Economic aspects of natural resource exploitation

Low entropy accumulations of matter and energy are more economic for humans to exploit as natural resources. This accumulation of a resource takes place over time and the most concentrated resources, such as fossil fuels, are created over geological ages. As the most concentrated resources become depleted it may be possible for technology to enable the exploitation of less concentrated resources, such as low-grade metal ores or thinly populated fishing grounds. Analysis of the timescales necessary to create different types of natural resource reveals three distinct groups. Further consideration of economic characteristics of resources, including ownership and access, and rate of consumption relative to rate of supply confirms the grouping of resources into the three distinct groups. Rate of change of entropy as a resource is exploited is an indicator of its impact on the environment. Consideration of this again suggests three distinct groups of resources, and this paper identifies them as: continuous natural resources (CNR), such as solar power and wind power; potentially renewable resources (PRR), such as fish and forests; and non-renewable resources (NRR), such as fossil fuels and metals.     

Economic growth,international trade,and the depletion or conservation of renewable natural resources

Conservation of renewable natural resources and promotion of economic growth are both sustainable development goals. Here, we study the interdependency between economic growth, international trade, and the use of renewable natural resources—under alternative institutional settings of either open access or full property rights—in an endogenous growth model. We find that if the resource is depleted over time, consumption growth is reduced. Economic growth and international trade only impact resource use when the resource is harvested under full property rights. Then, widening international trade can lead countries to shift from conservation to depletion. Changes in the institutional setting of resource use in one country may have repercussions on trading partners. Our results indicate potential trade-offs between the sustainable development goals and imply that policies focusing on resource use or trade (e.g., international trade bans or certified trade) are not sufficient to prevent resource depletion.     

Renewable Resources in an Overlapping Generations Economy Without Capital

We incorporate a renewable resource into an overlapping generations model without capital and with quasi-linear preferences. Besides being an input for production the resource serves as a store of value. We characterize the dynamics, efficiency, and stability of the steady-state equilibria. The stability properties are sensitive to the type of resource growth. For constant growth there is only one steady-state equilibrium which is stable and efficient. In the general case of the concave growth function, there are usually at least two steady-state equilibria, one of which is stable and the other one unstable. The unstable steady state is efficient, but the stable one may or may not be. We study the robustness of our results by assuming a logarithmic utility function. We show that for the Cobb–Douglas production function the steady state is unique and stable regardless of whether the equilibrium is efficient or inefficient. Our analytical results are illustrated by numerical calculations.     

A comment on linear control problems in the theory of renewable resource exploitation

Optimal steady state yields from a renewable resource are identified using capital theory and the notion of a most rapid approach path. The optimal stock level determined in this fashion is seen to be identical to that implied by Green's Theorem and Pontryagin's Maximum Principle.     

Renewable resource management with a backstop substitute and nonautonomous prices

Policies for managing a renewable resource in the presence of a backstop substitute are analyzed. Conditions for renewable and backstop resources to be “relevant” are discussed. The extinction issue, the role of myopic decision rules and the optimality of singular arc policies are examined with nonautonomous prices.     

中国的太阳能资源及应用潜力

太阳能资源被认为是21世纪最引人注目的可再生能源和洁净能源，为了经济的可持续发展，应该把环境保护和长期利益作为研究目标，文章估算了中国14个城市的太阳能资源，分析了太阳能热水系统和PIVP系统的经济性，研究结果表明，中国的太阳能利用潜力很大，政府应该对其发展发挥重要作用。     

The influence of potential reproductive rate and variation in mate quality on male and female choosiness in the sand goby, Pomatoschistus minutus

Recent models of choosiness in mate choice have identified two particularly important factors: the potential reproductive rate (PRR) of the choosing sex relative to that of the chosen sex, and the variation in quality of potential mates. This experimental study tested how these factors affected choosiness in male and female sand gobies, Pomatoschistus minutus. We manipulated relative PRR by means of water temperature, and mate quality by means of body length. The choosing male or female was offered a choice between two mates with either a small or a large difference in body length representing a small or a large variation in mate quality. Choosiness was measured as (1) preference for the larger mate, and (2) as whether or not spawning occurred with the smaller mate, while the larger mate was visible but screened off. We found that females preferred large males, and that their level of choosiness was affected by variation in male quality, but not by their own relative PRR. Males, on the other hand, seemed unselective in all treatments and were in general more likely than females to spawn with their provided partner. This suggests that in the sand goby, variation in male mate quality has a greater influence than relative PRR on facultative changes in female choosiness. However, a general difference in PRR between males and females may be one important factor explaining the observed sex difference in choosiness. Received: 17 April 2000 / Revised: 24 June 2000 / Accepted: 17 July 2000     

Biological Integrity and the Goal of Environmental Legislation: Lessons for Conservation Biology

Abstract: Passage of environmental legislation often creates a state of euphoria among supporters such that implementation programs are not rigorously evaluated Endangered species and water resource legislation are two examples of sound environmental legislation with major weaknesses in their implementation. Regulations to implement the US. Clean Water Act, for example, emphasize water quality (physical and chemical properties of water) by calling for uniform standards for contaminants rather than the broader goal of improving the quality of water resources. As a result, improvements in the quality of water resource quality have been limited despite massive expenditures. Natural resource agencies' narrow emphasis on harvested and threatened and endangered species has similar consequences. Unless a comprehensive and rigorous definition of the goals of biodiversity legislation is developed and adhered to by regulatory agencies, efforts to implement biodiversity legislation could lead to similar problems. Protection of biodiversity should be considered a subset of the need to protect the biological integrity of natural resource systems and the ecological health of the biosphere. Programs to protect biodiversity should reflect that more holistic goal and include provisions for evaluating success at attaining stated goals and for making midcourse adjustments in programs when resources are not being adequately protected.     

Control theory applied to natural and environmental resources an exposition

Four control theory models of natural and environmental resource use, drawn from the existing literature, are developed in a manner to emphasize their technical and decentralized interpretive similarity. Renewable, nonrenewable, and amenity resource use are treated as closely related problems of optimal (biological, earth material, ecological, or environmental) capital allocation over time. Thus nonrenewable resources, and the problem of exhaustion, are just limiting (zero growth) cases of renewable resources, and the problem of species extinction. Just as exhaustion can be optimal, extinction can be optimal. Waste recycling is treated as part of the problem of optimal regeneration of “sclean” environmental capital; wilderness use as a problem of managing the regeneration of ecological capital.     

珠江三角洲区域一体化的水利政策法规体系研究

建立珠江三角洲区域一体化的水利政策法规体系是珠江三角洲国民经济社会发展和水利现代化建设的需要。从珠江三角洲地区现行水利政策法规存在的问题入手,开展珠江三角洲区域一体化的政策法规体系研究。结果表明：珠江三角洲地区现行水利政策法规体系仍很不完善,许多立、改、废工作亟待进行,2008年水政执法有效率总体较高,但很少在珠江三角洲层面开展区域一体化的联合执法,珠江三角洲水利政策法规体系建设应重点加强与水利现代化建设、水资源一体化配置、保护及管理相关的政策法规,进而建立统一协调、快速高效的区域一体化的联合执法体系。     

The optimal extinction of a renewable natural resource

This paper examines conditions for extinction when the net benefits from a renewable resource are a nonlinear function of the harvest rate. As in the linear case, extinction depends on the size of the interest rate relative to the growth potential of the species. Here, however, the size of the initial resource stock is also crucial. It is shown that extinction is optimal if the interest rate is greater than the growth potential of the species, but only for small initial stocks. Indeed, if the initial stock is sufficiently high, extinction need not be optimal even if the interest rate is infinite.     

Competing land uses and fossil fuel,and optimal energy conversion rates during the transition toward a green economy under a pollution stock constraint

We study the transition to a carbon-free economy in a model with a polluting non-renewable resource and a clean renewable resource. Transforming primary energy into ready-to-use energy services is costly and more efficient energy transformation rates are more costly to achieve. Renewable energy competes with food production for land and the food productivity of land can be improved at some cost. To avoid catastrophic climate damages, the pollution stock is mandated to stay below a given cap. When the economy is not constrained by the cap, the efficiency of energy transformation increases steadily until the transition toward the ultimate green economy; when renewable energy is exploited, its land use rises at the expense of food production; food productivity increases together with the land rent but food production drops; the food and energy prices increase and renewables substitute for non-renewable energy. During the constrained phase, the economy follows a constant path of prices, quantities, efficiency rates, food productivity and land rent, a phenomenon we call the ‘ceiling efficiency paradox’.     

Renewable resources in an endogenously growing economy: balanced growth and transitional dynamics

We introduce a renewable resource sector into an endogenous growth model of a small economy, deriving the transitional dynamic equilibrium. The model generates a long-run equilibrium in which a resource sector of limited size can coexist with constant ongoing growth elsewhere. The key feature of the model is the allocation of labor between harvesting the resource and its use in the final output sector. This naturally generates the empirically observed negative relationship between resource abundance and growth. We examine both the dynamic and long-run responses of the economy to various shocks pertaining to technological production conditions and resource sector parameters.     

Decentralized regulation of a common property renewable resource industry with irreversible investment

The effectiveness of output controls for rationalizing a common property renewable resource has been called into question by the theoretical work of J. R. Gould [Economica, Nov., 383–402 (1972)]. A proper examination of this question requires an intertemporal analysis, one that takes into account that asymmetries between persistent factors of production (“immaleable capital”) and factors that are instantaneously consumed (“labor” or ldharvest effort”). We present here a nonlinear intertemporal model of a renewable resource industry, under conditions of irreversible capital investment, and undertake to analyze its dynamics, both at open access and under centralized optimal management. We then examine the theoretical possibility of decentralized regulation by Pigouvian taxes, and reconsider the proposition of Gould.     

A Bioeconomic Model of Marine Reserve Creation

This paper employs a dynamic and spatial model of renewable resource exploitation to investigate the effects of marine reserve creation. The model combines a metapopulation model incorporating resource patch heterogeneity and dispersal with a behaviorally based spatially explicit harvesting model that assumes that fishermen choose location in a manner that eliminates spatial arbitrage opportunities. The combined spatial bioeconomic model is used to simulate the effects of reserve creation under various ecological structures. We identify parameter configurations and ecological dispersal processes that give rise to a double-payoff in which both aggregate biomass and harvest increase after an area of the fishery is set aside and protected from exploitation.     

Social,environmental, and economic consequences of integrating renewable energies in the electricity sector: a review

The global shift from a fossil fuel-based to an electrical-based society is commonly viewed as an ecological improvement. However, the electrical power industry is a major source of carbon dioxide emissions, and incorporating renewable energy can still negatively impact the environment. Despite rising research in renewable energy, the impact of renewable energy consumption on the environment is poorly known. Here, we review the integration of renewable energies into the electricity sector from social, environmental, and economic perspectives. We found that implementing solar photovoltaic, battery storage, wind, hydropower, and bioenergy can provide 504,000 jobs in 2030 and 4.18 million jobs in 2050. For desalinization, photovoltaic/wind/battery storage systems supported by a diesel generator can reduce the cost of water production by 69% and adverse environmental effects by 90%, compared to full fossil fuel systems. The potential of carbon emission reduction increases with the percentage of renewable energy sources utilized. The photovoltaic/wind/hydroelectric system is the most effective in addressing climate change, producing a 2.11–5.46% increase in power generation and a 3.74–71.61% guarantee in share ratios. Compared to single energy systems, hybrid energy systems are more reliable and better equipped to withstand the impacts of climate change on the power supply.

     

Emergy analysis applied to the estimation of the recovery of costs for water services under the European Water Framework Directive

In this paper, the European Union's Water Framework Directive 2000/60/EC (WFD) that is intended to foster protection of water resources is examined, focusing on the improvement of ecological and chemical quality of surface and groundwater. The WFD includes the concept of full cost recovery (FCR) in accordance with the Polluter-Pays Principle, as one of the tools of an adequate and sustainable water resource management system. The WFD defines three different costs associated with water: resource costs (RC), financial costs (FC), and environmental costs (ECs).The FCR of water is examined from a biophysical perspective using emergy evaluation to: (1) establish resource values of water from different sources, (2) establish the full economic costs associated with supplying water, and (3) the societal costs of water that is used incorrectly; from which the resource costs, financial costs, and environmental costs, respectively, can be computed. Financial costs are the costs associated with providing water including energy, materials, labor and infrastructure. The emergy based monetary values vary between 0.15 and 1.73 €/m³ depending on technology. The emergy based, global average resource value (from which resource costs can be computed) is derived from two aspects of water: its chemical potential and its geopotential. The chemical potential monetary value of different sources such as rain, groundwater, and surface water derived from global averages of emergy inputs varies from 0.03 to 0.18 €/m³, depending on source, and the geopotential values vary from 0.03 to 2.40 €/m³, depending on location in the watershed. The environmental costs of water were averaged for the county of Spain and were 1.42 €/m³.Time of year and spatial location within the watershed ultimately influence the resource costs (computed from emergy value of chemical potential and geopotential energy) of water. To demonstrate this spatial and temporal variability, a case study is presented using the Foix watershed in northeastern Spain. Throughout the year, the resource value of water varies from 0.21 to 3.17 €/m³, depending on location within the watershed. It is concluded that FCR would benefit from the evaluation of resource costs using spatially and temporally explicit emergy accounting.     

木质纤维素生产燃料乙醇的关键技术研究现状

木质纤维素是自然界广泛存在且廉价的可再生资源.其主要成分纤维索、半纤维素是潜在的燃料乙醇生产原料.虽然由木质纤维素生产燃料乙醇的技术路线已具可行性,但存在着具体工艺环节复杂、生产能耗高等局限,严重阻碍了其规模化生产.目前纤维素燃料乙醇生产主要围绕预处理、酶解、发酵三大关键步骤进行技术攻关,其中预处理的能耗和效率、发酵过程的五碳糖利用等问题成为该工艺的重要制约因素.本文在综述国内外纤维素乙醇生产关键步骤的基础上,着重分析了各种物理、化学和生物预处理的优缺点以及新兴的预处理思路,归纳了各类纤维素乙醇生产菌的特点,包括耐高温和五碳糖的利用,并介绍了当前主要的发酵方式和优化措施,以期为木质纤维素生产乙醇提供新的研究思路.表5参86     

Models of withdrawing renewable and non-renewable resources based on Odum's energy systems theory and Daly's quasi-sustainability principle

This paper presents a theoretical model of withdrawing resources based on Odum's energy systems diagrams. According to the theory of a general pulsing principle, withdrawing resources changes in time shifting from the initial phases of growth and maturity to the phases of descent and low energy restoration. A simulation was performed in order to hypothesize potential future trends of withdrawing renewable and non-renewable resources and to show some aspects of their sustainability–unsustainability, respectively. According to Odum's theory, after the rapid growth of the last century, our civilization is living in a climax transition phase and it is now approaching a descent phase. A “way down” will be necessary due to the exhaustion of non-renewable and to the limited use of renewable resources. An integrated “renew–non-renew” model was developed by Odum to show how a “business as usual” trend will bring us to a drastic transition to a world that uses scarce renewable resources. Nevertheless, a different choice is possible, based on Daly's concept of quasi-sustainability that can inspire a new model. The latter argued that the exploitation of a non-renewable resource must be paired with a compensating investment in a renewable substitute. Our model shows that we can use non-renewable resources better to considerably improve our capacity of capturing renewable resources in the future. We present this as a necessary condition to address a sustainable environmental policy.     

Optimal exploitation of energy resources: Solar power and electricity generation in below sea level basins

This paper analyzes the generation of hydroelectric power by the transfer of seawater to locations which are significantly below sea level (e.g., the Dead Sea in Israel and the Qatara depression in Egypt) combined with solar energy that via evaporation will perpetuate the hydroelectric power capacity. Two scenarios are depicted. The first focuses on optimal planning of the canal capacity and optimal use of its water to generate hydroelectric power while filling the basin to its steady-state level. The second includes the impact of solar pools as a new technology whose date of adoption is a random event. It is shown that the optimal flow of water through the canal depends on the relationship between optimal canal capacity and the rate of water evaporation in the basin. The optimal design of the canal can be considered a hybrid between depletion of a natural resouce (the height differences in filling up the basin) and use of a renewable resource (solar energy to evaporate the basin water). The optimal policy is shown to consist of sequential intervals, some of which may vanish under certain conditions: first, the operation of the canal at full capacity; then the gradual decrease of water flow at a rate equal to the elasticity of the marginal product of electricity generation times the sum of interest rate and the marginal evaporation rate; and, finally, the stabilization of the water flow at the rate of steady-state evaporation. The stochastic model with the introduction of solar pools technology treated as a random event is formulated as a two-stage maximization problem. It is shown that, in contrast to the scenario without solar pools, the canal may be operated underutilizing its capacity in the initial period. But even in this case, the quantity of water flowing through the canal is a nonincreasing monotonic function over time with a jump in the quantity of flow at the date the solar pools are introduced.