The Challenge

Enhanced rock weathering (ERW) is a carbon dioxide removal (CDR) strategy that involves the spreading of alkaline feedstocks (e.g., silicates, carbonates, or other alkaline materials) on agricultural soils. In the last few years, there has been a dramatic increase in the number of commercial ERW deployments globally driven by voluntary carbon market demand. The quantification of carbon removal in an ERW deployment is complex, and involves a range of biogeochemical fluxes that can impact the net carbon balance across soil systems, groundwater, surface water systems, and the ocean. (See Cascade’s recently published, ‘Foundations for Carbon Dioxide Removal Quantification in ERW Deployments’↗).

For ERW deployments to be economically feasible at scale, it is highly likely that quantification of CDR will need to shift from “measurement-driven” to being increasingly reliant on biogeochemical models. Currently, models cannot reliably predict and quantify the net carbon balance resulting from ERW deployments, particularly across heterogeneous environments.

In the context of commercial ERW deployments, common quantification practice today¹ is to directly measure the release of base cations from the feedstock and subsequent cation or dissolved inorganic carbon (DIC) export within the top 20-30 cm of the soil profile². A key bottleneck for present modeling efforts, and for our broader understanding of rock weathering and solute transport dynamics, is a lack of high-quality measurements of biogeochemical processes in ERW deployments beyond the initial dissolution of the feedstock in surface soils. While not typically measured at high resolution in commercial deployments, these processes are still critical to constraining the net climate impact of an ERW project, and so field data is needed to better calibrate and validate future models.

The Objective

We welcome research proposals between $20,000 and $200,000 that aim to collect and publish high-quality ERW field datasets on existing or planned deployments, that go beyond typical commercial expectations for CDR quantification (e.g., beyond feedstock dissolution measurements in shallow soils). In these scientific partnerships, Deployment Partners agree to open up an existing or upcoming deployment site for additional monitoring and help coordinate logistics, and Researchers co-propose a study, collect and analyze the data, and publish the results.

We believe that this partnership model—in which researchers “piggyback” on existing deployments by carrying out measurements that go beyond what is already planned—will accelerate the collection of novel field datasets in ERW. It offers an attractive avenue for tackling high-priority research questions by decreasing the logistical and cost burden for researchers, while extracting even greater scientific learning value from the current wave of commercial ERW activity.

We expect that initial measurements characterizing the feedstock and initial soil conditions, as well as measurements of feedstock dissolution rates in surface soils, are already paid for in the deployment through some other means (e.g. commercial carbon credit sales). Thus, this RFP will not fund the collection of these Contextual Data variables; it will fund only the collection of the ‘additional’ dataset (e.g., sample collection and lab analyses) along with associated research and analysis.

Priority Topic Areas

We seek proposals that build upon the data typically collected in ERW commercial deployments, beyond the initial release and export of cations from the feedstock in surface soils. We welcome the creativity of the ERW community to propose the collection of any datasets that would advance the field. Below are some topic areas of particular interest:

• Measurement of secondary phases (e.g., silicates, carbonates, Fe- and Al-oxyhydroxides, amorphous phases) in deep soil cores (>50 cm)
• Measurement of the components of the carbonate system and/or cations in waters that drain ERW deployments (e.g., groundwater/porewater, tile drains, or low-order streams)
• Measurement of greenhouse gas fluxes (N2O, CH4, CO2)
• Cation sorption in deep soil cores
• Soil organic carbon stock monitoring

Research proposals focused on collecting field data to inform health and safety impacts of ERW (e.g., the transport and speciation of trace metals) will also be considered.

The following are not in scope for this RFP:

• Direct funding of new ERW deployments or field trials (e.g. feedstock transportation, logistics, spreading)
• Measurements that are often required for commercial MRV — see Appendix A for full list of Contextual Data expected at the deployment site. In some circumstances, if additional measurements of one or more of the Contextual Data variables is needed in order to increase the resolution of data collection already planned by the Deployment Partner, this request can be included in the proposal and funding will be considered on a case-by-case basis.

Important Dates

The proposals will be due on December 20th at 11:59pm ET, and funding decisions will be made by no later than February 6th. For proposals that have a start date in Spring 2025, Cascade can provide a letter that specifies our intent to fund the project upon selection.

Applications should be no longer than four to eight pages (exclusive of supporting information), and should be submitted via this form↗.  Applicants are welcome to include figures and references to papers, preprints, and similar as a part of the application; please have all citations at the end of the document. Applicants are advised to not share any information that is considered confidential or a trade secret.

For additional questions related to this RfP or the proposal process, please contact the Cascade Climate RFP Team at [email protected]↗.  Potential applicants are also encouraged to bring their questions to our webinar and Q&A session for this RFP, scheduled for Thursday, November 14th at 12PM ET. This will be recorded and made available on the Cascade website.

Footnotes

1. For example, see Isometric’s EW protocol or Puro’s ERW methodology. ↩
2. In addition to these “Near-Field Zone” measurements, models or geochemical calculations are frequently used to calculate conservative loss estimates associated with downstream loss processes in surface water and marine systems. ↩