How large is the carbon removal opportunity that investors see?
The potential scale of ERW is enormous, which is what first attracts investor interest. A global modeling study that simulated ERW on ~1,000 agricultural sites worldwide found that applying 10 tonnes of basalt dust per hectare could sequester 64 gigatons of CO₂ over 75 years across those sites, and when extrapolated to all agricultural land, the total rises to 217 gigatons of CO₂ over the same period [2]. To put that in perspective, global annual CO₂ emissions from fossil fuels are roughly 36 gigatons, so ERW could theoretically offset several years' worth of emissions. The same study notes that ERW becomes modestly more effective with global warming and that payback periods are significantly shorter in hot, humid environments — often in lower-income regions — which creates an investment case tied to agricultural development [2].
A separate reactive transport modeling study using forsterite as a proxy mineral found that with a one-time application of ~16 kg/m², complete weathering within five years is achievable, yielding a carbon removal rate of ~2.3 kg CO₂/m²/yr [3]. That is a high rate, but the authors stress it is highly variable depending on site-specific conditions like soil drainage and biological activity. Together, these two modeling studies — the first global in scope, the second process-based — converge on the same conclusion: ERW has a large theoretical capacity, but actual performance depends heavily on where and how it is deployed.
What are the risks that could produce weak carbon claims and scare off investment?
The biggest threat to investment is overestimating how much CO₂ is actually removed, which would produce carbon credits that are not 'durable, additional, and not overestimated' — the criteria for high-quality credits [5]. A 2025 study identifies three specific geochemical and mineralogical pitfalls that can inflate CDR estimates: (1) rock powders often contain highly reactive surfaces and phases that dissolve quickly at first, leading to overestimates of long-term rates; (2) accessory carbonate minerals within the basalt dissolve and release cations that can be misattributed to silicate weathering; and (3) methods that rely on measuring cations (like calcium or magnesium) can be misleading if those cations are not balanced with dissolved inorganic carbon from the atmosphere [5]. The authors recommend using high-dosage test plots to avoid replenishing fast-reacting surfaces, screening rock powders for carbonates with sensitive techniques, and directly measuring carbon rather than relying on proxy cations [5].
Another experimental review echoes this caution, stating plainly that 'ERW efficiency should not be taken for granted' and that current knowledge is insufficient for robust predictive capabilities [4]. It notes that basalt's heterogeneous mineralogy and local soil and climate conditions create large variations in effectiveness, and that CDR funds must be allocated based on solid science to maintain credibility [4]. A 2026 study on ERW in Indian agricultural contexts similarly concludes that robust monitoring, reporting, and verification (MRV) frameworks are essential for ERW to be a credible pathway for carbon market participation [1]. Across these papers, the message is consistent: without rigorous MRV, the risk of weak claims is real and could undermine the entire investment case.
Can MRV be made cost-effective enough to attract investment at scale?
Yes — a promising development is a lower-cost MRV method using X-ray fluorescence (XRF) instead of the current gold standard, inductively coupled plasma (ICP) analysis. A 2026 proof-of-concept study on Danish agricultural soils showed that XRF measurements, with simple sample preparation, can resolve magnesium weathering signals with sufficient precision to quantify feedstock dissolution [6]. The key advantage is cost: XRF is substantially cheaper per sample, which allows higher sample throughput and can help overcome the problem of soil heterogeneity — the study found that even ICP analysis struggled with low signal-to-noise ratios in heterogeneous soils [6]. So while XRF is not yet a complete replacement, it offers a path to affordable, scalable MRV that could satisfy investor demands for verifiable credits.
The same study also highlights that inherent soil heterogeneity is a dominant source of uncertainty in any MRV framework, meaning that even the best analytical method cannot eliminate all noise [6]. This reinforces the need for careful experimental design — such as the high-dosage test plots recommended in [5] — and for combining field measurements with geochemical modeling, as suggested in the Indian context study [1]. The global modeling study adds that a significant fraction of applied basalt does not weather even on multidecadal timescales, so optimizing application strategies (e.g., grain size, application rate) is critical for cost-effectiveness [2]. In short, the pieces for a credible MRV system exist, but they must be integrated and applied rigorously.
About These Sources
This answer is built on 6 studies (3 peer-reviewed, 3 preprints) — published from 2023 to 2026, 4 from 2024 or later, 2 in Q1 journals, collectively cited 74 times — selected as the most relevant from 7 studies that passed quality screening, drawn from 34 papers retrieved from a database of over 500 million.
Sources used in this answer
Enhanced Rock Weathering
This 2026 review of ERW in Indian agriculture quantifies carbon removal potentials of 0.3–1.0 tonnes CO₂ per tonne of basalt and projected credit yields of 2–8 tonnes CO₂ per hectare per year, concluding that robust MRV frameworks are essential for credible carbon market participation.
Impact of Climate on the Global Capacity for Enhanced Rock Weathering on Croplands
This global modeling study (the largest in scope among these papers) simulates ERW on ~1,000 agricultural sites and estimates 217 gigatons CO₂ sequestration over 75 years across all croplands, but notes that a significant fraction of basalt does not weather even on multidecadal timescales, requiring optimized application strategies.
The environmental controls on efficiency of enhanced rock weathering in soils
Using a detailed reactive transport model with forsterite as a proxy, this study finds that complete weathering within five years is achievable at ~2.3 kg CO₂/m²/yr under optimal conditions, but the rate is highly variable and depends on CO₂ availability via soil drainage and biological activity.
Geochemical Drivers of Enhanced Rock Weathering in Soils
This experimental review warns that ERW efficiency is subject to large variations due to basalt's heterogeneous mineralogy and local pedoclimatic parameters, and that current knowledge is insufficient for robust predictive capabilities, urging that CDR funds be allocated based on solid science.
Table 1_Are enhanced rock weathering rates overestimated? A few geochemical and mineralogical pitfalls.docx
This 2025 study identifies three geochemical pitfalls that can overestimate CDR: fast initial dissolution of reactive phases, accessory carbonate dissolution misattributed to silicates, and cation imbalance from non-carbonic acid weathering; recommends high-dosage test plots, carbonate screening, and direct carbon measurement.
Toward Cost-Effective MRV: An XRF-Based Approach to Quantifying Enhanced Rock Weathering
This 2026 proof-of-concept study demonstrates that XRF-based MRV can resolve Mg weathering signals with sufficient precision at lower cost than ICP, enabling higher sample throughput to address soil heterogeneity, though performance depends on soil characteristics.