A Simple Farming Trick That Could Remove CO₂ from the Atmosphere
How Spreading Rock Dust on Farms Could Help the U.S. Fight Climate Change
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.
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.
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.
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.
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.
We already have farming methods and soil regeneration systems that work without bringing in crushed rock(from where?). This is the problem of scientists not working with practical processes on the ground. A healthy soil structure holds carbon and it holds water. If we paid more attention to the living systems role in climate, instead of paving and destroying, we would find we may still have a chance. Look into the Soil Food Web, soil sponge and the role plants play in the hydrological cycle.
I know something about crushing stone. The locale where I was raised deemed itself the colored slate capital of the world. Once the petroleum industry began, roofing slate was replaced with asphalt shingles.
Still people wanted the look of slate, so slate was dynamited and crushed to a fine pebbly texture and formed into the surface of the asphalt shingles.
Those men who worked crushing the stone ( my grandfather included) all died due to dust exposure - at least 300 men in total; mostly of fibrotic lung disease, cancer or tuberculosis, but also by coronary artery and renal disease as complications.
Slate has a higher silicon content than basalt, but you propose grinding the stone finer, and grinding basalt has the same recognized complications as does grinding other hard rock. Those farmers applying it to their fields and their neighbors as well will face similar risks to an extent I cannot estimate.