Constraints on Dematerialisation and Allocation of Natural Capital along a Sustainable Growth Path

This paper extends the neoclassical growth model with natural capital by introducing two new concepts: allocation of natural capital and materialization. We consider that anthropogenic environmental impact is correlated with the throughput of the economy (materialisation). Materialisation is the material throughput per unit of economic activity. We capture the effect of the reduction of this throughput dematerialisation in the elasticities of materialisation and aggregate environmental impact. In our framework the fraction of natural capital devoted to production does not provide direct environmental services nor does it contribute to ecosystem functioning namely affecting the carrying capacity of natural capital.We analyse an optimal sustainable growth path, in the context of exogenous technological change. Our main conclusion is that the ratio of dematerialisation elasticities must equal the inverse of the share of natural capital in order to assure unbounded economic growth with constant natural capital

A One-sided Sustainability Test With Multiple Consumption Goods

In an economy with multiple consumption goods (including environmental amenities) that uniquely maximises the present value of utility with constant discounting, constant or falling augmented green net national product, or zero or negative augmented net investment, at any time implies that the economy is unsustainable then. "Augmented" means that time is treated as a productive stock, so augmented net investment includes the value of time. This allows future exogenous technical progress and changes in world prices to be included in a unified accounting framework, along with features such as resource depletion, pollution and foreign investment. The practical and philosophical rationale for testing sustainability in a present-value maximising, and therefore fully prescribed, development path are discussed.

One-sided Unsustainability Tests and NNP Measurement with Multiple Consumption Goods

In an economy with multiple consumption goods (including environmental amenities) that uniquely maximises the present value of utility with constant or falling augmented green net national product, or zero or negative augmented investment, at any time implies that the economy is unsustainable then. "Augmented" means that time is included as a productive stock, which incorporates future exogenous technical progress and changes in world prices in a unified accounting framework. Examples are given of calculating accounting prices for multiple goods. The practical and philosophical rationale for testing sustainability in a present-value maximising, and therefore fully prescribed, development path is discussed.sustainability, net investment,net national product, optimality,green accounting

A note on the consequences of an endogenous discounting depending on the environmental quality

International audienceOur intention is to study, in the framework of a very simple optimal growth model, the consequences on the optimal paths followed by consumption and the environmental quality of an endogenous discounting. Consumption directly comes from the use of environmental services and so is a direct cause of environmental degradation. The environment is valued both as a source of consumption and as an amenity. For a sustainability concern, we introduce an endogenous discount rate growing with the environmental quality, and compare the optimal growth paths with the ones obtained in the usual case of exogenous and constant discounting. We show that the convergence of the environmental quality towards a steady state occurs only for a very special configuration of the parameters in the exogenous discounting case, while it occurs generically in the endogenous discounting one. This happens for a utility discount rate becoming suficiently high when the environmental quality is high and suficiently low when the environmental quality is poor. In this case then, endogenous discounting with a positive marginal discount rate allows us to avoid the depletion of the environment

The Economics of Sustainability: A Review of Journal Articles

Concern about sustainability helped to launch a new agenda for development and environmental economics and challenged many of the fundamental goals and assumptions of the conventional, neoclassical economics of growth and development. We review 25 years’ of refereed journal articles on the economics of sustainability, with emphasis on analyses that involve concern for intergenerational equity in the long-term decisionmaking of a society; recognition of the role of finite environmental resources in long-term decisionmaking; and recognizable, if perhaps unconventional, use of economic concepts, such as instantaneous utility, cost, or intertemporal welfare. Taken as a whole, the articles reviewed here indicate that several areas must be addressed in future investigation: improving the clarity of sustainability criteria, maintaining distinctions between economic efficiency and equity, more thoroughly investigating many common assumptions in the literature about prospects for resource substitution and resource-enhancing technical change, and encouraging the empirical investigation of sustainability issues.economic efficiency, intergenerational equity, social optimality, sustainable development

The Ethics of Distribution in a Warming Planet

The discounted-utilitarian social welfare function (DU) is used by the great majority of researchers studying intergenerational resource allocation in the presence of climate change (e.g., W. Nordhaus, M. Weitzman, N. Stern, and P. Dasgupta). I present three justifications for using DU: (1) the view that the first generation’s preferences should be hegemonic, (2) the viewpoint of a utilitarian Ethical Observer who maximizes expected utility when the existence of future generations is uncertain, and (3) axiomatic justifications (as in classical social-choice theory). I argue that only justification (2) provides an ethically convincing justification, and that, only if one endorses utilitarianism as a good ethic. Recent work by Llavador, Roemer and Silvestre challenges the utilitarian assumption, and argues that sustaining human welfare at the highest possible level forever, or sustaining the growth rate of human welfare (at a fixed exogenous growth rate), are more attractive ethical choices. The work of these authors, which studies the optimal intergenerational paths of resource allocatiobn under the sustainabilitarian objectives, is briefly reviewed and contrasted with the discounted-utilitarian approach

Sustainability and Optimality in Economic Development: Theoretical Insights and Policy Prospects

This paper takes sustainability to be a matter of intergenerational welfare equality and examines whether an optimal development path can also be sustainable. It argues that the general “zero-net-aggregate-investment” condition for an optimal development path to be sustainable in the sense of the maximin criterion of intergenerational justice is too demanding to be practical, especially in the context of developing countries. The maximin criterion of sustainability may be more appealing to the rich advanced industrial countries, but is too costly and ethically unreasonable for developing nations as it would act as an intergenerational “poverty equalizer”. The paper suggests that a compromise development policy that follows the optimal growth approach but adopts certain measures to mitigate the intergenerational and intragenerational welfare inequalities may better serve these countries. Some of the principal elements of such a policy are highlighted.Sustainability, Intergenerational Equity, Optimality, Discounting, Development Policy

A One-Sided Sustainability Test with Multiple Consumption Goods

In an economy with multiple consumption goods (including environmental amenities) that uniquely maximises the present value of utility with constant discounting, constant or falling augmented green net national product, or zero or negative augmented net investment, at any time implies that the economy is unsustainable then. "Augmented" means that time is treated as a productive stock, so augmented net investment includes the value of time. This allows future exogenous technical progress and changes in world prices to be included in a unified accounting framework, along with features such as resource depletion, pollution and foreign investment. The practical and philosophical rationale for testing sustainability in a present-value maximising, and therefore fully prescribed, development path are discussed

Augmented Sustainability Measures for Scotland

We estimate and compare two empirical measures of the weak sustainability of an economy for the first time: the change in augmented green net national product (GNNP), and the interest on augmented genuine savings (GS). Yearly calculations are given for each measure for Scotland during 1992-99. Augmentation means including, using projections to 2020, changed production possibilities enabled by exogenous technical progress or changing oil prices. The change in augmented GNNP and interest on augmented GS are both always positive, showing no sustainability problem for Scotland then, according to the assumptions underlying our weak sustainability calculations. However, the former greatly exceeds the latter, a mismatch which poses an unresolved problem with the theory. Resolving it may require respecifying the utility functions used in mainstream growth theory.sustainability, Scotland, genuine savings, green NNP, augmentation

Discounting Dollars, Discounting Lives: Intergenerational Distributive Justice and Efficiency

The view that intergenerational distributive justice and efficiency should be treated separately is familiar, yet controversial. This article elaborates the often-implicit justifications for separate treatment and provides a more express statement of how and when such treatment is appropriate. Substantial attention is devoted to an approach that holds constant the intra- and intergenerational distribution of well-being, which proves to be a valuable analytical device even for intergenerational policies that are not distribution neutral. Also explored are possible interrelationships between intergenerational distributive justice and efficiency, the choice of interest rate for discounting dollars, and how the present approach relates to those that would employ direct social weights to dollars at different points in time.