Growth and multiple equilibria: A unique local dynamics

The paper investigates the local dynamics of a simple growth model with a public health factor. A notable feature of the model is that it employs a non-separable utility function between consumption and the level of public health infrastructure (publicly provided health environment). In addition to the effects on utility, an increase in the public health level contributes to labor productivity growth. From a three-dimensional dynamic system that includes physical capital, public health infrastructure and consumption, our model is found to have multiple equilibria (dual steady states) if the deep parameters of the utility function satisfy certain conditions. Then, numerical computations demonstrate that each equilibrium exhibits local saddle-path stability. This result deserves careful attention, as it indicates that the economy experiences a relatively undiversified growth pattern when converging on high- and low-growth equilibria. Our striking result has important implications in the study of growth and development.     

NONHOMOTHETIC GROWTH MODELS FOR THE ENVIRONMENTAL KUZNETS CURVE

We show the role of the elasticity of substitution between general consumption and the environment in environmental degradation. Specifically, our numerical experiments demonstrate, for a wide range of models, exponential utility generates the environmental Kuznets curve without adding any special assumptions. With exponential utility, the elasticity of substitution and hence the substitution effect between consumption and the environment are both decreasing in income. Hence, when income is low, society (the government) readily gives up environmental quality in return for more consumption, but it does not want to substitute consumption for the environment anymore, once it becomes wealthy enough.     

资源约束不断加深下的可持续增长

该文借用一个资源约束不断加深的经济增长模型,重点分析资源开采成本、环境质量要求、污染税对经济增长的影响,发现在资源开采成本不断上升时,如果效用函数中环境质量要求足够大、折现率足够低、那么污染税能够促进增长;当资源开发效率较低时,污染税对经济增长率有正效应。中国的进口资源—粗加工—再出口模式同时承担了巨大的资源价格上涨压力和粗加工过程中的环境污染压力,在新的资源来源难以保证的情况下,尤其需要在立法和执法过程中提高环境质量要求,降低环境效用的折现率,以通过严格执行污染税实现经济的可持续增长。     

Wealth inequality, preference heterogeneity and macroeconomic volatility in two-sector economies

We explore the link between wealth inequality, preference heterogeneity and macroeconomic volatility in a two-sector neoclassical growth model. First we prove that, if agents have homogeneous preferences, when the absolute risk tolerance is a strictly convex (concave) function, sufficiently high (low) levels of wealth inequality may lead to endogenous fluctuations in the neighborhood of the steady state. Second, we consider the effects of preference heterogeneity when agents are homogeneous with respect to their wealth. We show that when the utility function belongs to the HARA class, sufficiently high levels of preference heterogeneity may lead to endogenous fluctuations in the neighborhood of the steady state if the elasticity of intertemporal substitution in consumption is greater than one.     

Growth effects of environmental policy when pollution affects health

In this paper, we develop a R&D-based growth model with a pollution externality and a health production sector. We study how health-impairing pollution affects long term growth, and the effect of an emissions' reduction policy (tax). We show that a tighter environmental tax has positive effects on growth via two channels. On the one hand, it improves workers' health and, thereby, productivity; on the other hand, it induces a reallocation of resources towards R&D and, thereby, higher research intensity. The size of the growth effect of a tighter environmental tax, and the level of the optimal environmental tax, are both positively correlated with the weight individuals place on health relative to consumption. As for welfare, a tighter environmental tax brings about utility gains in the long run and, potentially, also in the short run.     

The Optimal Timing of Adoption of a Green Technology

We study the optimal timing of adoption of a cleaner technology and its effects on the rate of growth of an economy in the context of an AK endogenous growth model. We show that the results depend upon the behavior of the marginal utility of environmental quality with respect to consumption. When it is increasing, we derive the capital level at the optimal timing of adoption. We show that this capital threshold is independent of the initial conditions on the stock of capital, implying that capital-poor countries tend to take longer to adopt. Also, country-specific characteristics, as the existence of high barriers to adoption, may lead to different capital thresholds for different countries. If the marginal utility of environmental quality decreases with consumption, a country should never delay adoption; the optimal policy is either to adopt immediately or, if adoption costs are “too high”, to never adopt. The policy implications of these results are discussed in the context of the international debate surrounding the environmental political agenda.      

Renewable Resource Use and Nonseparable Amenity Benefits

We incorporate amenity benefits into an overlapping generations model with a renewable resource as a factor of production, source of amenity benefits and store of value. Unlike the conventional renewable resource problems studied under the assumption of additive consumption and amenity benefits, we let amenity benefits affect the utility of consumers in a nonseparable fashion. We examine the role that weights given to consumption and amenities have for harvesting and the resource stock. We characterize dynamics and stability of steady state equilibria with a logistic resource growth function. We demonstrate in parametric and numerical models that the weights given to consumption and amenities in the utility function matter substantially for the steady state equilibrium stock and its stability and dynamics. Both conventional saddle point equilibria and indeterminacy with infinite number of equilibria and saddle-node bifurcation is possible depending on the weights given to consumption and amenities. In addition, we show that for each inefficient equilibrium stock, there is a unique subsidy rate that can move the economy from an inefficient equilibrium to an efficient one. The presence of indeterminacy provides a challenge to resource policies, because the system becomes unpredictable. Therefore, expectations and market psychology may play an important role in resource utilization and provision of amenities.     

The endogenous formation of an environmental culture

This paper presents a mechanism explaining the surge in environmental culture across the globe. Based upon empirical evidence, we develop an overlapping generations model with environmental quality and endogenous environmental culture. Environmental culture may be costlessly transmitted intergenerationally, or via costly education.The model predicts that for low wealth levels, society is unable to free resources for environmental culture. In this case, society will only invest in environmental maintenance if environmental quality is sufficiently low. Once society has reached a certain level of economic development, then it may optimally invest a part of its wealth in developing an environmental culture. Environmental culture has not only a positive impact on environmental quality through lower levels of consumption, but it also improves the environment through maintenance expenditure for wealth-environment combinations at which, in a restricted model without environmental culture, no maintenance would be undertaken. Environmental culture leads to a society with a higher indirect utility at steady state in comparison to the restricted model.Our model leads us to the conclusion that, for societies trapped in a situation with low environmental quality, investments in culture may induce positive feedback loops, where more culture raises environmental quality which in turn raises environmental culture. We also discuss how environmental culture may lead to an Environmental Kuznets Curve.     

PRODUCT QUALITY,REPUTATION, AND MARKET STRUCTURE*

In a repeated game in which firms simultaneously choose price and product quality, but quality is observed only after consumption takes place, equilibria exhibiting high quality may exist in oligopoly markets even when the low‐quality one is a unique equilibrium outcome in monopoly and competitive markets. Oligopolists can sustain high quality through the threat of both a loss of reputation and a breakdown in tacit collusion. While we abstract from other reasons that market structure might affect product quality, we show that the inverted‐U shaped relationship between feasible quality and market structure is robust to several generalizations of the model.     

Optimal Thin Capitalisation Rule in a Simple Endogenous Growth Model with Tax Havens

In this paper we study the optimal thin capitalisation rules by developing a simple dynamic general‐equilibrium growth model incorporating tax havens. It is found that a stricter thin capitalisation rule will reduce the incentive to invest, and is therefore harmful to growth. This effect is ignored in previous static studies on the welfare analysis of tax havens. Accordingly, when taking the growth effect into consideration, reducing the utilisation of tax havens has ambiguous effects on social welfare. We also show that a looser thin capitalisation rule could be favourable for the policymakers if (i) the production technology is high; (ii) the existing income tax rate is high; (iii) the rate of time preference is low; or (iv) the weight factor of public consumption in utility is small.     

Green Attitude and Economic Growth

We analyze the interdependence between green attitude and equilibrium development of environmental quality in an endogenous growth model. Individuals take only part of their impact on pollution into account, hence there is a negative externality of capital accumulation on environmental quality. Increasing wealth or increasing pollution enhance green attitude and reduce the externality, because individuals care more about the environment if their income is higher or if pollution is more obvious. The time path of pollution as well as the evolution of equilibrium growth are shown to depend crucially on the determinants of green attitude. Ongoing growth may lead to complete internalization of the environmental externality if green attitude improves with increasing wealth, e.g. as a consequence of an increase in environmental education. In contrast, if green attitude is determined exclusively by the level of environmental quality, pollution remains at a suboptimally high level. The interdependence of wealth and pollution in the determination of environmental awareness implies more complex dynamics. Capital growth enhances green attitude and thereby decreases pollution. Improved environmental quality in turn may increase capital growth due to less green attitude and therefore slow down convergence to the sustainable balanced growth path.     

Search, Bargaining, Money, and Prices Under Private Information

This paper presents a model of money and search where bargaining determines prices and the quality of goods is private information. It studies how a lemons problem affects the purchasing power of money. There are multiple, Pareto-ranked equilibria. The superior equilibrium, where no lemons are produced, exists even if information about quality is relatively scarce. In other equilibria, there is price dispersion, and uninformed buyers pay higher prices than informed buyers for all goods. Taxing money balances (a proxy for inflation) makes buyers less selective, thus reducing the average quality of supply and the premium paid for known quality.     

Explaining shapes of Engel curves: the impact of differential satiation dynamics on consumer behavior

This paper presents a formal model in which differential satiation dynamics of various consumer needs explain (not only describe) the shapes of Engel curves. In the model, individuals allocate their income to various consumption categories proportional to corresponding need deprivation states, a decision making process called matching. The model allows explaining some empirical regularities that other models have difficulties accounting for. It can, for example, reconstruct that income elasticities for food tend to decrease with rising income, and that goods that are luxuries at relatively low income levels can become necessities at higher income levels. Moreover, the paper compares the Engel curves obtained from the matching model with Engel curves obtained from a utility maximization model. While both types of Engel curves are relatively similar at high income levels, at lower income levels matching and maximization lead to very different allocations of income. The paper shows that a given amount of income redistribution leads to less additional welfare when individuals follow matching behavior than when they maximize their utility. Accordingly, to obtain a given amount of additional welfare more income redistribution is needed than a policy maker who (mistakenly) assumes that individuals rationally maximize their utility predicts.     

Intellectual property rights and R&D subsidies: are they complementary policies?

IPR protection and R&D subsidy are simultaneously implemented in many economies. Are they complementary policies for improving the welfare of consumers? We address this question in a dynamic general equilibrium model with innovation-driven growth. Under concave utility, the answer is yes for two cases: (1) the economy does not begin from steady state and the elasticity of intertemporal substitution (EIS) is relatively large; (2) the economy begins from steady state with either a sufficiently small initial consumption and a relatively large EIS or a sufficiently big initial consumption and a relatively small EIS. Under linear utility, the answer is yes if the discounted lifetime utility is finite in equilibrium, no matter the economy begins from the steady state or not. As empirical evidence finds cross-country heterogeneity in EIS, they are not complementary for all economies. We also identify reasonable cases whereby they are substitute policies, so we show when it is not welfare-enhancing to simultaneously implement both policies.     

Public goods,voting, and growth

We study a parametric politico‐economic model of economic growth with productive public goods and public consumption goods. The provision of public goods is funded by a proportional tax. Agents are heterogeneous in their initial capital endowments, discount factors, and the relative weights of public consumption in overall private utility. They vote on the shares of public goods in gross domestic products (GDP). We propose a definition of voting equilibrium, prove the existence and provide a characterization of voting equilibria, and obtain a closed‐form solution for the voting outcomes. Also we introduce a “fictitious” representative agent and interpret the outcome of voting as a choice made by a central planner for his benefit. Finally, we undertake comparative static analysis of the shares of public goods in GDP and of the rate of balanced growth with respect to the discount factors and the preferences for public consumption. The results of this analysis suggest that the representative‐agent version of our model is capable of capturing the interaction between many voting heterogeneous agents only if the heterogeneity is one‐dimensional.     

Sustainable development,the Hartwick rule and optimal growth

Defining sustainable development as non-declining utility, the consistency of this concept with the Hartwick rule and optimal growth is explored when resources are exhaustible. A simple proof that a generalized Hartwick rule is necessary and sufficient for constant consumption is derived. The existence of a maximal constant consumption path is shown to depend critically on the elasticity of substitution; if this is less than 1, consumption declines; if it is greater than 1 then consumption is not maximal; if it is equal to 1 (the Cobb-Douglas case) then existence is proved. Consumption can increase along an optimal path if the pure rate of time preference is 0; if it is non-zero then consumption declines.     

The Relation between Real Wage Rates and Employment: An Intertemporal General- Equilibrium Analysis

Abstract. The paper studies the relation between real wage rates and employment in an intertemporal model in which expectations of subsequent real wage rates affect equilibrium capital investments and equilibrium interest rates in previous periods. Whether the wage–employment tradeoff is more favourable or less favourable in this model than in the static model with given capital depends on whether there is relatively more substitution in consumption or in production, or, more precisely, whether the elasticity of substitution in production is less than or greater than the inverse of the elasticity of marginal utility in consumption.     

Optimal Emission Policy under the Risk of Irreversible Pollution

We consider an optimal consumption and pollution problem that has two important features. Environmental damages due to economic activities may be irreversible and the level at which the degradation becomes irreversible is unknown. Particular attention is paid to the situation where agents are relatively impatient and/or do not care a lot about the environment and/or Nature regenerates at low rate. We show that the optimal policy of the uncertain problem drives the economy in the long run toward a steady state while, when ignoring irreversibility, the economy follows a balanced growth path accompanied by a perpetual decrease in environmental quality and consumption, both asymptotically converging toward zero. Therefore, accounting for the risk of irreversibility induces more conservative decisions regarding consumption and polluting emissions. In general, however, we cannot rule out situations where the economy will optimally follow an irreversible path and consequently will also be left, in the long run, with an irreversibly degraded environment.     

Replacing the U.S. income tax with a progressive consumption tax: A sequenced general equilibrium approach

This paper examines the welfare consequences of changing the current U.S. income tax system to a progressive consumption tax. We compute a sequence of single period equilibria in which savings decisions depend on the expected future return to capital. In the presence of existing income taxes, the U.S. economy is assumed to lie on a balanced growth path. With the change to a consumption tax, individuals save more and initially consume less. As the capital stock grows, consumption eventually overtakes that of the original path, and the economy approaches the new balanced growth path with higher consumption and a greater capital stock. Both the transition and the balanced growth paths enter our welfare evaluations. We find the discounted present value of the stream of net gains is approximately $650 billion in 1973 dollars, just over 1 percent of the discounted present value of national income. Larger gains occur if further reform of capital income taxation accompanies the change. We examine the sensitivity of the results, both to the design of the consumption tax and to the values of elasticity and other parameters. The paper also contains estimates of the time required to adjust from one growth path to the other.     

Growth,intergenerational welfare,and environmental policies in an overlapping generations economy

This paper examines the effects of the environmental tax on long‐run growth and intergenerational welfare in a discrete‐time overlapping generations (OLG ) model. We highlight that the role regarding how the environmental tax revenues are distributed between the young or old generations has important implications for the growth and welfare effects. Our results indicate that raising the environmental tax can exert different effects on the environmental utility of the existing young and old generations, implying an intergenerational welfare conflict of the environmental policy. However, if tax revenues are distributed appropriately, our numerical simulation shows that it is possible for a higher environmental tax to improve the welfare of all generations.