Climate change researchers are often asked to evaluate potential economic effects of climate stabilization policies. This paper examines what impact modelers' assumptions have on a model's results. Specifically, MIT's Emissions Prediction and Policy Analysis (EPPA) model is examined to understand how uncertainty in input parameters affect economic predictions of long-term climate stabilization policies. Eleven difference categories of parameters were varied in a Monte Carlo simulation to understand their effect on two different climate stabilization policies. The Monte Carlo simulation results show that the structure of stabilization policy regulations has regional welfare effects. Carbon permits allocated by a tax-based emissions path favored energy importers with developed economies (e.g., the US and the EU). Countries with energy-intensive economies (e.g., China) will likely have negative welfare changes because of strict carbon policy constraints. Oil exporters (e.g., the Middle East) will also be negatively impacted because of terms of trade fluxes. These insights have implications for stabilization policy design. The uncertainty surrounding economic projections exposes some countries to larger economic risks. Policies could be designed to share risks by implementing different permit allocation methods. Direct payments are another means to compensate countries disproportionately disadvantaged by a stabilization policy.
Previous system dynamics work models the tipping of a series of product development projects into fire-fighting mode in which rework overwhelms progress. Similar dynamics also threaten the performance of individual development projects. The current work extends previous tipping point dynamics research to single projects and demonstrates how a simple, common feed back structure can cause complex tipping point dynamics, trap projects in deteriorating modes of behavior, and cause projects to fail. Basic tipping point dynamics in single projects are described, analyzed, and demonstrated with the model. Researchers recommend dynamic resource allocation policies to improve project performance threatened by tipping point dynamics. This existing work and the potential robustness of adaptive policies suggest that dynamic resource allocation policies can protect projects tipping point-based failure. But this hypothesis has not been tested for specific policies. We test several strategies for managing projects near tipping points, including dynamic resource allocation. The effectiveness of dynamic resource allocation as protection against project failure are modeled and described. Implications for project management practice and future research opportunities are discussed.
There is a critical need to develop land planning processes that can build the
capacities of local communities to address stewardship and sustainability at both the individual and collective/landscape scales. Social learning has been advocated as a process by which to build the capacity of local communities to address these issues. This paper outlines a social learning process currently being conducted to collectively develop a common mental model (or schema) of local landscape change among private forest landowners of Morgan County, Tennessee. By seeking a shared schema of landscape change landowners will elucidate and engage hidden assumptions that guide their land use decisions. This learning process is expected to increase community capacity by giving landowners a common understanding from which to make and/or support more sustainable land use decisions. The effectiveness of the social learning process is evaluated using individual cognitive mapping in a pre/post test quasi-experimental research design.
The Climate Stewardship Act, a global warming mitigation policy calling for a cap-and-trade program, was reintroduced in the United States Senate this year. The Energy Information Administration analyzed the implications of the bill and found that under such a policy renewable energy will increase, with the strongest response coming from biomass energy. Dedicated energy crops are one source of biomass that is expected to contribute significantly to the future biomass energy supply. This paper describes a system dynamics model of the carbon impacts from a dedicated energy crop. The work relies on another carbon accounting model, GORCAM, which uses spreadsheet modeling to investigate various land management regimes. We were able to reproduce the GORCAM results for a 20-year harvest rotation; we then simulated several different harvesting intervals to gain insight into the carbon impacts of these rotations. Our results show that a shorter harvest rotation will remove more carbon from the atmosphere if the biomass is used to replace a fossil-fuel burning power plant compared with no-harvest or longer harvest scenarios. These results agree with previous work that found long-term benefits were greater for scenarios where trees were planted for energy generation rather than specifically for carbon sequestration.
By 2011 Switzerland aims to liberalise the milk market which will result in market changes in the basic conditions for agriculture. The impacts of the liberalisation are investigated with a composite model obtained by combining an optimisation model for the agricultural sector and a dynamic simulation model for the milk and meat market. The calculations with the composite model indicate that milk price depends strongly on the phasing out of market support, while the abolition of milk quotas in 2009 is less decisive. An introduction of a dairy cow premium leads to a higher milk production, especially with abolished milk quotas. In this case the European milk price level represents the lower limit for the milk price in Switzerland. Compared to the milk market, with falling quantities meat prices are likely to exhibit a stable development.
Abstract: This paper examines the nature and effects of collaboration using a System Dynamics Model. The goal of the model was to place collaboration into a System Dynamics operational construct using stocks and flows in order to examine its workings. Using simple representations of two analysts attempting to learn from a dynamic document set, questions regarding collaboration, skill, learning and the effects of rapidity of change within the document set are examined.
Findings indicate a knowledge-based rationale for collaboration during periods of increased operational tempo. However, there also appear to be knowledge-based reasons not to collaborate under certain conditions. The knowledge-based rationale is mirrored by the behavior of real social systems.
"Modeling Dynamics Systems: Lessons for a First Course" provides a set of tools that enable educators at the secondary and college levels to teach a one-semester or one-year course in System Dynamics. These lessons are also useful for trainers in a business environment. Developed for beginning modelers, the lessons contained in this book can be used for a core curriculum or for independent study. A set of student lessons, a teachers guide with all the answers to the student lessons (and additional comments to the instructor), as well as a CD containing all of the models, is provided with the book. Participants in the workshop will have a chance to build some simple models and gain a sense of the progression leading to a more sophisticated model. Student work will be demonstrated and a CD containing samples of student work and their technical papers will be provided to all participants.
In the UK, drug misuse gives rise to between £10 billion and £18 billion a year in social and economic costs, 99% of which are accounted for by problematic drug users. There are strong links between problematic drug use and crime. The Drug Interventions Programme (DIP) is a critical part of the Governments strategy for tackling drugs. The implementation of the UK Drug Intervention Programme poses a number of challenges. This includes providing a through-life approach to drug user treatment management. This must take place within a multi-agency system some of which have been newly formed. This paper discusses a study working with one such coordinating body Lancashire Drug Action Team (DAT) in its Drug Intervention Programme (DIP) strategy. Initial work has focused on Aftercare Services in the Burnley area. A systems modelling approach using System Dynamics has been adopted.
Water supply is a hydrologic phenomenon, whereas water demand is largely driven by human wants and needs. The combination of these two systems, hydrology and economics, is necessary for accurate modeling of our water resources. Moreover, in times of drought or water scarcity it is the human behavioral component that will determine whether a regions water supply can be sustained. The stakeholders of the San Juan Basin are many and varied, from Indian tribes, agriculture interests, and municipalities, to recreational fisherman, power generators and conservationists. Stakeholders must make policy decisions regarding shortage sharing in times of drought to ensure their water supplies are sustainable. We develop a system dynamics simulation model for the San Juan Basin watershed (located in the states of New Mexico and Colorado). The model can be used to quantify shortage-sharing amounts needed for sustainability of water supplies. Hydrology drives the water supply while economics drives the water demand.
This paper offers insights into the dynamics of carbon emissions in metropolitan regions. These
emerge from a system dynamics model of urban land-atmospheric interactions. The paper provides
contextual background, outlines modeling methodology, inventories insights and documents policy
implications. Section One considers climate change, worldwide urbanization, urban CO2 emissions and
urban land-use/transportation dynamics. Section Two identifies the study area, the modeling tool, its
dynamic organizing principle, its structure and the scenarios used to explore system behavior. Section
Three considers urban CO2 emissions and the mitigating effects of land-use and transportation
policies. It compares these to practicable improvements in fossil fuel combustion efficiencies and finds
that modifying urban form compare favorably to improving combustion efficiencies. Section Four
asserts that, given todays global-scale inter-metropolitan economic competition, todays urban
challenge will be largely met by cooperation at the metro-regional scale to tame the dynamics of
carbon-based metropoli.