Soil carbon credits offer the promise of better land management across millions of hectares of farmland, and they are a central focus of the International Conference on Agriculture, Food Security and Climate Change taking place this week in the Hague. But how does it work, and can carbon markets make it a reality? Steve Apfelbaum has spent the last two decades restoring the vanquished prairies of the American Midwest. One way to do this, he thinks, is to lock carbon in the dark black clods of prairie dirt. A decomposing mixture of plant matter, minerals, rock and billions of microorganisms, this rich soil recycles carbon dioxide from the air back into the earth. Yet centuries of deforestation, plowing, and overuse in the Midwest and around the world have released billions of tons of carbon into the atmosphere and damaged the land’s ability to produce. Advocates for soil organic carbon (SOC) see a chance to reverse this trend, and in the last 12 months, a flurry of new methodologies and prospective projects have been announced to help restore soils, boost yields and lower the cost of greenhouse gas (GHG) mitigation. Keeping organic matter in the soil, however, is no easy task in a world that needs to disrupt the earth to feed people. Soil carbon practices must enhance crop yields while moderating plowing, fertilization and other favorites of conventional monocropping. In natural ecosystems, fires or drainage can be prevented, and natural vegetation regrown.Soil Carbon Methodologies Long confined to the Chicago Climate Exchange (CCX), soil carbon is now gaining credibility around the world. Three methodologies – the blueprints to design, certify, and operate carbon projects – are awaiting validation under the Voluntary Carbon Standard (VCS), with several more in the pipeline. Canada’s Alberta Province has three approved protocols, and several more under study, while several regional US systems have joined the CCX in developing ways to claim carbon credits through soil sequestration. US federal agencies like the Environmental Protection Agency and the United States Department of Agriculture (through its Climate Change Program Office) are throwing research dollars behind the effort, and private sectors are pioneering ways to measure, monitor and enhance SOC – and turn a profit from it. One of these is Apfelbaum. His firm, Applied Ecological Services (AES), has restored landscapes and reclaimed mines or landfills in the US for years. Through a consortium called Earth Partners, “a diverse partnership of scientists, ecological engineers, financiers, PES methodology experts and businessmen,” Apfelbaum plans to submit a soil carbon methodology incorporating ecosystems services such as water, fertility and carbon as a complete package. “Landscape ecological science is what we’ve been using for years,” he says. “You think about ecosystems management – with carbon as just one outcome.” Farming the solution There is no shortage of potential. Most of the carbon stock in the world’s terrestrial biosphere resides in soil and living biomass. During the last two centuries, as the world’s forests fell and the soil was plowed for agriculture and development, about 456 billion tons of carbon were released. That’s equivalent to raising global CO2 concentrations by 114 parts per million (with some cycling back into the biosphere) – no small amount when you consider that today’s levels are at 392 parts per million. Although methane (CH4) from rice paddies and nitrous oxide (NO2) from livestock contribute the bulk of direct emissions from agriculture (not including indirect deforestation), the Intergovernmental Panel on Climate Change (IPCC) reports that soil carbon sequestration rivals the energy or industrial sectors for GHG mitigation potential – about 6 billion tons of carbon per year, most of it through cropland and grazing land management in developing countries (See the full IPCC report here). Carbon methodologies are meant to enhance this land-sink by attracting financing from carbon markets. For now, soil carbon is a small niche in the $136 billion compliance carbon market (and $700 million voluntary market). In 2008-2009, offsets from agriculture and land-use projects supplied a fraction of total credits – mostly in biomass or bioenergy, methane avoidance and (at least in voluntary markets) reforestation and afforestation projects. The most recent data shows 2.7 million tons in over-the-counter trades of agricultural-related Voluntary Emission Reduction (VER) certificates (5.4% of the voluntary market) and 21 million Certified Emission Reduction (CER) certificates under the Kyoto Protocol’s Clean Development Mechanism (6% of the market) – although the CDM does not permit stand-alone soil carbon projects (see Ecosystem Marketplace’s 2009 State of the Voluntary Carbon Market). To make soil carbon sequestration a market heavyweight, soil carbon methodologies will need to boost yields and carbon stocks through restoration of pasture or croplands, conservation of native vegetation and, of course, cost-effective measure and monitoring. Yet the process of creating an SOC methodology can take years of concerted political lobbying and rigorous scientific research. Even then, much depends on the political climate. Until now, this has deterred most aspirants, but field testing of new methodologies, as well as falling costs and rising accuracy of SOC measurement and computer modeling, means methodologies are hitting the market at a rapid clip. The three soil carbon methodologies under validation by the Voluntary Carbon Standard will join three in Alberta’s compliance offset market (already, half of the 30 protocol standards are related to agriculture), CCX’s rangeland carbon sequestration and agricultural soil methods, proposed protocol under the California Action Registry and others. These are outlined in the table below.