System Dynamics Model for Integrated Environmental Assessment of Large Scale Surface Irrigation

Problems of irrigation systems performance and agricultural environment in large scale surface irrigation is analysed with a dynamic simulation model. Present model is a simplified and validated version of an original model built for the analysis of relevant problems in Southeast Turkey. Model consists of components representing farmlands, land and water development, irrigation and salinization, soil nutrients and pest dynamics. In addition, population dynamics and urban development are integrated. Model components include hypothesis on irrigation authorities’ and farmers’ decisions on irrigation release, water consumption, land transformation, crop selection and fertilizer and pesticide application. Structure and behaviour analysis of the model helps understanding the effects of represented decisions on the irrigation system performance and agricultural environment in the long term at regional level. Model structure can further be explored and custom tailored for educational and managerial use in specific case studies

Local climate change assessment at five pilot sites in the Mediterranean region

The objective of this study is to provide an overview of local climate change over the Mediterranean (MED) area under the scope of the InTheMED project, EU funded in the framework of the PRIMA programme. Future precipitation and temperature projections are assessed until the end of this century for five different pilot sites, located in the MED region. To this end, the outputs of 17 Regional Climate Models under the RCP4.5 and RCP8.5 scenarios are used. For each pilot site, the raw climate model data were downscaled at each monitoring station location and bias-corrected on the basis of observations recorded in a 30-year historical period. The changes in the annual precipitation are heterogeneous across the five pilot sites: a negligible variation is expected for some areas and a decrease of up to 30% for others. On the contrary, a significant increase in temperature is expected for all sites, confirming the ongoing warming in the MED region

A System Dynamics Approach for Hospital Waste Management in a City in a Developing Country: The Case of Nablus, Palestine

Hospitals and health centers provide a variety of healthcare services and normally generate hazardous waste as well as general waste. General waste has a similar nature to that of municipal solid waste and therefore could be disposed of in municipal landfills. However, hazardous waste poses risks to public health, unless it is properly managed. The hospital waste management system encompasses many factors, i.e., number of beds, number of employees, level of service, population, birth rate, fertility rate, and not in my back yard (NIMBY) syndrome. Therefore, this management system requires a comprehensive analysis to determine the role of each factor and its influence on the whole system. In this research, a hospital waste management simulation model is presented based on the system dynamics technique to determine the interaction among these factors in the system using a software package, ithink. This model is used to estimate waste segregation as this is important in the hospital waste management system to minimize risk to public health. Real data has been obtained from a case study of the city of Nablus, Palestine to validate the model. The model exhibits wastes generated from three types of hospitals (private, charitable, and government) by considering the number of both inpatients and outpatients depending on the population of the city under study. The model also offers the facility to compare the total waste generated among these different types of hospitals and anticipate and predict the future generated waste both infectious and non-infectious and the treatment cost incurred

Modelling sustainability performance to achieve absolute reductions in socio-ecological systems

As the world’s natural resources dwindle and critical levels of environmental pollution are approached, sustainability becomes a key issue for governments, organisations and individuals. With the consequences of such an issue in mind, this paper introduces a unifying approach to measure the sustainability performance of socio-economic systems based on the interplay between two key variables: essentiality of consumption and environmental impact. This measure attributes to every system a ‘fitness’ value i.e. a quantity that reflects its ability to remain resilient/healthy by avoiding ecological, social and economic collapse as it consumes the available resources. This new measure is tested on a system where there is a limited supply of resources and four basic consumption types. The analysis has theoretical implications as well as practical importance as it can help countries, organisations or even individuals, in finding better ways to measure sustainability performance

Bringing the Nature Futures Framework to life: creating a set of illustrative narratives of nature futures

To halt further destruction of the biosphere, most people and societies around the globe need to transform their relationships with nature. The internationally agreed vision under the Convention of Biological Diversity—Living in harmony with nature—is that “By 2050, biodiversity is valued, conserved, restored and wisely used, maintaining ecosystem services, sustaining a healthy planet and delivering benefts essential for all people”. In this context, there are a variety of debates between alternative perspectives on how to achieve this vision. Yet, scenarios and models that are able to explore these debates in the context of “living in harmony with nature” have not been widely developed. To address this gap, the Nature Futures Framework has been developed to catalyse the development of new scenarios and models that embrace a plurality of perspectives on desirable futures for nature and people. In this paper, members of the IPBES task force on scenarios and models provide an example of how the Nature Futures Framework can be implemented for the development of illustrative narratives representing a diversity of desirable nature futures: information that can be used to assess and develop scenarios and models whilst acknowledging the underpinning value perspectives on nature. Here, the term illustrative refects the multiple ways in which desired nature futures can be captured by these narratives. In addition, to explore the interdependence between narratives, and therefore their potential to be translated into scenarios and models, the six narratives developed here were assessed around three areas of the transformative change debate, specifcally, (1) land sparing vs. land sharing, (2) Half Earth vs. Whole Earth conservation, and (3) green growth vs. post-growth economic development. The paper concludes with an assessment of how the Nature Futures Framework could be used to assist in developing and articulating transformative pathways towards desirable nature futures

System Dynamics Model for Integrated Environmental Assessment of Large Scale Surface Irrigation

Problems of irrigation systems performance and agricultural environment in large scale surface irrigation is analysed with a dynamic simulation model. Present model is a simplified and validated version of an original model built for the analysis of relevant problems in Southeast Turkey. Model consists of components representing farmlands, land and water development, irrigation and salinization, soil nutrients and pest dynamics. In addition, population dynamics and urban development are integrated. Model components include hypothesis on irrigation authorities’ and farmers’ decisions on irrigation release, water consumption, land transformation, crop selection and fertilizer and pesticide application. Structure and behaviour analysis of the model helps understanding the effects of represented decisions on the irrigation system performance and agricultural environment in the long term at regional level. Model structure can further be explored and custom tailored for educational and managerial use in specific case studies

Misperceptions of Global Climate Change: Information Policies

Global climate change is an atmospheric commons problem where the basic actors arethe states. In democratic nations national policy initiatives depend on the opinion of theelectorate. Unless there is a proper popular perception of climate change, it will bedifficult to undertake appropriate and timely measures. Previous experimental studiesof people’s understanding of climate change and of other renewable resource problemshave revealed that people misperceive the basic dynamics and that they favourdecisions that are systematically biased in the direction of over-utilisation. In thepresent laboratory experiment, with 251 students, the focus is on understanding whypeople misperceive and how misperceptions could be avoided. Using a simulator, thesubjects are asked to control total global emissions of CO2 to reach a given target forthe atmospheric CO2-concentration. Compared to a previous study we find that fullinformation about a simplified system leads to improved performance, particularlyamong students with a background in mathematics. Subjects perform better in ananalogous, however more easily visualisable system, indicating that they havedifficulties forming appropriate mental models of the more abstract atmosphericproblem. Two information treatments, thought to improve mental models, turn out tohave insignificant effects. Finally, information feedback about the development of theCO2-concentration helps. According to our findings, current information from the IPCCand the standard media coverage is not effective in helping people to choose policiesthat are consistent with their own preferences

Dynamic Simulation Model of Common Pool Resource Cooperation Experiments

We investigate the decision rules adopted by individuals in local communities, whoselivelihoods depend on common pool resource stocks and who face the cooperationdilemma in their everyday life. For this purpose, field experiments are modeled and themodel structure and output are confronted with experimental data and with the relevanttheory of collective action proposed by Ostrom (1998). The field experiments analyzethe cooperative action among coastal communities in Providence Island (ColombianCaribbean Sea). The simulation model is built according to the principles and methodsof System Dynamics. The model formalizes the feedback causality among reputation,trust and reciprocity as suggested by Ostrom (1998). Moreover, based on the payoffstructure used in the experiments, it considers other behavioral factors such astemptation to free ride, profit maximization, and awareness of the individuals infeedback perspective. Depending on the initial conditions and parameter values, modelbehavior replicates major patterns of the experimental data. It reveals path dependentcharacteristic to the initial trust of the individuals in the group. The variables anddecision rules built into the model structure provide the basis for a dialogue between thetheories of collective action and future experimental designs to test and improve suchtheories

Model simplification and validation: Illustration with indirect structure validity tests

Simplification of a large system dynamics model and validation of the simplified version is illustrated. The original model represents agricultural and environmental problems of irrigation development in Southeast Turkey and consists of 62 stock variables. Its simplified version with a narrow model boundary and higher level of aggregation is a general representation of its selected dynamics and consists of 11 stock variables only. Analysis of reference behaviours, indirect structure validity tests and scenario runs reveal simplified model as a valid and useful version of the original. Simplification helps distilling essential model structures that cause selected problems and increases the quality and understanding of models. It can also be a step towards building theory-like structures and general representation of case specific problems in various application domains