This article originally appeared in Outreach, a multi-stakeholder magazine published daily at COP 16.
By Goodspeed Kopolo and Christoph Steiner
Biochar offers one of those rare things in the climate change arena – a real win solution. As referred to under AFOLU – Agriculture, forestry and other land use have a unique potential to sequester carbon. Annual sequestration rates by living biomass amount to approximately 100 to 120 billion tons of carbon from the atmosphere.
Approximately the same amount is released by plant respiration and decay of dead plant material. The 60 billion tons released from decomposing biomass is almost 10 times more carbon than released by fossil fuel burning.
In light of this, it needs to be recognized that humans currently appropriate more than a third of the production of terrestrial ecosystems. This is a lot of carbon in our hands! It is important to consider the difficulties of changing a GHG source into a sink. Such a transformation needs to grapple with multiple considerations and ensure it doesn’t compete with food production as is the case with biofuels, soil fertility is not compromised, it is consistent with a changing climate and the change can be quantifiable.
Proposals for agricultural and forestry biomass utilization typically focus only on carbon sequestration or bioenergy production, failing to address the issues in tandem. Some suggest maximizing carbon sequestration by the burial of crop residues in the deep ocean or the storage of trees underground. On the other hand, maximizing renewable energy production from crops and crop residues should substitute for fossil fuels (an option currently eligible for carbon trading). However both these options neglect the removal of nutrients and carbon and its beneficial effects on soil fertility. It is imperative that carbon management does not compete with food production and/or compromise soil fertility.
The drawback of conventional carbon enrichment in soils (such as reduced tillage intensity) is that this carbon sink option depends on climate, soil type and site specific management. The issues of permanence, leakage and additionality are the greatest obstacles for land use and forestry (LULUCF and REDD) carbon projects. Furthermore, the permanence and vulnerability of these sinks is likely to change in a warming climate. Therefore carbon sequestered by LULUCF projects is generally considered only temporarily sequestered. The CDM board and Gold Standard deals with these challenges by either excluding or strictly limiting LULUCF projects.
Biochar Carbon Sequestration
Biochar may offer a tool to deal with these issues. Biochar is carbonized plant material produced by pyrolysis. Pyrolysis facilitates renewable energy production, and the remaining carbon (biochar) can be redistributed to agricultural fields to improve soil fertility. This facilitates crop residue utilization, soil carbon sequestration and enhancement of soil fertility in a synergistic way.
Carbonization of biomass increases the half-life time of the remaining carbon (50%) by order of magnitudes and can be considered a manipulation of the carbon cycle. While fire accelerates the carbon cycle the formation of biochar (= carbonized plant material, charcoal, black carbon) decelerates the carbon cycle. Biochar production transforms carbon from the active (crop residues or trees) to the inactive carbon pool. Therefore issues of permanence, land tenure, leakage, and additionalty are less significant for biochar projects.
Biochar sequestration of carbon might avoid difficulties such as accurate monitoring of soil carbon which is another main barrier to include agricultural soil management in emission trading. Independently from its use as soil amendment the turnover rate and the quantity of carbon could be used to assess the carbon sequestration potential.
The exclusiveness of rights to the land is one fundamental precondition for REDD and payments for environmental services. This poses another obstacle, in particular for small farmers. Insecure tenure reduces the incentive for long-term fertility improvements and those receiving the payments cannot exclude other people who could use forest and land resources in ways that are incompatible with providing the contracted service.
This does not apply for biochar carbon sequestration because the carbon once sequestered in the soil is permanent. There is no risk that altered management practices would reduce the carbon stock. Terra Preta soils in the Amazon Basin proof that.
An obstacle of acceptance:
Most carbon offset schemes do not accept the avoidance of CO2 emissions from decomposing plant material. The definition of a carbon sink should be revised to include the difference between a sink to the inactive carbon pool, such as biochar, and a sink that remains in the active carbon pool, such as reforestation.
Nevertheless, article 3.3 of the Kyoto Protocol counts carbon stock change in soil, as well as biomass. Article 3.4 allows parties to include sequestration in plants and soil through management of cropland, grazing and land and existing forests. The Millennium Development Goals (MDG) Carbon Facility’s mission is to improve access to carbon finance enabling a wider range of developing countries and project types to participate in the carbon market. They promote projects that generate additional sustainable development and poverty reduction benefits, thereby contributing to all MDGs. The Facility operates within the framework of the Clean Development Mechanism and Joint Implementation and is a joint project between UNEP and Fortis Bank. As such it might provide support to include biochar C offsets in the compliance market.
In this way Biochar is different from trade reductions in current emissions. Because biochar is an effective and permanent carbon sink, it has the potential to recapture historic emissions, thus providing an important path for industrialized nations to reduce their historic carbon dept. Therefore, on top of all its other attractions, biochar may present a pathway for negotiating reductions in GHG emissions with fast-growing economies such as China and India.