Nature study finds agricultural liming is a carbon sink, not a source, in the Mississippi River Basin

2 October 2026

A paper in Nature, in the issue dated 1 October 2026, reports that agricultural liming acts as a carbon sink in the Mississippi River Basin rather than a net source of carbon dioxide. Liming is the spreading of carbonate minerals such as limestone and dolomite on farmland to counter soil acidification. The authors estimate about 0.44 GtCO2 of carbon dioxide removal potential from the lime added to the basin since 1900, with roughly 90 per cent of that realised at the catchment scale. The Mississippi River Basin covers 41 per cent of the land area of the contiguous United States and 65 per cent of its cropland. The study argues that current accounting frameworks apply an incomplete counterfactual, attributing carbon dioxide emissions to the lime rather than to the human-caused acid inputs that drive the release. Measured against those acid inputs, liming is a net sink on decadal to century timescales while also improving crop yields and soil health. Institutions involved include the Environmental Defense Fund and Yale University.