Carbon offsets as an economic alternative to large-scale logging: a case study in Guyana

The objective of this study is to analyze the economic viability of carbon-offset projects that avoid logging in Guyana's forests. The results of this case study illustrate the cost effectiveness of alternative land-use options that reduce deforestation and associated greenhouse gas (GHG) emissions. This analysis demonstrates that using Guyana's rainforests for climate change mitigation can generate equivalent revenue to that of conventional large-scale logging without detrimental environmental impacts. At a 12% discount rate, the break-even price for carbon is estimated to be about US$ 0.20/tC. This estimate falls toward the low range of carbon prices for existing carbon offset projects that avoid deforestation.     

The opportunity cost of land use and the global potential for greenhouse gas mitigation in agriculture and forestry

This paper analyses the role of global land management alternatives in determining potential greenhouse gas mitigation by land-based activities in agriculture and forestry. Land-based activities are responsible for over a third of global greenhouse gas emissions, yet the economics of land-use decisions have not been explicitly modeled in global mitigation studies. In this paper, we develop a new, general equilibrium framework which effectively captures the opportunity costs of land-use decisions in agriculture and forestry, thereby allowing us to analyse competition for heterogeneous land types across and within sectors, as well as input substitution between land and other factors of production. When land-using sectors are confronted with a tax on greenhouse gas emissions, we find significant changes in the global pattern of comparative advantage across sectors, regions, and land types. Globally, we find that forest carbon sequestration is the dominant strategy for GHG emissions mitigation, while agricultural-related mitigation comes predominantly from reduced methane emissions in the ruminant livestock sector, followed by fertilizer and methane emissions from paddy rice. Regionally, agricultural mitigation is a larger share of total land-use emissions abatement in the USA and China, compared to the rest of the world, and, within agriculture, disproportionately from reductions in fertilizer-related emissions. The results also show how analyses that only consider regional mitigation, may bias mitigation potential by ignoring global market interactions. For example, USA-specific analyses likely over-estimate the potential for abatement in agriculture. Finally, we note that this general equilibrium framework provides the research community with a practical methodology for explicit modeling of global land competition and land-based mitigation in comprehensive assessments of greenhouse gas mitigation options.     

Economic Impacts of Multiple Agro-Environmental Policies on New Zealand Land Use

This paper investigates the implications of policy on farm income, land use, and the environment when New Zealand landowners face multiple environmental constraints. It also looks at the interaction between climate and nutrient reduction policy and the extent to which one policy can be used to meet the other’s objectives. We use a non-linear, partial equilibrium mathematical programming model of New Zealand land use to assess the economic impacts of climate and water policies at the New Zealand territorial authority level. The spatially explicit agro-environmental economic model estimates changes in land use, agricultural output, land management, and environmental impacts. The policies investigated include a range of carbon prices on land-based emissions ($0–30/tCO\(_{2\mathrm{e}}\)) as well a range of prices on nitrogen leaching from diffuse sources ($0–30/kgN). We estimate that implementing stand-alone greenhouse gas and nutrient emissions reduction policies for the agricultural and forestry sectors will create environmental benefits outside the scope of the policy. However, not all environmental outputs improve, and net farm revenue declines by between 0 and 11%. Simultaneously implementing the two policies results in the desired goals of reductions in nitrogen and greenhouse gas emissions with a marginal economic burden on landowners (i.e. 1–2% additional loss in farm profit relative to a stand-alone policy).     

Forest management for timber and carbon sequestration in the presence of climate change: The case of Pinus Sylvestris

Climatic changes will affect the dynamics of a forest ecosystem. Consequently, carbon sequestration costs can only be estimated correctly if changes in climatic conditions are considered. This article determines the changes in mitigation costs of an optimal forest management regime in the presence of climatic changes and varying prices, and takes account of substitution processes between timber production and carbon sequestration at the stand level. The study demonstrates that in the presence of climate change the sequestration costs per ton of carbon increase with higher amounts of carbon sequestered per hectare. This finding can be used to identify a threshold for the amount of sequestered carbon per hectare below which the costs of carbon sequestration are hardly influenced by climate change.     

Carbon Subsidies,Taxes and Optimal Forest Management

We consider the effect of carbon credit payment schemes on forest owners’ land use and harvest decisions. We study two possible credit allocation regimes: one where credits are allocated according to the actual amount of carbon sequestered by the trees on a piece of land and another where credits are allocated according to the long-run potential to sequester carbon on the land. Using a real options model with uncertain future timber prices, we examine the effect on the timing of harvests and the replanting-abandonment decision. We show that both schemes discourage deforestation. Compensating growers for actual carbon sequestration leads to longer rotation periods between harvests, while basing compensation only on the long-run potential level of sequestration induces shorter rotation periods. The former scheme leads to greater benefits of carbon sequestration at lower cost than the latter scheme. Although inducing moderate levels of sequestration is expensive under both schemes, the cost falls dramatically when the level of payments climbs above some threshold. Indeed, providing the payments are sufficiently generous, carbon credit payment schemes offer an effective means of increasing carbon sequestration. The views expressed in this paper are strictly those of the authors and do not represent the views of the New Zealand Commerce Commission. We thank Lewis Evans and two anonymous referees for many very helpful comments. Kevin Counsell, Steen Videbeck, and participants at an ISCR seminar also provided useful suggestions. Fletcher Forests Ltd and the New Zealand Ministry of Agriculture and Forestry generously provided data.     

Modeling Impact of Development Trajectories and a Global Agreement on Reducing Emissions from Deforestation on Congo Basin Forests by 2030

The Congo Basin encompasses the second largest rainforest area after the Amazon but the Congo Basin rainforest has been more preserved during the last decades with a much lower deforestation rate. At the same time, the region remains one of the least developed in the world. We use the partial equilibrium model GLOBIOM for the global agricultural, forestry and bioenergy sectors that seeks to find optimal land use options by spatially representing land qualities. We show the trade-offs between achieving agricultural growth at the expense of forests and protecting forests at the expense of agriculture development in the Congo Basin. The realization of the transportation infrastructures, which are already planned and funded, could multiply deforestation by three. In contrast, a global agreement on reduction of total emissions from deforestation could achieve important cuts in GHG emissions from deforestation in the Congo Basin. However, it could lead to substantial increases in food imports and food prices, which are in contradiction with the food security objectives.     

Transaction costs of carbon offset projects: A comparative study

The land-use change and forestry sector can be a cost-effective contributor to climate mitigation in at least three ways: providing carbon offsets through carbon sequestration in biomass and soils, reducing emissions of methane and other greenhouse gases, and producing biofuels that replace fossil fuels. The presence of carbon markets should help encourage these activities; however, most carbon trades to date have occurred in the energy sector. A major obstacle to carbon trades from land-use systems is the presence of high transaction costs of converting a carbon offset into a tradable commodity, so the prevailing market carbon prices may not provide enough incentive for adoption. This paper presents a model of the exchange of carbon offsets between a project developer and a group of landholders. The model is solved to derive project feasibility frontiers that show the minimum number of contracts necessary to make a project feasible at any given carbon price. The model is applied to two case studies (smallholder agroforestry in Indonesia and partial reforestation of family farms in Australia) under two types of contract (purchase of carbon flows and rental of carbon stocks). The paper concludes by identifying possible strategies to reduce transaction costs while maintaining project integrity.     

Climate change impacts on irrigation water requirements: Effects of mitigation, 1990–2080

Potential changes in global and regional agricultural water demand for irrigation were investigated within a new socio-economic scenario, A2r, developed at the International Institute for Applied Systems Analysis (IIASA) with and without climate change, with and without mitigation of greenhouse gas emissions. Water deficits of crops were developed with the Food and Agriculture Organization (FAO)–IIASA Agro-ecological Zone model, based on daily water balances at 0.5° latitude × 0.5° longitude and then aggregated to regions and the globe. Future regional and global irrigation water requirements were computed as a function of both projected irrigated land and climate change and simulations were performed from 1990 to 2080. Future trends for extents of irrigated land, irrigation water use, and withdrawals were computed, with specific attention given to the implications of climate change mitigation. Renewable water-resource availability was estimated under current and future climate conditions. Results suggest that mitigation of climate change may have significant positive effects compared with unmitigated climate change. Specifically, mitigation reduced the impacts of climate change on agricultural water requirements by about 40%, or 125–160 billion m³ (Gm³) compared with unmitigated climate. Simple estimates of future changes in irrigation efficiency and water costs suggest that by 2080 mitigation may translate into annual cost reductions of about 10 billion US$.     

Driving forces of global carbon emissions: From time- and spatial-dynamic perspectives

Up to date, collective efforts in greenhouse gas mitigation made by the international community have been rather ineffective. A major reason of the unsuccessfulness may be attributed to imprecise comprehension on the sources of greenhouse gas pollution and their changing dynamics. Utilizing the LMDI decomposition method, this paper investigates the time- and spatial-dynamics of drivers governing global carbon emissions. We decompose and quantify the effects of different drivers, that is, population, affluence, energy intensity and carbon intensity, across time on global carbon emissions. Next based on country-level decomposition, we also calculate and track the spatial gravity centers of the effects of the drivers. Our results show that energy intensity effect is the leading contributor for carbon emission mitigation, whereas economic development, carbon emission intensity and population serve as factors accelerating carbon emissions. We also find significant heterogeneities in the spatial dynamics of the contribution of different drivers, implying that differentiated climate change policies should be made at different countries to effectively curb global carbon emissions.     

Probabilistic temperature change projections and energy system implications of greenhouse gas emission scenarios

This paper explores the implications for global average temperature change of a set of reference and mitigation scenarios in a probabilistic framework. First, we use published probability density functions for climate sensitivity to investigate the likelihood of achieving targets expressed as levels or rates of global average temperature change. We find, for example, that limiting warming to 3 C above pre-industrial levels with at least a medium likelihood requires cumulative emissions reductions on the order of 30-60% below one unmitigated reference scenario by 2100, while a more favorable baseline scenario requires no reductions at all to achieve this outcome with the same likelihood. We further conclude that the rate of temperature change may prove to be more difficult to control, especially if most of the mitigation effort is postponed until later in the century. Rate of change targets of 0.1–0.2 °C/decade are unlikely to be achieved by a target for the long-term level of climate change alone. Second, we quantify relationships between mitigation costs and the likelihood of achieving various targets and show how this depends strongly on the reference scenario. Third, we explore relationships between medium-term achievements and long-term climate change outcomes. Our results suggest that atmospheric concentrations and the share of zero-carbon energy in the middle of the 21st century are key indicators of the likelihood of meeting long-term climate change goals cost-effectively. They also suggest that interim targets could be an effective means of keeping long-term target options open. Our analysis shows that least-cost mitigation strategies for reaching low climate change targets include a wide portfolio of reduction measures. In particular, fundamental long-term structural changes in the energy system in these scenarios are a necessary but not sufficient condition to achieve high likelihoods for low temperature targets. The cost-effective portfolio of emissions reductions must also address demand-side measures and include mitigation options in the industry, agriculture, and the forest sector.     

Renewable energy subsidies: Second-best policy or fatal aberration for mitigation?

This paper evaluates the consequences of renewable energy policies on welfare and energy prices in a world where carbon pricing is imperfect and the regulator seeks to limit emissions to a (cumulative) target. The imperfectness of the carbon price is motivated by political concerns regarding distributional effects of increased energy prices. Hence, carbon prices are considered to be temporarily or permanently absent or endogenously constrained by their effect on energy prices. We use a global general equilibrium model with an intertemporal fossil resource sector and calculate intertemporally optimal policies from a broad set of policy instruments including carbon taxes, renewable energy subsidies and feed-in-tariffs, among others. If carbon pricing is permanently missing, mitigation costs increase by a multiple (compared to the optimal carbon pricing policy) for a wide range of parameters describing extraction costs, renewable energy costs, substitution possibilities and normative attitudes. Furthermore, we show that small deviations from the second-best subsidy can lead to strong increases in emissions and consumption losses. This confirms the rising concerns about the occurrence of unintended side effects of climate policy – a new version of the green paradox. Smart combinations of carbon prices and renewable energy subsidies, however, can achieve ambitious mitigation targets at moderate additional costs without leading to high energy price increases.     

全国森林碳汇监测和计量体系的初步研究

森林碳汇是全球气候变化和陆地生态系统碳循环中的重要组成部分,森林碳汇的变化直接影响着大气层中主要温室气体的浓度,进而影响气候变化和陆地生态平衡.该文从应用角度出发,通过分析自然环境和森林区划等区域特征,进行监测区和样地布设,进行了森林碳库分类.明确了森林碳汇监测区样地调查内容和森林碳汇计量方法,并构建了网络信息化平台,建立监测信息系统,实现数据网络化管理,同时结合地理信息系统进行综合应用,为我国应对全球气候变化制定相关政策提供基础数据和决策支持.     

Individual option prices for climate change mitigation

Willingness-to-pay for climate change mitigation depends on people's perceptions about just how bad things will get if nothing is done. Individual subjective distributions for future climate conditions are combined with stated choices over alternative climate policies to estimate individual option prices (the appropriate ex ante welfare measure in the face of uncertainty) for climate change mitigation. We find statistically significant sensitivity of estimated option prices to both expected future conditions and uncertainty about future conditions.     

Willingness to Pay for Ancillary Benefits of Climate Change Mitigation

Assessing the Willingness to Pay (WTP) of the general public for climate change mitigation programmes enables governments to understand how much taxpayers are willing to support the implementation of such programs. This paper contributes to the literature on the WTP for climate change mitigation programmes by investigating, in addition to global benefits, the ancillary benefits of climate change mitigation. It does so by considering local and personal benefits arising from climate change policies. The Contingent Valuation Method is used to elicit the WTP for ancillary and global benefits of climate mitigation policies in the Basque Country, Spain. Results show that WTP estimates are 53–73% higher when ancillary benefits are considered.     

Biological conservation in dynamic agricultural landscapes: Effectiveness of public policies and trade-offs with agricultural production

Land use change and land management intensification are major drivers of biodiversity loss, especially in agricultural landscapes, that cover a large and increasing share of the world's surface. Incentive-based agri-environmental policies are designed to influence farmers' land-use decisions in order to mitigate environmental degradation. This paper evaluates the effectiveness of agri-environmental schemes for biological conservation in a dynamic agricultural landscape under economic uncertainty. We develop a dynamic ecological economic model of agricultural land-use and spatially explicit population dynamics. We then relate policies (subsidies to grassland, taxation of agricultural intensity) to the ecological outcome (probability of persistence of a species of interest). We also analyze the associated trade-offs between agricultural production (in value) and biological conservation (in probability of persistence) at the landscape scale.     

Economic Potential of Biomass Based Fuels for Greenhouse Gas Emission Mitigation

Use of biofuels diminishes fossil fuelcombustion thereby also reducing net greenhousegas emissions. However, subsidies are neededto make agricultural biofuel productioneconomically feasible. To explore the economicpotential of biofuels in a greenhouse gasmitigation market, we incorporate data onproduction and biofuel processing for thedesignated energy crops switchgrass, hybridpoplar, and willow in an U.S. AgriculturalSector Model along with data on traditionalcrop-livestock production and processing, andafforestation of cropland. Net emissioncoefficients on all included agriculturalpractices are estimated through crop growthsimulation models or taken from the literature. Potential emission mitigation policies ormarkets are simulated via hypothetical carbonprices. At each carbon price level, theAgricultural Sector Model computes the newmarket equilibrium, revealing agriculturalcommodity prices, regionally specificproduction, input use, and welfare levels,environmental impacts, and adoption ofalternative management practices such asbiofuel production. Results indicate no rolefor biofuels below carbon prices of $40 perton of carbon equivalent. At these incentivelevels, emission reductions via reduced soiltillage and afforestation are more costefficient. For carbon prices above $70,biofuels dominate all other agriculturalmitigation strategies.     

The Impact of Land-Use Change on Ecosystem Services,Biodiversity and Returns to Landowners: A Case Study in the State of Minnesota

Land-use change has a significant impact on the world’s ecosystems. Changes in the extent and composition of forests, grasslands, wetlands and other ecosystems have large impacts on the provision of ecosystem services, biodiversity conservation and returns to landowners. While the change in private returns to landowners due to land-use change can often be measured, changes in the supply and value of ecosystem services and the provision of biodiversity conservation have been harder to quantify. In this paper we use a spatially explicit integrated modeling tool (InVEST) to quantify the changes in ecosystem services, habitat for biodiversity, and returns to landowners from land-use change in Minnesota from 1992 to 2001. We evaluate the impact of actual land-use change and a suite of alternative land-use change scenarios. We find a lack of concordance in the ranking of baseline and alternative land-use scenarios in terms of generation of private returns to landowners and net social benefits (private returns plus ecosystem service value). Returns to landowners are highest in a scenario with large-scale agricultural expansion. This scenario, however, generated the lowest net social benefits across all scenarios considered because of large losses in stored carbon and negative impacts on water quality. Further, this scenario resulted in the largest decline in habitat quality for general terrestrial biodiversity and forest songbirds. Our results illustrate the importance of taking ecosystem services into account in land-use and land-management decision-making and linking such decisions to incentives that accurately reflect social returns.     

Ethanol Production, Food and Forests

This paper investigates the direct and indirect impacts of ethanol production on land use, deforestation and food production. A partial equilibrium model of a national economy with two sectors and two regions, one of which includes a forest, is developed. It analyses how an exogenous increase in the ethanol price affects input allocation (land and labor) between sectors (energy crop and food). The total effect of ethanol prices on food production and deforestation is decomposed into three partial effects. First, the well-documented effect of direct land competition between rival uses arises; it increases deforestation and decreases food production. Second, an indirect displacement of food production across regions, possibly provoked by the reaction of international food prices, increases deforestation and reduces the food sector’s output. Finally, labor mobility between sectors and regions tends to decrease food production but also deforestation. The total impact of ethanol production on food production is negative while there is an ambiguous impact on deforestation.     

Adoption of climate change mitigation practices by risk-averse farmers in the Ashanti Region,Ghana

Uncertainty and risk-aversion are notably absent in the modeling of farmers' adoption of climate change mitigation practices in developing countries even though most of the agricultural mitigation practices also have effects on yield variability. The objective of this paper is to explore the implications for climate change mitigation projects of modeling farmers as risk neutral while in actuality they behave as risk-averse agents. Results indicate that when risk averse farmers are modeled as risk-neutral agents, the size of the incentives needed to induce participation to a carbon sequestration program is miscalculated with serious implications either for the success for projects that aim at compensating for climate change mitigation services or for the economic efficiency of such projects.     

Property rights and liability for deforestation under REDD+: Implications for ‘permanence’ in policy design

Reducing Emissions from Deforestation and forest Degradation (REDD+) is critical in efforts to mitigate the effects of anthropogenic climate change. Despite uncertainty about the exact form of a future, international REDD+ system, REDD+ carbon property rights would need to be created and allocated with liability assigned for the potential loss of climate benefits in the event of carbon reversal from deforestation. This commentary explores the links between forest property rights and liability, to different REDD+ policy options and their implications for permanence. Should national governments retain liability for permanence then project-level activities that have individually-assigned REDD+ carbon rights may have a higher risk of carbon reversal than policies where rights are assigned to the state. Knowledge of pre-existing forest rights is necessary for some policies implemented with government-assigned REDD+ rights in order to compensate for potential income losses from policy implementation.