Is the transactional carbon credit tail wagging the virtuous soil organic matter dog?

Nature-based solutions are gaining momentum as approaches to address major environmental challenges, including markets for soil carbon (C) sequestration for mitigating climate change. This special collection of papers, stemming from a symposium of the 2021 Fall Meeting of the American Geophysical Union, poses several tough questions about the practical potential for significant C sequestration resulting from farmer participation in carbon markets. A common theme among these papers is that promotion of soil C sequestration through carbon markets has likely gotten ahead of the agronomic and biogeochemical science and especially the social science. We know a great deal about soil C dynamics and stabilization, but we know less about translating that knowledge to market-based solutions that have inherent challenges of validating sequestration rates and other potential pitfalls. Scientists can help provide rigor to carbon markets, although they must maintain objectivity and avoid conflicts of interests with well-intended evolving markets. Even when there is strong scientific support for the feasibility and the virtues of best management practices that provide numerous co-benefits while building soil organic matter, socio-economic barriers to farmer adoption remain poorly understood. Although soil markets currently focus almost exclusively on C, mitigation of methane and nitrous oxide emissions from agriculture could offer several advantages as well as challenges. The papers in this special collection offer a needed perspective urging soil scientists, biogeochemists, and social scientists to step up and offer honest appraisals of what is most likely to work, or not, and why.