The additionality of forest conservation interventions is frequently questioned. In particular, they are often considered to be located in places where forests are not threatened, which points to the existence of location biases. Revisiting this location bias concept, we conceptually distinguish potential and effective additionality and theoretically consider how the objectives of the implementer affect the siting choice of the forest conservation interventions and their additionality. Our theoretical intuition is that the choices of the implementers are influenced by the quality of institutions. Our results show that (1) the implementer's objective and local institutions may lead the implementer to select a site with low development potential and low forest threat, and (2) the selection of a site with low development potential, which is frequently presented as a location bias, does not necessarily preclude additionality.

Cover crops can generate both on-farm and water-quality benefits. However, their use in Iowa remains subdued, partly due to implementation costs faced by farmers. We tested the hypothesis that monetary incentives through cost-share programs are effective at increasing the area of farmland planted to cover crops in Iowa, as opposed to the alternative in which the participants of cost-share programs would have planted the same cover-crop acreage in the absence of payment. We found that cost-share payments induced a 15 percentage-point expansion in cover-crop acreage beyond what would have been planted in the absence of payment, among farmers who participated in cost-share programs. The estimated additionality rate was 54%, suggesting at least half of cost-share expenditures funded cover-crop acreage that would not have been planted without payment. Furthermore, we estimated the public cost to reduce nitrogen loads to Iowa waterways via cover crop, beyond what would have occurred in the absence of cost-share programs, to be $1.72–$4.70 lb−1 N ($3.79–$10.36 kg−1 N). Farmers absorbed about 70% of those costs as private losses, and cost-share payments offset the remaining 30%. Although the additionality rate estimated in this study is less than what has been found in other states, the cost-share programs in Iowa have been relatively cost-effective, due to their lower payment rate.

This study estimates how potential carbon policies targeted at reduction of greenhouse gas (GHG) emissions could affect selection of rice cultivars by conducting a life cycle assessment of GHG emissions and estimating the carbon sequestered for fourteen commonly sown rice cultivars across Arkansas. Market-oriented carbon-offset credits based on additionality likely would be insufficient to convince producers to change cultivars; nonetheless, there may be upstream pressure as food retailers strive to lower their overall carbon footprints. Given their higher yield per unit of GHG emission, hybrid rice cultivars appear to be positioned to respond to industry demand.

Payments for ecosystem services (PES) are emerging worldwide as important mechanisms to align investments in human and natural well-being. PES projects are often defined as voluntary transactions where well-defined environmental/ecosystem services (or land uses likely to secure those services) are bought by a minimum of one service buyer, from a minimum of one service provider, if and only if the service provider continuously secures service provision (conditionality). Further criteria of PES include limiting additional objectives and ensuring that payments reward behaviour that would otherwise not occur (additionality). Together these best practices for PES are increasingly accepted as the most efficient means to achieve desired outcomes and are guiding funding for PES projects. We used a series of water funds (watershed-oriented PES projects based on a trust fund model) to examine how theoretical best practices could inform and improve practice and also how theory could learn from practical efforts. We conclude that thoughtful consideration is required when evaluating the promise of a PES approach against a theoretical ideal. We found that requiring conditionality may limit the use of creative finance mechanisms such as trust funds that can provide long-term benefits for conservation and human well-being, and that requiring additionality can exclude benefits from social diffusion and result in the inefficient targeting of PES funds. Finally, public–private partnerships in water funds lead to multiple additional/side objectives but partnerships are likely to lower transaction costs and provide transparent, long-term landscape-scale watershed management.