Soil carbon credits fail climate justice in agriculture

Soil carbon has emerged as a focus of global climate and sustainability debates, with growing attention to the potential role of voluntary soil carbon markets in financing more sustainable farming. Yet there is little understanding of who would benefit from such markets, and therefore of whether they can contribute to just and equitable sustainable development and climate action. Here, using optimistic assumptions about market access and sequestration rates, I show that potential farm revenues from soil carbon credits are distributed highly unequally, both within and across countries, reflecting the concentration of farmland among a small number of large farms. As a result, farms benefiting most are disproportionately located in countries with greater historical responsibility for emissions and greater wealth, while smallholders who have the least potential revenues are disproportionately distributed in lower-income countries. Under per-hectare carbon crediting, the promise that voluntary soil carbon markets could finance more sustainable farming, particularly in low-income countries, is therefore constrained by the distribution of farmland. Recent studies remain optimistic that redesign of measurement, reporting and verification systems can reduce the overall cost and uncertainty associated to the voluntary carbon market, and that aggregating smallholders into larger projects can reduce the cost of participating. Neither, however, changes how land is distributed. I contend that addressing this inequity would require confronting land distribution and tenure directly. Without this, soil carbon crediting is likely to reproduce land inequality and to fall short of the transformation it is often promised to support.