[HN Gopher] Ocean geoengineering scheme aces its first field test
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Ocean geoengineering scheme aces its first field test
Author : rbanffy
Score : 53 points
Date : 2022-12-22 14:33 UTC (8 hours ago)
(HTM) web link (www.science.org)
(TXT) w3m dump (www.science.org)
| [deleted]
| bjelkeman-again wrote:
| Another method seems to be to weather silicate rock on land, it
| reacts with water and CO2, dissolved bicarbonates are produced
| and washed into the oceans where they form carbon rich sediments.
|
| This can be used as complimentary fertilizer on agricultural
| land.
| atourgates wrote:
| The kicker for this particular method is at the end:
|
| > "Caldeira's team wrote that its approach would be "infeasible"
| as a global solution. That's because it's difficult to make
| alkaline additives without emitting CO2, he says. Heating
| limestone to make lime, for example, releases so much of the gas
| that it partially offsets the increased uptake by the ocean. Even
| if low-emission lime could be made, it would probably be too
| costly to dump into the ocean."
| vagabund wrote:
| Olivine is readily abundant in the upper mantle and has similar
| decarbonizing and deacidifying effects. Theory and pilot
| programs suggest there's enough to completely offset the
| world's carbon output with relatively few mines and tropical
| coastlines.
|
| https://www.vesta.earth/
| londons_explore wrote:
| > releases so much of the gas that it partially offsets the
| increased uptake by the ocean
|
| Even that is a rather optimistic take... My Chemistry knowledge
| suggests it _more_ than offsets what is taken up by the
| ocean...
| kortex wrote:
| Cost aside, it is possible to calcine limestone with green
| electricity, and capture the outbound CO2.
|
| As mentioned, this is still quite costly, but it's likely a
| hurdle we will need to cross regardless to get to green cement.
| bamboozled wrote:
| Sad...
| DennisP wrote:
| That doesn't mean it's useless though.
|
| > Caldeira and colleagues added sodium hydroxide--also known as
| lye and an ingredient in many soaps and detergents--to a part
| of Australia's Great Barrier Reef. They found it raised pH
| levels nearly to preindustrial levels, allowing the natural
| calcification of the reef to increase.
| gs17 wrote:
| I'm glad to hear about this, ocean acidification does not get
| enough attention, which has always been weird to me since it
| seems to be linked to both CO2 emissions and bad things
| happening in ways that are much harder to deny.
| chris_va wrote:
| (disclaimer that I manage a climate research group)
|
| There has been quite a lot of interest in Ocean Alkalinity
| Enhancement (OAE) in the last few years.
|
| This is kind of an unfortunate title, as "geoengineering" (while
| not wrong) has a very negative connotation in non-scientific
| publications. Presenting OAE as ocean acidification remediation
| would have been a much nicer way to drive adoption.
|
| As a side note, lime can be very problematic under some
| conditions (parasitic CaCO3 precipitation can cause a net release
| of CO2). But ultramafic rock is alkaline and everywhere. It tuns
| out you need approximately one large mountain dissolved into the
| ocean to reverse climate change (neutralize ocean acidification
| and causes the ocean to take up any extra CO2 in the atmosphere).
| Or you can just remove acidity from the ocean using solar power,
| and pour it on rocks somewhere.
| eloff wrote:
| Are you kidding me? One large mountain? That can't be true. Why
| are we collectively losing our shit over climate change when we
| should just blow up some coastal mountains?
|
| This seems eminently doable and a lot cheaper than just moving
| every city away from the coast, among other things.
|
| I feel like there's some fineprint I'm missing.
| philipkglass wrote:
| 1) You can't just blow them up. You have to crush the rocks
| into something resembling sand to get the alkalinity released
| in human time scales.
|
| 2) Large means _quite large_. I ran a back-of-the-envelope
| estimate some years ago and found that the Hawaiian island
| [1] of Kauai could reduce atmospheric CO2 roughly back to
| pre-industrial levels if it were completely pulverized and
| weathered away down to the seafloor. That 's trillions of
| tons of rock.
|
| 3) The benefits of curbing CO2 are shared globally, but the
| costs are concentrated locally. It's the same kind of
| prisoner's dilemma that results in e.g. people still burning
| billions of tons of coal each year.
|
| I think that accelerated silicate weathering is the best
| geoengineering option and one that's likely to be deployed at
| scale later this century, but it's not really going to be
| easy.
|
| [1] AKA "underwater mountain, with the top poking above
| water"
| eloff wrote:
| I'm sold, where do I sign up? Seriously, this sounds so
| amazing, I'm blown away* that I'm only learning about it
| now!
|
| * pun intended
| epicureanideal wrote:
| For #3, I wonder if the way out of the prisoner's dilemma
| would be to use this method specifically for local ocean
| acidity reduction. Over time it helps globally but it
| doesn't do so quickly enough that other countries become
| disincentivized from doing the same.
| TaylorAlexander wrote:
| I don't know the details of this concept but even if it's
| true we have to decarbonize our economy or we'll just have to
| keep blowing up mountains. Also I presume the parent meant
| "one mountains worth of lime" and I presume most mountains
| aren't pure lime.
| eloff wrote:
| We will decarbonize. The only fossil fuel we have in
| massive abundance is coal, and it's already not economical
| for electricity generation. Natural market forces could get
| us there alone. The problem has always been that it doesn't
| get us there fast enough.
|
| If we can just mine a mountain worth of lime and dump it in
| the ocean, that seems simpler and cheaper than trying to
| move all our coastal cities. Even if we decarbonize at the
| maximum possible speed, we'll still have to do that.
| mistrial9 wrote:
| thank you for posting!
|
| > a very negative connotation in non-scientific publications.
|
| yes, after decades in higher ed, I too find a _very negative
| connotation_ in the field of "geoengineering"
| froggychairs wrote:
| I'm really interested in learning more about ocean
| modifications to enhance its ability to store carbon (not via
| seaweed farms) or protect life that is fragile to increase
| acidity levels. Do you have any recommendations for further
| reading? Feels like everything I real on this topic is either
| carbon removal or solar geoengineering
| chris_va wrote:
| This sort of thing?
|
| https://iopscience.iop.org/article/10.1088/1748-9326/ac002d/.
| ..
|
| ... Oceans equilibriate with the atmosphere after a few
| months (they absorbs more co2 in response to pH/carbonate
| shift), so one has to keep injecting alkalinity to keep a
| local ecological effect. The CDR effect is persistent,
| though.
| photochemsyn wrote:
| I think that 'large mountain estimate' depends heavily on
| atmosphere-ocean mixing rates, doesn't it? IIRC, ocean
| circulation takes about ~2000 years to mix the oceans.
|
| Ocean acidification is a local near-surface phenomenon caused
| by the oceans absorbing the higher levels of CO2 and pulling
| the carbonate equilibrium to the left, so to speak. CO2(atm)
| <-> (H2CO3) <-> (HCO3)- <-> (CO3)-2 -> CaCO3 precipitate ?
|
| I don't know a whole lot about this, but it seems you'd have to
| keep doing this steadily and gradually for > 100 years (maybe
| 1000 years) at global scale to get that effect? ...and that's
| assuming no more fossil fuel combustion was taking place?
|
| As a mitigation for coral reefs, oyster beds etc. it seems to
| have more immediate value.
| chris_va wrote:
| No, we'd need to dissolve that amount into the mix layer
| (call it the top 50m, for argument's sake), which takes a few
| months to equilibriate with the atmosphere through that
| carbonate chemistry. But, if one managed to do it all at once
| (not sure how), it would only take a few months.
|
| One would want to avoid downwelling regions that get sucked
| into deep ocean circulation before reaching equilibrium (e.g.
| the north atlantic), that alkalinity would take a long time
| to come back up and be useful.
| DennisP wrote:
| Um....is anyone working on the two methods you mentioned?
|
| If you have any links I'd love to learn more. (And if your
| climate research group is involved in stuff like this, I'd love
| to check that out.)
| chris_va wrote:
| Vesta, Ebb Carbon, Planetary Technologies, Heimdal (YC), some
| stealth companies, and some academics are looking at OAE
| directly.
|
| (may be missing a few)
|
| There are a lot of terrestrial enhanced weathering folks too,
| where the alkalinity eventually washes into the ocean after
| being spread on land.
| silicaroach wrote:
| When you know exactly how things will be affected, then feel free
| to make changes.
|
| When you don't know exactly how things will be affected, then you
| shouldn't make changes.
|
| This action was the second case and it was only done for monetary
| concerns. This wasn't motivated by environmental concerns, it was
| motivated by profit. And the profit motive is exactly what got
| this planet in to its climate situation.
| macintux wrote:
| > When you don't know exactly how things will be affected, then
| you shouldn't make changes.
|
| That's an impossible standard to uphold. I don't disagree with
| your overall premise, but the world is simply too complex to
| understand all of the ramifications of _anything_ meaningful.
| [deleted]
| bamboozled wrote:
| Every time you drive a car or get in an airplane you're in the
| "When you don't know exactly how things will be affected"
| category, you're adding more Co2 to the atmosphere and thus
| warming the planet at a never seen before rate. We don't know
| exactly how things will be affected.
|
| ...but trying to reverse some of this is bad now?
|
| From reading the article, it seems hard to say the experiment
| sounded negative?
| aporetics wrote:
| Read Elizabeth Kolbert's "Under A White Sky" for a history of
| how best-intentioned interventions into ecologies have
| consistently backfired, in each case the unpredictable and
| far reaching complexity of the system was thrown out of
| balance.
|
| I think the commenter's admonition may have been expressing
| the the same lesson: its hubristic to "fix" systems with
| hacks like this; whereas carbon drawdown is not a hack,
| because it operates within the mechanism of imbalance itself.
|
| For my part, this article had so little reporting of the
| complexity of ocean ecosystems and the potential dangers, not
| to mention how it buried the bit about how carbon intensive
| lye is (the same reason that makes concrete have such a huge
| carbon footprint) that it read like a puff piece.
| 2devnull wrote:
| Precaution seems appropriate but aren't we doing things we
| don't understand anyway? That seems like the default. Surely we
| can't roll back all of humanity, but maybe we can stand athwart
| history and yell "stop!" if only in hopes to slow down the
| stupid.
| acheron wrote:
| "That sounds cool. But I bet the first comment to the article
| is going to be some cynical negative bullshit."
|
| _click_
|
| "Yep."
|
| Never change HN.
| oifjsidjf wrote:
| Perhaps the issue is on your side because you don't ever even
| consider eg the precationary principle?
| aaron695 wrote:
| [dead]
| sausagefeet wrote:
| Are you making a general point or one specific to this? And is
| your first point (precautionary principle) connected to your
| second point (financial motivations)? The experiment referenced
| in the article is a small scale test, so it seems to me that it
| is following the precautionary principle. As for if the
| financial motivations are an issue, I don't know.
|
| Are you just being snarky and anti-establishment or do you have
| a concrete criticism to make? Please make it if you do.
| s1artibartfast wrote:
| I don't know the exact impacts of changing our current climate
| trajectory, or implementing green technology, so better to
| stick with our current course.
| _Algernon_ wrote:
| >When you don't know exactly how things will be affected, then
| you shouldn't make changes.
|
| We can hold to your standard the moment we hold to that
| standard for other activities, such as burning fossil fuels in
| the first place.
| paulgerhardt wrote:
| Feels like an appropriate tool to use in conjunction with
| tropospheric sulphur release (which while extremely effective at
| offsetting carbon causes some politically
| intractable...er...minor...acid rain) to flatten the curve on
| climate change in the next five years until more energy intensive
| carbon draw down solutions can be deployed. Ie harnessing fuel
| from the atmosphere using fusion power.
| DennisP wrote:
| I forget the details but I've seen work on doing that sulfur
| release plan with something else that doesn't cause acid rain.
| The main reason for the initial focus on sulphur dioxide is
| that we've already seen it done, by volcanoes.
| photochemsyn wrote:
| Note that there's a bit of a problem with fertilizing the oceans
| with iron (the other strategy mentioned in the article) to cause
| phytoplankton blooms which then sink to the seabed, thus removing
| carbon from the atmosphere. It's that microbes in the water
| column steadily break down sinking biomass, sucking down free
| oxygen levels as they do so.
|
| This results in large zones of anoxic bottom water, or at least
| hypoxic, aka 'dead zones' as in the Gulf of Mexico. These zones
| were much more widespread 100 million years ago when many oil and
| gas-bearing sediments were being laid down, but turning much of
| our modern ocean into a sulfurous stinking anoxic zone is not the
| brightest idea.
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