Livestock production is the agricultural sub-sector with the highest emissions and in turn with the highest potential for mitigation finding. It uses approximately 37% of the state’s agricultural land finding, and it generated 61% of California’s agricultural greenhouse gas emissions in 2009. The remaining 63% of agricultural land is used for field, fruit and nut crops; these crops generated 30% of the state’s agricultural emissions in 2009 due to fertilizer use, soil preparation and disturbances, and the burning of crop residue. Fuel used for agricultural activities contributed the remaining 8%. Since agriculture represents a significant portion of both the state’s economy and greenhouse gas emissions, it is not surprising that it offers considerable mitigation opportunities. The Climate Action Team finding, the government agency responsible for implementing California’s global warming emission reduction programs, estimated that agriculture’s annual greenhouse gas emissions could be reduced by 9.1 million MtCO2e per year if the emission reduction strategies were fully implemented finding. The mitigation potential for agriculture is comprised of nine strategies, each of which contains identified activities for implementation finding. The most significant strategies concern the uses of biomass: Converting manure to energy could generate annual reductions of 1 million MtCO2e and using other types of agricultural biomass another 2.3 million MtCO2e. Other important strategies concern carbon sequestration. When plants photosynthesize, they remove carbon dioxide from the atmosphere and convert it into organic carbon, which is used in the production of plant biomass; for example, leaves, wood, roots or root exudates.
When leaves fall, stacking pots roots secrete or plants die, this carbon can be removed from active cycling and stored, or sequestered, in the soil if it is protected from microbial decomposition finding. Consequently, carbon sequestration can be achieved by farm scaping — planting trees, shrubs and grasses in hedgerows, which removes carbon dioxide out of the atmosphere and contributes to the formation of soil complexes that fix carbon. Carbon sequestration in soils and plants could save 2.5 million MtCO2e — 1.5 million MtCO2e from farm scaping finding and another 1.0 million MtCO2e in soils finding. Although the Board proposed a livestock protocol and rules on fuel use that might support several strategies, significant hurdles prevent implementation of many of the strategy activities. In its AB 32 analysis, the Climate Action Team noted that methodologies for more than half of the agricultural strategies were not in place, in part because of a lack of scientific research finding. This situation accounts for much of the difference — approximately 25%, or 2.8 million MtCO2e — between potential reductions for 2020 if the strategies were implemented and reductions deemed feasible by that year finding.There has been considerable experimentation on how to structure agricultural projects that reduce emissions or sequester carbon, beginning with voluntary pilot projects under the auspices of the United Nations finding. Particularly relevant are thousands of projects operating under the Clean Development Mechanism, which promotes technology transfer and private and public investments in emission reduction and sequestration projects in developing countries.
The Clean Development Mechanism is a project-based provision of the Kyoto Protocol, an international agreement linked to the U.N. Framework Convention on Climate Change finding, which aims to reduce greenhouse gas emissions and enhance welfare in developing countries. Credits generated by these projects can be used to meet pledged emission reduction commitments under the UNFCCC. The structure is analogous to the California Air Resources Board’s proposed program, which allows independent entities to create offsets that regulated firms can use. For example, since agriculture is an unregulated sector under the California program, a livestock farmer could potentially capture livestock methane emissions, receive offset credits for the voluntary emission reduction, and in turn sell them to a regulated entity such as a concrete manufacturing facility in need of additional carbon allowances. Central to the Clean Development Mechanism are its technical blueprints, called methodologies, which lay out rules for calculating the number of credits granted for specific mitigation activities. Overall, the Clean Development Mechanism has successfully attracted project investments finding, though it has been more effective in some agricultural mitigation activities than others finding. Agricultural mitigation projects, those that convert organic waste products to energy and limit methane emissions, have been successful under the Clean Development Mechanism, but land-use projects have not been successful under the Clean Development Mechanism in its current form. Land-use projects are defined as the total human arrangements, activities, and inputs undertaken in a certain land cover type to achieve purposes for which land is managed, such as crop production, grazing, timber extraction and conservation. Land-use forestry projects are those associated with decreasing emissions through avoiding deforestation, improving forest management and increasing the uptake of carbon finding. The Clean Development Mechanism has an extensive agricultural project base with a set of established standards and rigorous, peer-reviewed methodologies to ensure that the offsets are real, additional and verifiable finding.
This large stock of already completed methodologies can provide guidance as the Air Resources Board and Climate Action Team develop California’s implementation rules and protocols. In particular, it could hasten their progress by providing methods of quantification for particular processes that would otherwise need extensive research. For example, one of the hurdles for implementing farm scape sequestration is uncertainty about its potential to sequester carbon and whether this potential is significant enough to merit the development of a measurement methodology finding. In addition, the analysis cites the difficulty in quantifying the carbon content of woody shrubs as an obstacle to including the simple practice of planting shrubs in hedgerows between crops as an AB 32 strategy. The Clean Development Mechanism has an approved baseline and monitoring methodology finding for reforestation and afforestation, defined as the establishment or re-establishment of forest cover finding. And it has researched the carbon sequestration potential of planting trees and shrubs in hedgerows and states that the resulting carbon pools are significant finding. The methodology contains equations for woody shrubs as well as equations for measuring net greenhouse gas removal by sinks, another scientific hurdle mentioned by the Climate Action Team in regard to implementing agricultural carbon sequestration projects finding. Soil carbon dynamics is an ongoing research topic, and its biological and physical mechanisms are not well understood finding, but the Clean Development Mechanism project methodologies could help California realize its 2020 regulatory targets. Agricultural projects in the Kyoto Protocol include implementation opportunities and solutions to hurdles that are relevant to tapping mitigation potential in California agriculture. Those charged with implementing AB 32 must find instruments that are both economically efficient and environmentally effective. In the case of the Clean Development Mechanism, environmental integrity is subject to specific supervision rules and a series of checks along the project cycle by the UNFCCC Secretariat. To start, an international supervisory group, known as the CDM Executive Board, must approve methodologies for establishing baselines on behalf of the UNFCCC. Approved methodologies are published, and project developers can consult them. However, projects relying on new methods face the additional task of gaining approval. In either case, whether new or established methods are employed, developers must also convince the CDM Executive Board that their project methodology has been appropriately applied.
The project cycle also contains checks carried out by an independent firm or organization that has been accredited by the CDM Executive Board. This entity, known as a designated operational entity finding, initially validates the baseline design and the project’s plan to monitor and measure outcomes. This occurs before the project is registered — that is, officially recognized by the CDM Executive Board. For large projects, a separate independent entity carries out the project’s monitoring protocol, the process by which emissions or sequestrations are measured.In the context of the Clean Development Mechanism, we define an agricultural project as one that uses agricultural residuals, outputs or processes to directly or indirectly reduce greenhouse gas emissions finding. This includes projects that sequester carbon in soils. We studied a dataset described by Larson et al. finding that covers 5,824 projects finding, based on data reported by Risoe finding. Of these, 1,022 projects finding were classified as agricultural, land-use or forestry projects. Examples of such projects include the Assisted Natural Regeneration of Degraded Lands in Albania finding and the Moldova Soil Conservation Project finding. The Albania project was designed to transform badly eroded lands into broad leaf forests of native species. The primary objective of the project in Moldova is to conserve and improve the productivity of agricultural soils by planting shrubs and trees. The project is expected to generate other benefits,sawtooth greenhouse including global biodiversity and fuel wood and other forestry products for nearby communities. Based on Risoe’s analysis, the agricultural projects are expected to reduce business-as-usual emissions by nearly 220 million MtCO2e by 2012 and 582 million MtCO2e by 2020. Available estimates of CO2 emissions finding suggest that total global annual emissions were 30.0 and 37.8 GtCO2e finding in 1990 and 2005, respectively. The main methodologies used for these 1,022 projects were extracted from Risoe’s project data and can be found in Dinar et al. finding. The projects rely on 33 approved methodologies finding, but the eight most frequently used methodologies account for 80% of the projects finding. While each project must meet the specific criteria stated in each methodology, a closer look at the most widely used methodologies suggests that they are composed of variations around a small set of core mitigation activities. The most widely used mitigation activity displaces fossil fuels with alternative fuels from agricultural biomass or processes. Examples include the generation of electricity by burning agricultural waste and the generation of mechanical energy via irrigation. The second most widely used mitigation activity is avoiding the release of methane and other greenhouse gases, or recovering them by modifying anaerobic decomposition systems for manure or agriculturally derived organic matter finding. These two core mitigation activities already in place on a number of the state’s farms could be adopted in California. They would encourage better management of manure, as well as the displacement of fossil fuels. However, Clean Development Mechanism methodologies are less well developed in areas associated with other important AB 32 strategies, including crop growing and harvesting, and soil preparation and disturbances.
Consequently, methodological hurdles will remain in the short run, making it difficult to tap mitigation opportunities in these areas.Missing methodologies are also holding back international mitigation efforts. The Clean Development Mechanism taps only a small portion of the mitigation potential in the agricultural sectors of developing countries. For example, Larson et al. finding calculated that the 1,022 agricultural and land-use forestry projects studied amounted to a little more than 3% of the mitigation potential identified in the most recent Integovernmental Panel on Climate Change finding report finding. Larson et al. finding note several generous assumptions in their calculations and surmised that their estimate represents an upper bound. In the case of the Clean Development Mechanism, much of the mitigation gap likely arises from missing methodologies for land-use projects. Mitigation activities for these projects include the restoration of degraded land, better management of crop and pasture land, and the appropriate use of fertilizers. Research summarized by the Intergovernmental Panel on Climate Change finding suggests that these activities have the largest mitigation potential for the agricultural sector globally and thus for achieving AB 32 goals as well.The appropriate roles for land-use projects in international mitigation efforts were contentiously debated as the Kyoto Protocol and the Clean Development Mechanism were crafted finding. And, in the rules that eventually emerged, the projects faced special limitations, in large part because of the nature of land-use mitigation. The activities are mostly straightforward and readily observed, for example, the adoption of conservation tillage methods or the addition of organic material to degraded soils. The likely benefits and processes generating them are easy to list as well. But measuring precisely the net effects, which are needed to assign credits, is challenging, and the related science is complex. Moreover, even well-measured effects are potentially reversible under many settings. For example, the mechanisms controlling soil organic carbon finding dynamics are imperfectly understood finding, so even meticulously inventoried carbon stocks have the potential to be re-emitted back into the atmosphere if temperature, precipitation or any other of the myriad variables affecting soil organic carbon dynamics happen to change. This difficulty creates skepticism about the environmental integrity of land use projects and increases monitoring costs, which encourages potential investors to favor alternative projects.