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.     

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.     

不同碳排放达峰情景对产业结构的影响——基于动态CGE模型的分析

依据2017年投入产出表数据,运用可计算一般均衡理论,构建包括13个中间产业部门和5个能源产业部门的动态CGE模型,考量不同碳排放达峰情景对于产业结构的影响。结果显示：碳减排政策能促进产业结构优化,包括农业、轻工业和服务业等在内的低碳产业部门在总产出中占比增加,高耗能产业部门如非金属矿物加工业、金属加工业等在总产出中占比下降;对能源产出结构影响显著,高碳能源如煤炭、石油在能源产出比例下降,低碳能源如天然气在能源产出比例增加,其中可再生能源比例上升幅度最大。鉴此,应完善碳交易市场运行配套政策和环境,加大技术创新力度,促进产业结构和能源结构优化升级。     

Climate change policy, market structure, and carbon leakage

The 1997 Kyoto Protocol on climate change obliges the industrialized countries to initiate the international effort of abating anthropogenic greenhouse gas (GHG) emissions. If such an initiative is to be taken, the associated competitive effects may lead to significant relocation of developed countries' energy-intensive production. This paper examines this issue. I adopt an oligopolistic structure combined with increasing returns to scale production technologies to represent the strategic interaction among the firms producing energy-intensive products. This representation is then embedded within a multi-regional computable general equilibrium model, which in turn is used for quantifying these relocational effects. The results suggest that significant relocation of energy-intensive industries away from the OECD may occur, depending on the type of market structure, with leakage rates as high as 130%, in which case GHG control policies in the industrialized countries actually lead to higher global emissions.     

Expansion of EU's Free Trade Agreements into Asian Countries and Its Impact on the Chinese Economy

Abstract

This study investigates the macroeconomic impact of EU's free trade agreements with Asian countries and the US on the Chinese economy. In addition we examine the impacts on the Chinese industry output based on the framework of production network and production fragmentation. The expansion of the EU's economic reach toward ASEAN and Japan through free trade agreement will generate a positive macroeconomic effect on negotiation participants while it generates a negative effect on the Chinese economy: Some portions of existing trade and foreign direct investment will be shifted to partner countries from non-partner countries. However, according to a sectorial analysis, EU's free trade agreements with three countries result in a positive impact on China's electronics and machinery industry, because China's industry is linked to the production fragmentation and foreign affiliates play a crucial role.     

Livestock intensification as a climate policy: Lessons from the Brazilian case

Brazil is trying to identify ways to ally economic growth with climate change mitigation. Productivity gains in livestock have been pointed out as a promising alternative to achieve that goal. Thus, this paper analyses the economic impacts of a policy of productivity gains in the Brazilian livestock. Besides, we evaluate if the policy may conciliate agricultural growth and deforestation control, bearing in mind the reduction of greenhouse gas (GHG) emissions from land-use changes. The analysis was carried out through a computable general equilibrium (CGE) model, tailored to represent land-use changes, GHG emissions and removals. Besides, it made progress modeling the heterogeneity of climate, soils, and emissions in inter-regional models with many regions. The results show that productivity gains can effectively “save” land and thus avoid deforestation, especially in the Amazon and Cerrado (savannah) biomes. The policy also may boost the economic growth, spreading it to other regions of Brazil, like Centre-West and North, and increasing income and consumption in those places. However, as a climate policy, focused on the reduction of GHG emissions, the results may be counterproductive. The net amount issued may increase, as a result of the positive stimulus of the policy on the economy, and GHG emissions are directly related to the economic growth.     

Forecasting development outcomes under alternative surplus labour assumptions

Economic forecasts are useful to policymakers both as aids to planning, and as baselines against which counterfactual scenarios can be compared. However, policy makers should be aware that assumptions relating to model structure can influence forecast results. We explore the sensitivity of forecasts to one aspect of model structure important in modelling developing economies: surplus agricultural labour. We outline a framework for modelling surplus agricultural labour that relies on average product remuneration. We embed this within a model of a developing economy (the Philippines) characterized by surplus agricultural labour. We compare the results of two forecasts that differ in their treatment of the agricultural labour market. In the first, the surplus labour theory is activated, establishing average product remuneration in agriculture. In the second, the surplus labour theory is not activated, creating a failure to recognize average product remuneration in agriculture. By comparing the two simulations, we show that failure to model the presence of average product remuneration, when it would be appropriate to do so, has an impact that would be material to economic planners, leading them to: under-estimate agricultural employment; over-estimate GDP growth; and, over-estimate important policy variables (like tax revenue) that are related to GDP growth.     

Migration and employment interactions in a crisis context

This article analyses how a crisis impacts labour markets in origin countries through migration channels. For this purpose, we develop a novel dynamic general equilibrium model with a focus on the interlinkages between migration, the labour market and education. The main innovation of the paper is the retrospective modelling in general equilibrium of the impact of an economic crisis to isolate the impact of migration on local unemployment. The impact of the crisis on education decision is captured through endogenous returns to education. The simultaneity of the crisis in Tunisia and its partners worsened the labour market situation mainly through the increase in labour supply. The main result of this study is that migration is indeed one of the main determinants of the unemployment increase and that remittances have a higher impact than the variation of emigration flows. The low skilled bear the highest costs in terms of unemployment and wage decline.     

基于CGE框架下的央行宏观经济模型研究

在充分吸收CGE模型优势的基础上,我们结合央行宏观经济模型特点,对二者进行有机整合,使之为宏观经济分析和货币政策决策服务。借助该模型不仅可以进行总量分析,还能进行结构分析,从而可以较全面地剖析货币政策对经济的影响过程。