Thermodynamics and process analysis for future economic scenarios

Economists are increasingly interested in forecasting future costs and benefits of policies for dealing with materials/energy fluxes, polluting emissions and environmental impacts on various scales, from sectoral to global. Computable general equilibrium (CGE) models are currently popular because they project demand and industrial structure into the future, along an equilibrium path. But they are applicable only to the extent that structural changes occur in or near equilibrium, independent of radical technological (or social) change. The alternative tool for analyzing economic implications of scenario assumptions is to use Leontief-type Input-Output (I-O) models. I-O models are unable to endogenize structural shifts (changing I-O coefficients). However, this can be a virtue when considering radical rather than incremental shifts. Postulated I-O tables can be used independently to check the internal consistency of scenarios. Or I-O models can be used to generate scenarios by linking them to econometric macro-drivers (which can, in principle, be CGE models). Explicit process analysis can be integrated, in principle, with I-O models. This hybrid scheme provides a natural means of satisfying physical constraints, especially the first and second laws of thermodynamics. This is important, to avoid constructing scenarios based on physically impossible processes. Process analysis is really the only available tool for constructing physically plausible alternative future I-O tables, and generating materials/energy and waste emissions coefficients. Explicit process analysis also helps avoid several problems characteristic of pure CGE or I-O models, viz. (1) aggregation errors (2) inability to handle arbitrary combinations of co-product and co-input relationships and (3) inability to reflect certain non-linearities such as internal feedback loops.     

对外贸易与中国制造业发展：基于可计算一般均衡（CGE）模型的模拟分析

运用CGE模型模拟分析了对外贸易对我国制造业主要行业的产出、收益及投资水平的作用效果。分析结果显示,制造业产出、收益和投资变化率与对外贸易变化率呈正相关;除了金属行业的收益增长率在贸易小幅增长时,其行业的收益率高于贸易的增长率以外,其余行业的贸易的增长率均大于各行业收益增长率,低于投资增长率;而贸易的小幅增长对于纺织业、金属行业、炼焦、煤气和石油加工业的收益水平的提升更有利;贸易的高度增长对于具有增长潜力的机械行业更有利;对于食品制造业、化学行业、非金属矿物制品业来讲贸易的适度增长对行业发展更有利。由此提出在大力发展制造业贸易的同时,要针对各行业对贸易的不同敏感程度,合理的调整产业政策,发挥技术创新能力,以此提升制造业的贸易利得。     

碳税循环政策对中国农村能源结构调整的作用——基于CGE模型的政策讨论

本文立足中国二元经济体系影响依然存在的社会现实，构建了基于CHAYANOV农民模型假设基础之上的CGE模型。并从二氧化碳减排、缓解常规能源供给压力的能源可持续发展角度出发，提出在常规能源部门收入碳税补贴现代生物质能发展的政策建议。文中重点分析了碳税循环政策实施后城乡两部门的社会经济综合变化，对碳税实施的假设给予充分肯定。     

The rebound effect on energy efficiency improvements in China’s transportation sector: A CGE analysis

Energy use is becoming more efficient due to technological innovations. We focused on the transportation sector in China to develop a national multisector computable general equilibrium (CGE) model for analyzing the rebound effect from an improvement of 10% in the energy efficiency. We compared the size of the energy rebound effect at both the macroeconomic and sectoral levels in different transportation modal subsectors, namely rail, road, water, and air travel. The findings showed that the magnitude of the rebound effect varies across the transportation modes. This is particularly true for the air transportation sector, which has an economy-wide rebound effect of 30.1% and an own-sector rebound effect of 74.6% because of a sharp increase in the export demand for air transport services. We also quantitatively evaluated the contribution of energy efficiency improvement in the transportation sector to China’s economic growth and carbon reductions and found a positive dividend effect on the economy as well as the environment. The modeling results suggest that improving overall transportation energy efficiency by 10% generates an economy-wide welfare gain of approximately 29 billion yuan, while 19 billion yuan are attributable to a more efficient road transportation subsector. Furthermore, to offset the effects of these mode-specific rebound effects, we simulated the effectiveness of different policies and solutions. These included economic instruments in the form of energy, environmental, and carbon taxes, household transport consumption structure adjustments, and energy structure adjustments. This study revealed that combining these sustainable development policies offers opportunities for economy-wide multisectoral improvements in energy savings, emissions reduction, and economic benefits.     

我国经济增长对二氧化碳排放影响的实证分析——基于一般均衡模型的分解方法

文章基于动态的一般均衡模型分析框架,利用中国1997--2040年的宏观经济数据和CO2排量数据,试图回答以下两个问题：第一,中国未来三十年的经济增长对CO2污染排量会有怎样的影响？第二,如何制定合理的政策实现中国政府承诺的CO2减排量？研究结论表明,如果实行正确的控污措施,在未来的30年里中国经济增长将不会造成CO2排量大量增加。通过对CO2排放量进行Divisia分解所得的结构效应和技术效应显示,污染排放量的有效控制可以通过重点减排活动、发展清洁燃料产品以及改进其使用技术得以实现。     

CGE assumptions under scrutiny: uncertainty in the ethanol promotion policy in Mexico

Based on a CGE exercise of a subsidy to initiate ethanol production in Mexico, we use Monte Carlo simulations for consumer demand elasticities and ethanol cost estimates. The analysis provides three conclusions: when markets vary smoothly and predictably, Monte Carlo methods can then help to gauge the actual probability that a given program will achieve a desired outcome. Second, secondary markets may display little or no sensitivity to these parameter variations. Finally, a ‘razor’s edge’ outcome with no positive benefits if a critical parameter falls below some critical value, reveals that an economic policy may not be conducive to ‘fine tuning’ by marginal adjustments.     

China’s Agricultural Policy Transition: Impacts of Recent Reforms and Future Scenarios

This article reviews recent developments in China’s agricultural domestic support policy, especially the transition from taxing farmers and agriculture to providing direct subsidies to grain production and purchased inputs. A model‐based quantitative analysis on the effects of these policy changes is presented. Simulation results suggest that recent policy changes have achieved the declared policy goals of increasing grain production and boosting farm income. Much of the increase in grain production and farm income can be attributed to higher per unit return to arable land, land reallocation to grain production and extra agricultural employment triggered by the policy changes. Based on the assumption that China’s public assistance to agriculture and farmers will continue and rise, two hypothetical future scenarios are simulated. Using all the support permitted under WTO de minimis limits with existing instruments, China’s policy will increase grain production, change trade patterns seemingly contrary to China’s comparative advantage, increase rural employment and significantly increase farm income (by more than 12%). If, however, decoupled instruments are applied to raise China’s agricultural domestic support to the same level, China’s agricultural production and trade will remain unchanged, rural employment remain stable, but farm income will be increased by nearly 15%.     

基于可计算的一般均衡模型的我国碳税政策“双重红利”研究

建立了分析我国减少二氧化碳排放而征收碳税的可计算的一般均衡模型,分析碳税政策的双重红利。结果显示:为减少二氧化碳排放而征收碳税,对社会经济变量将造成一定的负面影响。保持财政中性,在征收碳税的时候,减少居民或者企业间接税,都可以在减少二氧化碳排放量的同时提高社会福利或者保持社会福利变化不大,实现碳税的双重红利。但是在保持财政中性,在征收碳税的同时减少企业所得税,虽然减少了二氧化碳排放量,居民的社会福利却有了更大程度的下降。     

The ‘curse of dimensionality’ resolved: The effects of climate change and trade barriers in large dimensional modelling

Solving large scale optimisation problems over space and time quickly generates a computational impasse, termed the ‘curse of dimensionality’. This severely limits the practical use of economic models, especially for determining the effects of climate change and protectionist trade policies. In this paper, we employ an innovative approach to solving (otherwise unsolvable) large scale systems through the use of parallel processing methods and a proper ordering of variables and equations in a ‘Nested Doubly Bordered Block Diagonal’ form. We illustrate how the approach can be used to solve an intertemporal CGE model with more than 500 million equations. Using existing damage functions, the framework allows us to determine the impact of climate change on long-run economic growth for 112 countries as a result of the effect of sea-level rise on land endowments, variation in crop yields and productivity and shifts in the demand for energy and transportation. We also compare our solution to more common (and smaller dimensional) recursive methods, in terms of both the economic effects of climate change and potential increases in trade barriers, showing the power and efficiency of our computational approach and parallel processing routine.     

国家积极财政科技投入对中国经济的影响——基于CGE模型的研究

本文利用中国CGE模型(CHINGEM模型)对2009年中央预算中大幅增加的财政科技投入对中国经济的短、长期影响做了定量分析。从短期来看:国家积极的财政科技投入所引起的全要素生产率提高对促进中国经济增长,就业、出口增加,人民生活水平改善等都有显著作用,纺织、棉花产业受益较大,对沿海地区作用明显。在长期:公共事业、服务业和金融行业等第三产业受益较大,说明科技投入的增加在长期会促进我国产业结构的的升级。最后提出了政策建议。