共查询到20条相似文献，搜索用时 15 毫秒
1.
RAM RANJAN 《Natural Resource Modeling》2014,27(1):104-127
In water‐scarce regions of the world, water‐saving technology adoption augments farm productivity. But so does social capital. In this paper, the issue of ensuring livelihood for farmers through the combined use of social capital and water‐saving technology is modeled in the context of repeated droughts. The model presented here derives optimal resource conservation and accumulation strategies when the farmer must ensure minimum consumption during a set of repeated drought events in the future. Findings indicate that the path to drought resilience presents a complex trade‐off between accumulating one form of capital over another and is influenced by farmers’ wealth and water endowments, level of risk associated with the repeated droughts and the duration of the repeated drought event that the farmer plans to survive. A higher risk of repeated droughts leads to an increase in groundwater conservation efforts but delays technology adoption. Lower water endowments may also delay adoption and reduce social capital, however, a lower social capital or a slow rate of its growth is not a hindrance to adopting water‐saving technology earlier. Finally, social capital evolves to higher levels when farmer is simultaneously faced with a higher level of risks and a longer span of drought events. 相似文献
2.
RAGNAR ARNASON 《Natural Resource Modeling》2007,20(2):163-197
ABSTRACT. . Climate changes in the 21st century are expected to significantly increase ocean temperatures and modify other oceanographic conditions in the North Atlantic. Marine biological research suggests that the impacts on the commercially most important fish stocks in the Icelandic‐Greenland ecosystem may well be quite substantial. This will obviously lead to a corresponding impact on the economies of these two countries. However, the timing, extent and biological impact of global warming is quite uncertain. As a result the economic impact is similarly uncertain. This paper attempts to provide estimates of the impact of altered fish stocks due to global warming on the Icelandic and Greenland economies. The approach is one of stochastic simulations. This involves essentially three steps. The first is to obtain predictions of the impact of global warming on fish stocks and the associated probability distribution. For this we rely on recent marine biological predictions. The second step is to estimate the role of the fisheries sector in the two economies. This is done with the help of modern econometric techniques based on economic growth theory and historical data. Obviously these estimates are also subject to stochastic errors and uncertainty. The third step is to carry out Monte Carlo simulations on the basis of the above model and the associated uncertainties. The result of the Monte Carlo simulations consists of a set of dynamic paths for GDP over time with an expected value and a probability distribution for each future year. On this basis it is possible to calculate confidence intervals for the most likely path of GDP over time. The results indicate that the fisheries impact of global warming on the Icelandic GDP is more likely to be positive than negative but unlikely to be of significant magnitude compared to historical economic growth rates and fluctuations. The uncertainty of this prediction, however, is large. For Greenland, the impact on fish stocks and the GDP is highly likely to be positive and quite substantial relative to the current GDP. Due to less knowledge of the relationship between the fisheries sector and the Greenland economy, however, the confidence interval of this prediction is even wider than in the case of Iceland. 相似文献
3.
KENNETH R. STOLLERY 《Natural Resource Modeling》2005,18(1):91-112
ABSTRACT. This paper builds a Faustmann‐based model to study the effects of increased climate‐induced fire risk on the optimal forest rotation period. Simulations using species prevalent in North American forests indicate that both the commercial and socially optimal rotation ages decline as the risk increases. The reduced carbon absorbed by the standing timber can then create a positive feedback effect. This has potentially important policy implications. The Kyoto ratification agreement reached in the autumn of 2001 was dependent on allowing the ‘Umbrella Group’ of countries to use their forests' carbon‐absorbing ability to offset their need for fossil fuel emission reductions. This carbon‐absorbing ability will decline if rotation ages decrease with increased fire risk, weakening the force of the argument for allowing these countries to use their carbon ‘sinks’ to avoid reducing anthropomorphic emissions. 相似文献
4.
In this article we present a stylized model for optimal management of an unconfined groundwater resource when the threat of drought exists. The drought is modeled as a stochastic event that hits at an uncertain date and two benchmark management policies are investigated: (a) A policy of optimal dynamic management ignoring the threat of drought; and (b) an economically optimal policy that accounts for the threat of a drought. We show that the optimal predrought steady‐state equilibrium stock size of groundwater under policy b is larger than that under policy (a) Furthermore, we show that an increase in the probability of a drought gives rise to two counteracting effects: One in the direction of a larger predrought steady‐state equilibrium stock size (a recovery effect) and one in the direction of a lower predrought steady‐state equilibrium stock (an extinction effect). We find that the recovery effect dominates the extinction effect. Recommendations for Resource Managers: We analyze two groundwater extraction policies that can be used when a threat of drought exists: (a) Dynamic optimal management ignoring the threat of drought; and (b) dynamic optimal management taking the threat of drought into account. We show that the predrought steady‐state equilibrium stock size of water should be larger under the policy (b) than under policy (a). This conclusion has three implications for resource managers:
- Current groundwater management should take future extraction possibilities into account.
- A resource manager ought to take the threat of drought into account in groundwater management.
- A buffer stock of water should be built‐up before the drought to be drawn upon during the event.
5.
全球变暖的宏观经济增长模型 总被引：1，自引：0，他引：1
本文研究了全球变暖的减排对策及其对经济环境的影响.运用动态最优化的方法,对该系统进行静态与动态的分析,并且讨论了参数对经济环境的影响.对我国制定全球变暖的对策有一定启发意义. 相似文献
6.
本研究首先对Baumol和Oates构建的公共外部性模型的假设条件进行修正,从而构建起更符合实际的国际气候治理的数理模型;求解该数理模型,本研究推导出同时实现全球帕累托最优和自身财政收支平衡下,国际环境协议必须遵循的唯一政策规则;最后,以此为基础,本研究进一步构建起纳入政策预期的国际气候博弈模型,并通过数理分析论证,揭示了:如果世界各国都只考虑自身利益最大化,纳入政策预期下的气候博弈的均衡结果,将无法实现全球气候治理的帕累托最优。 相似文献
7.
In this paper, we consider the Cauchy problem of 2D tropical climate model without thermal diffusion and construct global smooth solutions by choosing a class of special initial data whose L∞ norm can be arbitrarily large. 相似文献
8.
Franz Wirl 《商业与工业应用随机模型》2004,20(2):95-114
This paper integrates two different but crucial aspects of global warming: free riding and uncertainty. Although certainty equivalence does not hold, an analytical solution is obtained if ‘clean up’ (e.g. reforestation) is possible. Assuming realistically irreversible emissions, numerical methods are necessary to obtain the value function and the implied strategies, which are shown to be unique (for the calibrated parameters). Although uncertainty stresses the importance of conservation, the incentives to free ride are almost the same. Beyond the particular application, the paper shows how to analyze stochastic, dynamic games. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
9.
The global small solutions of the tropical climate model are obtained with the fractional dissipative terms Λαu in the equation of the barotropic mode u and Λαv in the equation of the first baroclinic mode v. More precisely, we prove for 1<α ≤ 2 that the couple system has global unique strong solutions for small initial data with critical regularities. Moreover, the smallness assumption imposed on the initial barotropic mode of the velocity can be removed if α=2. We also study the large time behavior of the constructed solutions and obtain optimal time decay rates by a pure energy argument. 相似文献
10.
Marcus Brandenburg Kannan Govindan Joseph Sarkis Stefan Seuring 《European Journal of Operational Research》2014
Sustainability, the consideration of environmental factors and social aspects, in supply chain management (SCM) has become a highly relevant topic for researchers and practitioners. The application of operations research methods and related models, i.e. formal modeling, for closed-loop SCM and reverse logistics has been effectively reviewed in previously published research. This situation is in contrast to the understanding and review of mathematical models that focus on environmental or social factors in forward supply chains (SC), which has seen less investigation. To evaluate developments and directions of this research area, this paper provides a content analysis of 134 carefully identified papers on quantitative, formal models that address sustainability aspects in the forward SC. It was found that a preponderance of the publications and models appeared in a limited set of six journals, and most were analytically based with a focus on multiple criteria decision making. The tools most often used comprise the analytical hierarchy process or its close relative, the analytical network process, as well as life cycle analysis. Conclusions are drawn showing that numerous possibilities and insights can be gained from expanding the types of tools and factors considered in formal modeling efforts. 相似文献
11.
Hal Cochrane 《Natural Resource Modeling》1990,4(3):355-380
This paper demonstrates the principles of sequential choice. A numerical simulation model based on the theoretical framework is utilized to illustrate the economics of climate change. The model is used to relate the value of information and quasi-option value in situations where protective measures are nonbinary. 相似文献
12.
We establish the global well-posedness of a strong solution to the 3D tropical climate model with damping. We prove that there exists the global and unique solution for α, β, γ satisfying one of the following three conditions: (1)
13.
In this paper, we consider the Cauchy problem of 3D tropical climate model with zero thermal diffusion. Firstly, we establish the global regularity for this system with fractional diffusion $alpha=beta=5/4.$ Secondly, by adding only a damp term, we obtain the global well-posedness for small initial data. 相似文献
14.
The management of second-growth and old-growth forest stands has important implications for the global carbon cycle. This paper considers the optimal forest rotation when flows of CO2 to carbon have positive value. If benefits are derived only from carbon, then typically it will never be optimal to harvest any forest stands. This result is a formalization and extension of Harmon et al. [1990]. Private forest owners will often maximize net returns to timber, ignoring benefits from carbon sequestration. Thus, the privately and socially optimal rotations will not generally coincide. We show that the socially optimal rotation is always greater than the privately optimal rotation and less than or equal to the rotation when only carbon is valued. 相似文献
15.
JEAN‐DANIEL M. SAPHORES 《Natural Resource Modeling》2004,17(2):163-190
ABSTRACT. This paper shows that the timing of an investment to reduce the emissions of a stock pollutant under environmental uncertainty depends on the specification of uncertainty, on its level, and on the presence of a lower reflecting barrier for the stock pollutant. With quadratic damages, when variability increases with the level of pollution, emissions should be curbed immediately when uncertainty is large enough; when uncertainty is small, however, its impact is ambiguous. A lower reflecting barrier may also significantly influence the investment threshold. These results highlight the importance of better understanding the links between greenhouse gas concentration and weather variability. 相似文献
16.
Abstract As multiple countries share a river, the likelihood of conflicts over distributing water resources increases, particularly under the effects of climate change. In this paper, we demonstrate how countries can cooperate in sustainable transboundary water sharing under such conditions. We examine the case of water distribution in the Volta Basin of West Africa between the upstream country, Burkina Faso, and the downstream country, Ghana. The latter faces an additional tradeoff between the production of hydropower in the south, close to the outlet of the basin, and agricultural water use in the reservoir’s catchment area in the north. In the framework of a stochastic Stackelberg differential game, we show how sustainable water‐sharing agreements can be achieved by linking transboundary flows to hydropower exports. Our results indicate that, through cooperation, Ghana will have an opportunity to increase its water abstraction for agriculture, which has remained largely restricted. We also find that the equilibrium strategies for the long‐run distribution are stable even with increasing variances of water flow. 相似文献
17.
The increase of sea surface temperature in ocean changes the photosynthetic production rate of phytoplankton. Therefore, it is crucial to understand the relation between temperature and phytoplanktons photosynthesis to deal the extinction caused by excessive increase in temperature. It is worth observing that temperature is one of the most principal limiting factors for phytoplanktons production due to photosynthetic enzymes work at their optimum temperature levels. In this study, the fractional oxygen-phytoplankton-zooplankton model is considered by singular and nonsingular fractional operators within Caputo, Caputo-Fabrizio, and Atangana-Baleanu in Caputo sense. The rate of oxygen production is considered by a function of temperature account for the sea surface warming. At first, the temperature function is constant and then it starts to increase, after a certain time of increase, before the oxygen depletion begins, the temperature is set to a higher secure value. With this temperature function choice, detailed numerical simulations are carried out to provide details of the internal structure of the system. We observe that the species are more sustainable in Caputo model than its corresponding integer-order model. 相似文献
18.
This paper provides a formal framework to analyze informational and commitment requirements of several intertemporal price and quantity instruments for mitigating global warming. We ask under what conditions and to what extend the regulator can shift the complex and daunting intertemporal optimization of fossil resource use to markets. Mitigation always generates an intertemporal climate rent which reflects the stock‐dependent damages and emerging scarcities of the atmospheric carbon deposit. In order to calculate and to manage this climate rent appropriately, common policy instruments like Pigouvian taxes or emissions trading presume perfect information about resource demand, extraction costs, reserve sizes, and damages for the entire planning horizon. To reduce these informational requirements we develop an alternative policy approach—a state dependent tax rule—that relies only on current observations of cumulative extraction (or atmospheric carbon concentration). Within a cost–benefit analysis, this instrument is capable to shift the complex intertemporal optimization problem completely to the resource sector when resource owners are homogeneous. Under a cost‐effective carbon budget approach, emissions trading with banking and borrowing can also unburden the regulator from solving the intertemporal social planner optimization problem. Additionally, we discuss which instruments can obtain an optimal allocation even if resource owners employ discount rate mark‐ups (i.e., due to imperfect commitment or insecure property rights). While an emissions trading scheme without banking and borrowing is robust against discount rate mark‐ups, resource taxes have to be modified in order to achieve an optimal allocation. 相似文献
19.
《School science and mathematics》2018,118(1-2):43-52
The Going Green! Middle Schoolers Out to Save the World project aims to direct middle school students' enthusiasm for hands‐on activities toward interest in science and other STEM areas while guiding them to solve real‐world problems. Students in this project are taught by their teachers to use energy monitoring equipment to audit standby power consumed by electronic devices in their homes and communities. Major findings were: (a) Beliefs in climate change increased more for students in the treatment than comparison group, pre to post; and (b) For girls there was a larger positive impact on climate change beliefs than for boys. These and additional findings presented in this paper provide evidence that a hands‐on engaged‐learning curriculum can have a positive influence on climate change beliefs and intentions and strengthen the association between the two constructs. 相似文献
20.
针对气候变化及经济影响存在的巨大不确定性,研究了气候变化不确定性以及先验信息对社会碳成本的影响.在贝叶斯理论框架下,采用指数分布刻画气候变化的分布特征,假设尾部变化率是一个随机变量,给出其伽玛先验分布,推导了气候变化分布的贝叶斯先验预测分布.并分别基于指数分布以及帕累托先验预测分布计算了社会碳排放成本.模拟分析发现,在... 相似文献