Soil carbon sequestration “could offset 4% of average annual global greenhouse gas emissions over the rest of the century,” according to a report—but fresh policies are needed to facilitate the move.
The Organisation for Economic Co-operation and Development (OECD) research suggests that half of this potential could be achieved at subsidies based on carbon prices consistent with global efforts to limit global temperature increases by 2°C, with even greater CO2 removals possible by including peatland management in calculations.
Capturing benefits key to policy
Regulations are needed to stop the loss of soil carbon in situations where carbon is already saturated, such as preventing drainage and conversion of peatland soil, said the authors. This could be achieved with a tax on the CO2 emissions of landowners – however they note that no such policy is yet in place, with concerns around measurability proving an obstacle.
Policies are also needed to drive awareness of ‘win-win’ measures that both increase carbon stocks and increase farmers’ profits, they suggested, noting that R&D collaboration between farmers, government and industry in some of the OECD’s 38 member countries has brought good results in this respect.
Limits to market approaches
To enhance carbon stocks, the authors underlined that while market-based policies maybe be the most efficient option available, they have limitations. Nevertheless, these could be addressed with more innovative approaches to contracts between farmers and carbon credit providers, they said.
Non-permanence of soil carbon stocks is one issue. This could be guarded against by regular measurement, whereby both carbon credits and debits are possible based on whether carbon is being stored or released into the atmosphere.
Transaction costs, such as legal and brokerage fees, are another barrier to uptake, but here, aggregation of farmers’ contracts to create economies of scale could be used, they said.
Calculating accurate baselines for ‘business as usual’ on farms is also crucial in being able to ensure that ‘additionality’ – where practices on farms that sequester carbon are designed to go above and beyond the day-to-day – is achieved.
Environmental bonuses
To guide policy-making, more comprehensive cost-benefit comparisons are needed between market and non-market options, they said. They also noted that successful policies to encourage carbon storage in agricultural soils can have knock-on effects in terms of air and water quality and biodiversity.
“More than most other mitigation practices in agriculture, net SCS practices tend to positively affect the overall environmental performance of the agriculture sector. To be efficient, policies supporting the adoption of these practices need to take these interactions into account to enhance these environmental co-benefits, and resolve their environmental trade-offs,” they stressed.
