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> Previous studies have estimated this “enhanced” rock weathering could store 215 billion tons of carbon dioxide over the next 75 years if spread across croplan

by jlhawn 3y ago

> Previous studies have estimated this “enhanced” rock weathering could store 215 billion tons of carbon dioxide over the next 75 years if spread across croplands globally. This is an average rate of 2.8 Billion tons of CO2 per year. We currently emit over 35 Billion tons of CO2 every year so this could potentially offset about 8% of global emissions. Obviously not enough to get us to net zero but that is very significant in my opinion. I'm not certain how the economics of this solution would work. Is it easy to source, produce, and distribute this crushed volcanic rock? Would farmers get carbon credits for doing so? Or direct subsidies paid for by taxes on net-positive CO2 generating industries (which ironically is a lot of Ag itself)?

xjidjccudux 3y ago
[dead]
reaperman 3y ago
And how much would it affect agriculture? Do the plants thrive if you do this every year?
- philipkglass 3y ago
  Adding ground silicates can significantly increase agricultural productivity on various kinds of land. Here's one review article about the subject: "Remineralizing soils? The agricultural usage of silicate rock powders: A review" https://www.sciencedirect.com/science/article/pii/S004896972106054X https://www.sciencedirect.com/science/article/pii/S004896972... IIRC the soils that benefit the most include: - Soils depleted in micronutrients - Acidic soil - Silica depleted soil (significant for rice farming and other silica-sensitive crops) Most of the world's acidic and depleted soils that could benefit the most are in warm tropical regions with heavy rainfall. That's also where fresh mineral applications would weather most rapidly to draw down CO2. Unfortunately, it may also be harder (logistically and culturally) to encourage silicate applications on those soils than on the temperate climate soils of North America. After a certain point adding more silicates doesn't help increase soil productivity. The one thing that I haven't found any reporting on is where the "too much" point is reached for soil amendment with crushed silicates. I have seen that yields stop increasing with ever-increasing addition of ground rock. I haven't seen a point where they go down. I would guess that there's some point where yields actually start dropping, and that would mark the upper limit for agricultural soil amendments. Up to the point where yields keep increasing, you could expect farmers to spread crushed silicates on their fields for their own benefit, depending on the cost. In the high-application case where yields flatten out but carbon sequestration continues to increase, you'd need to pay subsidies to get higher application rates. You'd also need to pay subsidies in the lower-application-rate cases if yields increase but not enough to justify the expense on a yield basis.
spankalee 3y ago
The collective will we'd need to deploy this globally would probably indicate that we also somehow magically gained the collective will to reduce emissions. This is the problem with some of the geo-engineering approaches. We've shown that we can't really change how society and industry operate enough to reduce emissions, so what makes us think we can do the same for carbon capture? How do you actually get every farm to do this?
- delecti 3y ago
  The comment you replied to suggested carbon credits. That seems like a pretty obviously good answer. We're bad at forcing people to make broad changes, but nudging with money like that is often effective.
- deleted 3y ago
  [deleted]
- bluGill 3y ago
  Don't be so down. We have solved the ozone hole problem - it will take years to heal, but we emit very little ozone destroying things anymore. Last year my local utility generated more power from wind than there was demand. People do care and are making change. Change is slow to come, and even after it happens takes a long time to make a difference, but there are signs of change and the cause is being taken care of. Don't take that too far: there is a lot of work to do. However we have a good idea what that work is we just need to apply it.
  - mrkeen 3y ago
    It's big again https://www.esa.int/Applications/Observing_the_Earth/Copernicus/Sentinel-5P/Ozone_hole_goes_large_again https://www.esa.int/Applications/Observing_the_Earth/Coperni...
    - neon_electro 3y ago
      But still on track to shrink? From your source (thank you for the read): > Claus concludes, “Based on the Montreal Protocol and the decrease of anthropogenic ozone-depleting substances, scientists currently predict that the global ozone layer will reach its normal state again by around 2050.”
epistasis 3y ago
We need to get to negative emissions in the second half of this century. From 5-10Gton/year, IIRC. So this should not be used to offset new emissions, but thought of as a way to claw back the damage we are still creating today.
- mjan22640 3y ago
  Those emitting CO2 will pay, and those capturing will receive the money.
  - PeterisP 3y ago
    Perhaps that's how it should be in a perfect world, but in the world we live in that isn't the case and doesn't seem likely to be the case - there are some local markets for CO2 incentives, but on the international level there's no willingness for major emitter countries to pay other countries, no evidence that (or why) this willingness might appear, and there's no global government that could make or enforce any rules unless countries opt-in; nobody can force nuclear countries to pay others.
    - mschuster91 3y ago
      Agree on the rest, but on none of this: > but on the international level there's no willingness for major emitter countries to pay other countries, no evidence that (or why) this willingness might appear Of course no one wants to pay, but courts have already begun shifting their attitude in a number of historic rulings against large emitters, and there are a ton of cases being in progress at the moment [1]. IMHO it's only a matter of time until the first court orders direct international financial damage payments, particularly to countries that threaten to be literally flooded from the map like Vanuatu [2]. For what it's worth, most Western countries already pay large sums of money to the Global South as part of general development aid. > and there's no global government that could make or enforce any rules unless countries opt-in The US absolutely can, like they did with anti money-laundering legislation. Everything and everyone that touches the US dollar is, in the end, accountable to the US and its will. Besides, who would have thought that the world would eventually converge on getting rid of tax havens? To force the Swiss of all people to dismantle the holy grail of bank secrecy? Almost no one, given the absurd amounts of money at stake, and yet it happened (partially though as a consequence of the various leaks of tax evader data). [1] https://en.wikipedia.org/wiki/Climate_change_litigation https://en.wikipedia.org/wiki/Climate_change_litigation [2] https://www.washingtonpost.com/climate-solutions/2023/03/29/vanuatu-international-court-un/ https://www.washingtonpost.com/climate-solutions/2023/03/29/...
api 3y ago
It would more than offset global aviation, which is one of the areas where replacing fossil fuels is the most difficult.
marcosdumay 3y ago
> metabasalt and olivine Well, yes, a lot of farmers (not all, probably most) are interested on adding those to their soil and will do it if it's cheap enough. I'm not sure we can mine, pulverize, and distribute it in a carbon-negative way. But yeah, coupled with large scale implantation of renewables and decarbonization of transportation, it may be enough to even roll climate change back a little bit.
- vonwolfhausen 3y ago
  Olivine comes from Norway, which uses hydro power. The energy in extracting and crushing is around 4kg CO2/ton. Pulverizing is around 30-50kgCO2/ton rock. Majority of transport is on water (ocean, river), which is low emissions. In the end, for every ton of rock around 850kg of CO2 are removed. For basalt, it's around 200kg net, so the supply chains have to be shorter. I checked my math with the DOE's experts, and it checks out.
  - gattilorenz 3y ago
    Source for the numbers?
    - euroderf 3y ago
      Yes, further details would be very illuminating !
    - matznerd 3y ago
      Sibelco's Aheim mine essentially supplies a large part of the world's olivine today. It is located in a Fjord with its own port. The transportation distance is very small. See their website here: https://www.sibelco.com/en/150-years/aheim https://www.sibelco.com/en/150-years/aheim "The proximity of Aheim’s mine, processing facility and shipping terminal enables Sibelco to run a highly efficient operation with minimal transport or double-handling of materials. Quarried olivine is moved via conveyor belt through a 4km tunnel to the processing plant where it is crushed, dried and screened into different grades." When transporting mostly by ship, olivine ERW efficiency can remain >90% even with 1000+ kilometers of sea transit. See this working paper: Environmental life cycle assessment of CO2 sequestration through enhanced weathering of olivine https://legacy.projectvesta.org/wp-content/uploads/2019/06/Environmental-life-cycle-assessment-of-CO2-sequestration-through-enhanced-weathering-of-olivine.pdf https://legacy.projectvesta.org/wp-content/uploads/2019/06/E...
chinchilla2020 3y ago
Let's not forget the massive CO2 generated by mining, processing, and transporting crushed rock. I used to work on SAG (semiautonomous grind) mills for fine grind on copper-bearing ore. Grinding rock is incredibly energy inefficient. I would suspect this entire process is carbon-positive despite the atmospheric capture. It seems we will do anything to avoid the obvious - we need to reduce energy use and transition to green generation.
- klysm 3y ago
  what about using rock that's already being crushed for processes like that? Still have the transport but may as well use the ground stuff for something.
  - chinchilla2020 3y ago
    Possibly. I am not familiar with the sort of basalt they are using here. It may very well make sense under those conditions.
    - kisamoto 3y ago
      Olivine is in ready supply as a by-product from the mining industry. There are piles of it laying around (which don't have the same effect as spreading it out) although they do need to be transported to projects.
      - klysm 3y ago
        By-product is the word I was looking for. Hopefully there isn’t a need for primary production
  - kansface 3y ago
    We are talking about adding it to farmland so we really care about yields and safety.
- fudged71 3y ago
  Do you think gravity-assisted rock crushing could be feasible?
mhandley 3y ago
If 2.8 billions tonnes isn't enough, can we just spray additional olivine powder over the surface of the ocean? Presumably it would lock up CO2 in the seawater just fine, allowing more CO2 to be absorbed by the ocean from the air.
- matznerd 3y ago
  Need very fine particles for that and its usually classed then as ocean alkalinity enhancement (OAE). A hybrid method has been proposed in the literature, to use beaches and is currently being implemented via a project I started (but which I am no longer with) that has been turned into a company called Vesta -> https://vesta.earth https://vesta.earth Rolling stones; fast weathering of olivine in shallow seas for cost-effective CO2 capture and mitigation of global warming and ocean acidification https://esd.copernicus.org/preprints/2/551/2011/esdd-2-551-2011.pdf https://esd.copernicus.org/preprints/2/551/2011/esdd-2-551-2... https://smartstones.nl/research/publications-2/ https://smartstones.nl/research/publications-2/
supergeek 3y ago
Agriculture is currently massively carbon intensive and is one of the hardest modern technologies to decarbonize. It relies on fertilizer production that is currently completely reliant on fossil fuels. If this can decarbonize agriculture, that's a massive win for our chances to reach net zero carbon emissions on time.
ben_w 3y ago
8% sounds good to me. The required reduction in emissions is 99.9% (net), which is approximately "everything everywhere except maintaining grassland"[0] if done by reducing gross emissions; the last percentage point of a problem is usually the most difficult, so if we can get a whole 8% by making a cheap sink, that's probably for the best. Just so long as it's in the sweet spot of "cheap enough" without crossing over into the realm of "people can make money mining the CO2 out of the air", because if that happens then the same economic pressure that means we have too much CO2 now will become one of too little CO2. [0] https://ourworldindata.org/ghg-emissions-by-sector https://ourworldindata.org/ghg-emissions-by-sector
kisamoto 3y ago
Very significant impact. There is no silver bullet that can remove the excess emissions on it's own, however combinations of these removal methods (coupled with decarbonization of course) will be essential to addressing excess atmospheric CO₂. Regarding economics; there is plenty of olivine rock already available as a mining by-product. Disadvantages are that it takes up to 1000 years to fully sequester however this is logarithmic with a large portion of this achievable in the first century (why they mention 75 years in this article). This can be accelerated with further grinding to increase surface area. I would imagine that regulations for net-zero will push for carbon removals to be sold similar to carbon credits have been (as net-zero can only be achieved with removals, not credits). These could either be sold as they are created annually or pre-purchased as the mineralization is a pretty sure thing to happen. Whether this (as in CO₂ removal, not limited to enhanced rock weathering) evolves into a public service equivalent to garbage collection or a utility like water is yet to be seen.
- oldbbsnickname 3y ago
  I would bet seaweed or phytoplankton plus floating farm rigs would readily lead to scalable CCS. A few small regions of Earth's oceans would need to be sacrificed for sequestration. https://www.businessinsider.com/sargassum-turning-smelly-seaweed-into-a-carbon-removal-opportunity-2023-5 https://www.businessinsider.com/sargassum-turning-smelly-sea...
TaylorAlexander 3y ago
> if spread across croplands globally That’s a big if! Reminds me of “the market for comics is $32 billion a year. If NFTs can capture just 1% of the market that’s $320 million per year.” Also what are the CO2 emissions of transporting all these rocks??
- awb 3y ago
  No kidding. I’m struggling to think of any technology or technique that’s ubiquitous globally. Not to mention the labor and emissions required to harvest, transport and spread heavy rock across even a small percentage of fields.
jamescrowley 3y ago
I thought it worth mentioning that a startup called UNDO (https://un-do.com/ https://un-do.com/) is already doing this - and have designed a carbon credit methodology with Puro.earth (https://puro.earth/accelerate/undo-enhanced-rock-weathering-uk-100240 https://puro.earth/accelerate/undo-enhanced-rock-weathering-...) The crushed basalt they use is already a byproduct from quarries they partner with from what I understand.
rmason 3y ago
You have to ask yourself the question why would farmers allow you to spread crushed rock on their farmland? There is no positive benefit for them. The academics didn't study the long term effects of it on the land. The land is the tool the farmers use to make their living.
- matznerd 3y ago
  Actually, this incorrect, soils naturally acidify through nutrient loss (e.g. natural minerals) and the breakdown of nitrogen fertilizers. And soil have been amended with limestone (and volcanic soils) for a very long time. In fact, terrestrial enhanced rock weathering (ERW) was created to replace the cost of liming fields for farmers, which leads to the release of carbon. Many farmers are open to it because they need to balance their soil's ph. Which as you said, is important to farmers because the land "is the tool the farmers use to make their living" therefore, you can consider ERW/liming as the maintianence on their tool...
ruiisnwn 3y ago
Whom decided we need to reach the rediculous Net Zero target? We dont need to get anywhere near 0 to solve the problem
oldbbsnickname 3y ago
Nit: Confusing units. The proper unit for this field is Gt (Gigatonnes).
deleted 3y ago
[deleted]
globular-toast 3y ago
We'll compensate for that by emitting more carbon. But hey, someone got a job out of spreading rocks.
mnky9800n 3y ago
Those rocks come from the mantle. You can find them in outcrops in places like Oman and Norway. Typically they get to the surface through tectonics.

by jlhawn 3y ago

xjidjccudux 3y ago

[dead]

reaperman 3y ago

And how much would it affect agriculture? Do the plants thrive if you do this every year?

philipkglass 3y ago
Adding ground silicates can significantly increase agricultural productivity on various kinds of land. Here's one review article about the subject: "Remineralizing soils? The agricultural usage of silicate rock powders: A review" https://www.sciencedirect.com/science/article/pii/S004896972106054X https://www.sciencedirect.com/science/article/pii/S004896972... IIRC the soils that benefit the most include: - Soils depleted in micronutrients - Acidic soil - Silica depleted soil (significant for rice farming and other silica-sensitive crops) Most of the world's acidic and depleted soils that could benefit the most are in warm tropical regions with heavy rainfall. That's also where fresh mineral applications would weather most rapidly to draw down CO2. Unfortunately, it may also be harder (logistically and culturally) to encourage silicate applications on those soils than on the temperate climate soils of North America. After a certain point adding more silicates doesn't help increase soil productivity. The one thing that I haven't found any reporting on is where the "too much" point is reached for soil amendment with crushed silicates. I have seen that yields stop increasing with ever-increasing addition of ground rock. I haven't seen a point where they go down. I would guess that there's some point where yields actually start dropping, and that would mark the upper limit for agricultural soil amendments. Up to the point where yields keep increasing, you could expect farmers to spread crushed silicates on their fields for their own benefit, depending on the cost. In the high-application case where yields flatten out but carbon sequestration continues to increase, you'd need to pay subsidies to get higher application rates. You'd also need to pay subsidies in the lower-application-rate cases if yields increase but not enough to justify the expense on a yield basis.

spankalee 3y ago

The collective will we'd need to deploy this globally would probably indicate that we also somehow magically gained the collective will to reduce emissions. This is the problem with some of the geo-engineering approaches. We've shown that we can't really change how society and industry operate enough to reduce emissions, so what makes us think we can do the same for carbon capture? How do you actually get every farm to do this?

delecti 3y ago
The comment you replied to suggested carbon credits. That seems like a pretty obviously good answer. We're bad at forcing people to make broad changes, but nudging with money like that is often effective.
deleted 3y ago
[deleted]
bluGill 3y ago
Don't be so down. We have solved the ozone hole problem - it will take years to heal, but we emit very little ozone destroying things anymore. Last year my local utility generated more power from wind than there was demand. People do care and are making change. Change is slow to come, and even after it happens takes a long time to make a difference, but there are signs of change and the cause is being taken care of. Don't take that too far: there is a lot of work to do. However we have a good idea what that work is we just need to apply it.
- mrkeen 3y ago
  It's big again https://www.esa.int/Applications/Observing_the_Earth/Copernicus/Sentinel-5P/Ozone_hole_goes_large_again https://www.esa.int/Applications/Observing_the_Earth/Coperni...
  - neon_electro 3y ago
    But still on track to shrink? From your source (thank you for the read): > Claus concludes, “Based on the Montreal Protocol and the decrease of anthropogenic ozone-depleting substances, scientists currently predict that the global ozone layer will reach its normal state again by around 2050.”

epistasis 3y ago

We need to get to negative emissions in the second half of this century. From 5-10Gton/year, IIRC. So this should not be used to offset new emissions, but thought of as a way to claw back the damage we are still creating today.

mjan22640 3y ago
Those emitting CO2 will pay, and those capturing will receive the money.
- PeterisP 3y ago
  Perhaps that's how it should be in a perfect world, but in the world we live in that isn't the case and doesn't seem likely to be the case - there are some local markets for CO2 incentives, but on the international level there's no willingness for major emitter countries to pay other countries, no evidence that (or why) this willingness might appear, and there's no global government that could make or enforce any rules unless countries opt-in; nobody can force nuclear countries to pay others.
  - mschuster91 3y ago
    Agree on the rest, but on none of this: > but on the international level there's no willingness for major emitter countries to pay other countries, no evidence that (or why) this willingness might appear Of course no one wants to pay, but courts have already begun shifting their attitude in a number of historic rulings against large emitters, and there are a ton of cases being in progress at the moment [1]. IMHO it's only a matter of time until the first court orders direct international financial damage payments, particularly to countries that threaten to be literally flooded from the map like Vanuatu [2]. For what it's worth, most Western countries already pay large sums of money to the Global South as part of general development aid. > and there's no global government that could make or enforce any rules unless countries opt-in The US absolutely can, like they did with anti money-laundering legislation. Everything and everyone that touches the US dollar is, in the end, accountable to the US and its will. Besides, who would have thought that the world would eventually converge on getting rid of tax havens? To force the Swiss of all people to dismantle the holy grail of bank secrecy? Almost no one, given the absurd amounts of money at stake, and yet it happened (partially though as a consequence of the various leaks of tax evader data). [1] https://en.wikipedia.org/wiki/Climate_change_litigation https://en.wikipedia.org/wiki/Climate_change_litigation [2] https://www.washingtonpost.com/climate-solutions/2023/03/29/vanuatu-international-court-un/ https://www.washingtonpost.com/climate-solutions/2023/03/29/...

api 3y ago

It would more than offset global aviation, which is one of the areas where replacing fossil fuels is the most difficult.

marcosdumay 3y ago

> metabasalt and olivine Well, yes, a lot of farmers (not all, probably most) are interested on adding those to their soil and will do it if it's cheap enough. I'm not sure we can mine, pulverize, and distribute it in a carbon-negative way. But yeah, coupled with large scale implantation of renewables and decarbonization of transportation, it may be enough to even roll climate change back a little bit.

vonwolfhausen 3y ago
Olivine comes from Norway, which uses hydro power. The energy in extracting and crushing is around 4kg CO2/ton. Pulverizing is around 30-50kgCO2/ton rock. Majority of transport is on water (ocean, river), which is low emissions. In the end, for every ton of rock around 850kg of CO2 are removed. For basalt, it's around 200kg net, so the supply chains have to be shorter. I checked my math with the DOE's experts, and it checks out.
- gattilorenz 3y ago
  Source for the numbers?
  - euroderf 3y ago
    Yes, further details would be very illuminating !
  - matznerd 3y ago
    Sibelco's Aheim mine essentially supplies a large part of the world's olivine today. It is located in a Fjord with its own port. The transportation distance is very small. See their website here: https://www.sibelco.com/en/150-years/aheim https://www.sibelco.com/en/150-years/aheim "The proximity of Aheim’s mine, processing facility and shipping terminal enables Sibelco to run a highly efficient operation with minimal transport or double-handling of materials. Quarried olivine is moved via conveyor belt through a 4km tunnel to the processing plant where it is crushed, dried and screened into different grades." When transporting mostly by ship, olivine ERW efficiency can remain >90% even with 1000+ kilometers of sea transit. See this working paper: Environmental life cycle assessment of CO2 sequestration through enhanced weathering of olivine https://legacy.projectvesta.org/wp-content/uploads/2019/06/Environmental-life-cycle-assessment-of-CO2-sequestration-through-enhanced-weathering-of-olivine.pdf https://legacy.projectvesta.org/wp-content/uploads/2019/06/E...

chinchilla2020 3y ago

Let's not forget the massive CO2 generated by mining, processing, and transporting crushed rock. I used to work on SAG (semiautonomous grind) mills for fine grind on copper-bearing ore. Grinding rock is incredibly energy inefficient. I would suspect this entire process is carbon-positive despite the atmospheric capture. It seems we will do anything to avoid the obvious - we need to reduce energy use and transition to green generation.

klysm 3y ago
what about using rock that's already being crushed for processes like that? Still have the transport but may as well use the ground stuff for something.
- chinchilla2020 3y ago
  Possibly. I am not familiar with the sort of basalt they are using here. It may very well make sense under those conditions.
  - kisamoto 3y ago
    Olivine is in ready supply as a by-product from the mining industry. There are piles of it laying around (which don't have the same effect as spreading it out) although they do need to be transported to projects.
    - klysm 3y ago
      By-product is the word I was looking for. Hopefully there isn’t a need for primary production
- kansface 3y ago
  We are talking about adding it to farmland so we really care about yields and safety.
fudged71 3y ago
Do you think gravity-assisted rock crushing could be feasible?

mhandley 3y ago

If 2.8 billions tonnes isn't enough, can we just spray additional olivine powder over the surface of the ocean? Presumably it would lock up CO2 in the seawater just fine, allowing more CO2 to be absorbed by the ocean from the air.

matznerd 3y ago
Need very fine particles for that and its usually classed then as ocean alkalinity enhancement (OAE). A hybrid method has been proposed in the literature, to use beaches and is currently being implemented via a project I started (but which I am no longer with) that has been turned into a company called Vesta -> https://vesta.earth https://vesta.earth Rolling stones; fast weathering of olivine in shallow seas for cost-effective CO2 capture and mitigation of global warming and ocean acidification https://esd.copernicus.org/preprints/2/551/2011/esdd-2-551-2011.pdf https://esd.copernicus.org/preprints/2/551/2011/esdd-2-551-2... https://smartstones.nl/research/publications-2/ https://smartstones.nl/research/publications-2/

supergeek 3y ago

Agriculture is currently massively carbon intensive and is one of the hardest modern technologies to decarbonize. It relies on fertilizer production that is currently completely reliant on fossil fuels. If this can decarbonize agriculture, that's a massive win for our chances to reach net zero carbon emissions on time.

ben_w 3y ago

8% sounds good to me. The required reduction in emissions is 99.9% (net), which is approximately "everything everywhere except maintaining grassland"[0] if done by reducing gross emissions; the last percentage point of a problem is usually the most difficult, so if we can get a whole 8% by making a cheap sink, that's probably for the best. Just so long as it's in the sweet spot of "cheap enough" without crossing over into the realm of "people can make money mining the CO2 out of the air", because if that happens then the same economic pressure that means we have too much CO2 now will become one of too little CO2. [0] https://ourworldindata.org/ghg-emissions-by-sector https://ourworldindata.org/ghg-emissions-by-sector

kisamoto 3y ago

Very significant impact. There is no silver bullet that can remove the excess emissions on it's own, however combinations of these removal methods (coupled with decarbonization of course) will be essential to addressing excess atmospheric CO₂. Regarding economics; there is plenty of olivine rock already available as a mining by-product. Disadvantages are that it takes up to 1000 years to fully sequester however this is logarithmic with a large portion of this achievable in the first century (why they mention 75 years in this article). This can be accelerated with further grinding to increase surface area. I would imagine that regulations for net-zero will push for carbon removals to be sold similar to carbon credits have been (as net-zero can only be achieved with removals, not credits). These could either be sold as they are created annually or pre-purchased as the mineralization is a pretty sure thing to happen. Whether this (as in CO₂ removal, not limited to enhanced rock weathering) evolves into a public service equivalent to garbage collection or a utility like water is yet to be seen.

oldbbsnickname 3y ago
I would bet seaweed or phytoplankton plus floating farm rigs would readily lead to scalable CCS. A few small regions of Earth's oceans would need to be sacrificed for sequestration. https://www.businessinsider.com/sargassum-turning-smelly-seaweed-into-a-carbon-removal-opportunity-2023-5 https://www.businessinsider.com/sargassum-turning-smelly-sea...

TaylorAlexander 3y ago

> if spread across croplands globally That’s a big if! Reminds me of “the market for comics is $32 billion a year. If NFTs can capture just 1% of the market that’s $320 million per year.” Also what are the CO2 emissions of transporting all these rocks??

awb 3y ago
No kidding. I’m struggling to think of any technology or technique that’s ubiquitous globally. Not to mention the labor and emissions required to harvest, transport and spread heavy rock across even a small percentage of fields.

jamescrowley 3y ago

I thought it worth mentioning that a startup called UNDO (https://un-do.com/ https://un-do.com/) is already doing this - and have designed a carbon credit methodology with Puro.earth (https://puro.earth/accelerate/undo-enhanced-rock-weathering-uk-100240 https://puro.earth/accelerate/undo-enhanced-rock-weathering-...) The crushed basalt they use is already a byproduct from quarries they partner with from what I understand.

rmason 3y ago

You have to ask yourself the question why would farmers allow you to spread crushed rock on their farmland? There is no positive benefit for them. The academics didn't study the long term effects of it on the land. The land is the tool the farmers use to make their living.

matznerd 3y ago
Actually, this incorrect, soils naturally acidify through nutrient loss (e.g. natural minerals) and the breakdown of nitrogen fertilizers. And soil have been amended with limestone (and volcanic soils) for a very long time. In fact, terrestrial enhanced rock weathering (ERW) was created to replace the cost of liming fields for farmers, which leads to the release of carbon. Many farmers are open to it because they need to balance their soil's ph. Which as you said, is important to farmers because the land "is the tool the farmers use to make their living" therefore, you can consider ERW/liming as the maintianence on their tool...

ruiisnwn 3y ago

Whom decided we need to reach the rediculous Net Zero target? We dont need to get anywhere near 0 to solve the problem

oldbbsnickname 3y ago

Nit: Confusing units. The proper unit for this field is Gt (Gigatonnes).

deleted 3y ago

[deleted]

globular-toast 3y ago

We'll compensate for that by emitting more carbon. But hey, someone got a job out of spreading rocks.

mnky9800n 3y ago

Those rocks come from the mantle. You can find them in outcrops in places like Oman and Norway. Typically they get to the surface through tectonics.