Liming agricultural fields with crushed limestone could capture billions of tons of CO2 and improve soil health, according to a Yale-led study. This eco-friendly method could be crucial in combating climate change and enhancing farm productivity.
In a new study published in Nature Water, researchers led by Yale University have found that adding crushed calcium carbonate, or limestone, to agricultural fields can play a pivotal role in fighting climate change by removing significant amounts of carbon dioxide from the atmosphere. This method also has the potential to improve crop yields, presenting a dual benefit for both the environment and agriculture.
Greenhouse gases in the atmosphere reached a record high in 2024, hitting over 420 parts per million. The U.N. Intergovernmental Panel on Climate Change (IPCC) has emphasized that merely halting carbon emissions will not be enough to combat global warming. Instead, carbon removal strategies are necessary to limit the temperature rise to 1.5°C above pre-industrial levels.
“There is growing scientific consensus that removing carbon from the atmosphere is necessary to hit carbon goals. At this point, halting emissions won’t be enough,” Peter Raymond, the Oastler Professor of Biogeochemistry at the Yale School of the Environment and co-director of the Yale Center for Natural Carbon Capture (YCNCC), said in a news release.
Raymond and his team explored the potential of using crushed limestone as a natural means of carbon capture. Their findings suggest that limestone not only enhances soil productivity but also significantly boosts carbon sequestration.
Calcium carbonate, mainly derived from limestone created by fossilized marine life, is frequently applied to farmlands to correct soil pH affected by nitrogen fertilizers. However, its capacity to store carbon makes it an even more valuable asset in the fight against climate change.
When limestone interacts with soil, it forms bicarbonate, which can then wash into rivers and oceans, potentially storing carbon for thousands of years, Raymond explained.
Study coauthor Noah Planavsky, an associate professor of earth and planetary science at Yale and a member of YCNCC’s scientific leadership team, highlighted the enormous potential of this method.
Applying multiple tons of limestone per acre has the potential to remove billions of tons of carbon dioxide from the atmosphere by the end of the century, according to Planavsky. He added that limestone amendments could be combined with other soil treatments, such as silicate rocks and organic materials, to transform agricultural lands from carbon sources to carbon sinks.
The agricultural sector is one of the largest emitters of greenhouse gases. While the IPCC has previously listed lime as a carbon source due to its reaction with nitrogen fertilizers, the Yale-led researchers argue that it is the acid from the fertilizers that is the real issue. In most cases, adding sufficient limestone to neutralize this acidity will result in net CO2 removal over time.
Beyond carbon sequestration, liming offers additional environmental benefits. Bicarbonate formed from agricultural liming that ends up in oceans can help to raise ocean pH levels and aid in shell formation for marine life.
“To me, ocean acidification is just as important of a problem as atmospheric CO2 levels,” added Raymond. “Other carbon dioxide removal mechanisms don’t always address oceans, but liming does. But first and foremost, modifying liming practices is a way to drive carbon removals that helps farmers. It should be a priority.”
The findings of this study position liming as a promising method for achieving critical climate goals while simultaneously supporting sustainable agricultural practices.
Source: Yale School of the Environment