Published in Environmental Research Letters, the research draws on support from the Stanford Woods Institute for the Environment's Environmental Ventures Program and Stanford's Sustainability Accelerator. The authors challenge widely used approaches to gauging biochar's durability and urge the adoption of more sophisticated frameworks.
Their investigation stemmed from early examinations of soil's ability to capture carbon dioxide. "We realized that even though biochar is really important component of the carbon removals market, there is very little useful data on how it actually behaves," said study coauthor Kate Maher. Maher, a professor of Earth system science in the Stanford Doerr School of Sustainability and a senior fellow at the Stanford Woods Institute for the Environment, noted, "It is important for policymakers and buyers to be aware of this."
The primary measure for judging biochar's stability has traditionally been its hydrogen-to-carbon ratio. According to the study, this solitary metric omits essential variables, including soil composition, environmental conditions, and differences in feedstock, all of which affect how well biochar stores carbon in the field.
"Biochar has immense potential for carbon dioxide removal, but it will be viewed as less valuable by the market until we can confidently establish and predict its long-term durability," said study coauthor A.J. Ringsby, a chemical engineering Ph.D. student in the Stanford School of Engineering. "To get to a place where biochar stacks up against highly durable solutions like direct air capture, we need to move beyond one-size-fits-all metrics and do the ground work to develop more useful datasets."
Laboratory methods often supply the data that feed durability projections, but these controlled settings rarely capture the complexities of natural systems. Soil properties, climatic conditions, and how biochar is applied can drastically affect its decomposition rate and potential for carbon retention. By failing to account for these factors, existing protocols may underestimate how much carbon biochar can truly keep out of the atmosphere. That underestimation could lower the value assigned to biochar in emerging carbon offset markets.
To remedy this gap, the team suggests a two-step process. First, they propose using preliminary data to estimate a given biochar project's carbon removal capacity. Then, after field deployment, researchers can collect actual performance data to adjust these estimates. Such a system could bolster project valuation and modeling accuracy.
The authors emphasize the urgency of conducting coordinated global field trials. These initiatives could deliver the robust data needed to create new durability benchmarks that reflect varied environments. "Unlike most technologies in the market, biochar is shovel-ready and delivering carbon removal today," Ringsby said. "To unlock its full potential, we need better data, stronger standards, and to work together as a community to design the right experiments." The researchers say this collaborative push will guide more precise approaches to carbon crediting and help biochar gain broader acceptance.
Research Report:Do oversimplified durability metrics undervalue biochar carbon dioxide removal?
Related Links
Stanford Woods Institute for the Environment
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