Harald Bergland, P. Mishra, P. A. Pedersen, Arkadi Ponossov, J. Wyller
We analyze the impacts of pollution on fishery sector using a dynamical system approach. The proposed model presupposes that the economic development causes emissions that either remediate or accumulate in the oceans. The model possesses a block structure where the solutions of the rate equations for the pollutant and the economic activity act as an input for the biomass and effort equation. We also account for distributed delay effects in both the pollution level and the economic activity level in our modeling framework. The weight functions in the delay terms are expressed in terms of exponentially decaying functions, which in turn enable us to convert the modeling framework to a higher‐order autonomous dynamical system by means of a linear chain trick. When both the typical delay time for the economic activity and the typical delay time for the pollution level are much smaller than the biomass time scale, the governing system is analyzed by means of the theory for singularly perturbed dynamical systems. Contrary to what is found for population dynamical systems with absolute delays, we readily find that the impact of the distributed time lags is negligible in the long‐run dynamics in this time‐scale separation regime.
{"title":"Time delays and pollution in an open‐access fishery","authors":"Harald Bergland, P. Mishra, P. A. Pedersen, Arkadi Ponossov, J. Wyller","doi":"10.1111/nrm.12363","DOIUrl":"https://doi.org/10.1111/nrm.12363","url":null,"abstract":"We analyze the impacts of pollution on fishery sector using a dynamical system approach. The proposed model presupposes that the economic development causes emissions that either remediate or accumulate in the oceans. The model possesses a block structure where the solutions of the rate equations for the pollutant and the economic activity act as an input for the biomass and effort equation. We also account for distributed delay effects in both the pollution level and the economic activity level in our modeling framework. The weight functions in the delay terms are expressed in terms of exponentially decaying functions, which in turn enable us to convert the modeling framework to a higher‐order autonomous dynamical system by means of a linear chain trick. When both the typical delay time for the economic activity and the typical delay time for the pollution level are much smaller than the biomass time scale, the governing system is analyzed by means of the theory for singularly perturbed dynamical systems. Contrary to what is found for population dynamical systems with absolute delays, we readily find that the impact of the distributed time lags is negligible in the long‐run dynamics in this time‐scale separation regime.","PeriodicalId":49778,"journal":{"name":"Natural Resource Modeling","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41914899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present initiative study has been planned to develop a conceptual model for watershed resilience for which rare documents have been reported yet, particularly in developing countries where such studies are necessary. In this vein, different ecological, social, economic, and infrastructural and cultural key domains were applied for the modeling processes of watershed resilience for the Shazand Watershed in Iran. To this end, watershed resilience was firstly conceptualized according to the prevailing conditions for three periods 1986–1998, 1999–2008, and 2009–2016. Accordingly, the watershed health index was used for the ecological dimension, and 13, 8, and 13 criteria were consequently considered for social, economic, and infrastructural and cultural dimensions, respectively. The whole data required for the last three dimensions were collected through the distribution of questionnaires among the stockholders of the Shazand Watershed. The principal component analysis (PCA) method was used to weighting and prioritize the criteria and dimensions. The overall resilience index was ultimately calculated by aggregating all four dimensions using a geometric mean. The effect of each dimension on resilience was also assessed by applying multivariable regression. According to the resilience map of the period 2009–2016, 40%, 9%, 34%, and 17% of the Shazand Watershed has been classified as very low and low resilience, moderate, high, and very high resilience. This study showed that the resilience of the Shazand Watershed has improved over time. The necessity of resilience modeling for practical and integrated management of watersheds was also confirmed during the present research.
{"title":"Spatial and temporal zoning of watershed resilience using a multidimensional composition approach","authors":"P. Farzi, S. Sadeghi, M. Jomehpour","doi":"10.1111/nrm.12362","DOIUrl":"https://doi.org/10.1111/nrm.12362","url":null,"abstract":"The present initiative study has been planned to develop a conceptual model for watershed resilience for which rare documents have been reported yet, particularly in developing countries where such studies are necessary. In this vein, different ecological, social, economic, and infrastructural and cultural key domains were applied for the modeling processes of watershed resilience for the Shazand Watershed in Iran. To this end, watershed resilience was firstly conceptualized according to the prevailing conditions for three periods 1986–1998, 1999–2008, and 2009–2016. Accordingly, the watershed health index was used for the ecological dimension, and 13, 8, and 13 criteria were consequently considered for social, economic, and infrastructural and cultural dimensions, respectively. The whole data required for the last three dimensions were collected through the distribution of questionnaires among the stockholders of the Shazand Watershed. The principal component analysis (PCA) method was used to weighting and prioritize the criteria and dimensions. The overall resilience index was ultimately calculated by aggregating all four dimensions using a geometric mean. The effect of each dimension on resilience was also assessed by applying multivariable regression. According to the resilience map of the period 2009–2016, 40%, 9%, 34%, and 17% of the Shazand Watershed has been classified as very low and low resilience, moderate, high, and very high resilience. This study showed that the resilience of the Shazand Watershed has improved over time. The necessity of resilience modeling for practical and integrated management of watersheds was also confirmed during the present research.","PeriodicalId":49778,"journal":{"name":"Natural Resource Modeling","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43592830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper derives rational ecological–economic equilibrium outcomes—capital and variable input allocations, harvests, discards, revenue, costs, and stock abundances—in a spatially heterogeneous, multispecies fishery that is regulated with individual fishing quotas (IFQs). The production setting is decentralized; a manager chooses species‐specific, seasonal, and spatially nondelineated quotas. Industry controls all aspects of harvesting operations. We present a solution concept and computational algorithm to solve for equilibrium harvests, discards, and profits across species, space, and time (within the regulatory cycle). The rational equilibrium mapping that we derive, used recursively, can be used to implement management‐preferred bioeconomic outcomes. The model offers an essential IFQ regulation‐to‐outcome mapping that enables more precise implementation of management goals in multiple‐species and heterogeneous fishery settings.
{"title":"A model of rational equilibrium in quota‐regulated multiple‐species fisheries","authors":"Rajesh K. Singh, Quinn Weninger","doi":"10.1111/nrm.12361","DOIUrl":"https://doi.org/10.1111/nrm.12361","url":null,"abstract":"This paper derives rational ecological–economic equilibrium outcomes—capital and variable input allocations, harvests, discards, revenue, costs, and stock abundances—in a spatially heterogeneous, multispecies fishery that is regulated with individual fishing quotas (IFQs). The production setting is decentralized; a manager chooses species‐specific, seasonal, and spatially nondelineated quotas. Industry controls all aspects of harvesting operations. We present a solution concept and computational algorithm to solve for equilibrium harvests, discards, and profits across species, space, and time (within the regulatory cycle). The rational equilibrium mapping that we derive, used recursively, can be used to implement management‐preferred bioeconomic outcomes. The model offers an essential IFQ regulation‐to‐outcome mapping that enables more precise implementation of management goals in multiple‐species and heterogeneous fishery settings.","PeriodicalId":49778,"journal":{"name":"Natural Resource Modeling","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44654136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Forestland can be managed for timber and environmental goods simultaneously. A conservation contract allows a government agency to pay a landowner for the portion of property rights encumbered in the production of environmental goods. In this study, a theoretical model is developed to examine optimal contract provisions for carbon sequestration on working forests under a budget constraint for the agency. The analyses reveal that a landowner requires a higher payment if more property rights are encumbered in a conservation contract. A landowner whose land can sequester more carbon also requires a more favorable contract arrangement. Assuming a logistic growth path for carbon sequestration, the agency under a budget constraint tends to have a shallower relationship with more landowners, that is, encumbering a smaller portion of property rights from more landowners. This tendency supports the use of conservation contracts with a shorter term and a higher enrollment share in a forest community.
{"title":"Optimal contract arrangements for conservation on working forests","authors":"Changyou Sun, B. Mei, Yanshu Li","doi":"10.1111/nrm.12351","DOIUrl":"https://doi.org/10.1111/nrm.12351","url":null,"abstract":"Forestland can be managed for timber and environmental goods simultaneously. A conservation contract allows a government agency to pay a landowner for the portion of property rights encumbered in the production of environmental goods. In this study, a theoretical model is developed to examine optimal contract provisions for carbon sequestration on working forests under a budget constraint for the agency. The analyses reveal that a landowner requires a higher payment if more property rights are encumbered in a conservation contract. A landowner whose land can sequester more carbon also requires a more favorable contract arrangement. Assuming a logistic growth path for carbon sequestration, the agency under a budget constraint tends to have a shallower relationship with more landowners, that is, encumbering a smaller portion of property rights from more landowners. This tendency supports the use of conservation contracts with a shorter term and a higher enrollment share in a forest community.","PeriodicalId":49778,"journal":{"name":"Natural Resource Modeling","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46349267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The accurate evaluation of the relationship between nature reserves and poverty is highly significant for the harmonious coexistence between human and nature. It is widely recognized that the establishment of nature reserves is of great importance to the income poverty of farmers, but less attention has been paid to the impact of different reserves on the multidimensional relative poverty of farmers. Based on the survey data of Panda Nature Reserves in China, we analyze the influence of reserve regulation (or not) and regulation intensity on the multidimensional relative poverty of farmers and its mechanism. Results show that farmers in reserves are more likely to fall into multidimensional relative poverty than those outside the reserves, and there is a U‐shaped relationship between regulation intensity and multidimensional relative poverty. Further, the mechanism analysis show that, on average, the establishment of reserves has no significant impact on farmers' resource utilization capability, but too high or too low regulation intensity will affect farmers' resource utilization capacity, and aggravate their multidimensional relative poverty. The conclusions of this paper are not only conducive to the expansion of theoretical research on regulation and poverty, but also provide policy implications for realizing the coordinated development between biodiversity conservation of nature reserves and rural livelihood.
{"title":"Reserve regulation and multidimensional relative poverty of farmers: Evidence from the Panda Nature Reserves in China","authors":"Chao-Ching Lin, Lan Gao","doi":"10.1111/nrm.12358","DOIUrl":"https://doi.org/10.1111/nrm.12358","url":null,"abstract":"The accurate evaluation of the relationship between nature reserves and poverty is highly significant for the harmonious coexistence between human and nature. It is widely recognized that the establishment of nature reserves is of great importance to the income poverty of farmers, but less attention has been paid to the impact of different reserves on the multidimensional relative poverty of farmers. Based on the survey data of Panda Nature Reserves in China, we analyze the influence of reserve regulation (or not) and regulation intensity on the multidimensional relative poverty of farmers and its mechanism. Results show that farmers in reserves are more likely to fall into multidimensional relative poverty than those outside the reserves, and there is a U‐shaped relationship between regulation intensity and multidimensional relative poverty. Further, the mechanism analysis show that, on average, the establishment of reserves has no significant impact on farmers' resource utilization capability, but too high or too low regulation intensity will affect farmers' resource utilization capacity, and aggravate their multidimensional relative poverty. The conclusions of this paper are not only conducive to the expansion of theoretical research on regulation and poverty, but also provide policy implications for realizing the coordinated development between biodiversity conservation of nature reserves and rural livelihood.","PeriodicalId":49778,"journal":{"name":"Natural Resource Modeling","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45631069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marie‐Catherine Riekhof, L. C. Kluger, R. Salvatteci, Lotta Siebert, Rudi Voss
We introduce six steps to define a “Window of Tipping Point Analysis” which serves as a framework to increase the understanding of processes and tipping points in social‐ecological systems. We apply the Window of Tipping Point Analysis to a mathematical model and two case studies (i.e., Baltic Sea and the Humboldt Current Upwelling system), focusing on three aspects. In “to tip or be tipped” we look at agency in preventing (or driving) tipping. In “to be tipped or not to be tipped” we discuss intertemporal developments and chosen time periods for delineating regime shifts. In “to tip or not to tip” we discuss the desirability of states and their relation to the elements included. We argue that agency in tipping‐point management, the occurrence of tipping points, and desirable states depend on the window chosen for the analysis.
{"title":"To tip or not to tip: The Window of Tipping Point Analysis for social‐ecological systems","authors":"Marie‐Catherine Riekhof, L. C. Kluger, R. Salvatteci, Lotta Siebert, Rudi Voss","doi":"10.1111/nrm.12357","DOIUrl":"https://doi.org/10.1111/nrm.12357","url":null,"abstract":"We introduce six steps to define a “Window of Tipping Point Analysis” which serves as a framework to increase the understanding of processes and tipping points in social‐ecological systems. We apply the Window of Tipping Point Analysis to a mathematical model and two case studies (i.e., Baltic Sea and the Humboldt Current Upwelling system), focusing on three aspects. In “to tip or be tipped” we look at agency in preventing (or driving) tipping. In “to be tipped or not to be tipped” we discuss intertemporal developments and chosen time periods for delineating regime shifts. In “to tip or not to tip” we discuss the desirability of states and their relation to the elements included. We argue that agency in tipping‐point management, the occurrence of tipping points, and desirable states depend on the window chosen for the analysis.","PeriodicalId":49778,"journal":{"name":"Natural Resource Modeling","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42140147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seong‐Hoon Cho, James C. Mingie, Nawon Kang, G. Zhu, Sreedhar Upendram
The purpose of this study is to understand how solutions from single‐ and multiobjective optimization for the conservation of multiple species are different and what impacts these differences. We identify optimal conservation investment allocations maximizing expected species' habitat ranges for multiple pairs of species using two approaches in the central and southern Appalachian region. We find that disparities between the two approaches are affected by differences in the involved species' expected habitat ranges (i.e., contrasting and similar) and their correlation pattern (i.e., positive, negative, and insignificant). Using a single metric by aggregating species' habitats for multiple species to carry out single‐objective optimization is shown to favor the species with a larger habitat distribution more if the involved species' expected habitat distributions are negatively correlated and their distribution difference is larger. Framing multiple metrics of species' habitats separately using multiobjective optimization for the same set of multiple species, in contrast, does not show such a drastic disparity.
{"title":"Understanding the differences between single‐ and multiobjective optimization for the conservation of multiple species","authors":"Seong‐Hoon Cho, James C. Mingie, Nawon Kang, G. Zhu, Sreedhar Upendram","doi":"10.1111/nrm.12356","DOIUrl":"https://doi.org/10.1111/nrm.12356","url":null,"abstract":"The purpose of this study is to understand how solutions from single‐ and multiobjective optimization for the conservation of multiple species are different and what impacts these differences. We identify optimal conservation investment allocations maximizing expected species' habitat ranges for multiple pairs of species using two approaches in the central and southern Appalachian region. We find that disparities between the two approaches are affected by differences in the involved species' expected habitat ranges (i.e., contrasting and similar) and their correlation pattern (i.e., positive, negative, and insignificant). Using a single metric by aggregating species' habitats for multiple species to carry out single‐objective optimization is shown to favor the species with a larger habitat distribution more if the involved species' expected habitat distributions are negatively correlated and their distribution difference is larger. Framing multiple metrics of species' habitats separately using multiobjective optimization for the same set of multiple species, in contrast, does not show such a drastic disparity.","PeriodicalId":49778,"journal":{"name":"Natural Resource Modeling","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41726730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many natural resources around the world are being overexploited (FAO Fisheries Department, 2022; IPBES, 2019), sometimes to the extent that ecosystems are on the brink of collapse. This is especially true for marine systems where overfishing is a continuous and globally increasing ecological and economic issue, also resulting in impacts on society and culture. Marine ecosystems are threatened to cross tipping points, leading to abrupt changes in recruitment, biomass, and consequently in catches (Möllmann et al., 2021). In the past years, tipping point analysis has spread to various interdisciplinary fields such as natural resource modeling. A historic example is found in the shallow lakes theory where several stable states have been shown to exist and to reverse tipping from a healthy ecosystem to a eutrophicated state may require more than just nutrient removal (Scheffer, 1997). The optimal management of these systems requires interdisciplinary approaches that account for the vulnerability of ecosystems to tipping but also to consider multiple economic costs and benefits (Voss & Quaas, 2021). In an integrated perspective of natural resource systems that takes the feedbacks between ecological and socioeconomic processes into account, tipping points in the system are not necessarily a bad thing. These systems may be on an unsustainable path, and achieving sustainability may require to shift the system toward another domain of attraction (Derissen & Quaas, 2013). The aim of the 2021 World Conference on Natural Resource Modeling was to discuss how to change ecological‐economic system dynamics toward long‐term sustainability. As worldwide pandemic restrictions were in place it was the first fully virtual conference of the Resource Modeling Association. Owing to low costs and sessions convenient to all time zones the conference became a particularly inclusive event, with a wide range of papers and topics from all over the world. The collection of papers in this special issue represents a selection of contributions toward the fields of tipping point analysis and the management of coupled ecological socioeconomic systems. In “To tip or not to tip: The Window of Tipping Point Analysis for social‐ecological systems” Riekhof et al. (2022) introduce a new framework to increase the understanding of processes and tipping points in social‐ecological systems and discuss the desirability of alternative stable states. In “A stylized model of stochastic ecosystems with alternative stable states” Stecher and Baumgärtner (2022) advance the field of multistability by introducing stochasticity in the ecosystem state and identifying a multitude of important applications. Finally, in “Joint management of marine mammals and a fish species: The case of cod and grey seals in the Nordic‐Baltic Sea countries” Blomquist et al. (2022) point out the importance of taking multiple costs and benefits of predators and harvested prey in a managed marine ecosystem into account. We wo
{"title":"Editorial","authors":"F. Meier, Hanna Schenk","doi":"10.1111/nrm.12359","DOIUrl":"https://doi.org/10.1111/nrm.12359","url":null,"abstract":"Many natural resources around the world are being overexploited (FAO Fisheries Department, 2022; IPBES, 2019), sometimes to the extent that ecosystems are on the brink of collapse. This is especially true for marine systems where overfishing is a continuous and globally increasing ecological and economic issue, also resulting in impacts on society and culture. Marine ecosystems are threatened to cross tipping points, leading to abrupt changes in recruitment, biomass, and consequently in catches (Möllmann et al., 2021). In the past years, tipping point analysis has spread to various interdisciplinary fields such as natural resource modeling. A historic example is found in the shallow lakes theory where several stable states have been shown to exist and to reverse tipping from a healthy ecosystem to a eutrophicated state may require more than just nutrient removal (Scheffer, 1997). The optimal management of these systems requires interdisciplinary approaches that account for the vulnerability of ecosystems to tipping but also to consider multiple economic costs and benefits (Voss & Quaas, 2021). In an integrated perspective of natural resource systems that takes the feedbacks between ecological and socioeconomic processes into account, tipping points in the system are not necessarily a bad thing. These systems may be on an unsustainable path, and achieving sustainability may require to shift the system toward another domain of attraction (Derissen & Quaas, 2013). The aim of the 2021 World Conference on Natural Resource Modeling was to discuss how to change ecological‐economic system dynamics toward long‐term sustainability. As worldwide pandemic restrictions were in place it was the first fully virtual conference of the Resource Modeling Association. Owing to low costs and sessions convenient to all time zones the conference became a particularly inclusive event, with a wide range of papers and topics from all over the world. The collection of papers in this special issue represents a selection of contributions toward the fields of tipping point analysis and the management of coupled ecological socioeconomic systems. In “To tip or not to tip: The Window of Tipping Point Analysis for social‐ecological systems” Riekhof et al. (2022) introduce a new framework to increase the understanding of processes and tipping points in social‐ecological systems and discuss the desirability of alternative stable states. In “A stylized model of stochastic ecosystems with alternative stable states” Stecher and Baumgärtner (2022) advance the field of multistability by introducing stochasticity in the ecosystem state and identifying a multitude of important applications. Finally, in “Joint management of marine mammals and a fish species: The case of cod and grey seals in the Nordic‐Baltic Sea countries” Blomquist et al. (2022) point out the importance of taking multiple costs and benefits of predators and harvested prey in a managed marine ecosystem into account. We wo","PeriodicalId":49778,"journal":{"name":"Natural Resource Modeling","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41610545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We consider the problem of optimal harvesting of a renewable resource whose dynamics are governed by logistic growth and whose payoff is proportional to the harvest. We consider both the case of a finite and an infinite time horizon and analyse the structure of the optimal solutions and their dependence on the parameters of the model. We show that the optimal policy can only have one of three structures: (1) maximal harvesting effort until the resource is depleted, (2) zero harvesting during an initial time interval followed by a subsequent switch to maximal harvesting effort, or (3) a singular solution, which corresponds to an intermediate level of harvesting, accompanied by the most rapid approach path. All three scenarios emerge, with minor variations, with finite and infinite time horizons, depending on the particular combination of parameters of the system. We characterize the conditions under which the singular solution is optimal and present suggestions for designing an optimal and sustainable harvesting strategy.
{"title":"The structure of optimal solutions for harvesting a renewable resource","authors":"Thorsten Upmann, D. Gromov","doi":"10.1111/nrm.12355","DOIUrl":"https://doi.org/10.1111/nrm.12355","url":null,"abstract":"We consider the problem of optimal harvesting of a renewable resource whose dynamics are governed by logistic growth and whose payoff is proportional to the harvest. We consider both the case of a finite and an infinite time horizon and analyse the structure of the optimal solutions and their dependence on the parameters of the model. We show that the optimal policy can only have one of three structures: (1) maximal harvesting effort until the resource is depleted, (2) zero harvesting during an initial time interval followed by a subsequent switch to maximal harvesting effort, or (3) a singular solution, which corresponds to an intermediate level of harvesting, accompanied by the most rapid approach path. All three scenarios emerge, with minor variations, with finite and infinite time horizons, depending on the particular combination of parameters of the system. We characterize the conditions under which the singular solution is optimal and present suggestions for designing an optimal and sustainable harvesting strategy.","PeriodicalId":49778,"journal":{"name":"Natural Resource Modeling","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63504218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Using a fossil fuel extraction model that treats the atmosphere as a depletable resource, we study the optimal price of carbon in the presence of endogenous uncertainty around a climatic regime shift. We find that the optimal carbon tax should account an uncertainty‐adjusted cost term associated with the environment's scarcity. This term is shown to be sensitive to the natural sequestration rate of the atmosphere and to the probability surrounding a climate tail event. Our analysis also shows that in the presence of uncertainty, the shadow price of the environment should grow at a faster rate. Lastly, compared to the endogenous uncertainty case, we find that if the probability surrounding a regime shift is exogenously given, this shadow price should even grow at a higher rate.
{"title":"Polluting resource extraction and climate risk","authors":"Israa Hashem, Walid Marrouch","doi":"10.1111/nrm.12354","DOIUrl":"https://doi.org/10.1111/nrm.12354","url":null,"abstract":"Using a fossil fuel extraction model that treats the atmosphere as a depletable resource, we study the optimal price of carbon in the presence of endogenous uncertainty around a climatic regime shift. We find that the optimal carbon tax should account an uncertainty‐adjusted cost term associated with the environment's scarcity. This term is shown to be sensitive to the natural sequestration rate of the atmosphere and to the probability surrounding a climate tail event. Our analysis also shows that in the presence of uncertainty, the shadow price of the environment should grow at a faster rate. Lastly, compared to the endogenous uncertainty case, we find that if the probability surrounding a regime shift is exogenously given, this shadow price should even grow at a higher rate.","PeriodicalId":49778,"journal":{"name":"Natural Resource Modeling","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2022-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44709436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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