A study finds that agricultural liming in the Mississippi River Basin acts as a net carbon sink.

What it means

This study from Nature shows that agricultural liming—adding crushed limestone to farm fields—has removed an estimated 300-400 million metric tons of CO₂ from the atmosphere in the Mississippi River Basin since 1900, making it a net carbon sink. It overturns the long-held assumption that liming is a net source of CO₂ because the chemical reaction releases gas when applied. The work uses historical records and empirical measurements to argue that the long-term carbon stored outweighs the initial emissions.

Accuracy & sourcesSourced

The claim is based on a peer-reviewed paper in Nature (doi:10.1038/s41586-026-11040-2), the primary source. Reporting by Yale News and other outlets closely mirrors the paper's conclusions. The findings rest on historical data and modeling, so while the direction is solid, specific tonnage estimates may be refined as more empirical data emerge.

How new

Genuinely new; the paper was published in Nature in 2026 and is being reported on September 23, 2026.

Go deeper

• Phys.org — first to publish