Yale-Led Study Identifies Agricultural Liming as Significant Carbon Sink Over 120 Years
A Yale-led study, published in Nature, challenges long-held assumptions by concluding that agricultural liming has removed between 300 and 400 million metric tons of carbon dioxide from the atmosphere in the Mississippi River Basin since 1900. This finding contradicts the default methodology of major climate assessments, including the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, which have historically treated liming as an emission source. The study, a retrospective analysis of 120 years of records from an area covering 41% of the contiguous United States and approximately 65% of U.S. croplands, argues that the error stemmed from an incomplete framework. Instead of measuring carbon released by limestone, the researchers focused on what would have occurred without liming, revealing a net carbon removal. Agricultural lime, primarily composed of calcium and magnesium carbonates, is routinely applied to U.S. croplands to manage soil pH, which is crucial for crop yields and nutrient availabilit...
