Hacker News Re-Imagined

Spreading rock dust on farms as a climate solution

  • 223 points
  • 13 days ago

  • @penneyd
  • Created a post

Spreading rock dust on farms as a climate solution


@jeremygaither 13 days

Replying to @penneyd 🎙

There is probably a lot of leftover rock from extracting everyday things like aluminum, as well as rare earth elements, which electronics manufacturing needs for many components. If the generation of the stones that get crushed and used for dusting is an output of other essential mining projects, that could further offset the costs associated with generating rock dust. It could also potentially reduce the shortage of these rare earth minerals, and associated electronic components, by attracting more mining operations to operate in additional countries.

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@snidane 13 days

Replying to @penneyd 🎙

If the rock dust captures so much CO2, what will the plants breathe?

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@penneyd 13 days

Replying to @penneyd 🎙

Any obvious downsides to this approach?

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@dgan 12 days

Replying to @penneyd 🎙

> "assuming a baseline application rate of 40 t ha−1 yr−1 of basalt rock dust"

I am sorry, what? 40 tonnes of basalt dust per hectar?? What's hilarious is that when you look up basalt dust on internet, merchants sell it in bags of 2kg, "to be applied 20 grammes/sq meter", while 40t/ha is 4kg per sq meter!

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@jvanderbot 13 days

Replying to @penneyd 🎙

Crushing and distributing the required amount of rock seems challenging. Unless crushed rock is really produced enough by mining and is somehow really cheap to move (eg trains are coming back empty anyway)? It probably also adds another trip around the field for the combines?

Still, if it's this easy we really need to be doing this.

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@ck2 13 days

Replying to @penneyd 🎙

Is "rock dust" proven, peer-reviewed and reproduced or is it some pet-theory of an academic or two?

Because one thing I've noticed especially over the past two years of covid research, once some PhD seems to vapor-lock onto a single substance as a "miracle cure" they can write endlessly, breathlessly about it without mentioning a single downside or limitation.

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@travisporter 13 days

Replying to @penneyd 🎙

Discussed by the late David mackay. http://www.withouthotair.com/c31/page_246.shtml

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@wokwokwok 13 days

Replying to @penneyd 🎙

It's hard not to be skeptical.

If only there was a way to solve climate change with carbon capture that was low tech, easy to do, simple to understand, didn't pose any long term side effects and pretty cheap to do.

Oh, and it can solve all the CO2 emissions you could ever want, so you know, you don't even have to make significant changes to your industry or way of life, because your emissions are pretty much flat out neutralized by this one simple thing.

Sounds perfect right?

Sounds like a silver bullet.

...but, silver bullets don't exist.

So, I can guarantee it's not that simple. Maybe it's another useful tool to help tackle climate change, probably with more research as to how to actually works. ...but, I think anyone who's excited by this needs to calllllmmm the F down, because this idea has been around for quite a while, and no one is using it; so I suspect there are some things that still need to be figured out like:

- do the benefits scale linearly, or is it a logarithmic curve (like most things)?

- can you actually measure the amount of carbon captured to prove its working?

- does it have any side effects on the ecosystem?

- does it have any impact on, you know, the farms you're putting it on?

- does their model (which is all they did, create a Matlab model) actually work in the real world?

- how often do you have to do it for it to stay effective?

It's complicated right.

I mean, sounds promising... but this:

> The simple act of sprinkling rock dust—an abundant byproduct of mining—on farmland could capture 45% percent of the carbon dioxide required to help the UK meet its 2050 net-zero targets.

Is just idle wishing the problem away. It might. It might not. There's a model that suggests it might.

I'm not convinced we should be sprinkling rock dust over the entire country quite yet.

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@credit_guy 13 days

Replying to @penneyd 🎙

> by 2050, it could be removing up to 30 million tons of CO2 from the atmosphere each year, capturing almost half—45%—of the emissions the UK needs to vanquish from its atmosphere.

The UK emits about 450 million tons of CO2. They are off by a factor of 6.75

https://en.m.wikipedia.org/wiki/Greenhouse_gas_emissions_by_...

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@legitster 13 days

Replying to @penneyd 🎙

There's an obvious path to a future where we can avoid the worst outcomes of climate change affordably using geoengineering.

But the loudest detractors of these ideas are those who feel any path free of suffering or moralizing must be wrong. You can almost never get to a debate on the merits.

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@eru 13 days

Replying to @penneyd 🎙

Compare Gwern's proposal: https://www.gwern.net/CO2-Coin

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@alfor 12 days

Replying to @penneyd 🎙

Also consider that volcanic rock contain every elements necessary for plant and animal life. Volcanic rock dust + wood chips is a popular organic way to increase soil fertility. The rock supply all the elements and the wood chip the organic matter to feed the mycelium and other soil life.

It’s also a way to move away from chemical fertilizer made from mined minerals and natural gas

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@datadata 13 days

Replying to @penneyd 🎙

Adding iron to the ocean to fertilize carbon sequester ING plankton is a interesting related approach: https://en.m.wikipedia.org/wiki/Iron_fertilization

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@blenderdt 13 days

Replying to @penneyd 🎙

What about silicosis?

Rock dust doesn't sound very healthy. People and animals next to the farm will breathe it when the weather is dry.

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@greeneggs 13 days

Replying to @penneyd 🎙

The Future Forest Company spreads basalt on forestland for carbon sequestration [1].

Wren offers it as one of its carbon offsets [2]. However, it is currently the most expensive of their offset programs, per ton of carbon offset or removed, and significantly so.

[1] https://www.fastcompany.com/90642582/this-company-is-crushin...

[2] https://www.wren.co/projects/mineral-weathering-in-scotland

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@csnover 13 days

Replying to @penneyd 🎙

Previous discussions on this approach:

Spreading rock dust on fields could remove vast amounts of CO2 from air (2020; 109 comments) - https://news.ycombinator.com/item?id=23770718

Potential large-scale CO2 removal via enhanced rock weathering with croplands (2020; 90 comments) - https://news.ycombinator.com/item?id=23831411

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@spenrose 13 days

Replying to @penneyd 🎙

Paper from researchers: https://www.nature.com/articles/s43247-022-00436-3

"Using life-cycle assessment modelling of potential supply chain impacts for twelve nations undertaking Enhanced Rock Weathering deployment to deliver up to net 2 Gt CO2 yr−1 CDR, we find that rock grinding rather than mining exerts the dominant influence on environmental impacts. This finding holds under both a business-as-usual and clean energy mix scenario to 2050 but transitioning to undertaking Enhanced Rock Weathering in the future with low carbon energy systems improves the sustainability of the Enhanced Rock Weathering supply chain. We find that Enhanced Rock Weathering is competitive with other large-scale Carbon Dioxide Removal strategies in terms of energy and water demands."

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@faleidel 13 days

Replying to @penneyd 🎙



@rascul 13 days

Replying to @penneyd 🎙

Is this meant to be spread on cropland? I figure so because they say farmland and the (stock?) photo appears to be crops but I didn't see it specifically mentioned. What affects will it have on the crops?

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@paulcole 13 days

Replying to @penneyd 🎙

Whatever it takes so that nobody in America has to make any substantive changes in their way of life.

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@hosh 13 days

Replying to @penneyd 🎙

Isn’t that adding more dead dirt to dead dirt, rather than cultivating soil? How does rock dust encourage soil bacteria and fungi that symbiotically trade minerals for sugars with the plants?

It might be low-tech, but it’s not really a regenerative approach.

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@lifeplusplus 12 days

Replying to @penneyd 🎙

What happens after multiple layering / years after, won't you at some point remove rock layer to keep fertile soil

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@verisimi 12 days

Replying to @penneyd 🎙

> The simple act of sprinkling rock dust—an abundant byproduct of mining—on farmland could capture 45% percent of the carbon dioxide required to help the UK meet its 2050 net-zero targets.

Has this news been brought to me via the 'mining board'? Is it an attempt to get us to pay for their waste?!

And won't rock dust degrade the soil quality?

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@gomijacogeo 12 days

Replying to @penneyd 🎙

1. How much additional energy does it take to pulverize the rock? 2. What about the effect the rock will have on soil pH? 3. What about leached salts and heavy metals?

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@daodedickinson 13 days

Replying to @penneyd 🎙

I have rocks to sell if anyone's buying.

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@mrfusion 13 days

Replying to @penneyd 🎙

So why would rocks do this but not the soil that’s already on the ground there? Isn’t it basically the same stuff?

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