Land-based measures to mitigate climate change: Potential and feasibility by country.

Land-based climate mitigation measures have gained significant attention and importance in public and private sector climate policies. Building on previous studies, we refine and update the mitigation potentials for 20 land-based measures in >200 countries and five regions, comparing "bottom-up" sectoral estimates with integrated assessment models (IAMs). We also assess implementation feasibility at the country level. Cost-effective (available up to $100/tCO2 eq) land-based mitigation is 8-13.8 GtCO2 eq yr-1 between 2020 and 2050, with the bottom end of this range representing the IAM median and the upper end representing the sectoral estimate. The cost-effective sectoral estimate is about 40% of available technical potential and is in line with achieving a 1.5°C pathway in 2050. Compared to technical potentials, cost-effective estimates represent a more realistic and actionable target for policy. The cost-effective potential is approximately 50% from forests and other ecosystems, 35% from agriculture, and 15% from demand-side measures. The potential varies sixfold across the five regions assessed (0.75-4.8 GtCO2eq yr-1 ) and the top 15 countries account for about 60% of the global potential. Protection of forests and other ecosystems and demand-side measures present particularly high mitigation efficiency, high provision of co-benefits, and relatively lower costs. The feasibility assessment suggests that governance, economic investment, and socio-cultural conditions influence the likelihood that land-based mitigation potentials are realized. A substantial portion of potential (80%) is in developing countries and LDCs, where feasibility barriers are of greatest concern. Assisting countries to overcome barriers may result in significant quantities of near-term, low-cost mitigation while locally achieving important climate adaptation and development benefits. Opportunities among countries vary widely depending on types of land-based measures available, their potential co-benefits and risks, and their feasibility. Enhanced investments and country-specific plans that accommodate this complexity are urgently needed to realize the large global potential from improved land stewardship.

Reductions in emissions from deforestation from Indonesia's moratorium on new oil palm, timber, and logging concessions.

To reduce greenhouse gas emissions from deforestation, Indonesia instituted a nationwide moratorium on new license areas ("concessions") for oil palm plantations, timber plantations, and logging activity on primary forests and peat lands after May 2011. Here we indirectly evaluate the effectiveness of this policy using annual nationwide data on deforestation, concession licenses, and potential agricultural revenue from the decade preceding the moratorium. We estimate that on average granting a concession for oil palm, timber, or logging in Indonesia increased site-level deforestation rates by 17-127%, 44-129%, or 3.1-11.1%, respectively, above what would have occurred otherwise. We further estimate that if Indonesia's moratorium had been in place from 2000 to 2010, then nationwide emissions from deforestation over that decade would have been 241-615 MtCO2e (2.8-7.2%) lower without leakage, or 213-545 MtCO2e (2.5-6.4%) lower with leakage. As a benchmark, an equivalent reduction in emissions could have been achieved using a carbon price-based instrument at a carbon price of $3.30-7.50/tCO2e (mandatory) or $12.95-19.45/tCO2e (voluntary). For Indonesia to have achieved its target of reducing emissions by 26%, the geographic scope of the moratorium would have had to expand beyond new concessions (15.0% of emissions from deforestation and peat degradation) to also include existing concessions (21.1% of emissions) and address deforestation outside of concessions and protected areas (58.7% of emissions). Place-based policies, such as moratoria, may be best thought of as bridge strategies that can be implemented rapidly while the institutions necessary to enable carbon price-based instruments are developed.

Structuring economic incentives to reduce emissions from deforestation within Indonesia.

We estimate and map the impacts that alternative national and subnational economic incentive structures for reducing emissions from deforestation (REDD+) in Indonesia would have had on greenhouse gas emissions and national and local revenue if they had been in place from 2000 to 2005. The impact of carbon payments on deforestation is calibrated econometrically from the pattern of observed deforestation and spatial variation in the benefits and costs of converting land to agriculture over that time period. We estimate that at an international carbon price of $10/tCO(2)e, a "mandatory incentive structure," such as a cap-and-trade or symmetric tax-and-subsidy program, would have reduced emissions by 163-247 MtCO(2)e/y (20-31% below the without-REDD+ reference scenario), while generating a programmatic budget surplus. In contrast, a "basic voluntary incentive structure" modeled after a standard payment-for-environmental-services program would have reduced emissions nationally by only 45-76 MtCO(2)e/y (6-9%), while generating a programmatic budget shortfall. By making four policy improvements--paying for net emission reductions at the scale of an entire district rather than site-by-site; paying for reductions relative to reference levels that match business-as-usual levels; sharing a portion of district-level revenues with the national government; and sharing a portion of the national government's responsibility for costs with districts--an "improved voluntary incentive structure" would have been nearly as effective as a mandatory incentive structure, reducing emissions by 136-207 MtCO(2)e/y (17-26%) and generating a programmatic budget surplus.

Climate change and the cost of conserving species in Madagascar.

We examined the cost of conserving species as climate changes. We used a Maxent species distribution model to predict the ranges from 2000 to 2080 of 74 plant species endemic to the forests of Madagascar under 3 climate scenarios. We set a conservation target of achieving 10,000 ha of forest cover for each species and calculated the cost of achieving this target under each scenario. We interviewed managers of projects to restore native forests and conducted a literature review to obtain the net present cost per hectare of management actions to maintain or establish forest cover. For each species, we added hectares of land from lowest to highest cost per additional year of forest cover until the conservation target was achieved throughout the time period. Climate change was predicted to reduce the size of species' ranges, the overlap between species' ranges and existing or planned protected areas, and the overlap between species' ranges and existing forest. As a result, climate change increased the cost of achieving the conservation target by necessitating successively more costly management actions: additional management within existing protected areas (US$0-60/ha); avoidance of forest degradation (i.e., loss of biomass) in community-managed areas ($160-576/ha); avoidance of deforestation in unprotected areas ($252-1069/ha); and establishment of forest on nonforested land within protected areas ($802-2710/ha), in community-managed areas ($962-3226/ha), and in unprotected areas ($1054-3719/ha). Our results suggest that although forest restoration may be required for the conservation of some species as climate changes, it is more cost-effective to maintain existing forest wherever possible.

The costs and benefits of primary prevention of zoonotic pandemics.

The lives lost and economic costs of viral zoonotic pandemics have steadily increased over the past century. Prominent policymakers have promoted plans that argue the best ways to address future pandemic catastrophes should entail, "detecting and containing emerging zoonotic threats." In other words, we should take actions only after humans get sick. We sharply disagree. Humans have extensive contact with wildlife known to harbor vast numbers of viruses, many of which have not yet spilled into humans. We compute the annualized damages from emerging viral zoonoses. We explore three practical actions to minimize the impact of future pandemics: better surveillance of pathogen spillover and development of global databases of virus genomics and serology, better management of wildlife trade, and substantial reduction of deforestation. We find that these primary pandemic prevention actions cost less than 1/20th the value of lives lost each year to emerging viral zoonoses and have substantial cobenefits.

Gap Analysis of Giant Panda Conservation as an Example for Planning China's National Park System.

Protected areas have been the cornerstone for conservation globally [1], but gaps still exist in preserving biodiversity [2]. Meanwhile, areas designated as protected have overlaps between designations and might vary in their management [3, 4]. All three phenomena-coverage gaps, overlapping designations, and disparities in management-are present in China [5, 6]. China plans to establish a national park system for the first time, aiming to reform the existing protected-area system [7-9]. However, there has been no quantitative spatial analysis that can aid the planning of national parks. This study shows how an improved conservation gap analysis can inform the construction of new national parks. Taking the proposed Giant Panda National Park as an example, we analyzed the relationship between panda habitat and the existing protected areas, considering not only de jure designated coverage but also de facto levels of two types of potentially harmful activities (timber extraction and human disturbance). We find that, first, there are coverage gaps in the four mountains comprising the potential national park, and existing protected areas have overlaps between designations. Second, current protected areas have gaps and disparities in terms of restrictions on timber extraction and human disturbance. Third, overlapped designations and less restrictive management appear to have adverse effects on panda protection. On the basis of these results, we propose integrated management under a single national park administration, focusing on the key gaps, which we identify. This study can serve as a reference for the establishment of other national parks in China and the world.

National mitigation potential from natural climate solutions in the tropics.

Better land stewardship is needed to achieve the Paris Agreement's temperature goal, particularly in the tropics, where greenhouse gas emissions from the destruction of ecosystems are largest, and where the potential for additional land carbon storage is greatest. As countries enhance their nationally determined contributions (NDCs) to the Paris Agreement, confusion persists about the potential contribution of better land stewardship to meeting the Agreement's goal to hold global warming below 2°C. We assess cost-effective tropical country-level potential of natural climate solutions (NCS)-protection, improved management and restoration of ecosystems-to deliver climate mitigation linked with sustainable development goals (SDGs). We identify groups of countries with distinctive NCS portfolios, and we explore factors (governance, financial capacity) influencing the feasibility of unlocking national NCS potential. Cost-effective tropical NCS offers globally significant climate mitigation in the coming decades (6.56 Pg CO2e yr-1 at less than 100 US$ per Mg CO2e). In half of the tropical countries, cost-effective NCS could mitigate over half of national emissions. In more than a quarter of tropical countries, cost-effective NCS potential is greater than national emissions. We identify countries where, with international financing and political will, NCS can cost-effectively deliver the majority of enhanced NDCs while transforming national economies and contributing to SDGs. This article is part of the theme issue 'Climate change and ecosystems: threats, opportunities and solutions'.

Cross-discipline evidence principles for sustainability policy.

Evidence-based approaches to sustainability challenges must draw on knowledge from the environment, development and health communities. To be practicable, this requires an approach to evidence that is broader and less hierarchical than the standards often applied within disciplines.