Because of global climate change,the natural environment is rapidly changing in the Arctic.The large amount of sea ice melting in the Arctic can lead to a great increase in the use of the world’s natural resources.Th...Because of global climate change,the natural environment is rapidly changing in the Arctic.The large amount of sea ice melting in the Arctic can lead to a great increase in the use of the world’s natural resources.This thesis focuses on the exploration and utilization of public waters in the Arctic region based on the economic theory of the Tragedy of the Commons,analyzes the current situation of Arctic governance,and predicts potential problems in the Arctic region,mainly including overfishing and environmental problems caused by coal and natural gas exploitation.Additionally,it makes an in-depth analysis on the current Arctic governance model based on the Arctic Council,and finally proposes some countermeasures and suggestions for Arctic governance.展开更多
In common property studies,increasing number of users has been considered as a major threat for the long-term sustainability of natural resources. This perception has been true in a few cases. However,the 40-years emp...In common property studies,increasing number of users has been considered as a major threat for the long-term sustainability of natural resources. This perception has been true in a few cases. However,the 40-years empirical research conducted in a variety of environmental settings,reveals that population pressure is not the only factor responsible for the degradation of natural resources. In remote areas,where the local inhabitants highly depend on available natural resources for subsistence livelihood,the economically important resources are kept under different ownership regimes. The local inhabitants have established autochthonous insti-tutions,and formulated rules and regulations for proper management of these resources. In this paper an attempt has been made to explore the response of a small fodder user community to the increasing population. For this purpose a micro-level study has been conducted in a remote mountain environment in the eastern Hindu Kush. For this research,data has been collected through fieldwork and focus group discussion. The results of this study reveal that fodder user communities have responded very well to the problem of population pressure. To maintain equity and long-term sustainability they have adopted a number of strategies including changing the ownership,and a resource kept under private ownership at the time of low population has been changed to a common property with increase in population. Based on this study it can be concluded that in mountainous areas and fragile environment the local inhabitant have both the capacity and capability to change their behaviour with regard to changing resource productivity as well as increasing number of users,and this situation does not always lead to the tragedy of commons.展开更多
Climate change is one of the most important challenges of the 21st Century. As greenhouse gas concentration of the atmosphere has reached the 400ppm threshold of a 2°C global warming on 9 May 2013 and irreversibl...Climate change is one of the most important challenges of the 21st Century. As greenhouse gas concentration of the atmosphere has reached the 400ppm threshold of a 2°C global warming on 9 May 2013 and irreversible tipping points of the climatic system at some point of time have got even more likely, the question of the individual contribution to climate change becomes more and more virulent. For a long time, the absorption capacity of the environment has been regarded as limitless, and based on this perception, the economic entities used the environment for hundreds of years without constraints. Today, with progress of scientific knowledge, we are now aware of the possible negative impacts of climate change to environmental, economic and social systems on Earth. This awareness, however, did not lead to a significant change of individual behavior, because the perceived individual contribution to both the anthropogenic cause of climate change and its mitigation is still regarded as marginal. To encounter this misperception or “diffusion of environmental responsibility”, this article presents an alternative calculation of the individual contribution to climate change taking the incremental approach to a tipping point or a 2°C global warming threshold into account.展开更多
Human-natural systems(HNS)are complex,adaptive systems where human activities and natural processes are deeply intertwined.Stochastic processes,nonlinear couplings,feedback loops,and emergent phenomena collectively sh...Human-natural systems(HNS)are complex,adaptive systems where human activities and natural processes are deeply intertwined.Stochastic processes,nonlinear couplings,feedback loops,and emergent phenomena collectively shape the interactions between human behaviors and natural dynamics.While environmental models in Earth system science are relatively well-established(equation-or process-based),modeling human systems remains insufficient.Moreover,there lacks a unified framework for effectively characterizing these complex interactions,posing significant challenges for HNS modeling and decision-making.To fill these gaps,this study proposes an integrated multi-agent deep reinforcement learning(MADRL)framework that combines Markov decision process(MDP),agent-based modeling(ABM),and deep reinforcement learning(DRL)to address modeling and decision-making challenges in HNS.The framework is structured as an MDP,defined by four core components:states of the environment(natural system),actions of agents(human system),transitions of the states(evolution of the HNS),and rewards.We introduce ABM to simulate human behaviors,decision-makings,and interactions among multi-hierarchical stakeholders,including individuals,groups,communities,governments,and non-governmental organizations.Additionally,DRL is employed to tackle the high-dimensional solving challenges of the MDP.Finally,a classic case study based on the“Tragedy of the Commons”is designed,featuring multiple fishermen operating under specific decision rules around a shared fishpond resource.The results demonstrate that under purely economic-driven incentives,fishermen tend to adopt high-intensity fishing strategies.This leads to fish populations rapidly declining from an initial 1,600 units to near-zero within 20 time steps,reproducing the classic“Tragedy of the Commons”phenomenon.In contrast,introducing sustainability penalty mechanisms or cooperative mechanisms effectively guides fishermen to adjust their fishing strategies.These mechanisms promote more stable and moderate fishing behaviors,maintaining fish populations at approximately 500 units and 1,500 units respectively throughout the simulation period.Furthermore,by incorporating behavioral parameters(greediness factors),the model effectively captures heterogeneity in fishing propensities.Highgreediness fishermen exhibit aggressive behaviors while low-greediness fishermen adopt more conservative strategies,revealing the impact of individual behavioral differences on system dynamics.These findings validate our proposed MADRL framework's ability to capture the dynamic feedback loops between heterogeneous agents and their environment,as well as emergent non-linear phenomena.By providing an integrated framework for analyzing and understanding these core mechanisms among multiple processes,agents,and activities of HNS,this study lays the foundation for future large-scale numerical experiments that address governance and decision-making challenges across multiple scales.展开更多
Explaining the"Tragedy of the Commons"of the evolution of cooperation remains one of the greatest problems for both biology and social science.Asymmetrical interaction,which is one of the most important char...Explaining the"Tragedy of the Commons"of the evolution of cooperation remains one of the greatest problems for both biology and social science.Asymmetrical interaction,which is one of the most important characteristics of cooperative systems,has not been sufficiently considered in the existing models of the evolution of cooperation.Considering the inequality in the number and payoff between the cooperative actors and recipients in cooperation systems,discriminative density-dependent interference competition will occur in limited dispersal systems.Our model and simulation show that the local but not the global stability of a cooperative interaction can be maintained if the utilization of common resource remains unsaturated,which can be achieved by density-dependent restraint or competition among the cooperative actors.More intense density dependent interference competition among the cooperative actors and the ready availability of the common resource,with a higher intrinsic contribution ratio of a cooperative actor to the recipient,will increase the probability of cooperation.The cooperation between the recipient and the cooperative actors can be transformed into conflict and,it oscillates chaotically with variations of the affecting factors under different environmental or ecological conditions.The higher initial relatedness(i.e.similar to kin or reciprocity relatedness),which is equivalent to intrinsic contribution ratio of a cooperative actor to the recipient,can be selected for by penalizing less cooperative or cheating actors but rewarding cooperative individuals in asymmetric systems.The initial relatedness is a pivot but not the aim of evolution of cooperation.This explains well the direct conflict observed in almost all cooperative systems.展开更多
基金supported by the“Fundamental Research Funds for the Central Universities”
文摘Because of global climate change,the natural environment is rapidly changing in the Arctic.The large amount of sea ice melting in the Arctic can lead to a great increase in the use of the world’s natural resources.This thesis focuses on the exploration and utilization of public waters in the Arctic region based on the economic theory of the Tragedy of the Commons,analyzes the current situation of Arctic governance,and predicts potential problems in the Arctic region,mainly including overfishing and environmental problems caused by coal and natural gas exploitation.Additionally,it makes an in-depth analysis on the current Arctic governance model based on the Arctic Council,and finally proposes some countermeasures and suggestions for Arctic governance.
文摘In common property studies,increasing number of users has been considered as a major threat for the long-term sustainability of natural resources. This perception has been true in a few cases. However,the 40-years empirical research conducted in a variety of environmental settings,reveals that population pressure is not the only factor responsible for the degradation of natural resources. In remote areas,where the local inhabitants highly depend on available natural resources for subsistence livelihood,the economically important resources are kept under different ownership regimes. The local inhabitants have established autochthonous insti-tutions,and formulated rules and regulations for proper management of these resources. In this paper an attempt has been made to explore the response of a small fodder user community to the increasing population. For this purpose a micro-level study has been conducted in a remote mountain environment in the eastern Hindu Kush. For this research,data has been collected through fieldwork and focus group discussion. The results of this study reveal that fodder user communities have responded very well to the problem of population pressure. To maintain equity and long-term sustainability they have adopted a number of strategies including changing the ownership,and a resource kept under private ownership at the time of low population has been changed to a common property with increase in population. Based on this study it can be concluded that in mountainous areas and fragile environment the local inhabitant have both the capacity and capability to change their behaviour with regard to changing resource productivity as well as increasing number of users,and this situation does not always lead to the tragedy of commons.
文摘Climate change is one of the most important challenges of the 21st Century. As greenhouse gas concentration of the atmosphere has reached the 400ppm threshold of a 2°C global warming on 9 May 2013 and irreversible tipping points of the climatic system at some point of time have got even more likely, the question of the individual contribution to climate change becomes more and more virulent. For a long time, the absorption capacity of the environment has been regarded as limitless, and based on this perception, the economic entities used the environment for hundreds of years without constraints. Today, with progress of scientific knowledge, we are now aware of the possible negative impacts of climate change to environmental, economic and social systems on Earth. This awareness, however, did not lead to a significant change of individual behavior, because the perceived individual contribution to both the anthropogenic cause of climate change and its mitigation is still regarded as marginal. To encounter this misperception or “diffusion of environmental responsibility”, this article presents an alternative calculation of the individual contribution to climate change taking the incremental approach to a tipping point or a 2°C global warming threshold into account.
基金supported by the National Natural Science Foundation of China(Grant Nos.42301545,42430112)China Postdoctoral Science Foundation(Grant No.2023M733606)。
文摘Human-natural systems(HNS)are complex,adaptive systems where human activities and natural processes are deeply intertwined.Stochastic processes,nonlinear couplings,feedback loops,and emergent phenomena collectively shape the interactions between human behaviors and natural dynamics.While environmental models in Earth system science are relatively well-established(equation-or process-based),modeling human systems remains insufficient.Moreover,there lacks a unified framework for effectively characterizing these complex interactions,posing significant challenges for HNS modeling and decision-making.To fill these gaps,this study proposes an integrated multi-agent deep reinforcement learning(MADRL)framework that combines Markov decision process(MDP),agent-based modeling(ABM),and deep reinforcement learning(DRL)to address modeling and decision-making challenges in HNS.The framework is structured as an MDP,defined by four core components:states of the environment(natural system),actions of agents(human system),transitions of the states(evolution of the HNS),and rewards.We introduce ABM to simulate human behaviors,decision-makings,and interactions among multi-hierarchical stakeholders,including individuals,groups,communities,governments,and non-governmental organizations.Additionally,DRL is employed to tackle the high-dimensional solving challenges of the MDP.Finally,a classic case study based on the“Tragedy of the Commons”is designed,featuring multiple fishermen operating under specific decision rules around a shared fishpond resource.The results demonstrate that under purely economic-driven incentives,fishermen tend to adopt high-intensity fishing strategies.This leads to fish populations rapidly declining from an initial 1,600 units to near-zero within 20 time steps,reproducing the classic“Tragedy of the Commons”phenomenon.In contrast,introducing sustainability penalty mechanisms or cooperative mechanisms effectively guides fishermen to adjust their fishing strategies.These mechanisms promote more stable and moderate fishing behaviors,maintaining fish populations at approximately 500 units and 1,500 units respectively throughout the simulation period.Furthermore,by incorporating behavioral parameters(greediness factors),the model effectively captures heterogeneity in fishing propensities.Highgreediness fishermen exhibit aggressive behaviors while low-greediness fishermen adopt more conservative strategies,revealing the impact of individual behavioral differences on system dynamics.These findings validate our proposed MADRL framework's ability to capture the dynamic feedback loops between heterogeneous agents and their environment,as well as emergent non-linear phenomena.By providing an integrated framework for analyzing and understanding these core mechanisms among multiple processes,agents,and activities of HNS,this study lays the foundation for future large-scale numerical experiments that address governance and decision-making challenges across multiple scales.
基金supported by the National Basic Research Program of China(Grant No 2007CB411600)the National Natural Science Foundation of China(Grant Nos 30670272,30770500 and 10761010)+1 种基金the Yunnan Natural Science Foundation(Grant No 2009CD104)the West Light Foundation of the Chinese Academy of Sciences and the National Social Science Foundation of China(Grant No 08XTJ001)
文摘Explaining the"Tragedy of the Commons"of the evolution of cooperation remains one of the greatest problems for both biology and social science.Asymmetrical interaction,which is one of the most important characteristics of cooperative systems,has not been sufficiently considered in the existing models of the evolution of cooperation.Considering the inequality in the number and payoff between the cooperative actors and recipients in cooperation systems,discriminative density-dependent interference competition will occur in limited dispersal systems.Our model and simulation show that the local but not the global stability of a cooperative interaction can be maintained if the utilization of common resource remains unsaturated,which can be achieved by density-dependent restraint or competition among the cooperative actors.More intense density dependent interference competition among the cooperative actors and the ready availability of the common resource,with a higher intrinsic contribution ratio of a cooperative actor to the recipient,will increase the probability of cooperation.The cooperation between the recipient and the cooperative actors can be transformed into conflict and,it oscillates chaotically with variations of the affecting factors under different environmental or ecological conditions.The higher initial relatedness(i.e.similar to kin or reciprocity relatedness),which is equivalent to intrinsic contribution ratio of a cooperative actor to the recipient,can be selected for by penalizing less cooperative or cheating actors but rewarding cooperative individuals in asymmetric systems.The initial relatedness is a pivot but not the aim of evolution of cooperation.This explains well the direct conflict observed in almost all cooperative systems.
