Quantifying COVID-19's silver lining: Avoided deaths from air quality improvements in Bogotá.

In cities around the world, COVID-19 lockdowns have significantly improved outdoor air quality. Even if only temporary, these improvements could have longer-lasting effects by making chronic air pollution more salient and boosting political pressure for change. To that end, it is important to develop objective estimates of both the air quality improvements associated with lockdowns and the benefits they generate. We use panel data econometric models to estimate the effect of Bogotá's 16-month lockdown on PM2.5 and NO2 pollution, epidemiological models to simulate the effect of reductions in these pollutants on long- and short-term mortality, and benefit transfer methods to value the avoided mortality. We find that on average, Bogotá's lockdown cut PM2.5 pollution by 15% and NO2 pollution by 21%. However, the magnitude of these effects varied considerably over time and across the city's neighborhoods. Equivalent permanent reductions in these pollutants would reduce long-term premature deaths from air pollution by 23% each year, a benefit valued at $1 billion annually. Finally, we estimate that if they occurred ceteris paribus, the temporary reductions in pollutant concentrations in 2020-2021 due to Bogotá's lockdown would have cut short-term deaths from air pollution by 19%, a benefit valued at $244 million.

Diminishing returns: Nudging Covid-19 prevention among Colombian young adults.

Nonpharmaceutical interventions (NPIs) like social distancing, face masks, and handwashing will continue to be a frontline defense against Covid-19 for some time. But their effectiveness depends critically on compliance by young adults, who are most likely both to become infected and to infect others. We conducted a randomized controlled trial in Bogotá, Colombia, to assess the effectiveness of informational nudges emphasizing the private and public benefits of compliance on university students' concern about Covid-19, recent compliance with NPI recommendations, and intended future compliance. Although nudges boosted concern, they had limited effects on either recent or intended future compliance. We attribute these null results to high baseline levels of information about and compliance with NPIs, an informational diminishing returns scenario that is likely to be increasingly common globally.

Forest-linked livelihoods in a globalized world.

Forests have re-taken centre stage in global conversations about sustainability, climate and biodiversity. Here, we use a horizon scanning approach to identify five large-scale trends that are likely to have substantial medium- and long-term effects on forests and forest livelihoods: forest megadisturbances; changing rural demographics; the rise of the middle-class in low- and middle-income countries; increased availability, access and use of digital technologies; and large-scale infrastructure development. These trends represent human and environmental processes that are exceptionally large in geographical extent and magnitude, and difficult to reverse. They are creating new agricultural and urban frontiers, changing existing rural landscapes and practices, opening spaces for novel conservation priorities and facilitating an unprecedented development of monitoring and evaluation platforms that can be used by local communities, civil society organizations, governments and international donors. Understanding these larger-scale dynamics is key to support not only the critical role of forests in meeting livelihood aspirations locally, but also a range of other sustainability challenges more globally. We argue that a better understanding of these trends and the identification of levers for change requires that the research community not only continue to build on case studies that have dominated research efforts so far, but place a greater emphasis on causality and causal mechanisms, and generate a deeper understanding of how local, national and international geographical scales interact.

Natural climate solutions.

Better stewardship of land is needed to achieve the Paris Climate Agreement goal of holding warming to below 2 °C; however, confusion persists about the specific set of land stewardship options available and their mitigation potential. To address this, we identify and quantify "natural climate solutions" (NCS): 20 conservation, restoration, and improved land management actions that increase carbon storage and/or avoid greenhouse gas emissions across global forests, wetlands, grasslands, and agricultural lands. We find that the maximum potential of NCS-when constrained by food security, fiber security, and biodiversity conservation-is 23.8 petagrams of CO2 equivalent (PgCO2e) y-1 (95% CI 20.3-37.4). This is ≥30% higher than prior estimates, which did not include the full range of options and safeguards considered here. About half of this maximum (11.3 PgCO2e y-1) represents cost-effective climate mitigation, assuming the social cost of CO2 pollution is ≥100 USD MgCO2e-1 by 2030. Natural climate solutions can provide 37% of cost-effective CO2 mitigation needed through 2030 for a >66% chance of holding warming to below 2 °C. One-third of this cost-effective NCS mitigation can be delivered at or below 10 USD MgCO2-1 Most NCS actions-if effectively implemented-also offer water filtration, flood buffering, soil health, biodiversity habitat, and enhanced climate resilience. Work remains to better constrain uncertainty of NCS mitigation estimates. Nevertheless, existing knowledge reported here provides a robust basis for immediate global action to improve ecosystem stewardship as a major solution to climate change.

Titling indigenous communities protects forests in the Peruvian Amazon.

Developing countries are increasingly decentralizing forest governance by granting indigenous groups and other local communities formal legal title to land. However, the effects of titling on forest cover are unclear. Rigorous analyses of titling campaigns are rare, and related theoretical and empirical research suggests that they could either stem or spur forest damage. We analyze such a campaign in the Peruvian Amazon, where more than 1,200 indigenous communities comprising some 11 million ha have been titled since the mid-1970s. We use community-level longitudinal data derived from high-resolution satellite images to estimate the effect of titling between 2002 and 2005 on contemporaneous forest clearing and disturbance. Our results indicate that titling reduces clearing by more than three-quarters and forest disturbance by roughly two-thirds in a 2-y window spanning the year title is awarded and the year afterward. These results suggest that awarding formal land titles to local communities can advance forest conservation.

An agenda for assessing and improving conservation impacts of sustainability standards in tropical agriculture.

Sustainability standards and certification serve to differentiate and provide market recognition to goods produced in accordance with social and environmental good practices, typically including practices to protect biodiversity. Such standards have seen rapid growth, including in tropical agricultural commodities such as cocoa, coffee, palm oil, soybeans, and tea. Given the role of sustainability standards in influencing land use in hotspots of biodiversity, deforestation, and agricultural intensification, much could be gained from efforts to evaluate and increase the conservation payoff of these schemes. To this end, we devised a systematic approach for monitoring and evaluating the conservation impacts of agricultural sustainability standards and for using the resulting evidence to improve the effectiveness of such standards over time. The approach is oriented around a set of hypotheses and corresponding research questions about how sustainability standards are predicted to deliver conservation benefits. These questions are addressed through data from multiple sources, including basic common information from certification audits; field monitoring of environmental outcomes at a sample of certified sites; and rigorous impact assessment research based on experimental or quasi-experimental methods. Integration of these sources can generate time-series data that are comparable across sites and regions and provide detailed portraits of the effects of sustainability standards. To implement this approach, we propose new collaborations between the conservation research community and the sustainability standards community to develop common indicators and monitoring protocols, foster data sharing and synthesis, and link research and practice more effectively. As the role of sustainability standards in tropical land-use governance continues to evolve, robust evidence on the factors contributing to effectiveness can help to ensure that such standards are designed and implemented to maximize benefits for biodiversity conservation.

Producer-level benefits of sustainability certification.

Initiatives certifying that producers of goods and services adhere to defined environmental and social-welfare production standards are increasingly popular. According to proponents, these initiatives create financial incentives for producers to improve their environmental, social, and economic performance. We reviewed the evidence on whether these initiatives have such benefits. We identified peer-reviewed, ex post, producer-level studies in economic sectors in which certification is particularly prevalent (bananas, coffee, fish products, forest products, and tourism operations), classified these studies on the basis of whether their design and methods likely generated credible results, summarized findings from the studies with credible results, and considered how these findings might guide future research. We found 46 relevant studies, most of which focused on coffee and forest products and examined fair-trade and Forest Stewardship Council certification. The methods used in 11 studies likely generated credible results. Of these 11 studies, nine examined the economic effects and two the environmental effects of certification. The results of four of the 11 studies, all of which examined economic effects, showed that certification has producer-level benefits. Hence, the evidence to support the hypothesis that certification benefits the environment or producers is limited. More evidence could be generated by incorporating rigorous, independent evaluation into the design and implementation of projects promoting certification.

Resumen: Las iniciativas de certificación de productores de bienes y servicios que se apegan a estándares ambientales y de producción de bienestar social son cada vez más populares. De acuerdo con los proponentes, estas iniciativas crean incentivos financieros para que los productores mejoren su desempeño ambiental, social y económico. Revisamos la evidencia para ver si esas iniciativas tienen tales beneficios. Identificamos estudios ex post y a nivel de productores sometidos a revisión cientifica external, en sectores económicos en los que la certificación es particularmente prevalente (plátano, café, productos pesqueros, productos forestales y operaciones turísticas), los clasificamos considerando si su diseño y métodos generaron resultados creíbles, sintetizamos los hallazgos de los estudios con resultados creíbles y consideramos como estos hallazgos pueden dirigir investigaciones en el futuro. Encontramos 46 estudios relevantes, muchos de ellos enfocados en café y productos comerciales y con certificación de comercio justo y Forest Stewardship Council. Los métodos utilizados en 11 estudios generaron resultados creíbles. De estos 11 estudios, nueve examinaron los efectos económicos y dos los efectos ambientales de la certificación. Los resultados de cuatro de los 11 estudios, todos examinando efectos económicos, mostraron que la certificación tiene beneficios a nivel de productores. Por lo tanto, la evidencia para apoyar la hipótesis de que la certificación beneficia al ambiente o a los productores es limitada. Se deben generar mas evidencia mediante la incorporación de evaluaciones independientes más rigorosas en el diseño e implementación de proyectos que promueven la certificación.

Colombia's discharge fee program: incentives for polluters or regulators?

Colombia's discharge fee system for water effluents is often held up as a model of a well-functioning, economic incentive pollution control program in a developing country. Yet few objective evaluations of the program have appeared. Based on a variety of primary and secondary data, this paper finds that in its first 5 years, the program was beset by a number of serious problems including limited implementation in many regions, widespread noncompliance by municipal sewerage authorities, and a confused relationship between discharge fees and emissions standards. Nevertheless, in some watersheds, pollution loads dropped significantly after the program was introduced. While proponents claim the incentives that discharge fees created for polluters to cut emissions in a cost-effective manner were responsible, this paper argues that the incentives they created for regulatory authorities to improve permitting, monitoring, and enforcement were at least as important.