Peter Raymond, the Oastler Professor of Biogeochemistry at the Yale School of the Environment, recently led a study that made an important discovery. This find has potentially far-reaching implications for our efforts to address climate change. Most recently, one of our studies found that halting greenhouse gas emissions is insufficient. Second, we have to actually get carbon dioxide out of the atmosphere. One of the most promising, but lesser-known methods is the application of limestone, or crushed calcium carbonate, to farmland. This multi-pronged approach can significantly accelerate carbon capture opportunities while increasing agricultural productivity.
The research, recently published in the journal Nature Water, shows how limestone moves in soil is important in generating bicarbonate. Such a compound, released every time it rains and carried into rivers and oceans, would sequester carbon for thousands of years. Even still, the researchers recommend applying several tons of limestone per acre. Combined with complementary actions, this move would sequester billions of tons of carbon dioxide by century’s end, contributing to the goal of keeping carbon levels in our atmosphere at no more than 350 parts per million.
The Role of Limestone in Carbon Removal
Limestone has been used for centuries in agriculture to neutralize acidic soils and improve crops. It helps support healthy plant growth and counteracts the acidity produced by nitrogen-based fertilizers that tend to acidify soils. The new research indicates that its potential impacts go far beyond agriculture and outsize its benefits to feed, with unexpected environmental benefits.
Peter Raymond and his team argue for a change in liming practices that would enable these practices to actively incorporate carbon removal strategies. Noah Planavsky is an associate professor of Earth and planetary science at Yale. He is the study’s co-author and stresses that these practices can have a huge influence. By improving the way farmers apply limestone, farmers will be able to play an important role in carbon removal efforts while increasing their crop production.
Their ambitious goal of removing 15 billion tons of carbon from the atmosphere annually requires new solutions. The Yale-led study serves to underscore the effectiveness of limestone application. This implementation approach is an important step that could greatly advance this goal of equity and justice.
Implications for Climate Change Mitigation
This research has deep implications. In 2024, greenhouse gas concentrations were at their highest ever, reaching over 420 ppm. This troubling trajectory highlights the need for robust, effective carbon capture strategies. Limestone’s natural capacity to store carbon for thousands of years provides a necessary long-term counterbalance to more immediate climate change effects.
Farmers can increase their productivity and profitability by adopting the targeted limestone application into their farm plans. It positions them to be at the forefront of global carbon removal initiatives. Limestone provides an additional, two-fold boon. Not only is it one of our most valuable agricultural assets, but it is an indispensable part of our overall plan to fight climate change.
The study makes clear that reducing emissions is essential, but that this work needs to be accompanied by proactive carbon removal efforts. Among such practices, limestone application not only represents a highly cost-effective and sustainable solution but one which suits the interests of both farming operations and the environment.
Future Directions and Considerations
While the scientific community continues to directly or indirectly expand the universe of limestone applications in CCS, unavoidable questions about implementation at scale linger. The logistics of applying multiple tons of limestone per acre across diverse agricultural landscapes will require careful planning and consideration.
Policymakers and agricultural stakeholders need to have real conversations about how we might incentivize limestone application. Developing implementation frameworks that create strong incentives for farmers to implement and maintain these practices will be key to unlocking the full suite of environmental benefits.
