Recursive Sustainability: Intertemporal Efficiency and Equity

PV-optimality in a capital-resource economy can imply decreasing utility over some portion of the time horizon. Various criteria have been proposed to maintain intergenerational equity defined as nondeclining utility, but these have some limitations and problems. This paper proposes a new welfare criteria incorporating present value to maintain efficiency, and an equity function with convex costs on declining utility. This criterion is economically efficient, time-consistent and recursive. An extension of dynamic programming to multiple value functions is developed to solve this problem. Increasing the equity weight increasingly eliminates declining portions of utility time paths. Sustainability implies increasing consumption in the early time periods and some intermediate time periods relative to PV-optimality. A surprising result is that sustainability can actually result in increased resource usage in early time periods, followed later by higher levels of resource stocks compared to PV-optimality. The sustainability analysis shows that while conventional benefit-cost and valuation analysis contribute to efficiency, they do not necessarily induce sustainability due to incorrect dynamic GE prices. Similar comments apply to Green NNP analysis. The concepts and extended DP methods developed in this paper extend naturally to uncertainty and can also be applied to generalized consumer and social choice models beyond those typically considered in the literature.growth, environment, intergenerational equity, dynamic programming, Research Methods/ Statistical Methods,

Dynamic analysis of lunar gravity simulator

Dynamic analysis of lunar gravity simulato

EXHAUSTIBLE RESOURCE ALLOCATION, INTERGENERATIONAL EQUITY, AND SUSTAINABILITY

An OLG model with exhaustible resources and solar energy is developed, and equilibrium time paths are characterized numerically using recursive methods. For the parameter values considered, resource prices increase over time, and extractions, output, and utility decline over time until a steady-state is reached. Decreasing the intertemporal elasticity of substitution or raising consumers' subjective discount rate hastens exhaustion of the resource stock. Market equilibrium can result in much quicker use of the stock than social optimality under a constant discount rate, with consequent higher utility for early generations and lower utility for future generations in contrast to social optimality.Resource /Energy Economics and Policy,

DYNAMIC REGIONAL ANALYSIS OF THE CALIFORNIA ALFALFA MARKET WITH GOVERNMENT POLICY IMPACTS

Alfalfa's heavy reliance on irrigation water and its role as an alternate to program crops makes it susceptible to changes in government farm policies. This article presents a dynamic spatial equilibrium model of the California alfalfa market. The model is used to forecast alfalfa acreage, prices paid and received, and transportation flows for the short run and the long run under the base year conditions. The base year results then are compared to a situation of changing demand due to reductions in federal water subsidies and the implementation of a cotton acreage-reduction program.Agricultural and Food Policy, Crop Production/Industries,

A Stochastic-Dynamic Model of Costly Reversible Technology Adoption

We develop a stochastic-dynamic model of technology adoption that imposes fewer restrictions on behavior than do previous studies of similar decision problems. Like these previous studies, our model is forward-looking and can be used to demonstrate the additional "hurdle rate" that must be met before adoption will take place when the future state of the world is uncertain. Unlike these previous studies, our approach does not impose the untenable assumptions that investment in a new technology is irreversible or that technologies have unlimited useful lifetimes. Rather, we address the more reasonable situation of costly reversibility and limited lifetimes. Our solution method utilizes Bellman's equation and standard dynamic programming techniques. Similar methods have been used previously to examine irreversible investment and adoption problems, but to our knowledge no application to costly reversible adoption has yet to appear in the literature. Our behavioral simulations, calibrated for irrigated cotton farming in California's San Joaquin Valley, demonstrate that the more restrictive approach can produce significant model prediction errors and can overlook important features of the adoption problem when decisions are reversible and technologies eventually become obsolete. Policy implications are discussed.dynamic optimization, irrigation, reversible, technology adoption, water, Research and Development/Tech Change/Emerging Technologies,

REGIONAL DRAINWATER MANAGEMENT: SOURCE CONTROL, AGROFORESTRY, AND EVAPORATION PONDS

Source control is one way to address salinity and drainage problems in irrigated agriculture, and reuse of drainage flows on salt-tolerant crops or trees in agroforestry production is another. A regional model of agricultural production with drainwater reuse and disposal is developed. Deep percolation flows are controlled through choice of crop areas, irrigation systems, and applied-water quantities. Crop drainwater may by reused in agroforestry production, and residual emissions are disposed of in an evaporation pond. A significant role for both source control and reuse is found. Sensitivity to various cost and revenue parameters is also analyzed.Resource /Energy Economics and Policy,

Estimated Incident Cost Savings in Shipping Due to Inspections

The effectiveness of safety inspections has been analysed from various angles, but until now, relatively little attention has been given to translate risk reduction into incident cost savings. This paper quantifies estimated cost savings based on port state control inspections and industry vetting inspections. It is based on a unique dataset of 515,194 ship arrivals and inspections from the United States of America and Australia, and inspections of three industry vetting inspection regimes, for the time period 2002 to 2007. The risk reducing effect of inspections is estimated by means of duration models, in terms of inspection gains based on the probability of survival. The results suggest average total estimated cost savings in the range of USD 74 to 192 thousand (median USD 19 to 46 thousand) owing to reduced risk of total loss due to a port state control inspection. Cost savings for industry inspections are found to be even higher, especially for tankers. The savings vary by type, age and size of the ship. The benefits of an inspection are in general larger for older and larger vessels, and also for vessels with undefined flags and unknown classification societies. As inspection costs are relatively low in comparison to potential cost savings, the results underline the importance in determining high risk ships to prevent costs due to total loss of ships.maritime safety;duration analysis;ship inspection

Nitrogen as a Capital Input and Stock Pollutant: A Dynamic Analysis of Corn Production and Nitrogen Leaching under Non-Uniform Irrigation

A spatially dynamic programming model of nonuniform irrigation is developed to investigate the nitrogen leaching problem associated with irrigated agriculture. We evaluate the importance of temporal and spatial elements in (i) appropriately modeling the interseasonal corn production problem with nitrogen carry-over and leaching under non-uniform irrigation, and (ii) in adequately evaluating alternative policy instruments for pollution control. Comparisons of the time profiles under spatially variable nitrogen levels arising from nonuniform irrigation are provided along with an evaluation of three different price-based policy instruments for reducing nitrogen leaching.Environmental Economics and Policy,