Spreading rock dust on farms could be a major climate action:
Eventually (ideally sooner rather than later), efforts to reduce greenhouse gas emissions are going to have to be joined by a technology that actively removes CO2 from the atmosphere. There are a number of options [...] and a new feasibility study suggests that one of them—spreading crushed rock on farm fields—deserves serious consideration.
[...] Using crushed rocks isn't a new idea. Some common minerals react with water and CO2 as they weather, converting CO2 from the air into bicarbonate dissolved in water. That bicarbonate (along with some calcium and magnesium) may hang out in groundwater or make its way into the ocean. And along the way, it can also turn into solid carbonate. Whatever route it takes, it's no longer a greenhouse gas in the air.
Over hundreds of thousands or millions of years, this process has an important stabilizing influence on Earth's climate. Warmer climates encourage more weathering, pulling greenhouse gas out of the atmosphere.
[...] One way to accelerate weathering is to grind up that rock into small particles. Just as powdered sugar dissolves in water much more quickly than a large solid candy would, these small particles will weather much faster. Spreading that crushed rock over farm fields not only nicely exposes it to the elements but can also be beneficial for the soil, replenishing nutrients and counteracting pH changes in heavily farmed soils.
[...] Globally, the researchers estimate that this process could be used to capture 500 million to 2 billion tons of CO2 per year in 2050. For comparison, scenarios that limit global warming to 2°C generally involve capturing something like 2 to 10 billion tons per year in a few decades from now.
[...] In the US, EU, and Canada, the researchers estimate that all this would cost about $160 to 190 per ton of CO2 captured, while China, India, and Brazil could do it for $55 to 120 per ton. That's in the same ballpark as other some options for atmospheric CO2 removal..
Journal Reference:
David J. Beerling, Euripides P. Kantzas, Mark R. Lomas, et al. Potential for large-scale CO 2 removal via enhanced rock weathering with croplands, Nature (DOI: 10.1038/s41586-020-2448-9)
Additional Information:
Johannes Lehmann, Angela Possinger. Removal of atmospheric CO2 by rock weathering holds promise for mitigating climate change, Nature (DOI: 10.1038/d41586-020-01965-7)
(Score: 2) by c0lo on Friday July 17 2020, @08:44AM (8 children)
Until the majority of the energy comes from renewables, we won't be able to do anything about climate warming.
Those rocks didn't weather because they didn't get crushed yet. And crushing them is not a free energetic lunch.
Yeah, maybe a nice idea, except we can't apply it today on large scale without causing more damage. It's easier/cheaper to plant more trees than crush enough rock.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 1, Insightful) by Anonymous Coward on Friday July 17 2020, @09:13AM (3 children)
I already apply crushed rock on my fields. If this stuff ends up a similar cost, accomplishes the same thing, and helps the environment to boot, then why not do this stuff instead? Of course, I'd actually have to see numbers on those first two points.
(Score: 2) by c0lo on Friday July 17 2020, @09:38AM (1 child)
Of course you will need to see those numbers to understand if applying crushed rock is beneficial or not.
What I can tell you is that the energy required by crushing those rock is more likely to be obtained by emitting more CO2 than they'll ever capture by weathering.
And it won't be just probability, it will be certainty if everybody rushes to spread crushed rocks on their fields at large scales.
https://www.youtube.com/watch?v=aoFiw2jMy-0
(Score: 0) by Anonymous Coward on Friday July 17 2020, @07:59PM
I am unsure if you understand that we are already crushing rocks and putting it on fields. Due to this fact, comparison shouldn't be between zero and the new system but between the old one and the new one.
(Score: 2) by pdfernhout on Saturday July 18 2020, @12:15AM
https://www.remineralize.org/ [remineralize.org]
Example: https://www.remineralize.org/2019/09/planting-a-trillion-trees-to-save-earth-remineralization-can-help/ [remineralize.org]
"In an RTE study, Dr. Goreau found that Acacia Mangium tree seedlings planted in a thin layer of local basalt rock dust from a Panama quarry had an eight-fold increase in biomass, 2.17 increase in tree height and four times the survivability over five years when compared to other study samples. Trees planted on the local soil did not survive. Hard silicate rock is one of the most abundant resources on the planet. It is readily available as a byproduct from the aggregate industry, and RTE promotes its simple, low-cost application to soils and forests."
The biggest challenge of the 21st century: the irony of technologies of abundance used by scarcity-minded people.
(Score: 1, Touché) by Anonymous Coward on Friday July 17 2020, @12:18PM
This is the solution to global cooling, not global warming.
(Score: 0) by Anonymous Coward on Friday July 17 2020, @03:00PM
Full employment for our large prison population?
(Score: 3, Interesting) by VLM on Friday July 17 2020, @05:38PM
Oh its a lot larger scale than you seem to think.
You'd have to do subsidies or whatever to convince farmers to dump anti-CO2 stuff along with their existing rock based fertilizers.
Aside from industrial grain farming there's also BIG business in soil amendments. Blueberries would be an obscure rarity without massive soil amendment.
Also from a chemical engineering perspective the energy required to crack liquid water molecules off their buddies to make steam is very consistent and well defined thermodynamics whereas in theory I guess an infinitely small force could shatter crumbly enough rock ore. There's no free lunch to manufacture steam for turbines, but there is no inherent lower bound to the energy cost of smooshing rocks. That's the bottom up argument. The top down argument is that high explosives for mining actually have a very low energy density compared to most anything yet shatter lots of ore. Infinitely high instantaneous power is what makes little rocks out of big rocks, not total energy expended.
Someday, as capacitors and switching semiconductors get more ridiculous, I think mines might not use chemical explosives every again, just exploding plain old metal wires connected to unimaginably huge low internal resistance capacitors for maybe a nanosecond.
(Score: 0) by Anonymous Coward on Saturday July 18 2020, @04:16PM
Precisely, ideas like this might be a part of the solution once we're operating at a net negative emissions level to put us back where we were at the beginning of the century. In essence speeding up the cooling process. But, by lightening areas that had been darker, you're not really doing much to get snow back where it belongs. That is the glaciers and the polls. It would be more effective to make those lighter.
Unfortunately, that makes the problem of energy generation to complete the problem even larger as the untold tons of rock dust needed would need zero or extremely low carbon emission energy sources to not cancel out the effect.
In the long run, it's probably going to be a patchwork of these sorts of ideas on top of drastically cutting our emissions that works. Unfortunately, I don't see that happening quickly enough to stave off the worst of it. And even if we magically hit slightly negative emissions right now, we've already lost a ton of wildlife that will take centuries or longer to recover the biodiversity to handle future climate problems.
(Score: 0) by Anonymous Coward on Friday July 17 2020, @10:54AM (3 children)
Or, we could just pay the Sahara desert, or any number so similar geologic features, to grind rock into very small particles, called "sand", and then further reduce that until it blows away, like "dust", and is deposited in "places". Or, not.
(Score: 0) by Anonymous Coward on Friday July 17 2020, @12:48PM
You might try reading up a bit on "chemistry" before posting again in this story.
(Score: 2) by HiThere on Friday July 17 2020, @01:55PM (1 child)
Well, most sand is already oxidized, so it won't weather very much. Sand is generally what is left when everything more soluble/softer has been washed away. So it's generally fairly pure silicon dioxide. That won't absorb CO2, and isn't even that useful for the main purpose of applying crushed rock to fields: Restoring the minerals that the plants have mined out of it to convert to food, wood, etc.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 0) by Anonymous Coward on Friday July 17 2020, @08:38PM
Saharan sand is the main source of nutrients for the Amazon rainforest...
(Score: 0) by Anonymous Coward on Friday July 17 2020, @03:39PM (2 children)
So they can start coming up with a scheme for selling rock dust credits.
(Score: 0) by Anonymous Coward on Friday July 17 2020, @03:51PM
There must be some Al Gore Rhythm for that.
(Score: 0) by Anonymous Coward on Saturday July 18 2020, @04:18PM
Possibly, but theoretically, this would make far more sense than giving farmers money to not grow crops. Giving them money to do something with the acreage that addresses climate change would make far more sense. Whether that being growing crops that are well-suited to carbon neutral fuel or that are suited to being buried as part of a carbon sequestration scheme.
These efforts would likely have minimal impact, but they would have some and we're already paying them money to effectively not grow crops.
(Score: 0) by Anonymous Coward on Friday July 17 2020, @07:16PM
1) the carbon absorbing basalt dust is blown in a wide radius
2) the volcano might reactivate and make even more basalt and light reflecting sulfur