Design of government policies that seek greater adoption of anaerobic digesters can benefit from a greater understanding of the motivations for adoption. Using a nationwide survey of U.S. dairy and swine producers, this study seeks to determine how policies, peer group influences, environmental beliefs, and farm characteristics affect the decision to adopt a digester. Results suggest that neighborhood effects, farm type and size, and nonmarket benefits of anaerobic digestion are important for predicting whether or not a producer will consider this technology for manure management. However, the decision to actually adopt is more dependent on government policies and economic considerations.

Reducing emissions from deforestation and forest degradation (REDD+) has emerged as a potentially important component of the global policy mix to mitigate climate change. Against a background of increasing engagement between private sector entities and conservation organizations, private sector investment has emerged in REDD+. Despite slow developments at the international scale, there continues to be private sector interest in REDD+ and continued voluntary investments in REDD+ projects and initiatives. In order to better understand possible models for private sector engagement in REDD+, this study analysed the motivation of private sector stakeholders to engage in REDD+, the perception of the potential of REDD+, the critical obstacles to making REDD+ functional and how actors perceive themselves as part of future REDD+ scenarios. Based on interviews and a workshop with private sector actors, this study found that few expect a regulatory market for REDD+ to emerge and that credits from the voluntary market have to be tailored to specific needs. As a carbon offset, REDD+ provides insufficient motivation for investment, particularly if cheaper alternatives exist. Co-benefits such as biodiversity conservation and community development are more important when traditional corporate social responsibility motivations play a role. Project scale remains important not only for the fact that smaller projects are viewed as offering more visible benefits to stakeholders but also as a means of having more control over risks on the ground, posing a challenge for the design of jurisdictional REDD+. Moving towards supply chains that are free from deforestation offers an opportunity to tackle commodity-driven deforestation. While questions remain about how such an approach might be integrated into REDD+, it could help address a perceived gap between private sector understanding of the values of REDD+ and the risks associated with these values not arising – termed here as a ‘missing middle’.

Mangroves are an imperilled biome whose protection and restoration through payments for ecosystem services (PES) can contribute to improved livelihoods, climate mitigation and adaptation. Interviews with resource users in three Solomon Islands villages suggest a strong reliance upon mangrove goods for subsistence and cash, particularly for firewood, food and building materials. Village-derived economic data indicates a minimum annual subsistence value from mangroves of US$ 345–1501 per household. Fish and nursery habitat and storm protection were widely recognized and highly valued mangrove ecosystem services. All villagers agreed that mangroves were under threat, with firewood overharvesting considered the primary cause. Multivariate analyses revealed village affiliation and religious denomination as the most important factors determining the use and importance of mangrove goods. These factors, together with gender, affected users’ awareness of ecosystem services. The importance placed on mangrove services did not differ significantly by village, religious denomination, gender, age, income, education or occupation. Mangrove ecosystem surveys are useful as tools for raising community awareness and input prior to design of PES systems. Land tenure and marine property rights, and how this complexity may both complicate and facilitate potential carbon credit programmes in the Pacific, are discussed.

Production of belowground organic matter is critical to sustainability of salt marshes. It plays a role in vertical soil accretion, a process essential for salt marshes to maintain their relative elevation and persist as sea levels rise. This paper examines belowground production and soil carbon of a high-latitude saltmarsh in the St Lawrence Estuary (Québec, Canada), which had been subjected to six years of sheep grazing. In the seventh year, without sheep, organic matter production in grazed and ungrazed sections was assessed by examining harvests of plant litter, end-of-season standing crop, and the roots and rhizomes present in in-growth cores. Excepting salinity, porewater chemistry varied little. The grazed marsh had higher soil carbon density and belowground production, yet lower aboveground biomass. Grazing reduces plant litter and increases solar exposure, soil temperature (at this latitude, soil remained frozen until April) and evapotranspiration, thus raising soil salinity and nitrogen demand, the latter a driver of root production. Grazing may not be detrimental to soil carbon storage. Permitting certain types of grazing on restored salt marshes previously drained for agriculture would provide economic incentive to restore tidal flooding, because the natural carbon sink provided in the recovered marsh would make these lands eligible for carbon payments.

This paper demonstrates the need to integrate biophysical and economic data to assess the competitiveness of US agriculture to provide soil carbon (C) and participate in a market for C credits. The paper discusses alternative methods of calculating the costs of soil C sequestration and compares the cost of sequestering soil C in Iowa and Montana. Results indicate that the opportunity cost per Mg of sequestered C varies in response to regional resource endowments and net returns. Economic models show that Montana could sequester a relatively small amount of soil C annually at a lower opportunity cost per Mg than Iowa, but Iowa can sequester larger quantities more efficiently. These results are compared with estimates of the cost of C sequestration from other domestic and international studies, and suggest that US agriculture could be competitive in domestic or international markets for C reduction credits.