Only a fraction of the Earth’s carbon is present in the biosphere at any one time. Volcanoes spew more of it out. River deltas and coal formation sequesters some more. But a lot of carbon dioxide is taken out of the air by reacting with rocks. Mineral sequestration has been proposed as a safe way of disposing of concentrated CO2 from electricity generation. But what if we could somehow increase the rate at which rocks absorbed CO2 from the atmosphere?
That’s precisely what one Dutch professor has proposed; mine rocks rich in a mineral called Olivine, and add it to soils in the tropics, or along beaches in tropic latitudes. An earlier paper suggests the substitution of crushed olivine rocks for lime as a fertilizer. The costs? Professor Schuiling estimates in the order of 10 Euro per tonne of CO2 sequestered. Even at twice the price, it’s still cheap.
Again, there are undoubtedly considerable gaps between equations in a scientific paper and actually doing this on a large scale, not least the potential for environmental side effects of this process. But it’s the kind of thing we should be seriously looking in to.
I’d love it if there were an easy ‘out’ for us on climate change, because we’re not doing much about the harder stuff. Robert, what is your sense of whether it will work, and what percentage of CO2 might we be able to sequester this way. And what is olivine sand like on the tender feet of beachgoers?
There goes the city of Toowoomba, TableTop & adjacent exurbs! They all sit atop ancient olivine basalt (bluestone) deposits – including 2 quarries, one with exposed volcanic vents – which, with the planned International-standard Quarry gardens, will be part of a geological-garden park (the Bridge St quarry, for anyone who wants to see them which in Toowoomba).
In fact, these are a typical of olivine basalt deposits. Use of them as fertilisers would destroy ranges & the typical lava flows, plugs etc formed by ancient volcanoes.
All very well when you come from a former sea-bed (Holland) and have nothing to lose, but the antithesis of Environmentally-friendly to those who love their olivine-basalt landscapes.
Yaz: I’m no chemist or geologist.
From what little I do know about chemistry, the biggest problem is the rate at which the chemical reactions occur, and whether the result of the reactions represent a locally hazardous byproduct.
DeeCee: I doubt that Toowoomba represents the only source of olivine in Australia.
And we’re perfectly prepared to dig massive holes in the landscape to extract coal and ruin the global environment. At least this process involves digging massive holes in the landscape to protect the global environment.
How much CO2 is generated in the process of mining olivine and spreading it around though?
FWIW, I’ve long suspected we will need at least one from of geoengineering such as this if we’re to pull CO2 levels back to anything safe in the next half century.
wizofaus: I’d think far less than would be absorbed.
Ten euros of diesel – $20 worth of diesel. Let’s say 20 liters of the stuff. That’s about 60 kg of CO2 emissions.
So even if the entire cost of extraction was spent burning $1-per-litre diesel, you’d sequester at least 15 times more CO2 than you’d release in the process.
Its worth pointing out for those who haven’t waded through that paper (‘waded’ isn’t fair, its very well-written and concise actually) that the olivine itself can’t act as a fertiliser (N and P contributor) – the authors propose mixing the sand with some chemical fertiliser before spreading it.
Its an interesting idea, but I have a few concerns wrt its use in acid sulfate soil (ASS) areas. Science-babble ahead, tell me if I’m not explaining things enough:
The weathering process that the authors correctly claim would sequester CO2 and neutralise acids would also release more iron into the soil/groundwater system, which feeds a couple of nasty pH-dependant reactions that release further acidity in an ASS-affected system (the iron chemistry is pretty complex and I’m still struggling to understand all the details myself, but I’m pretty sure of this much). I suspect that olivine sand might be an ok inoculant in situations where an ASS deposit is not too sulfide-heavy and not too heavily disturbed (so, cane farms and the like), but I’m rather less sure that it would be an effective substitute neutralising agent in badly-affected ASS areas, or disturbances caused by construction work.
In particular, I suspect that the slow rate of reaction would not protect concrete placed in oxidising ASS – but the paper doesn’t give solubility figures for the olivine sands, so I can’t compare it with lime. It’d be nice to know, because alternatives to lime use would be great.
Grumphy: thanks for the interesting comment.
Off the top of your head, is there anything else that could be added to the mix to prevent the iron reactions you’re worried about?
Hmm. The reactions are pretty unavoidable above pH 4 (all you need is Fe2+ or 3+, water, and oxygen), and more olivine would only add yet more iron, so you’d probably just have to throw in a bit of lime to catch the extra acid generated by its conversion from free ions to iron hydroxides. Back to square one, d’oh
ASS’s are a bugger to mess with – there’s lots of compounds that can neutralise the acidity created when they’re exposed to air, but the trick lies in their solubility. The agent has to be able to sit around in the soil matrix and ‘catch’ any incoming acid. If its too soluble it’ll just wash away in the groundwater before that happens. The other thing is that some agents are *too* alkaline, and can raise the soil pH too high. The theoretical max pH that ag-lime can raise a soil to is only 8.2, and realistically it rarely gets soil above 6.5-7 (neutral). That’s why its the most common neutraliser applied to soils – it sticks around, and can’t cause too much trouble. Unfortunately, lime neutralisation releases CO2, so, problem.
Really, the ultimate solution is to stop disturbing ASS in the first place, but people will insist on their canal McMansions and marinas. *le sigh*.
Grumphy wrote:
must…. resist… comment…
SR, you caused me to spray coffee all over my monitor. Bastard!
Robert Merkel @ 5. I didn’t say “only”; I said “typical”. Olivine basalt is volcanic, and olivine crystals grow in holes in the basalt – I’ve a nice wall of it in front, where you can actually see how olivine forms. If you buy a load of crusher dust from an OB quarry, you/ your kids can have fun picking little crystals out of it.
Coal deposits are typically found in fairly flat (formerly marsh) land, often near old sea coasts. If coal is mined by opencut, huge holes are left in the ground. With enough rain, these might become huge lakes, like crater lakes – quite effective dams.
Cut down basalt mountains for OB, and what impact does that have on rainfall & creek/ river formation? For example, flatten the OB basalt deposits of SE Qld’s Great Divide, and you knock out the headwaters of western creeks & rivers feeding the Warrego & Maranoa etc. By removing the Escarpment’s effect on rainfall that feeds rivers like the Brisbane, cities East of the Escarpment lose much of their water supply. The two Toowoomba bluestone quarries are only on the Escarpment’s dry (“rainshadow”)sides; but their clients were limited to the railway & local roads, with stone etc available for local use.
Wizofaus @ #5 The Bridge St quarry switched from blasting to high-pressure water drilling c1982. Blasting is cheaper, by has significant side-effects; water “drilling’s” most significant side-effect is water usage. I’d imagine that crushing uses a great deal of power. It, stockpiling & loading also create clouds of fine gritty dust; so when the BSt operated, the crusher-loading area was constantly watered. Had it not been closed before the current drought, it would have had to cease operations years ago.
*chuckle* @ #9. You’d be surprised how easy it is to make, erm, filthy jokes in soil science…
DeeCee, there’s a *lot* of basalt in the SEQ ranges. Even with a lot of it only being in caps in the hilltops, ‘flattening’ is a bit of an overstatement. The hills aren’t about to disappear even if we get really carried away. Plus, there’s an active olivine mine near Armidale already.
Not that I’m not concerned with a drive to mine the stuff locally, it would be bad, but lets keep it in perspective. EG of ‘bad-enough’ prospective damage: There’s actually a little old basalt quarry just off the road to Montville, and seeing places like that opened up to extraction again would be bad. Can’t imagine what even a small extraction project there would do to the local area D:
Rewind back to the start of the year when Ensham Coal Mine near Emerald had 5 Sydney harbors dumped on it in 36 hours, busting the levees and doing just as you say. Lost coal production was intolerable, the EPA OK’d them mega-pumping into the Nagoa River, which flows into the Fitzroy. Which they did for months until in August downstream folks pointed out their water was a bit suss. At which point Qld Health said anyone on a low sodium diet and babies should avoid it at all costs. The mine stopped pumping in Sept. Anna Bligh set up an enquiry in how f’d up the Fitzroy now is, to report
just after the next electionby the end of the year.Meanwhile they were still underwater, and Qld Treasury was still needing Coal royalties, so apparently they came up with the idea of using a whole lot of clean dam water to dilute the filthy mine water down to legalistically OK average concentrations and then dump it in the river and on the land , working on the theory that the overall salt load doesn’t matter. But it’s not being mixed thoroughly and the hyper-salty/mineralised stuff sinks to the bottom, and gets backed up by the weirs, hanging around doing it’s foul eco-destroying business.
Coal uber alles.
This was in February. Waiting for developments.
New materials can selectively capture carbon dioxide, UCLA chemists report
“For each liter of ZIF, you can hold 83 liters of carbon dioxide,” Banerjee said.
http://newsroom.ucla.edu/portal/ucla/new-materials-can-selectively-45139.aspx
The technical challenge of selectively removing carbon dioxide has been overcome. Now we have structures that can be tailored precisely to capture carbon dioxide and store it like a reservoir, as we have demonstrated. No carbon dioxide escapes. Nothing escapes—unless you want it to do so. We believe this to be a turning point in capturing carbon dioxide before it reaches the atmosphere.
http://www.greencarcongress.com/2008/02/zifs-new-framew.html
Robert,
I’m wondering more about the possible distribution by wind (having recently seen our topsoil in one of NZ’s fine glaciers!).
From reading the paper I gather they’re looking at coastal zones – but areas with even a low breeze could prove to be problematic given the material (100um is pretty damn fine) could end up on someones ASS (pun intended).
Thanks Grumphy – I figured some chemistry would show up somewhere with potential issues – acidity would not just be an issue for the soils but any equipment used in the process (can anyone say “heavy metals”).
danny @ 13, my brother grows beef in the area and the farmers are pretty pissed off about always being blamed for polluting the rivers when they see what’s happening with coal.
The Review of the Fitzroy River Water Quality
or lack thereofIssues / prepared by Professor Barry Hart for the Queensland Premier is out.It gives the gov’t the quote it needed – “no serious health effects” – per the terms of reference, noting “there are a number of other issues relating to coal mining in the Fitzroy Catchment” which were off-limits to the report.
Re: ‘unserious’ effects, the report acknowledges, coyly, “it is possible that the poor quality water did increase the effects of a viral gastroenteritis outbreak”; “increased salinity and sodium concentrations in Rockhampton’s drinking water supply… concentrations are likely to increase further during November (and even December…If Rockhampton’s water supply decreases further in quality, problems are also expected at the Rockhampton Hospital and its Dialysis Clinics and Home Dialysis service.There is a real possibility that blue-green algal blooms will occur”
Re: ecologic damage – “.. insuffucient information, insufficient information, insufficient information… The response of relevant Government agencies to assessing the possible impacts of the mine affected water on the riverine biota has been tardy to say the least”. Someone saw some sick catfish somewhere.
It’s not just the farmers who are pissed off: the report notes, bluntly ” … a cynical community view .. that the Government is waiting for the wet season rains to ‘solve’ the problem, and that nothing will be learned from this issue to change Government response processes.” The EPA gets a bit of a caning, and the elephant is sensibly observed ie “the desire by Ensham and Government to get the mine back into productions as rapidly as possible”