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Soil carbon assets

Research Digest
University of East Anglia University of East Anglia

By altering land/soil management practices, agriculture could make a substantial contribution to carbon capture and storage efforts. Sam Keenor and Brian Reid of University of East Anglia discuss what a carbon trading platform needs to be successful.  They are focussing current research on estates in Norfolk, including those involved in the Wendling Beck Environment Project, near Dereham, where plans are advancing for a pioneering landscape-scale habitat creation, nature recovery and regenerative farming project.

How to incentivise soil re-carbonisation

Sam Keenor and Brian Reid
Sam Keenor and Brian Reid

“To incentivise soil recarbonisation practices over ‘business as usual’ a source of economic remuneration is required to catalyse the transition,” says Sam Keenor of the University of East Anglia (UEA). Sam and Brian Reid, Professor of Soil Science at UEA, are co-authors on the paper ‘Capturing a Soil Carbon Economy’.

The researchers propose that creation of a successful soil carbon trading platform to support such payments will require three key elements:

(i) To incentivise soil re-carbonisation, an attractive and fair soil carbon price will be needed.

(ii) To give confidence to both the sellers and buyers of credits, establishment of a verified and trusted soil carbon accounting and trading platform, along with a robust audit system to preclude double-counting will also be needed.

(iii) assurances on long-term soil carbon storage will be essential for credit validity and trust while ensuring against double counting and emissions leakage.

Payments need to be at least £25 a tonne to make it meaningful

Setting a unit price for a soil carbon credit is not trivial. At present, soil carbon is being traded in a fledgling market for around the £10-£15 price mark (per 1 tonne CO2e). Such a price does not reflect the true value of soil carbon, nor does this reconcile with outgoings faced by farmers in achieving this sequestration. Sam highlights that: “with the projected increases in both the price of carbon and wider adoption of carbon pricing initiatives in the private sector, financial incentives to sequester carbon will intensify. This, in turn, will drive the soil carbon credit price up.

“For meaningful large-scale sequestration to occur, payments need to increase to a threshold of at least £25 per tonne of CO2e”.

Beyond this threshold even higher unit prices could be commanded where they conflate the value of carbon sequestration and the wider value linked to uplifted delivery of soil ecosystem services. Such an approach would align with “additionality” requirements; wherewith benefits beyond carbon sequestration per se are realised. To ensure opportunities to enhance soil carbon stocks are not missed, clearly defining additionality within the context of soil carbon sequestration remains wanting.

Essential to ascribing a proportionate carbon price is the existence of a trusted platform upon which credits may be traded. Here, one approach might consider the use of direct measurement and re-measurement after an allotted period, with any carbon uplift being available to the market for trade. But, under this approach it will take time for carbon to accrue and revenue to be realised; a significant issue in a cash-flow strapped sector.

Carbon fate modelling offers alternative

An alternative approach would be if the stability of soil carbon could be predetermined then this information could support tailored carbon fate modelling (tethered to specific regimes and practices) that can quantify stable carbon stock in the future. This method acknowledges that soil carbon models have been successfully used to predict the impact of agricultural activities on soil carbon and CO2 emissions. Such an approach could prove superior to costly re-measurement of soil carbon stock increases in real time and mitigate issues currently associated with such practices.

Above all, if soil carbon is to emerge as a tradable commodity, surety on the “permanence” of carbon storage will be essential. It would be inappropriate for carbon credits to be sold if these credits were underpinned by degradable soil carbon that disappears in a few years. Worse still, if this carbon is converted to CO2 and emitted to the atmosphere; who would want to buy an emission?

Brian Reid comments: “unequivocally, soil carbon credits must be tethered to stable carbon, that is not easily degraded and therefore sustains long-term carbon sequestration. With efforts being made to develop a Soil Carbon Code we can but hope for acknowledgement that, ‘when it comes to soil carbon, not all carbon is equal!’ What really matters is distinguishing stable carbon, that can be used ascribe High Integrity Soil Carbon Credits, from degradable carbon, that delivers additionality in terms of soil biodiversity net-gains and uplift to the delivery of soil ecosystem services”.

Sam and Brian’s research is providing deeper understanding of the linkages between soil carbon and the soil ecosystem service it supports.

Royal Society “Capturing a Soil Carbon Economy” paper is available on open access here.