Our working paper about MRV for ERW using traditional methods vs. CO2-in-soil-gas-based methods is out

[Dirk Paessler]

FYI: We have published a working paper about the results of the last 2 years and how CO2 sensors in the soil might be helpful for MRV.

Carbon Drawdown Initiative has published a detailed report about their attempts to measure the speed of enhanced rock weathering on croplands in four extensive field-experiments over more than two years. The traditional leachate- and EC/pH-based MRV approaches have not shown any signal (yet!). But by measuring the basalt's dissolution rate and especially by measuring CO2 in the soil gas they seem to be able to assess the CDR effect as early as weeks or months after basalt application. In the future, this novel approach could provide a faster way to assess the effectiveness of ERW in removing CO₂ from the atmosphere.

https://www.carbon-drawdown.de/blog/2023-5-17-monitoring-co2-concentrations-in-soil-gas-a-novel-mrv-approach-for-cropland-based-erw

Dirk

Carbon Drawdown Initiative Carbdown GmbH

www.carbon-drawdown.de - Wilhelmshavener Str. 64, D-90766 Fürth
Registration: Amtsgericht Fürth HRB 17909 - VAT-ID DE328445765

Management/Geschäftsführer: Dirk Paessler, Ralf Steffens

[Robert Höglund]

This is a super important paper

We have a lot of companies selling carbon removal from ERW now as if we know it works. But clearly, we don't know it yet. Purchases of CDR should be going to actors that use the deployments to help figure it out. Its not the time to scale for sure

Robert

[Toby Bryce]

Curious to hear any counterpoint from EW practitioners to Robert's assertion here!

[Michael Hayes]

Bellow is a paper that does indicate that it works, yet a full scale up would likely require a rather large number of individual efforts. This conclusion is inline with most prior views:

https://www.pmel.noaa.gov/public/pmel/publications-search/search_abstract.php?fmContributionNum=5358

Scale up, and speed of scale up, are critical issues for all CDRs, that's nothing new. Getting the startups properly funded ASAP is what is needed. We don't have time to spare.

Many mCDRs can start by addressing local impacts, not global gigton scale levels as it will take time to reach gigton scales. As the early small scale systems start to gain scale/experiance, the finer details of any global scale negative environmental impacts can be more tightly scrutinized and the mCDR system can then be adjusted to address any concerns, if needed.

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[Michael Hayes]

Apologies, ERW is not OAE using minerals. I must have rocks in my head this morning.

Yet, funding early stage deployment of all reasonably sound CDRs is something I do recommend.

[Greg Rau]

Regarding the C Drawdown paper, please explain how the suppression of soil resp via rock additions doesn’t account for the reduction in CO2 flux observed rather than direct ERW CDR? In calculating CDR via CO2 flux, the difference in CO2 flux between controls and experimentals is assumed to represent the effect of CDR. That only works if you show that the production rate of CO2 (respiration) is the same across treatments. Lack of corroborating lysimeter data, tells me it’s suppressed respiration not direct ERW that’s going on, but prove me wrong. Suppressed resp is still a good thing for air CO2, but maybe not for soil/plant ecology.

Greg

Sent from my iPhone

On May 18, 2023, at 10:19 AM, Michael Hayes <electro...@gmail.com> wrote:



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[Jelle Bijma]

Dear Robert,

Agreed, we have not (yet) fully sorted out the dissolution kinetics of rock flour to the extend needed for a compliance market but we all know that "it works", as this is how Mother Earth deals with excess carbon, and we also know that we can speed up natural weathering substantially. The natural global weathering rate is on the order of 0.5 to 1 Gt CO2 annually. So speeding that up by a factor of 10 or 20 brings us already in the same order of magnitude as the anthropogenic perturbation.

Another important question to consider is whether we have the luxury to wait with upscaling until the MRV is fully in place. We will need to remove at least 1 Gt of CO2 annually in 7 years from now. ERW is, IMHO, one of the best options for fast upscaling of permanent CDR as it is low cost, low tech, does not require a lot of new infrastructure nor additional energy and does not compete for space nor food production. All it requires is to create a decent business case for farmers.

Frontier buyers have just signed the first $53M in offtake agreements with Charm Industrial.  Why not think about offtake agreements for ERW? Let us learn of the job. I strongly believe that in a couple of years from now our MRV will be good enough for the compliance market but we need to start scaling up before we enter a runaway greenhouse world of permafrost thawing.

--
all the best,
Jelle

Prof. Dr. Jelle Bijma

Deputy section head Marine Biogeosciences
Speaker graduate school POLMAR

Am Handelshafen 12 D-27570 Bremerhaven Germany
Phone (office) +49(471)4831-1831
Fax (office) +49(471)4831-2020
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Google Scholar: https://scholar.google.de/citations?user=-BTyjHYAAAAJ
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[Jelle Bijma]

Dear Greg,

an interresting point you raise. In general, I would argue that the application of powdered basalt on farmland is not a new practise but something has been done for a long time, not because the goal was to store CO2 but because it replaces mineral fertiliser, increases the resistance of the crops and increased the yield. In Germany it is legally allowed and practisioned by "bio farmers". We have noted ourselves in field trials and in the XXL lysimeter experiments that the plants grow bigger and carry more flowers.

As for a medicine, in our efforts to understand the kinetics of ERW and to calculate the speed of carbon storage, we keep in mind that the dose makes the poison.

most of the initial experiments looked into carbonate chemistry calculations. However, carbonate chemistry analyses in soil leachate are much more complicated on land than in the oceans due to additional inorganic and organic acids (manure), organic alkalinity,  etc. Even though laboratory experiments offer more control, they fail to reproduce the true complexity of field settings. It seems reasonable to assume that carbonate chemistry based calculations provide a weathering estimate at the lower end of the spectrum.

Lithos Carbon developed a complementary approach based on the analyses of the solid phase instead of analysing soil leachate. Using MC-ICP-MS (multi-collector inductively-coupled-plasma mass-spectrometry) they analyse the fraction of basalt remaining/lost due to dissolution, by measuring changes in the ratio of mobile cations vs. titanium. Their calculations provide an estimate at the high end of the weathering spectrum (i.e. the max. potential of rocks to store carbon based on the stoichiometry of its composition).

Both methods, analyzing the remaining fraction of basalt in the solid phase or the dissolution products in the leachate, suffer from similar weaknesses: Heterogeniety in the field, the fate of the cations related to secondary processes, unquantified impact of organic alkalinity, etc.

To close the gap between the two estimates, a model can be employed to deal with the unknowns (e.g. Lithos Carbon) or we need to identify a parameter that summarizes all the processes. The last option is now being investigated by the Carbon Drawdown Initiative (see blog). They moved to work in the greenhouse where soil heterogeneity can be better controlled and the fate of the cations can be followed. They are testing both methods and have added an independent third parameter: the CO2 concentration in the soil and the flux of CO2 to the atmosphere.

I firmly believe that soil/atmosphere flux measurements are the way forward towards a robust and scalable MRV of ERW, maybe in combination with annual but possibly lower frequency analysis of soil samples to measure the basalt fraction that has dissolved.

--
all the best,
Jelle

--
all the best,
Jelle

Prof. Dr. Jelle Bijma

Deputy section head Marine Biogeosciences
Speaker graduate school POLMAR

Am Handelshafen 12 D-27570 Bremerhaven Germany
Phone (office) +49(471)4831-1831
Fax (office) +49(471)4831-2020
e-mail: jelle...@awi.de

Google Scholar: https://scholar.google.de/citations?user=-BTyjHYAAAAJ
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Phone (home) +49(4746)1560
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[Tom Goreau]

Soil CO2 is very dynamic due to biological sources, and can change on short time scales, so it reflects much more than weathering alone!

 

Soil CO2 is greatly elevated over the atmosphere due to organic matter decomposition and soil respiration, which are much more than the decrease caused by weathering.

 

I developed methods for rapid measurement of CO2, N2O, and methane soil-atmosphere fluxes for my PhD thesis in the 1970s and made thousands of measurements at Hubbard Brook Experimental Forest, the Everglades, and Amazonia.

 

In Amazonia we found that around 80% of the CO2 exhaled by soil came from root respiration or fauna that relied on living roots by measuring the decrease in CO2 fluxes following deforestation.

 

Thomas J. F. Goreau, PhD
President, Global Coral Reef Alliance

Chief Scientist, Blue Regeneration SL
President, Biorock Technology Inc.

Technical Advisor, Blue Guardians Programme, SIDS DOCK

37 Pleasant Street, Cambridge, MA 02139

gor...@globalcoral.org
www.globalcoral.org
Skype: tomgoreau
Tel: (1) 617-864-4226 (leave message)

 

Books:

Geotherapy: Innovative Methods of Soil Fertility Restoration, Carbon Sequestration, and Reversing CO2 Increase

http://www.crcpress.com/product/isbn/9781466595392

 

Innovative Methods of Marine Ecosystem Restoration

http://www.crcpress.com/product/isbn/9781466557734

 

No one can change the past, everybody can change the future

 

It’s much later than we think, especially if we don’t think

 

Those with their heads in the sand will see the light when global warming and sea level rise wash the beach away

 

Geotherapy: Regenerating ecosystem services to reverse climate change

 

 

 

Carbon Drawdown Initiative Carbdown GmbH

www.carbon-drawdown.de - Wilhelmshavener Str. 64, D-90766 Fürth
Registration: Amtsgericht Fürth HRB 17909 - VAT-ID DE328445765

Management/Geschäftsführer: Dirk Paessler, Ralf Steffens

 

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[Greg Rau]

Thanks, Jelle.  Obviously a lot of amazing work went into this. I'm just saying that if adding rock reduces CO2 flux from solis you've got to separate out possible negative effects on respiration vs direct ERW CDR. You can do that by showing whether or not respiration is the same among treatments and controls, and you can't use CO2 flux to do that because it's confounded with ERW. Eg, show me that O2 concentrations or fluxs among controls and treatments was the same and I'll believe the ERW story. Otherwise, lack of soil chem data supporting the ERW hypothesis seems suspicious. 

Regards,

Greg

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Greg H. Rau, Ph.D.

Senior Research Scientist
Institute of Marine Sciences
Univer. California, Santa Cruz
https://www.researchgate.net/profile/Greg_Rau
Co-founder and manager, the Carbon Dioxide Removal Google group
Co-founder and CTO, Planetary Technologies, Inc.
510 582 5578

510 363 1519 c

[Jelle Bijma]

Absolutely, the very high soil pCO2 values (3000 to > 10.000 ppm) are exactly the reason why ERW can potentially be so efficient in CDR (tropical soils have not just higher soil pCO2 values but also higher T and likely water!)... and yes, it is very, very dynamic on a daily basis, showing that photosynthesis and respiration dominate the scene.... but what we're looking at is the flux difference between treated vs. untreated, and that value reflects a measure of the sum of all processes giving rise to "negative emissions", weather it results directly from ERW or suppression of soil resp via rock additions needs to be established (and is underway).

--
all the best,
Jelle

Prof. Dr. Jelle Bijma

Deputy section head Marine Biogeosciences
Speaker graduate school POLMAR

Am Handelshafen 12 D-27570 Bremerhaven Germany
Phone (office) +49(471)4831-1831
Fax (office) +49(471)4831-2020
e-mail: jelle...@awi.de

Google Scholar: https://scholar.google.de/citations?user=-BTyjHYAAAAJ
ResearchGate: https://www.researchgate.net/profile/Jelle_Bijma
Orcid ID: https://orcid.org/0000-0003-4371-1438

Phone (home) +49(4746)1560
Cellphone +49(177)3185663
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Adjunct Prof. Marine Geosciences, Physics & Earth Sciences, Jacobs University https://www.jacobs-university.de/directory/bijma

[Jelle Bijma]

Hi Greg,

your point is well taken and that's exactly were we're going. I was speaking to Dirk this morning and we will install O2 sensors and also compare bacterial communities (treated versus non treated). As you said before, suppressed resp is would still a good thing for air CO2, but maybe not for soil/plant ecology..... and we want to avoid a negative impact on soil functioning.

--
all the best,
Jelle

Prof. Dr. Jelle Bijma

Deputy section head Marine Biogeosciences
Speaker graduate school POLMAR

Am Handelshafen 12 D-27570 Bremerhaven Germany
Phone (office) +49(471)4831-1831
Fax (office) +49(471)4831-2020
e-mail: jelle...@awi.de

Google Scholar: https://scholar.google.de/citations?user=-BTyjHYAAAAJ
ResearchGate: https://www.researchgate.net/profile/Jelle_Bijma
Orcid ID: https://orcid.org/0000-0003-4371-1438

Phone (home) +49(4746)1560
Cellphone +49(177)3185663
https://www.awi.de/en/about-us/organisation/staff/jelle-bijma.html
Adjunct Prof. Marine Geosciences, Physics & Earth Sciences, Jacobs University https://www.jacobs-university.de/directory/bijma

[Dirk Paessler]

Hi Greg,

I completely agree that we will need to separate CDR effect and potentially other effects, e.g. changes to the bacterial life caused by the rock dust. We are already experimenting with an additional O2 sensor in our fluxmeters. Also lab analysis of bacteria colonies from soil samples should help to understand this. We'll report later.

In the end the several potential candidates for MRV-like measurements that we already use in our greenhouse must converge, otherwise we have not reliably proven CDR in the first place. One single measurement method alone isn't enough to proof this IMO (maybe except TA, but that takes too long). Doing it with multiple methods on the same experiments is our goal. But as soon as we see this convergence then the cheapest, most easily scalable, working solution will likely be rolled out. We just don't know which one this will be.

FYI, On Twitter I posted this: "We need to keep in mind, though, that us not being able to measure CDR (YET!) does not mean that the weathering processes are not happening. The dissolution data from @LithosCarbon in our paper shows that part of the rock is actually gone. The tricky thing is to measure the CDR effect that follows. The unknown territory lies between showing the rock's dissolution and finding bicarbonates in the leachate waters (which is the ultimate "rock solid" proof of the CDR effect). The time between these two steps seems to be quite long, likely longer than we can afford when we try to build an ERW industry and have to be able to show CDR effects to customers. We may need other means of measurement, that's why we suggest looking at CO2 directly. In the long run (i.e. hundreds of years) the CDR effect will happen, I have not met any geo-science person who would doubt that. The question is not "if" it helps the climate, but "when"."

Dirk  

[Greg Rau]

Thanks Dirk and all - great work. I don't want to belabor this for the non-ERW readers on the list, but here's another idea dredged up from my stable isotope days of yesteryear.  Get a Picaro instrument out there and measure and graph up the plots of surface soil 13C/12C CO2 vs 1/[CO2] for treatments and controls. If you get no relatioship between 13C/12C and [CO2] that would suggest that only soil respiration is being turned up and down. If you get a different trend in the treatments (e.g., increasing d13C CO2 with declining [CO2]), that would indicate isotopically selective CO2 uptake by ERW that you could graphically quantify (if you know the values of the end members). So whole fields can be wired with Picaros with wireless data transfer, push the button, sit back and do MRV from your office(?) Maybe not super cheap, but effective? Cheaper than hiring hundreds of graduate students and multiple labs? See a related appllication attached.

;-)

Greg  

https://groups.google.com/d/msgid/CarbonDioxideRemoval/8533b34a-7aae-4d1c-8dd8-660541816aadn%40googlegroups.com

.

[Dirk Paessler]

Hi Greg,

Yes, isotopes should help. I am not yet too deep in the isotope thing, but there are already C isotope measurements going on in our experiments by University of Erlangen, Christina‘s Master Thesis mentions this even in the summary, see:

https://www.carbon-drawdown.de/blog/2023-5-17-xxl-lysimeters-scientific-documentation-of-the-first-3-months-master-thesis

Dirk

--

[Adam Wolf]

Hi Robert - 

I disagree strongly with your statement here, speaking for myself as someone who is directly involved in empirical studies and mechanistic analyses with university and national lab collaborators.   There is a large volume of important work that has recently come out, or has recently been submitted, which puts to rest the key process uncertainties associated with ERW.

I think this statement:

"We have a lot of companies selling carbon removal from ERW now as if we know it works. But clearly, we don't know it yet." 

Should be more accurately be written:

"There are some companies selling carbon removal from ERW as though they know how it works. But I am excited for them to disseminate their work so that we can see substantiation of their claims." 

For people playing along at home, the key uncertainty in ERW is how to characterize the speed of weathering, measuring this phenomenon empirically by some means.  This has led to a pre-occupation with numerical simulation as a stand-in for direct measurement, but in my view the models suffer for having few observational constraints. This slowed the growth of ERW as an investable CDR approach in 2021 and 2022, but a large amount of work being now published will overcome this impasse starting in 2023. 

Going back to 2021, a barometric reading from the field, the left from June 21 2021, the right from May 5, 2022.  

At the time, the field was focused on quantifying weathering rates by measuring DIC in effluent waters, and finding that this approach was challenged by methodological errors. For example, if CDR rate is defined as a concentration (the DIC, mol/m3) times a velocity (m/s) to yield a flux (mol/m2/s), then the observation system can be dominated by errors/variation in the vertical flow rate.   Amann and Hartmann's proposal was to use electrical conductivity to correlate with alkalinity to compute a flux.  As someone who ran a company that sold thousands of EC sensors for use in croplands, I did not expect it to work, and Dirk's recent post corroborates that.  That's okay! Every scientist has had the experience of something not turning out as hoped for.  

Contemporaneous with this sensor-driven work, our lab was investigating the use of immobile trace elements as a means to constrain the weathering rates.  We later learned that Noah Planavsky's lab was investigating immobile trace elements as well.  It turns out to be a rich area for inquiry, very little work has been done on this suite of tracers to explore biogeochemical processes.  

Planavsky's initial work was recently published as a pre-print here: https://arxiv.org/abs/2302.05004

Our (Eion's) work, conducted at the University of Illinois Energy Farm with collaborators at UIUC and Univ Sheffield, was submitted last month.  I believe that another paper with the Yale team, UIUC team and Sheffield team was also submitted last month (I was not a coauthor so I can't speak to the details).  Expect that all of this work is slower to come out than CDI's because it will face withering peer review and the authors were exceptionally cautious to be certain of their work. 

I also want to highlight some really important work from the Georgia Tech group (Chris Reinhart), with contributions from the Yale team: https://academic.oup.com/pnasnexus/article/2/4/pgad059/7101163 

This investigates the fate of carbon after it has been captured, and speaks to its retention and storage on long timescales.  The Sheffield team has a complementary paper investigating the downstream hydrologic cycle that was also submitted recently (I am a coauthor).

This year will also see publication of a variety of works speaking to niche processes such as the so-called "strong acid effect", the magnitude of plant uptake, riverine carbonate precipitation, metals, etc.  We should also see publication, using these immobile trace element approaches, of the weathering rates of more feedstocks in more soils.  Together, these will put to rest uncertainty in whether it works.

In general, carbon buyers don't want to know about all the details, they just want to know that it works. I can say definitively It works.  Results will vary depending on this feedstock or that soil, but bottom line, it works.  There is not a weird "gotcha". 

The hard part now is Can it scale, and that is an area that requires the attention by a lot more people, many of whom have talents completely outside this wonky academic arena.  I want to highlight Milkywire's efforts as a catalytic buyer and popularizer of CDR to be crucial to this step, and express my gratitude for the role you play here.

Best wishes, 

Adam

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[Robert Höglund]

Hi Adam, thank you for providing this context! I am glad to see that there is upcoming evidence potentially putting some of the concerns to rest. 

I am sorry if my email came out the wrong way. I tried to communicate that scaling up - as if we know it works - must wait until sufficient public evidence exists. We can still deploy tonnes ofc, especially to produce the necessary evidence, but the uncertainty should be communicated. The risk of backlash is just too high otherwise. 

I have always had the understanding that ERW for sure works and it's more a question of how much, how fast. It's just in the last couple of weeks I've had that confidence shaken a bit. 

Thank you for your hard work in advancing the knowledge in the field! 

Best regards

Robert Höglund
marginalcarbon.com  

twitter.com/roberthoglund 
marginalcarbon.substack.com
linkedin.com/in/roberthoglund 

+46 8 559 25 515 

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[Pol Knops]

Hello all,

A few notes.

First to start with:

-0- Enhanced weathering conference:

 24 May is the yearly  enhanced weathering conference, hybride (so both Life in Delft/Netherlands and online) at which about 2- researchers will show their results. So it actually works (and you can measure it)..

https://climatecleanup.org/double-nature-summit-2023/#program

The presentations will be shared and the conference itself will be recorded.

So quite a lot of researchers will show their present work.

-1-  Basalt versus Olivine:

Now about the confusion if ERW works.

First it is important to identify that the various feedstocks are behaving very differently. And can change orders of magnitude with regards to speed, CO2 uptake per ton and side-effects.

As far as I saw the report of Dirk Pässler c.s. they are using basalt. 

Basalt is known to be slower to sequester (and less CO2 per ton) as i.e. olivine.

And I am aware of their reasons for using basalt (which are making sense for agricultural applications), but it would be not properly to transfer these results from basalt to other minerals and make a general statement that "

Olivine/serpentine:

Deltares recently finished a two year research with 11 plots, measured at two depths, in eacht plot was an open field and a mesocosm.

https://publications.deltares.nl/11204378_000_0002.pdf

So in total 44 data points, which were measured over time. The 11 plots were supplied with 2 types of olivine/serpentine (and Wollastonite and a reference) and on purpose very coarse material was chosen (the same material as mostly used in the Netherlands, 0 - 3 mm). So from a rock flour point of view that was  very coarse material.

CO2 removal:

This shows clearly a good signal. And this was also within the range we previously expected it to be.

"Results show that 6 to 8.5 percent of the initial mineral dose was dissolved after two years. Applying the Shrinking Core Model to each grain size, the dissolution over time could be calculated accurately."

Please note: this experiment was not aimed at to maximise the weathering rate, but the measure the weathering rate of the material that is most common applied in the Netherlands.

Nickel:

One reason for the choice towards basalt is the Nickel concentration.

This was also part of the same study. See this quote:

"Nickel concentrations in pore waters are elevated compared to the reference plot. However, 96 % of all Ni measurements are below the analytical upper reporting limit. Only two measurements (Norwegian olivine source) exceed the generic quality standards but only short after application."

And I realise if fines olivine would have been used, with more CO2 uptake the Nickel release would also been higher.

Model validation:

Before the test was setup we made intensive model runs to determine on forehand the expected CO2/Magnesium/Nickel etc effect.

This model is described in this (open access) paper:

https://www.mdpi.com/2075-163X/13/2/235

It goes also quite intense about the consequences of the Nickel release (and its behaviour).

Summary:

And I know real open field experiments are inherently difficult. And as the "signal" of basalt is lower (given the slower dissolution kinetics, lower Magnesium concentrations), measuring this is inherently more difficult. But it would help if the feedstocks (and its characteristics) are better clarified.

Personally I am very doubtful if a CO2 signal of the flux will give a good signal, but I am looking forward to the actual measurements.

My reasons are: partially given the huge up and downflux. And also there will be quite some seasonal fluctuations and other factors that are not part of the mineralisation cycle. But as stated I am looking forward to the results.

And I am always a big fan of obtaining more advantages as solely CO2 removal.

Basalt has the option to deliver nutrients for agricultural needs (and lowering the chemical fertiliser needs). And sequestering CO2.

Olivine has the option to replace sand/pebbles at civil projects or delivery alkalinity/Magnesium  (and sequestering CO2). And for sure Nickel is to be checked (but as shown above can be calculated on forehand).

Best regards,

Pol Knops

P.S. Robert Hoglund:

Your statement "But clearly, we don't know it yet." is not valid, for sure not for olivine ;-).

And we should NOT wait until we know all last remaining details. 

Frankly we don't have the time and there will be always some uncertainties. If the DAC people had the same approach they would still be in the lab and currently they are building plants.

And Robert there are quite some olivine projects of which we know the CO2 uptake over time. So if you are looking for funding these I can bring you in contact with them (or we can wait until we know more and very controversially  the longer we wait the faster the kinetics will be (after it driven by the atmospheric CO2 ;-( ).

Op zondag 21 mei 2023 om 04:09:02 UTC+2 schreef robert.d...@gmail.com:

[Tom Goreau]

Thanks, Paul!

 

Soil CO2 concentrations are very dynamic and can change rapidly, so vast numbers of measurements will be needed to get past variability noise.

 

The advantage of basalt over olivine, despite its slower rate of weathering, is that it provides balanced nutrition for plants, which olivine does not.

 

Basalt therefore produces much more biomass and soil carbon storage in the long run than the bicarbonate released by olivine weathering.

 

Thomas J. F. Goreau, PhD
President, Global Coral Reef Alliance

Chief Scientist, Blue Regeneration SL
President, Biorock Technology Inc.

Technical Advisor, Blue Guardians Programme, SIDS DOCK

37 Pleasant Street, Cambridge, MA 02139

gor...@globalcoral.org
www.globalcoral.org
Skype: tomgoreau
Tel: (1) 617-864-4226 (leave message)

 

Books:

Geotherapy: Innovative Methods of Soil Fertility Restoration, Carbon Sequestration, and Reversing CO2 Increase

http://www.crcpress.com/product/isbn/9781466595392

 

Innovative Methods of Marine Ecosystem Restoration

http://www.crcpress.com/product/isbn/9781466557734

 

No one can change the past, everybody can change the future

 

It’s much later than we think, especially if we don’t think

 

Those with their heads in the sand will see the light when global warming and sea level rise wash the beach away

 

Geotherapy: Regenerating ecosystem services to reverse climate change

 

 

 

From: <carbondiox...@googlegroups.com> on behalf of Pol Knops <plan...@gmail.com>
Date: Sunday, May 21, 2023 at 4:28 PM
To: Carbon Dioxide Removal <carbondiox...@googlegroups.com>
Subject: Re: [CDR] Re: Our working paper about MRV for ERW using traditional methods vs. CO2-in-soil-gas-based methods is out

 

Hello all,

 

At the time, the field was focused on quantifying weathering rates by measuring DIC in effluent waters, and finding that this approach was challenged by methodological errors. For example, if CDR rate is defined as a concentration (the DIC, mol/m3) times a velocity (m/s) to yield a flux (mol/m2/s), then the observation system can be dominated by errors/variation in the vertical flow rate.   Amann and Hartmann's proposal was to use electrical conductivity to correlate with alkalinity to compute a flux.  As someone who ran a company that sold thousands of EC sensors for use in croplands, I did not expect it to work, and Dirk's recent post corroborates that.  That's okay! Every scientist has had the experience of something not turning out as hoped for.  

 

Contemporaneous with this sensor-driven work, our lab was investigating the use of immobile trace elements as a means to constrain the weathering rates.  We later learned that Noah Planavsky's lab was investigating immobile trace elements as well.  It turns out to be a rich area for inquiry, very little work has been done on this suite of tracers to explore biogeochemical processes.  

 

Planavsky's initial work was recently published as a pre-print here: https://arxiv.org/abs/2302.05004

Our (Eion's) work, conducted at the University of Illinois Energy Farm with collaborators at UIUC and Univ Sheffield, was submitted last month.  I believe that another paper with the Yale team, UIUC team and Sheffield team was also submitted last month (I was not a coauthor so I can't speak to the details).  Expect that all of this work is slower to come out than CDI's because it will face withering peer review and the authors were exceptionally cautious to be certain of their work. 

 

I also want to highlight some really important work from the Georgia Tech group (Chris Reinhart), with contributions from the Yale team: https://academic.oup.com/pnasnexus/article/2/4/pgad059/7101163 

This investigates the fate of carbon after it has been captured, and speaks to its retention and storage on long timescales.  The Sheffield team has a complementary paper investigating the downstream hydrologic cycle that was also submitted recently (I am a coauthor).

 

This year will also see publication of a variety of works speaking to niche processes such as the so-called "strong acid effect", the magnitude of plant uptake, riverine carbonate precipitation, metals, etc.  We should also see publication, using these immobile trace element approaches, of the weathering rates of more feedstocks in more soils.  Together, these will put to rest uncertainty in whether it works.

 

In general, carbon buyers don't want to know about all the details, they just want to know that it works. I can say definitively It works.  Results will vary depending on this feedstock or that soil, but bottom line, it works.  There is not a weird "gotcha". 

 

The hard part now is Can it scale, and that is an area that requires the attention by a lot more people, many of whom have talents completely outside this wonky academic arena.  I want to highlight Milkywire's efforts as a catalytic buyer and popularizer of CDR to be crucial to this step, and express my gratitude for the role you play here.

 

Best wishes, 

Adam

On Thu, May 18, 2023 at 12:02 PM, Robert Höglund <robert.d...@gmail.com> wrote:

This is a super important paper

We have a lot of companies selling carbon removal from ERW now as if we know it works. But clearly, we don't know it yet. Purchases of CDR should be going to actors that use the deployments to help figure it out. Its not the time to scale for sure

 

Robert

torsdag 18 maj 2023 kl. 01:48:12 UTC+7 skrev di...@dirkpaessler.com:

FYI: We have published a working paper about the results of the last 2 years and how CO2 sensors in the soil might be helpful for MRV.

 

Carbon Drawdown Initiative has published a detailed report about their attempts to measure the speed of enhanced rock weathering on croplands in four extensive field-experiments over more than two years. The traditional leachate- and EC/pH-based MRV approaches have not shown any signal (yet!). But by measuring the basalt's dissolution rate and especially by measuring CO2 in the soil gas they seem to be able to assess the CDR effect as early as weeks or months after basalt application. In the future, this novel approach could provide a faster way to assess the effectiveness of ERW in removing CO₂ from the atmosphere.

 

https://www.carbon-drawdown.de/blog/2023-5-17-monitoring-co2-concentrations-in-soil-gas-a-novel-mrv-approach-for-cropland-based-erw

 

Dirk

 

 

Carbon Drawdown Initiative Carbdown GmbH

www.carbon-drawdown.de - Wilhelmshavener Str. 64, D-90766 Fürth
Registration: Amtsgericht Fürth HRB 17909 - VAT-ID DE328445765

Management/Geschäftsführer: Dirk Paessler, Ralf Steffens

 

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[Pol Knops]

Hello Thomas,

I agree.

Basalt gives more nutrients and is slower to weather.

But the main point was:

The signal of basalt with regards to CO2 sequestration is less pronounced as Olivine. So transferring the results of basalt to other minerals and then obtaining a statement " But clearly, we don't know it yet." is false (sorry Robert). Or more precise for Olivine we know and can measure the weathering rate.

And some other remarks to the differences:

- in a highly nurtured field in Germany, with ((just as the Netherlands an excess of manure) there will be plenty of nutrients for the forthcoming time. But for a nutrient depleted field that is differently.

- at some places you might not want these nutrients (I was discussing forestry applications, so adding nutrients can be be disadvantageous) 

- some crops (i.e. grapes) are requiring the nutrient Magnesium that olivine produces at bigger amounts

- olivine gives more alkalinity (so to replace agricultural lime that could be a good choice). Or you might want to use Wollastonite for this use (as more and more done in Canada)

 https://www.canadianwollastonite.com/lime-with-wollastonite-an-easier-decision-than-you-might-think/

So my general points are:

- for olivine we know and can measure and model the weathering rate. 

- the different minerals will have a different behaviour.

- for agricultural applications either basalt (nutrients) or olivine (alkalinity, Magnesium) or a combination can be a good choice. But requires knowing the current nutrients, aimed nutrients (and for sure Calcium/Magnesium competition, Nickel release) are points to consider before applying.

And with regards to you statement "Soil CO2 concentrations are very dynamic and can change rapidly, so vast numbers of measurements will be needed to get past variability noise.", that is exactly what Dirk Pässler c.s. is able to perform. 

Best regards,

Pol Knops

Op zondag 21 mei 2023 om 22:52:21 UTC+2 schreef goreau:

[Robert Höglund]

There is for sure a lot of evidence pointing to ERW working, especially for olivine. 

Is there any risk of ERW (esp basalt) turning out not to produce net removal in a relevant time frame? Maybe we can say there is no such risk given the total available evidence, but there are some recent developments like Dirks paper, that made me spooked, and it seemed to me that we do not *know* this for certain. 

I do wish I had phrased my self a bit more carefully and specific, sorry about that. 

Robert 

www.twitter.com/roberthoglund

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[Pol Knops]

Hello all,

In my opinion we should be focussing LESS on the pure CO2 removal.

The applied minerals will have various effects, some wanted, some unwanted.

And each of them have their own pros and cons.

Basalt releases nutrients, that can be beneficial for plants (given the type and unless the soil is already supplied with sufficient nutrients).

But sometimes these nutrients will not be required. 

Olivine gives more Magnesium and alkalinity (and also Nickel). And how strange it may sound even the Nickel can be beneficial as a micro-nutrient (although in general it is hardly in deficit 

https://pubmed.ncbi.nlm.nih.gov/3076427/)

So look for the bigger picture and use the CO2 uptake as a result and not a starting point.

Wednesday the 24th May the enhanced weathering conference, where 20 researchers will share their work. And questions can be asked. the event is online free (and modest fee for attending life).

https://www.eventbrite.nl/e/rock-weathering-day-double-nature-summit-2023-tickets-569349398377

Most of the work will be shared later on a website. 

Best regards,

Pol Knops

 

Op maandag 22 mei 2023 om 02:33:16 UTC+2 schreef robert.d...@gmail.com:

[Dirk Paessler]

Hi Robert, Hi Pol, Hi all other commenters,

are we potentially mixing different perspectives in the recent discussion about our paper? Let me try to move this conversation into a more nuanced discussion (and bare with me, I tend to have an entrepreneur's engineering/economical view on things): 

We need to discern, I think, two quite different perspectives on ERW:

• One is the geological and geo-chemical perspective, which cares less about time (or all the small steps on the way) and more about the eventual outcomes of reactions/processes.
• Then there is a more short term, maybe even biological perspective, which is much closer aligned to a human-centric MRV perspective when we consider the people who we want money from for certificates that they can book into their corporate CO2 net-neutrality packages.

On a geologic time frame, we know that ERW is working, the whole planet is proof of that. Look at Ithacas' methodology which is based on a thorough review of the publications until fall 2022. Their paper is formulated very conservatively. Until further scientific evidence is available they decided to assume 100 years until the stoichiometric potential of a rock is fully converted into a CDR effect with regards to the atmosphere. Which is a hard sell.

Measuring the dissolution of the rock over time (Lithos Method, Eion Method) is a necessary indicator for any CDR effect and it already lessens the uncertainty: without it, we can not have any CDR. As described in our paper we think of this as the upper bound of what's possible. As we have also shown in our paper in numerous experiments over 2 years with a lot of highly scientific assistance by over 20 scientists and professors from 6 universities we were not able to find a signal in the leachate water which could prove the CDR effect using actual carbon accounting.

One could argue that the planet and the climate "ticks" in geologic time scale anyway, so it is not super important if it takes 20, 30 or 50 years to do CDR. But in a world where economic competitors like DAC or biochar can deliver 1 ton of CDR "now" with almost 0% uncertainty the expectations on ERW data are much higher.

If I were a buyer of CDR who pays hundreds of Euro or Dollars for a ton of removed CO2 I'd want to have a proof with actual carbon measurements (e.g.. bicarbonates) instead of proxies and I would not pay anyone money for something that _might_ be delivered in 100 years when I am not even alive anymore. I would demand to be shown an earlier effect of my money (or buy DAC). Companies who want to use ERW in their carbon portfolio will also demand uncertainty on the time axis of less than "less than 100 years" so they can account X tons for year Y. An alternative would be to sell CDR by ERW as a means to offset "lifetime footprints", then the time axis becomes much less of a problem, but if this can be done economically, I don't know.

Over the last 2 years we realized that there are numerous hurdles the dissolved rock's effect has to overcome to have an actual CDR effect.

Just to name a few:

• If too much nitric acid is in the field (fertilizer) then a part of the rock dissolution can be caused by it instead of CO2/carbonic acid. 
• During the migration of carbon/bicarbonates through the soil precipitation and clay formation can happen which can free up a considerable amount of the initial carbon sequestration and give it back to the biological cycle (then it is not removed from the atmosphere). Many of these processes will continue to collect C later down the road (years?), but you have an increase in time-uncertainty again. 
• Let me also remind you of the delaying effects of the cation exchange capacity.
• Also, biology is a concern: What did we do to the microorganisms by adding rock? Did we fertilize them (so they create more CO2? Will this cause more efflux or more sequestration?) or did we poison them? Will these effects improve the dissolution and the CDR effect, or the opposite? And how will the whole effect progress over time and over seasons?
• Finally this is not a question of basalt or olivine. First this is like a comparison of cakes (rocks) and eggs (minerals), as someone explained to me: A cake contains eggs, but eggs by themselves are not cakes. This needs to become a more cake-oriented discussion. Our friends at silicate are using crushed concrete, others are considering sludges. And there are various other things that we could use. We need to talk about grain size configurations, too.

As an entrepreneur the longer I am looking at this mess of processes out of which some are barely understood I must come to the conclusion that we need to find faster, simpler and less uncertain measurement methods (in a first step regardless of necessary effort), and it sounds logical to me to look at the carbon fluxes themselves (as we try with our fluxmeter CO2 measurements in 3 sec intervalls on 350 pots over months). This might work around all the effects mentioned above and hopefully gives a faster signal. This might help us to prove that the CDR calculations derived from cheaper/easier to scale methods like dissolution measurements are actually correct - but this time with a reasonable time-perspective. Ultimately this would evolve in extensive models which make many measurements obsolete.

In the end we need a _carbon_ accounting for the _carbon_ markets. This will need to agree with rock dissolution accounting and alkalinity measurements, but might be faster and help prove CDR speed. In a time scale of months. Not decades. If we can reduce the uncertainty of CDR effects this way from now 100 years to e.g. 10 years we would have made a major leap forward.

Improving this whole situation is what we want to achieve by asking many, sometimes uncomfortable questions. Being directly invested in more than a handful of the most prominent ERW companies shows that we are a strong subscriber and promoter to the ERW idea! We really want this to work properly.

Dirk

 

Carbon Drawdown Initiative Carbdown GmbH

www.carbon-drawdown.de - Wilhelmshavener Str. 64, D-90766 Fürth
Registration: Amtsgericht Fürth HRB 17909 - VAT-ID DE328445765

Management/Geschäftsführer: Dirk Paessler, Ralf Steffens

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[Dirk Paessler]

Hi Adam,

Thank you for your thoughtful reply.

I fully agree with you that CO2 flux measurements are not suitable for scaled-out ERW projects in the future. Because it's completely impractical with many plots and to work with fluxmeters at scale in open fields. For industry-scale MRV we may need much simpler approaches that can be based e.g. on dissolution measurements once or twice a year.

But before I buy into this I need to see in lab/greenhouse/field-trial scale that we actually DO successful CDR in the first place and in a timely manner. As we have shown we did not succeed with this using TA and other means in over 2 years in our experiments. Arthur Vienne had similar problems which sent him on an interesting journey.

It's good to hear that you and others did not have these issues. In our greenhouse, after 110 days, we also have pots that already have a TA signal. Fine! But nobody has offered an explanation or way to measure this yet (at least as far as I understood it, but my personal possibilities as an engineer/entrepreneur may be limited here). Likely biology is involved. What does that mean for field scale work? Is there something that we are missing and that we need to check on a field before applying basalt except for pH or other simple things? Or are we hunting a yeti?

At the same time we think we have successfully measured a signal using pCO2 sensors in the soil and using our fluxmeters. Just this week we measured 3 soils from a radius of 40 km, 2 even from the same farmer, amended with 40 t/ha basalt for 2 days each. One set of replicas seems to be a CO2 source on day 110 compared to control, while the others seem to be really nice CO2 sinks (one reduced the nightly efflux even by 50% with rock dust). The signal seems stable and statistically significant. Keep in mind, this is on day 100-110 after setup and it is very early, limited data. We will continue to iterate over our 350 pots (15 soils/11 rocks/>80 variations) in the next few weeks and report back.

So I think the scope of your arguments is looking at quantifying ERW in scaled up work based on proxies if necessary while my perspective is looking at detailed plot-by-plot, pot-by-pot, field-by-field scale ideally based on C accounting. Our work here is to support the large scale approach with good data from the detailed view, but we need both approaches to converge. I am optimistic that we are not far away from that. 

The closer we can get to measuring carbon, the better. But some level of abstraction/simplification will likely be necessary at scale, I agree.

Dirk

Carbon Drawdown Initiative Carbdown GmbH

www.carbon-drawdown.de - Wilhelmshavener Str. 64, D-90766 Fürth
Registration: Amtsgericht Fürth HRB 17909 - VAT-ID DE328445765

Management/Geschäftsführer: Dirk Paessler, Ralf Steffens

On Thu, May 25, 2023 at 5:49 PM Adam Wolf <ad...@eion.team> wrote:

I love this rich discussion. Thanks Pol for your thoughtful comments and field building efforts.

I certainly want to celebrate Dirk's discoveries that there is something interesting about measuring gas phase CO2 in soils for ERW studies.  After some inconclusive work, this is exciting to see signal, and I am excited to see more as it unfolds. 

But Dirk on your point that "we need to measure carbon if we are in carbon markets": I think it misses a couple really key issues that for me are central to MRV in ERW.

First: Measuring fluxes is way harder than measuring stocks. 

Second: Most institutional carbon monitoring is measuring stocks, and is not directly measuring carbon.

By way of examples,

• The Forest Inventory and Analysis system of the USFS measures forest carbon by measuring the diameter of trees every few years.  
  
• The DOE's carbon budgeting tools measure changes in stocks of fluids, not CO2 coming out of tailpipes. 
  
• The EPA has regulatory authority for GHG budgets in the US. Most MRV methods for 40CFR Part 98 are measures of stocks.  In the case of Subpart S, Lime Manufacture, the basis is around CaO and MgO content of the stocks being measured, and the change in those stocks over time. This is very similar in principle to an MRV for ERW. 
  
• The USGS riverine carbon budgets are evaluated using stock measurements (GLORICH and works derived from this analyze these datasets extensively) 
  
• The NOAA carbon monitoring program, to the best of my knowledge, constrains stocks of pCO2 in ocean water by measurements of TA and pH, not by direct measurement of carbon itself, solving the system using tools like CO2sys. 
  
• NASA has efforts to measure continental photosynthesis using fluorescence, because it is otherwise challenging to directly measure CO2 exchange at ecosystem scale.  
  

What all these have in common is an observation system that constrains the key drivers of uncertainty that vary in space and time (for us, rock composition, weathering rate), and the use of experiments to parameterize some key values (strong acid effect, plant uptake) that are impractical to measure operationally.  

One of the key issues with measuring fluxes is around sensor calibration, placement, maintenance, and gap-filling.  I spent a lot of time with the Eddy Covariance community and it is really valuable for the few sites where it is done well, but nonetheless challenging to do well.   Stocks, by contrast, make use of centralized lab facilities where quality control is well maintained, and samples can generally be captured by less specialized personnel.

As far as your comment that you have not found alkalinity or bicarb in the leachate, we have not had that problem.  We've done bench trials, and field trials, and the DIC signal is there and matches both with chemical equilibrium models, as well as the other "Eion Method" measurements.  I haven't done a meta analysis for why some groups find results and others don't.  That would be a lively debate!  I have my own ideas, but we're getting our pubs out the door, and I think that provides a better baseline for discussion. 

A

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[Toby Bryce]

Hello all,

Eion and Adam are on This Is CDR 12p ET next Tues -- encourage you all to join, ask questions, and continue the discussion there -- https://www.eventbrite.com/e/eion-driving-innovation-of-enhanced-weathering-in-agriculture-tickets-621863298867

Best, Toby