From COVID-19 to Green Recovery with natural capital accounting.

The COVID-19 pandemic and related social and economic emergencies induced massive public spending and increased global debt. Economic recovery is now an opportunity to rebuild natural capital alongside financial, physical, social and human capital, for long-term societal benefit. Yet, current decision-making is dominated by economic imperatives and information systems that do not consider society's dependence on natural capital and the ecosystem services it provides. New international standards for natural capital accounting (NCA) are now available to integrate environmental information into government decision-making. By revealing the effects of policies that influence natural capital, NCA supports identification, implementation and monitoring of Green Recovery pathways, including where environment and economy are most positively interlinked.

Quantifying and categorising national extinction-risk footprints.

Biodiversity, essential to delivering the ecosystem services that support humanity, is under threat. Projections show that loss of biodiversity, specifically increases in species extinction, is likely to continue without significant intervention. Human activity is the principal driver of this loss, generating direct threats such as habitat loss and indirect threats such as climate change. Often, these threats are induced by consumption of products and services in locations far-removed from the affected species, creating a geographical displacement between cause and effect. Here we quantify and categorise extinction-risk footprints for 188 countries. Seventy-six countries are net importers of extinction-risk footprint, 16 countries are net exporters of extinction-risk footprint, and in 96 countries domestic consumption is the largest contributor to the extinction-risk footprint. These profiles provide insight into the underlying sources of consumption which contribute to species extinction risk, a valuable input to the formulation of interventions aimed at transforming humanity's interactions with biodiversity.

The value of forest water purification ecosystem services in Costa Rica.

Forest cover improves surface water quality by minimizing soil erosion, reducing sediment in water and trapping or filtering water pollutants in forest litter. Because the amount of chemicals needed to produce potable water depends on the quality of intake water, upstream forest cover protection may help reduce the extent and cost of water treatment downstream. However, many other drivers exist for the cost of water treatment, so the magnitude and relevance of the influence of forest cover on water treatment cost is an empirical question. We analyze the impact of forest cover on the quality of raw water and the extent of water treatment required at the water treatment plants in Costa Rica, using monthly panel data in 2008-2014 from the drinking water treatment plants managed by the national public utility. We find that forest cover change during the study period statistically significantly affected the chemical use by water treatment plants. In economic terms, the estimated value of water purification service provided by forests is USD 9.5 per hectare per year. Depending on the discount rate, this results in a net present value of water purification service ranging between USD 315.4 and USD 113.9 per hectare. The results indicate that the economic value of the water purification service of forest is 1.7% of the value for recreational services; between 3.2% and 1.1% relative to the value of forest carbon sequestration typical in Costa Rica, depending on the discount rate; and around 13% of the payments for watershed protection program by the National Forest Financing Fund. The results also show that the marginal contribution of forest, on a per hectare basis, on water quality becomes larger as the size of catchment decreases.

A metric for spatially explicit contributions to science-based species targets.

The Convention on Biological Diversity's post-2020 Global Biodiversity Framework will probably include a goal to stabilize and restore the status of species. Its delivery would be facilitated by making the actions required to halt and reverse species loss spatially explicit. Here, we develop a species threat abatement and restoration (STAR) metric that is scalable across species, threats and geographies. STAR quantifies the contributions that abating threats and restoring habitats in specific places offer towards reducing extinction risk. While every nation can contribute towards halting biodiversity loss, Indonesia, Colombia, Mexico, Madagascar and Brazil combined have stewardship over 31% of total STAR values for terrestrial amphibians, birds and mammals. Among actions, sustainable crop production and forestry dominate, contributing 41% of total STAR values for these taxonomic groups. Key Biodiversity Areas cover 9% of the terrestrial surface but capture 47% of STAR values. STAR could support governmental and non-state actors in quantifying their contributions to meeting science-based species targets within the framework.

Systematically Incorporating Environmental Objectives into Shale Gas Pipeline Development: A Binary Integer, Multiobjective Spatial Optimization Model.

Shale gas pipeline development can have negative environmental impacts, including adverse effects on species and ecosystems through habitat degradation and loss. From a societal perspective, pipeline development planning processes should account for such externalities. We develop a multiobjective binary integer-programming model, called the Multi Objective Pipeline Siting (MOPS) model, to incorporate habitat externalities into pipeline development and to estimate the trade-offs between pipeline development costs and habitat impacts. We demonstrate the utility of the model using an application from Bradford and Susquehanna counties in northeastern Pennsylvania. We find that significant habitat impacts can be avoided for relatively low cost, but the avoidance of the additional habitat impacts becomes gradually and increasingly costly. For example, 10% of the habitat impacts can be avoided at less than a two percent pipeline cost increase relative to a configuration that ignores habitat impacts. MOPS or a similar model could be integrated into the pipeline siting and permitting process so oil and gas companies, communities, and states can identify cost-effective options for habitat conservation near shale gas development.

Naturally available wild pollination services have economic value for nature dependent smallholder crop farms in Tanzania.

Despite the importance of naturally available wild pollination ecosystem services in enhancing sub-Saharan African smallholder farms' productivity, their values to actual farming systems remain unknown. We develop a nationally representative empirical assessment by integrating nationally representative plot level panel data with spatially and temporally matched land cover maps to identify the contribution of wild pollinators to crop revenue. Our estimation results reveal distinct and robust contributions by natural habitats of wild pollinators - forests - to plot-level crop revenue, where habitats in near proximity to plots contribute much more value than those farther away. When contrasting between pollinator-dependent and pollinator-independent crops, we find that the positive effects emerge only for pollinator-dependent crops, while pollinator-independent crops show no benefits. We conclude the empirical assessment by using our estimates to evaluate changes in crop revenue associated with the actual habitat reduction during 2008-2013. We find that this change in the natural habitats of wild pollinators has reduced crop revenue possibly by as much as 29% (mean) and 4% (median). To our knowledge, this is the first empirical assessment to use nationally representative smallholder farms to assess the value of naturally available wild pollination ecosystem services. Our results magnify the documented benefits of forest conservation, as this preserves pollinators' natural habitats, and by extension its inhabitants, who play an important role in boosting crop yields of nature dependent smallholder farms.

Natural climate solutions for the United States.

Limiting climate warming to <2°C requires increased mitigation efforts, including land stewardship, whose potential in the United States is poorly understood. We quantified the potential of natural climate solutions (NCS)-21 conservation, restoration, and improved land management interventions on natural and agricultural lands-to increase carbon storage and avoid greenhouse gas emissions in the United States. We found a maximum potential of 1.2 (0.9 to 1.6) Pg CO2e year-1, the equivalent of 21% of current net annual emissions of the United States. At current carbon market prices (USD 10 per Mg CO2e), 299 Tg CO2e year-1 could be achieved. NCS would also provide air and water filtration, flood control, soil health, wildlife habitat, and climate resilience benefits.

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.

Policy Analysis: Valuation of Ecosystem Services in the Southern Appalachian Mountains.

This study estimates the economic value of an increase in ecosystem services attributable to the reduced acidification expected from more stringent air pollution policy. By integrating a detailed biogeochemical model that projects future ecological recovery with economic methods that measure preferences for specific ecological improvements, we estimate the economic value of ecological benefits from new air pollution policies in the Southern Appalachian ecosystem. Our results indicate that these policies generate aggregate benefits of about $3.7 billion, or about $16 per year per household in the region. The study provides currently missing information about the ecological benefits from air pollution policies that is needed to evaluate such policies comprehensively. More broadly, the study also illustrates how integrated biogeochemical and economic assessments of multidimensional ecosystems can evaluate the relative benefits of different policy options that vary by scale and across ecosystem attributes.

Global economic potential for reducing carbon dioxide emissions from mangrove loss.

Mangroves are among the most threatened and rapidly disappearing natural environments worldwide. In addition to supporting a wide range of other ecological and economic functions, mangroves store considerable carbon. Here, we consider the global economic potential for protecting mangroves based exclusively on their carbon. We develop unique high-resolution global estimates (5' grid, about 9 × 9 km) of the projected carbon emissions from mangrove loss and the cost of avoiding the emissions. Using these spatial estimates, we derive global and regional supply curves (marginal cost curves) for avoided emissions. Under a broad range of assumptions, we find that the majority of potential emissions from mangroves could be avoided at less than $10 per ton of CO(2). Given the recent range of market price for carbon offsets and the cost of reducing emissions from other sources, this finding suggests that protecting mangroves for their carbon is an economically viable proposition. Political-economy considerations related to the ability of doing business in developing countries, however, can severely limit the supply of offsets and increases their price per ton. We also find that although a carbon-focused conservation strategy does not automatically target areas most valuable for biodiversity, implementing a biodiversity-focused strategy would only slightly increase the costs.

Potential biodiversity benefits from international programs to reduce carbon emissions from deforestation.

Deforestation is the second largest anthropogenic source of carbon dioxide emissions and options for its reduction are integral to climate policy. In addition to providing potentially low cost and near-term options for reducing global carbon emissions, reducing deforestation also could support biodiversity conservation. However, current understanding of the potential benefits to biodiversity from forest carbon offset programs is limited. We compile spatial data on global forest carbon, biodiversity, deforestation rates, and the opportunity cost of land to examine biodiversity conservation benefits from an international program to reduce carbon emissions from deforestation. Our results indicate limited geographic overlap between the least-cost areas for retaining forest carbon and protecting biodiversity. Therefore, carbon-focused policies will likely generate substantially lower benefits to biodiversity than a more biodiversity-focused policy could achieve. These results highlight the need to systematically consider co-benefits, such as biodiversity in the design and implementation of forest conservation programs to support international climate policy.

Contributions of the US state park system to nature recreation.

Nature recreation in the United States concentrates in publicly provided natural areas. They are costly to establish and maintain, but their societal contributions are difficult to measure. Here, a unique approach is developed to quantifying nature recreation services generated by the US state park system. The assessment first uses data from five national surveys conducted between 1975 and 2007 to consistently measure the amount of time used for nature recreation. The surveys comprise two official federal surveys and their predecessors. Each survey was designed to elicit nationally representative, detailed data on how people divide their time into different activities. State-level data on time use for nature recreation were then matched with information on the availability of state parks and other potentially important drivers of recreation, so that statistical estimation methods for nonexperimental panel data (difference-in-differences) could be used to examine the net contribution of state parks to nature recreation. The results show that state parks have a robust positive effect on nature recreation. For example, the approximately 2 million acres of state parks established between 1975 and 2007 are estimated to contribute annually 600 million hours of nature recreation (2.7 h per capita, approximately 9% of all nature recreation). All state parks generate annually an estimated 2.2 billion hours of nature recreation (9.7 h per capita; approximately 33% of all nature recreation). Using conventional approaches to valuing time, the estimated time value of nature recreation services generated by the US state park system is approximately $14 billion annually.

Prioritizing conservation activities using reserve site selection methods and population viability analysis.

In recent years a large literature on reserve site selection (RSS) has developed at the interface between ecology, operations research, and environmental economics. Reserve site selection models use numerical optimization techniques to select sites for a network of nature reserves for protecting biodiversity. In this paper, we develop a population viability analysis (PVA) model for salmon and incorporate it into an RSS framework for prioritizing conservation activities in upstream watersheds. We use spawner return data for three closely related salmon stocks in the upper Columbia River basin and estimates of the economic costs of watershed protection from NOAA to illustrate the framework. We compare the relative cost-effectiveness of five alternative watershed prioritization methods, based on various combinations of biological and economic information. Prioritization based on biological benefit-economic cost comparisons and accounting for spatial interdependencies among watersheds substantially outperforms other more heuristic methods. When using this best-performing prioritization method, spending 10% of the cost of protecting all upstream watersheds yields 79% of the biological benefits (increase in stock persistence) from protecting all watersheds, compared to between 20% and 64% for the alternative methods. We also find that prioritization based on either costs or benefits alone can lead to severe reductions in cost-effectiveness.

Air emissions of ammonia and methane from livestock operations: valuation and policy options.

The animal husbandry industry is a major emitter of ammonia (NH3), which is a precursor of fine particulate matter (PM2.5)--arguably, the number-one environment-related public health threat facing the nation. The industry is also a major emitter of methane (CH4), which is an important greenhouse gas (GHG). We present an integrated process model of the engineering economics of technologies to reduce NH3 and CH4 emissions at dairy operations in California. Three policy options are explored: PM offset credits for NH3 control, GHG offset credits for CH4 control, and expanded net metering policies to provide revenue for the sale of electricity generated from captured methane (CH4) gas. Individually these policies vary substantially in the economic incentives they provide for farm operators to reduce emissions. We report on initial steps to fully develop the integrated process model that will provide guidance for policy-makers.

Turning brownfields into greenspaces: examining incentives and barriers to revitalization.

This study employs interviews, document review, and a national survey of local government officials to investigate the factors that influence the success of efforts to convert underutilized contaminated properties into greenspace. We find that the presence of contamination continues to be a concern despite federal and state efforts to ease liability fears but also that site and project features can overcome this hurdle. In particular, jurisdictions appear more likely to convert distressed properties into greenspace if recreational parks, rather than open space, are planned, sites are already owned rather than available only through tax foreclosure, and the state is perceived as being supportive of the conversion. In addition, mixed public-private funding and site locations in residential areas are more likely to attract community support for conversion projects.