatever-else accounts-for-the-remainder sector.

of course, if one transitioned everything to electricity and at the same time implemented source capture, that would solve the problem, but we are currently a long way from that.

but something along the latter lines is clearly going to HAVE to happen if we ever hope to reduce emissions to zero.

Anonymous said...

20 years ago, if someone had proposed that we deal with the SO2 problem by capturing SO2 from ambient air, they would rightly have been dismissed as a kook.

Today, for some odd reason, these people are actually taken seriously, at least by the media.

The current situation (with Iraq, global warming and all the rest) reminds me of "The King of Hearts" for some reason.

Anonymous said...

That fact that he uses the word "backstop" implies that Roger Pielke has probably RTFP.
on air capture feasibility.

But it appears that Roger only read part of TFP, and missed (or perhaps chose to ignore) the critical part entirely:

"We don’t expect air capture will ever be competitive with capture from point sources. If it were, our
lower bound calculation suggests it would have to be based on a process other than calcination."

"By acting as a hedge against low probability,high-damage climate scenarios, it also shifts relatively more emissions reduction to the future.

"the danger is ...that opponents of CO2 regulation will use
air capture as a political argument against action on the climate problem. If successful these arguments could lead to near term emissions far higher than optimum from a social welfare perspective.
This is indeed a point of which air capture proponents should be wary.

And the results of this analysis
should serve as a reminder that, while air capture is feasible, the cost could be very high. At 250 $/t-CO2,
air capture is best viewed as an option for use in only the direst of climate emergencies and should be little
comfort for present-day emitters."

EliRabett said...

Bingo. We have smart anonymice here.

Still a 40% reduction (it's probably more because there are other stationary sources such as cement kilns and we can shift from fossil fuel for heating houses to electricity and cogeneration) takes the world a far way.

Anonymous said...

"But it appears that Roger only read part of TFP, and missed (or perhaps chose to ignore) the critical part entirely: [in reference to warnings that capture could be used as a delaying strategy]"

On the contrary, it looks increasingly likely that Pielke and the rest are quite familiar with exactly that aspect.

For a group that seems to be constantly screaming about how they aren't delayers, this is rich.

I'd love to know where BI is getting its funding.

Anonymous said...

Biomass power plus CCS is a form of open air capture that might be feasible (emphasis on "might"). It doesn't get much emphasis though, and was dissed by RPJr. in one exchange I had with him, for some reason.

Anonymous said...

Mr. Rabett, I think you are failing to recognize that the double down on air capture is little more than the latest RPJr. scam to hook a couple of journalists.

I think we can all agree that RPJr's real audience has always been reporters looking for a bombastic quote, or person for balance. Most scientists, I believe, tend to ignore little Pielke.

Mus musculus anonymouse

Anonymous said...


The economic viability of air capture is questionable. The risk that a vague hope of future air capture (think of how controlled fusion was viewed in the 1950's) will be used to excuse inaction is serious. However,the entropy argument is not as big a showstopper as people think. The reason is that the entropy you need to work against is only logarithmic in the CO2 concentration. That reduces the difference between air capture and smokestack capture to far lower than you might intuitively think.

True, the low hanging fruit is to do IGCC and conventional coal effluent capture first. Then, one shouldn't bank on air capture being possible until it's demonstrated. it's not obviously out of play, though.

EliRabett said...

Hi raypierre,

IEHO the entropy argument is WHY it is inherently more efficient to do IGCC and coal power effluent capture first. It's not that air capture is not possible, it obviously is. The question about whether it is economic or energy neutral is even secondary, it's just that if it is possible you obviously don't need it because capture from fixed concentrated sources coupled with some obvious technology changes make it superfluous.

Which, of course raises the policy point, why are people pushing it. I'm afraid my answers are very pessimistic.

Anonymous said...

Not to sound like a doomsdayer, but if atmospheric CO2 keeps rising and especially if volcanism and methane hydrates are added to the mix, then Earth's biosphere could very well face another P-Tr-style event. So Roger and The Breakers really oughta stop piddling around trying to capture CO2 out of thin air and instead try to figure out how to turn carbon lifeforms into silicon ones. After all, silicon-based life will have a much greater chance of surviving a P-Tr-style event than carbon-based life!

Anonymous said...

Cynthia, see here for a discussion current research on that subject. I've asked David Archer to do an RC post on this and it sounds as if he will. My impression was that the field had largely written off the Arctic hydrates as being any sort of short-term threat, but the reported methane emission figures may be grounds for reconsidering that conclusion.

Anonymous said...

Cheap solution for ambient CO2 capture:
Plant rapid growing trees, harvest them when fullgrown and bury the wood. Plant new trees in the harvest zone.
Knock on effect: It creates also cool recreational areas.

Anonymous said...

Thanks for the link, Steve (Bloom)!

I heard a couple of paleo-guys on BBC Radio 4 the other day chatting about the (P-T) extinction. One of them mentioned that it's looking more and more like methane hydrate was to (P-T) as an asteroid was to (K-T).

Anonymous said...

That seems firm, Cynthia, although for a long time the question was what triggered it. See here for an accessible review of the whole subject.

I don't think the hydrate supply on the ESS is enough to get us into anything like those past events, but I do wonder about feedbacks. Hopefully David will be able to address that.

Anonymous said...


Re Siberian/Arctic Methane Clathrates.

I posted this deliberately understated post at RealClimate. I was half hoping someone would say why 1+1 does not equal 2, as it appears to here. I'm still waiting. Good to hear David Archer may post.

Julian Flood post #258 on that page mentions a recent change in atmospheric methane carbon isotope signature. Anyone know more about this?

Steve, with regards the amount of clathrate: Perhaps not enough in itself to cause a PT, but if even just a significant fraction were released it could provoke feedbacks elsewhere, and exacerbate the situation in the Arctic. Early freeze-season local increases in methane could have an impact on IR loss, which could aid the regional warming trend and ice loss.

IMHO Definitely one to watch (Lovelock worries me more and more).


Anonymous said...


Since I can't say for sure whether I was having a senior moment (wise of otherwise) regarding methane hydrate, I don't know for sure whether this frozen latticelike substance has got legs -- or for that matter, wings...