The Dynamic Competitiveness of U.S. Agricultural and Forest Carbon Sequestration

Society is increasingly turning attention toward greenhouse gas emission control with for example the Kyoto Protocol has entered into force. Since many of the emissions come from energy use, high cost strategies might be required until new technological developments reduce fossil fuel dependency or increase energy utilization efficiency. On the other hand biologically based strategies may be used to offset energy related emissions. Agricultural soil and forestry are among the largest carbon reservoirs on the planet; therefore, agricultural and forest activities may help to reduce the costs of greenhouse gas emission mitigation. However, sequestration exhibits permanence related characteristics that may influence this role. We examine the dynamic role of carbon sequestration in the agricultural and forest sectors can play in mitigation. A 100-year mathematical programming model, depicting U.S. agricultural and forest sectoral activities including land transfers and greenhouse gas consequences is applied to simulate potential mitigation response. The results show that at low cost and in the near term agricultural soil and forest management are dominant sectoral responses. At higher prices and in the longer term biofuels and afforestation take over. Our results reveal that the agricultural and forest sector carbon sequestration may serve as an important bridge to the future helping to hold costs down until energy emissions related technology develops.     

The opportunity cost of preserving the Brazilian Amazon forest

We estimate the trade‐off between forest preservation and agricultural production for the Legal Amazon region, using census and deforestation data for municipalities in 2006. We use a directional distance function to represent the production possibility frontier, and then calculate the shadow price of reducing deforestation in terms of agricultural income foregone. Results indicate that, on average, to preserve 1 ha of forest, $797 in annual agricultural GDP must be foregone. Using a discount rate of 10% and average forest carbon density of 132 tons per hectare, these results imply an average shadow price of $16 per ton of CO₂ permanently sequestered.     

Estimating the opportunity costs of reducing carbon dioxide emissions via avoided deforestation,using integrated assessment modelling

Estimates show that, in recent years, deforestation and forest degradation accounted for about 17% of global greenhouse gas emissions. The implementation of REDD (Reducing Emissions from Deforestation and Forest Degradation in Developing Countries) is suggested to provide substantial emission reductions at low costs, although cost estimates show large uncertainty. Cost estimates can differ, as they depend on the approach chosen, for example: giving an economic stimulus to entire countries, taking landowners as actors in a REDD framework, or starting from protecting carbon-rich areas. This last approach was chosen for this analysis. Proper calculation of the economic cost requires an integrated modelling approach involving biophysical impact calculations and their associated economic effects. To date, only a few global modelling studies have applied such an approach. In modelling REDD measures, the actual implementation of REDD can take many forms, with implications for the results. This study assumes that non-Annex I countries will protect carbon-rich areas against deforestation, and therefore will refrain from using these areas as agricultural land. The opportunity costs of reducing deforestation within the framework of REDD were assessed using an integrated economic and land-use modelling approach comprising the global economic LEITAP model and the biophysical IMAGE model. One of the main methodological challenges is the representation of land use and the possibility to convert woodlands land into agricultural land. We endogenised the availability of agricultural land by introducing a flexible land supply curve, and represented the implementation of REDD policies as a reduction in the maximum amount of unmanaged land that potentially would be available for conversion to agriculture, in various regions in the world. In a series of model experiments, carbon-rich areas in non-Annex I countries were protected from deforestation. In each consecutive scenario the protected area was increased, starting off with the most carbon rich lands, worldwide systematically working down to areas with less carbon storage. The associated opportunity costs, expressed in terms of GDP reduction, were calculated with the economic LEITAP model. The resulting net reduction in carbon dioxide emissions from land-use change was calculated with the IMAGE model. From the sequence of experiments, marginal cost curves were constructed, relating carbon dioxide emission reductions to the opportunity costs. The results showed that globally a maximum of around 2.5 Gt carbon dioxide emissions could be avoided, annually. However, regional differences in opportunity costs are large and were found to range from about 0 to 3.2 USD per tonne carbon dioxide in Africa, 2 to 9 USD in South America and Central America, and 20 to 60 USD in Southeast Asia. These results are comparable to other studies that have calculated these costs, in terms of both opportunity costs and the regional distribution of emissions reduction.     

Does carbon farming provide a cost‐effective option to mitigate GHG emissions? Evidence from China

In this study, we apply a whole farm bioeconomic analysis to explore the changes in land use, farm practices and on‐farm greenhouse gas (GHG) emission under varying levels of agricultural greenhouse gas abatement incentives in the form of a carbon tax for a semi‐arid crop‐livestock farming system in China's Loess Plateau. Our results show that the optimised agricultural enterprises move towards being cropping‐dominated reducing on‐farm emission since livestock perform is the major source of emission. Farmers employ less oats‐based and rapeseed‐based rotations but more dry pea‐based rotations in the optimal enterprise mix. A substantial reduction in on‐farm greenhouse gas emission can be achieved at low cost with a small increase in carbon incentives. Our estimates indicate that crop‐livestock farmers in China's Loess Plateau may reduce their on‐farm GHG emission between 16.6 and 33 per cent with marginal abatement costs <￥100/t CO₂e and ￥150/t CO₂e in 2015 Chinese Yuan. The analysis implies that reducing greenhouse gas emission in China's semi‐arid crop‐livestock agriculture is potentially a low‐cost option.     

Investment Attractiveness of Afforestation in Canada Inclusive of Carbon Sequestration Benefits

Afforestation is one of several possible mechanisms available to sequester carbon and help reduce greenhouse gas concentrations. We have developed a spatial Monte Carlo-based simulation model, Canadian Forest Service—Afforestation Feasibility Model (CFS-AFM) to help assess the financial attractiveness of afforestation as a means of carbon storage in Canada. The model tracks five carbon pools and simulates costs and benefits of plantation investments. In this paper we simulate three afforestation scenarios that could be used in Canada; plantations using hybrid poplar, hardwoods, and softwoods with average growth rates of 14 and 6–7 m³/ha/year, respectively. The attractiveness of afforestation is driven by regional cost and plantation productivity variation and carbon price expectations. The results indicate that afforestation would be an attractive investment in many areas of the country at carbon prices of $10 per metric ton of CO₂ or higher. However, with a zero carbon price, very little afforestation would be financially viable. Thus, with low carbon price expectations, other co-benefits may be required to make afforestation more attractive to Canadian investors.     

Quantifying the impact of farmers' social networks on the effectiveness of climate change mitigation policies in agriculture

To reduce agricultural greenhouse gas (GHG) emissions, farmers need to change current farming practices. However, farmers' climate change mitigation behaviour and particularly the role of social and individual characteristics remains poorly understood. Using an agent-based modelling approach, we investigate how knowledge exchange within farmers' social networks affects the adoption of mitigation measures and the effectiveness of a payment per ton of GHG emissions abated. Our simulations are based on census, survey and interview data for 49 Swiss dairy and cattle farms to simulate the effect of social networks on overall GHG reduction and marginal abatement costs. We find that considering social networks increases overall reduction of GHG emissions by 45% at a given payment of 120 Swiss Francs (CHF) per ton of reduced GHG emissions. The per ton payment would have to increase by 380 CHF (i.e., 500 CHF/tCO₂eq) to reach the same overall GHG reduction level without any social network effects. Moreover, marginal abatement costs for emissions are lower when farmers exchange relevant knowledge through social networks. The effectiveness of policy incentives aiming at agricultural climate change mitigation can hence be improved by simultaneously supporting knowledge exchange and opportunities of social learning in farming communities.     

Mitigation potential and costs for global agricultural greenhouse gas emissions1

Agricultural activities are a substantial contributor to global greenhouse gas (GHG) emissions, accounting for about 58% of the world's anthropogenic non‐carbon dioxide GHG emissions and 14% of all anthropogenic GHG emissions, and agriculture is often viewed as a potential source of relatively low‐cost emissions reductions. We estimate the costs of GHG mitigation for 36 world agricultural regions for the 2000–2020 period, taking into account net GHG reductions, yield effects, livestock productivity effects, commodity prices, labor requirements, and capital costs where appropriate. For croplands and rice cultivation, we use biophysical, process‐based models (DAYCENT and DNDC) to capture the net GHG and yield effects of baseline and mitigation scenarios for different world regions. For the livestock sector, we use information from the literature on key mitigation options and apply the mitigation options to emission baselines compiled by EPA.     

Efficiency of U.S. conservation-compliance program

Under the conservation-compliance program, most of the individual producers are forced to cut their soil erosion to 7 t per acre annually irrespective of the marginal cost of controlling soil erosion. In a system where coupons to a ton of soil loss were issued to producers and traded, the marginal cost of controlling soil loss within each soil type and across different soil types would be equalized. An instrumental variable procedure was used to determine the effect of soil erosion on net profits. The results for Iowa show that there is considerable difference in the marginal opportunity cost of controlling soil erosion between soil types. By assigning one ton of erosion to Iowa soil type Downs (5-10% slope) instead of Clarion (2-5% slope), there is a savings of $5.00 per acre for the society as a whole. The tradable coupon system is not only efficient, but will also bring in more land under soil conservation.     

耕地经营规模对农业生产效率及环境压力的影响研究——以黄淮海地区为例

[目的]基于耕地经营规模效应,考察耕地经营规模对农业生产效率及环境压力的影响,为农业现代化与可持续发展政策制定提供科学依据。[方法]文章通过理论推导与实证检验,从时间序列和横截面2个维度对耕地经营规模与农业生产效率、环境压力的关系进行定量分析。[结果]（1）耕地经营规模对农业生产效率和环境的影响存在不确定性,并非所有区域都存在一致的时空效应。（2）耕地经营规模与单位耕地面积农业机械碳排放、单位耕地面积粮食产量存在明显的负相关关系,这些关系与机械使用效率、技术和劳动力要素投入密切相关。（3）耕地经营规模越小,农业机械使用效率越低,单位耕地面积农业机械碳排放越高;而耕地经营规模增加则会降低化肥、劳动力等要素的投入强度导致农业生产粗放化,进而影响单位耕地面积粮食产量。[结论]农业生产过程中需要构建现代农业产业体系、生产体系和经营体系,降低传统生产要素的投入,不断增加新要素和新技术投入,以实现减碳、增产的双重目标。     

Forest carbon benefits,costs and leakage effects of carbon reserve scenarios in the United States

This study evaluated the potential effectiveness of future carbon reserve scenarios, where U.S. forest landowners would hypothetically be paid to sequester carbon on their timberland and forego timber harvests for 100 years. Scenarios featured direct payments to landowners of $0 (baseline), $5, $10, or $15 per metric ton of additional forest carbon sequestered on the set aside lands, with maximum annual expenditures of $3 billion. Results indicated that from 1513 to 6837 Tg (Teragrams) of additional carbon (as carbon dioxide equivalent, CO₂e) would be sequestered on U.S. timberlands relative to the baseline case over the next 50 years (30–137 Tg CO₂e annually). These projected amounts of sequestered carbon on timberlands take into account projected increases in timber removal and forest carbon losses on other timberlands (carbon leakage effects). Net effectiveness of carbon reserve scenarios in terms of overall net gain in timberland carbon stocks from 2010 to 2060 ranged from 0.29 tCO₂e net carbon increase for a payment of $5/tCO₂e to the landowner (71% leakage), to 0.15 tCO₂e net carbon increase for a payment of $15/tCO₂e to the landowner (85% leakage). A policy or program to buy carbon credits from landowners would need to discount additions to the carbon reserve by the estimated amount of leakage. In the scenarios evaluated, the timber set-asides reduced timberland area available for harvest up to 35% and available timber inventory up to 55%, relative to the baseline scenario over the next 50 years, resulting in projected changes in timber prices, harvest levels, and forest product revenues for the forest products sector.     

Economics of carbon sequestration in community forests: Evidence from REDD+ piloting in Nepal

Reducing Emissions from Deforestation and Forest Degradation (REDD+) has been piloted in developing countries as a climate change mitigation strategy, providing financial incentives for carbon sequestration in forests. This paper examines the economic feasibility of REDD+ in community forests within two watersheds in central Nepal, Ludikhola and Kayarkhola, using data on forest product demand, carbon sequestration, carbon price and REDD+ related costs. The benefits of REDD+ are about $7994, $152, and $64 per community forest, per hectare of forest area, and per household in Ludikhola watershed compared to $4815, $29, and $56 in Kayarkhola watershed, respectively, under the business-as-usual scenario. Compared to the EU ETS carbon price ($10.3/tCO₂e), the average break-even carbon price in community forests is much higher in Kayarkhola watershed ($41.8/tCO₂e) and much lower in Ludikhola watershed ($2.4/tCO₂e) when empirical estimates of annual expenditure in community forests are included in the analysis. The incorporation of annual expenditure estimates and opportunity cost of sequestered carbon (in the form of firewood prices in local markets) in the analysis suggests that community forests are economically infeasible for REDD+ at the prevailing carbon prices. The implication of our findings is that economic feasibility of REDD+ in community forests depends on the local contexts, carbon prices and the opportunity costs, which should be carefully considered in designing REDD+ projects.     

The Need for Comprehensive Climate Change Mitigation Policies in European Agriculture

During the last decade the European Union has shown a firm determination to move to a low carbon economy. Since 2008 the agricultural sector has been part of this strategy and is included in the EU effort sharing decision. Introducing specific GHG mitigation obligations for agriculture could be one option to achieve an overall GHG emission reduction target. One argument for this strategy would be that the agricultural sector is the main contributor of non‐CO₂ greenhouse gases. Nevertheless, a comprehensive EU mitigation policy would most likely have to take into account the particularities of its diverse agricultural sector, reflected by different trends in historical GHG emission reductions, and a varied mitigation cost structure between farming systems. Consequently, using targeted but flexible policy instruments may more equitably distribute the mitigation efforts across Member States and reduce cost inefficiencies. The increased uptake of technological and management emission mitigation measures would be crucial to keep mitigation costs for EU farmers at a minimum. However, while unilateral action would initially signal the EU's commitment to serious GHG mitigation effort in the sector, ultimately a multilateral agreement is needed to minimise emission leakage and to reduce global GHG emissions effectively.     

Does extensification lead to enhanced provision of ecosystems services from soils in UK agriculture?

Extensification is offered as a management strategy to reduce the perceived negative effects of intensive agricultural management, e.g. nutrient loss through leaching, emissions of the greenhouse gas N₂O, loss of soil carbon through carbon dioxide emissions, increased nutrient, carbon and sediment loading to surface water, and reduced biodiversity. As part of managed extensification implemented under the European Union's Common Agricultural Policy intensively managed land use types (arable and grassland) are taken out of production for either 5, 7 or 10 years in the UK. The ultimate objective is to establish species-rich grassland (SRG) to which limited or no fertiliser is applied, which attracts subsidy payments under the European Agricultural Fund for Rural Development. There is little scientific evidence for the anticipated environmental benefits of these newly created SRGs. The legacy of intensive management on soils is likely to limit ecosystem service (ES) provision from former intensively managed sites for many decades following extensification and this commentary addresses this issue. Clearly, programmes of long-term experimental research are needed to quantify the environmental and economic benefits of current extensification schemes in UK agriculture in order to determine whether the benefits for ES delivered by soils out-weigh the costs in terms of loss of production.     

经济新常态下创新驱动型现代低碳农业发展研究*——以成都平原地区为例

[目的]在全球气候变暖,资源枯竭的背景下,发展低碳农业是农业可持续发展的迫切需求。文章通过分别计算种植业、畜牧业、农业生产用具碳排放量得出成都市近年来碳排放情况,为成都平原地区农业低碳经济发展提供研究与实践基础。[方法]选取2004—2015年科技发展财政投入数据与农业碳排放量,运用回归模型验证农业科技投入与农业碳排放量的关系,探究农业科技投入对农业减排的促进作用。[结果](1)成都市的种植业碳排放在40年整体呈下降趋势,主要原因是种植面积的减少;(2)化肥碳排放量在1999—2015年整体呈下降趋势,减排效果较为明显,农业灌溉碳排放量整体平稳下降而减少的势头还未放缓,其在未来仍具有较大的减排潜力;(3)农业机械的碳排放最小也最为稳定, 16年来一直保持在1.6万t左右,碳排放强度也在0.017 t/hm~2上下,可见成都市农业在21世纪初到目前的农业机械使用量基本稳定,对其依赖性较弱,有进一步减排的可能。(4)技术因素对减少农业碳排放具有驱动作用,并且随着技术资金投入的增加,减排工作会进入到"瓶颈",碳排放量减少的速度将逐渐放缓。[结论]通过理论分析与案例研究,发现技术、制度、文化与农业碳排放量的内在逻辑关系,为促进低碳农业发展,应从制度、技术、文化3个方面推动创新。     

支农财政、技术进步偏向的农田利用碳排放效应研究

研究目的:识别农田利用方式转型期支农财政、农业技术进步偏向及其交互作用对农田利用碳排放的影响及其区域差异,评价支农财政和农业技术进步的环境效率,提出减排政策建议。研究方法:构建农田利用碳排放强度指标,通过估计核密度函数揭示其区域分布,基于加入交互项的固定效应模型实证检验核心变量对农田利用碳排放强度的影响效果。研究结果:单位播种面积农田利用碳排放均值逐年增加,区域差异扩大;单位产值农田利用碳排放均值逐年减小,区域差异缩小;支农财政倾向于提高农田利用碳排放强度,效果与种植结构相关;与资源禀赋耦合的农业技术进步偏向具有减排效应,并有利于降低支农财政的促排效果,该交互作用亦与种植结构相关。研究结论:支农财政政策应关注由其产生的环境压力,通过提高生产要素利用效率、推动与资源禀赋相耦合的农业技术进步等途径促进农田利用碳减排,充分考虑农作物种植结构的区域差异,提高政策的精准性。     

Economic value of carbon sequestration in forests under multiple sources of uncertainty

The purpose of this paper is to calculate the value of stochastic carbon sequestration in climate change mitigation when also carbon dioxide emissions from fossil fuels and abatement costs are stochastic. The replacement cost method is used where the value of carbon sink is calculated as associated cost savings from replacement of more expensive mitigation options for achieving a given emission target. Minimum costs with and without carbon sinks are derived with a safety-first approach in a chance constrained programming framework which also accounts for variability in control costs. The theoretical results show that for high enough risk discount, carbon sink is not included in a cost effective mitigation program even when the carbon sink cost is zero. The empirical application to the EU independent commitment of 20% reduction in carbon dioxides shows large variation in carbon sink value depending on risk discount. Under no uncertainty, the value can correspond to 0.33% of total GDP in EU, but it declines due to the uncertainty associated with forest carbon sink and is zero for high probability levels in achieving the target. Thus, whether or not to recommend the inclusion of carbon sink in the EU climate policy depends on the uncertainty of carbon sinks in relation to other sources and on the importance of reaching stipulated emission reduction targets.     

Effects of changes in forestland ownership on deforestation and urbanization and the resulting effects on greenhouse gas emissions

This study analyzes the extent to which greenhouse gas (GHG) emissions may be affected by a plan to purchase private forestland for the expansion of carbon sinks, focusing on how changes in forestland ownership affect deforestation and urbanization and how subsequent changes in deforestation and urbanization affect GHG emissions, using South Korea as a case study. The results from ex ante simulations imply that carbon dioxide equivalent emissions could increase between 17.4 and 19.2 million tons with private forestland purchases from a constrained budget of $750 million, compared with an increase of 34.5 million tons without the purchasing plan.     

Carbon-accounting methods and reforestation incentives

The emission of greenhouse gases, particularly carbon dioxide, and the consequent potential for climate change are the focus of increasing international concern. Temporary land-use change and forestry projects (LUCF) can be implemented to offset permanent emissions of carbon dioxide from the energy sector. Several approaches to accounting for carbon sequestration in LUCF projects have been proposed. In the present paper, the economic implications of adopting four of these approaches are evaluated in a normative context. The analysis is based on simulation of Australian farm–forestry systems. Results are interpreted from the standpoint of both investors and landholders. The role of baselines and transaction costs are discussed.     

Agriculture's Likely Role in Meeting Canada's Kyoto Commitments*

Voluntary adoption of beneficial management practices will be the primary means by which farmers cut net greenhouse gas (GHG) emissions. The offset system will not be a major driver due to (a) the relatively low prices likely to be offered by large final emitters facing an emission cap, (b) discounts applied to those prices for temporary sequestration, (c) the transaction costs and risk premiums associated with signing carbon contracts, and (d) the low elasticity of supply of CO₂ abatement. Although Canadian farmers are likely to participate to only a limited extent in the carbon‐offset market, many will find it profitable to adopt one or more of the BMPs for reducing net GHG emissions. Canadian agriculture is likely to contribute significantly to net emission reductions by voluntarily sequestering carbon due to the adoption of zero till in the last decade, and possibly by cutting fertilizer levels in the next decade. The contribution will be mainly a response to meeting personal economic objectives rather than being induced by direct incentives through the offset program.     

西北干旱区农地利用碳排放与农业经济增长的响应关系

[目的]试图找出我国西北干旱区农地利用碳排放与农业经济增长之间的关系,以期为制定该地区农地利用碳减排政策提供理论支撑。[方法]测算西北干旱区"九五"至"十二五"期间农地利用的碳排放量,采用"Tapio脱钩"理论探究农地利用碳排放与农业经济增长的响应关系,并运用LMDI模型分析了农地利用碳排放的影响因素,继而对农地利用碳排放零增长的时间节点进行了预测。[结果]西北干旱区农地碳排放呈现"快速增长-缓慢增长"两阶段变化特征,其碳排放强度变化轨迹与此基本一致;农地利用碳排放与农业经济增长间响应关系显著,以弱脱钩效应为主;农地利用碳排放的驱动因子中,农业生产效率因素、劳动力因素对农地利用碳减排的成效最为明显,农业产业结构因素对农地利用碳减排略有促进作用,而农业经济发展因素是促进碳排放的主要因素。[结论]西北干旱区有望在2017年实现农地利用碳排放的零增长,虽在短期内可能实现农地利用碳排放的零增长,但农业收入在农户家庭收入中仍占较大比重,农业碳减排压力依然较大。