How Spreading Rock Dust on Farms Could Help the U.S. Fight Climate Change

A Simple Farming Trick That Could Remove CO₂ from the Atmosphere

I often talk about climate change solutions in my lectures and talks, and I usually get a question from both audiences: What would it take for us to solve the climate crisis?

My usual answer? Innovation.

Let’s look at a recent example that could have an enormous impact: imagine if fighting climate change was as simple as sprinkling crushed rock on fields.

Sounds too easy, right? Yet, that’s the core idea behind enhanced weathering (EW) — a process where crushed basalt is spread on agricultural lands to speed up natural rock weathering, capturing carbon dioxide (CO₂) in the process.

A new study published in Nature explores how this method could make a meaningful contribution to the U.S.’s efforts to reach net-zero emissions by 2050.

Led by Professor David Beerling at the Leverhulme Centre for Climate Change Mitigation, the research provides a detailed analysis of the carbon removal potential, costs, and feasibility of deploying EW across U.S. farmland. It suggests that, while EW won’t replace deep emissions cuts, it could be a valuable tool in reducing atmospheric CO₂, improving soil health, and even enhancing air quality.

Sounds good, right? Let’s see how they performed the study.

Atmospheric CDR by enhanced weathering with US agriculture. a, Net annual cumulative CDR by EW as constrained by 1 Gt yr−1 and 2 Gt yr−1 rock extraction scenarios, 2020–2070 (annual crushed basalt application of 40 t ha−1). The shaded area shows the 90% uncertainty envelope due to differences in the mineralogy of basalt sourced from the supply states. b, Mean (with 90% confidence limits) annual CDR rates of the top ten states (2 Gt rock yr−1 scenario). c,d, Spatial patterns of net annual CDR rates per hectare in 2040–2050 © and in 2060–2070 (d) for the 2 Gt rock yr−1 by 2070 scenario. All simulations are illustrative for crushed basalt with a particle size P80 of 100 µm, that is, 80% of particles less than or equal to 100 µm diameter; previous work indicates that particle size has a relatively minor effect on net CDR over decadal timescales11. All CDR figures are net and account for the CO2 emissions penalty associated with mining, grinding, transporting and distributing rock dust. e,f, Sankey diagrams illustrating the main transfer pathways of crushed rock from basalt source states to recipient cropland states in 2040 (e) and 2070 (f), for the 2 Gt yr−1 rock extraction by 2070 scenario; only fluxes greater than 20 Mt yr−1 are shown for clarity — Beerling, David J., et al. “Transforming US Agriculture for Carbon Removal with Enhanced Weathering.” *Nature*, 2025, pp. 1–10, https://doi.org/10.1038/s41586-024-08429-2. Accessed 9 Feb. 2025.

The study used geochemical models and climate-carbon cycle simulations to estimate how much CO₂ EW could remove under different scenarios. These models capture as many variables as they can to get as close to the natural scenario as computationally possible.

The researchers mapped basalt supply locations across the U.S. and examined how quickly crushed rock would react in different soil and climate conditions.

However, they did something that most studies usually fail to do. They factored in the logistics, costs, and energy requirements of mining, transporting, and spreading basalt. This helped scientists ensure the solution wasn’t worse than the problem itself (aka. carbon emissions).

By layering all these elements together, they built a state-by-state picture of EW’s potential over the next 50 years.

And the big question: How much carbon could we remove following this method?

Well, according to the study, spreading crushed basalt on U.S. farmland could remove between 160 and 300 million metric tons of CO₂ per year by 2050. That said, that number could rise to 250 to 490 million metric tons per year by 2070 — equivalent to about 6% of current U.S. emissions.

Not bad, considering that this represents net removal.

River and ocean responses to enhanced weathering. a, Locations of river and stream sites from the aqueous geochemical database used to estimate river calcium carbonate saturation states (Ωcalcite). The filled circles show individual monitoring sites and the grey shading indicates the US states in which EW was applied. b, Watersheds over which river cation and dissolved inorganic carbon data were interpolated for use in our Earth system model. The shaded polygons show the watershed extent and the filled circles show the outflow locations. The six large watersheds considered are the Mississippi, Colorado, Columbia, Sacramento, Lawrence and Nelson. c,d, Ridgeline plots of Ω (log10) for US river systems in the background state (grey) and for each decade between 2020 and 2070 for the 1 Gt yr−1 © and 2 Gt yr−1 (d) rock extraction scenarios by 2070. e,f, Carbon leakage from the ocean during EW for the 1 Gt yr−1 rock extraction scenario (e) and 2 Gt yr−1 rock extraction scenario (f) by 2070. The solid lines and shaded regions show the median and percentile values, respectively, for our 984-member model ensemble. Base leakage refers to CO2 outgassing from the ocean; EW is the residual re-release of CO2 captured through EW — Beerling, David J., et al. “Transforming US Agriculture for Carbon Removal with Enhanced Weathering.” *Nature*, 2025, pp. 1–10, https://doi.org/10.1038/s41586-024-08429-2. Accessed 9 Feb. 2025.

That’s a big deal. Even if it doesn’t eliminate the need for other carbon capture methods, EW could account for up to 30% of the U.S.’s required CO₂ removal by 2050. “What we’re proposing could offer a genuine step-change in how the U.S. captures carbon to meet its increasingly urgent net-zero target and safeguard our planet’s future,” said Dr. Beerling.

One of the most appealing aspects of EW is that it leverages existing agricultural infrastructure. The crushed rock can be applied much like limestone, which farmers already use to reduce soil acidity. That means there’s no need to build a whole new system from scratch — just tweak the way things are done.

However, it turns out there are even more benefits to this.

EW does more than just lock away carbon — it also has real-world benefits for farmers and the environment.

For one, it improves soil health. Basalt slowly releases essential nutrients like potassium (K) and phosphorus (P), reducing the need for synthetic fertilizers. With global fertilizer prices fluctuating and supply chains under pressure, this could offer a cost-effective alternative for farmers while lowering emissions tied to fertilizer production.

See what we meant when we said climate change innovation could have long-lasting positive effects on our economies.

Even more, it also reduces agricultural emissions of nitrous oxide (N₂O), a potent greenhouse gas. “Enhanced weathering not only captures carbon and reduces soil N₂O emissions but also provides cleaner air by reducing harmful pollutants like ground-level ozone and fine particulate matter,” said Dr. Maria Val Martin, a co-author of the study.

That’s right — spreading crushed rock on fields could improve air quality. The chemical reactions triggered by EW reduce the release of nitrogen-based pollutants, which in turn lowers ground-level ozone and fine particulate matter. This isn’t just good for the climate; it helps crops grow better and benefits public health, especially in agricultural regions.

Benefits of enhanced weathering for agricultural soils. a, Boxplots with decadal average distributions of topsoil (0–15 cm depth) pH for grid cells representing the top ten Corn Belt states (defined by CDR potential), with EW deployment. Boxes show the interquartile range and median line, with whiskers extending to the 90% confidence interval. The dots depict the 80% confidence interval. b, Decreasing fraction of acidified lands in the same ten Corn Belt states over time with EW deployment. The shading denotes 90% confidence limits. A threshold pH value of 6.5 is used as this is beneficial for most arable crops and serves as a reasonable middle ground for safeguarding yields. Only a small fraction of grid cells will have an average pH value close to the 6.5 boundary value each year, resulting in a narrow confidence interval range. c,d, Frequency histograms of phosphorus (P) release © and potassium (K) release (d) by EW with basalt over successive decades for Corn Belt states (2030–2070). Also indicated in c and d are the application rates of P and K fertilizers for individual states growing soybean, maize and wheat. Simulation results for annual crushed basalt applications of 40 t ha−1. The red and blue in a–d indicate the 1 Gt yr−1 and 2 Gt yr−1 rock extraction by 2070 scenarios. CI, confidence interval — Beerling, David J., et al. “Transforming US Agriculture for Carbon Removal with Enhanced Weathering.” *Nature*, 2025, pp. 1–10, https://doi.org/10.1038/s41586-024-08429-2. Accessed 9 Feb. 2025.

WWell, all of this looks promising, but what are the roadblocks preventing us from scaling up?

Despite its promise, scaling up EW won’t happen overnight. “Significant uncertainties remain in the quantification of carbon removal fluxes in the field, requiring the adoption of industry-standard Monitoring-Reporting-Verification protocols,” said Dr. Euripides Kantzas, one of the study’s authors.

In other words, we still need better real-world data to confirm how much CO₂ is removed and ensure carbon stays locked away for the long haul.

Another challenge is the logistics of mining and transporting basalt. The Corn Belt, home to vast stretches of U.S. farmland, isn’t always close to basalt-rich regions. Moving millions of tons of rock dust across the country takes energy, and keeping transport emissions low is critical.

Fortunately, many Midwestern states already have quarrying infrastructure that could be adapted for EW, which helps keep costs down.

Then, there’s the issue of public perception and policy support. While EW doesn’t require significant land-use changes, it still means spreading large amounts of crushed rock across farmland , which requires farmers to buy in.

“Massive amounts of carbon dioxide removal are needed for meeting climate goals. Our work strengthens the case that enhanced weathering can drive large amounts of carbon removal while helping farmers and strengthening rural economies,” said Dr. Noah Planavsky of Yale University.

Benefits of enhanced weathering for surface ozone and crop production. a, Simulated summer surface ozone (O3) for 2070 (control; anthropogenic emissions + biomass burning + present-day biogenic emissions, no EW effects), with widespread reductions by 2050 and 2070 due to EW lowering soil nitrogen trace gas emissions. b, Average calculated increases in yields of maize, soybean and wheat for 2070 of three ozone exposure–crop yield functions. c, Calculated avoided economic yield losses for maize, soybean and wheat per state due to lower surface O3 exposure levels in 2070 with EW — Beerling, David J., et al. “Transforming US Agriculture for Carbon Removal with Enhanced Weathering.” *Nature*, 2025, pp. 1–10, https://doi.org/10.1038/s41586-024-08429-2. Accessed 9 Feb. 2025.

So, let’s recap. Is this something worth investing in, then?

EW isn’t a silver bullet for climate change, but the numbers suggest it’s a serious tool worth exploring. Unlike high-tech carbon capture solutions that are expensive and difficult to scale, EW builds on an ancient natural process and fits within existing farming practices.

A low hanging fruit in the climate change mitigation toolkit.

Dr. James Hansen, a co-author of the study, put it bluntly: “Ongoing acceleration of global warming calls for urgent reduction of fossil fuel emissions and actions to mitigate climate change. Our analysis lays out the overlooked potential and wider benefits of enhanced weathering in U.S. agriculture for U.S. policymakers.”

This research reminds us that the most effective solutions sometimes come from understanding and working with nature. We might find an unexpected ally in the fight against climate change—right beneath our feet — by simply harnessing a process that’s been shaping our planet for billions of years.