Showing papers by "International Institute for Applied Systems Analysis published in 1995"

A New Scenario Decomposition Method for Large-Scale Stochastic Optimization

Abstract: A novel parallel decomposition algorithm is developed for large, multistage stochastic optimization problems. The method decomposes the problem into subproblems that correspond to scenarios. The subproblems are modified by separable quadratic terms to coordinate the scenario solutions. Convergence of the coordination procedure is proven for linear programs. Subproblems are solved using a nonlinear interior point algorithm. The approach adjusts the degree of decomposition to fit the available hardware environment. Initial testing on a distributed network of workstations shows that an optimal number of computers depends upon the work per subproblem and its relation to the communication capacities. The algorithm has promise for solving stochastic programs that lie outside current capabilities.

The carbon sequestration potential of a global afforestation program

Abstract: We analyzed the changes in the carbon cycle that could be achieved with a global, largescale afforestation program that is economically, politically, and technically feasible We estimated that of the areas regarded as suitable for large-scale plantations, only about 345 million ha would actually be available for plantations and agroforestry for the sole purpose of sequestering carbon The maximum annual rate of carbon fixation (148 Gt/yr) would only be achieved 60 years after the establishment of the plantations - 114 Gt by above-ground biomass and 034 Gt by below-ground biomass Over the period from 1995 to 2095, a total of 104 Gt of carbon would be sequestered This is substantially lower than the amount of carbon required to offset current carbon emissions (38 Gt/yr) in order to stabilize the carbon content of the atmosphere

On convergence of an augmented Lagrangian decomposition method for sparse convex optimization

Abstract: A decomposition method for large-scale convex optimization problems with block-angular structure and many linking constraints is analysed. The method is based on a separable approximation of the augmented Lagrangian function. Weak global convergence of the method is proved and speed of convergence analysed. It is shown that convergence properties of the method are heavily dependent on sparsity of the linking constraints. Application to large-scale linear programming and stochastic programming is discussed.

Energy use, emissions, and air pollution reduction strategies in Asia

Abstract: In contrast to Europe and North America, air pollution in Asia is increasing rapidly, resulting in both local air quality problems and higher acidic depositions. In 1989, an east-west group of scientists initiated a multi-institutional research project on Acid Rain and Emissions Reduction in Asia, funded for the past two years by the World Bank and the Asian Development Bank. Phase I, covering 23 countries of Asia, focussed on the development of PC-based software called the Regional Air Pollution INformation and Simulation Model (RAINS-ASIA). A 94-region Regional Energy Scenario Generator was developed to create alternative energy/emission scenarios through the year 2020. A long-range atmospheric transport model was developed to calculate dispersion and deposition of sulfur, based upon emissions from area and large point sources, on a one-degree grid of Asia. The resulting impacts of acidic deposition on a variety of vegetation types were analyzed using the critical loads approach to test different emissions management strategies, including both energy conservation measures and sulfur abatement technologies.

Derivatives of probability functions and some applications

Abstract: Probability functions depending upon parameters are represented as integrals over sets given by inequalities. New derivative formulas for the intergrals over a volume are considered. Derivatives are presented as sums of integrals over a volume and over a surface. Two examples are discussed: probability functions with linear constraints (random right-hand sides), and a dynamical shut-down problem with sensors.

Keeping the climate treaty relevant

Abstract: Conventional wisdom holds that the proper next step for an effective climate treaty is to negotiate binding targets and timetables for greenhouse gases. But this is not the best approach.

Integrated assessment of emission control scenarios, including the impact of tropospheric ozone

Abstract: The RAINS (Regional Air Pollution INformation and Simulation) model was developed at IIASA as an integrated assessment tool to assist policy advisors in evaluating options for reducing acid rain. In recent years, the European implementation of this model has been used to support the negotiations on an updated, effect-based Sulphur Protocol under the Convention on Long-range Transboundary Air Pollution. The development of future strategies for reducing the environmental damage caused by air pollutants requires a multi-pollutant, multi-effect approach. In this context, the RAINS model is being further developed to include ozone. This paper outlines the development of an integrated assessment model for tropospheric ozone, which combines information on the emissions of ozone precursors (NOx and VOCs), the available control technologies and abatement costs, the formation and transport of ozone and its environmental effects in Europe.

A system for evaluation of growth and mortality in Russian forests

Abstract: A modelling system (MS) for evaluation of current increment (net and gross growth) and mortality in Russian forests is presented. The informational basis of the MS are the data of the Russian forest state account (growing stock by dominant species, age, site indices, stocking) and some additional indicators (types of age structure, average species composition, type and intensity of disturbance regimes by ecoregions and/or landscapes. The MS includes model blocks generated with available information including yield tables (general, regional, full-stocked, with different stocking and types of age structure), growth tables, models, and experimental data for managed and unmanaged, disturbed and undisturbed forests. Two-dimensional (by age and site index) and three-dimensional (age, site index and stocking) models by species and ecoregions, based on regularities of coefficients of Mitscherlich growing functions, were used as the nuclei of the MS. The preliminary results, received for several Russian forest forming species gave a good fit to experimental data.

Decision support systems for dangerous goods transportation

Abstract: This paper presents three information and decision support systems which can be used to improve the availability and access to relevant data and information regarding the risk assessment associated with hazardous materials. These systems offer quick and effective generation, display, analysis, evaluation and comparison of different alternatives. These alternatives involve technological environmental, socio-economic and political elements which are in a usable form of risk analysis.

Soil sensitivity due to acid and heavy metal deposition in East Central Europe

Abstract: Simultaneous soil acidification and deposition of heavy metals is a major concern for forest and agricultural soils of the Black Triangle region of East Central Europe including southern former East Germany, northern Bohemia of the Czech Republic, and southern Poland. The objective of this project was to develop historical and future projections of acid and heavy metal deposition to soils (As, Cd, Pb, Zn) and to produce a preliminary map of soil sensitivity to cadmium pollution and uptake by crops. Ultimately, we wish to assess the relative hazard and recovery times of soils to metals deposition in the region. Emission and deposition data bases obtained from several models developed at IIASA were linked using the Geographical Information System ARC/INFO to produce soil maps of sensitivity to cadmium mobility based on metals deposition, soil type, soil texture, organic matter content, and acid deposition. RAINS 6.1 (Alcamo et al., 1990) was utilized to produce maps of acid deposition for EMEP grids (150 km x 150 km). The largest amount of acid load is deposited in southern East Germany. Sulfur deposition in that area was 10–12 gS/m2/yr in 1990, and S+N deposition exceeded 8000 eq/ha/yr. But the “hot spot” for metals deposition is further to the east, in the Silesia area of southern Poland. The TRACE2 trajectory model of Alcamo, Bartnicki, and Olendrzynski (1992) was used to estimate cumulative metals deposition since 1955 with scenarios to 2010. Pb has improved over Europe since 1970 when depositions in the Ruhr River Valley of West Germany exceeded 60 mg/m2/yr. But cadmium deposition in southern Poland (Katowice and Krakow) has now accumulated to 60–70 mg/m2 by atmospheric deposition alone. During base case simulations from 1955–87, approximately 1.8 mg/kg Pb and 0.12 mg/kg Cd have been added to the mixed plow-layer of ∼30 cm. If these emissions continue indefinitely, the accumulation of metals will become problematic for agriculture and the food chain.

The Russian Forest Sector: Production, Consumption, and Export Prospects

Abstract: The forest sector of Russia is described at the country level of detail, including a description of the growth of the forest resource over time and of the historical utilization of the forest resource, with a focus on the shares of output allocated for domestic consumption and for export. The resource available for the future then is presented in terms of economic accessibility. Longer-term export opportunities are identified using a scenario analysis generated by the Russian Forest Sector Assessment Model. 14 figures, 12 references.

Valuation of global afforestation programs for carbon mitigation

Abstract: Discussions of global afforestation programs, like most proposals for adaptation to or mitigation of climate change, are routinely subjected to cost-benefit analyses. The results are usually controversial. Supporters of traditional cost-benefit valuations say that they area proven method of guarding against inevitable changes over time in our perception of value (e. g. Dixon et al., 1991). Critics suggest that such analyse s are meaningless in the long time frame of climate change; that conventional costbenefit analyses may in fact obscure important aspects of the climate change debate and confuse policy makers and other nonspecialists (e.g., Miller, 1991; Broome, 1992). The purpose of this editorial is to briefly review some aspects of the debate about the application of traditional cost-benefit analysis to long-term environmental problems, especially defective cost and benefit data, the use of discount rates and the requirement for marginal cost-benefit analysis, and to demonstrate how these concepts apply to a study of global afforestation described in Nilsson and Schopfhauser (1995) in this issue of Climatic Change. The point is that good economists, each starting from a solid theoretical foundation, can propose costbenefit procedures that yield valuations differing by more than an order of magnitude. Given this range, one can ask whether the discipline is advanced enough to make any meaningful statements about costs and benefits related to long-term environmental problems. Generally accepted concepts of the use and value of forestry plantations have changed greatly in the past 40 years. For many years they were seen as vital tools for production ofraw materials for industrialization (Westoby, 1962) and a strong link forward and backward to general economic development (Hirschman, 1958). For a long time development agencies accepted these ideas (see for example World Bank 1978). Today the global forestry agenda is dominated by issues and values outside the market. Hyde et al., (1991) point out that the current discussion concentrates on five topics (Table I). Any attempt to assign an economic value to proposals for afforestation must consider a mixture of global public values, local values, and characteristics specific to each proposed site. Hyde et al. (1991) underline that one of the crucial issues is the importance of market failure (recreation, water supply, erosion, etc.) in the provision of the forest services. Many studies have discussed the possibility of using a global afforestation program to slow the buildup of atmospheric carbon dioxide (e.g. Andrasko, 1990;

On the Regularized Decomposition Method for Stochastic Programming Problems

Abstract: Application of the regularized decomposition method to large scale structured linear programming problems arising in stochastic programming is discussed. The method uses a quadratic regularizing term to stabilize the master but is still finitely convergent. Its practical performance is illustrated with numerical results for large real world problems.

On writing good histories of climate change and testing social science theories - An Editorial Comment

Abstract: 1995 marks the first meeting of the Conference of Parties (COP) of the Framework Convention on Climate Change (FCCC). Fears of global warming drove negotiation of the Convention, which was signed in 1992 and rapidly entered-into-force two years later.* The Convention could be a durable feature of international politics there are reasons to be concerned about global warming, and it is a long-term problem that requires long-term policy responses. In 2010 or 2030 the CoP could still be meeting regularly and managing a complex web of international protocols and policies. The last few formative years of the Convention could have lasting effects, just as the early days of the GATT in the 1940s still affect the style and implementation of international trade policy five decades later. In this issue of Climatic Change, Alan Hecht and Dennis Tirpak (1995) provide a history of US policy-making on international climate policy. The United States has played an active role throughout the international negotiations. Throughout the modern history of climate modeling and climate-related science, the US has had the largest research program, and US scientists have been active in scientific assessments of the risks of global warming. Today the relative power of the US is less hegemonic than a few decades ago, and it is conceivable that the rest of the world could make international climate policy without the US, but the US is the largest emitter of greenhouse gases and it remains the most powerful country in world affairs. What happens in the US matters. Hecht and Tirpak show that the science of global warming has a long history that spans several disciplines.** Climate modelling, the central component of that history, has its origins in the 1950s from a combination of scientific curiosity and fears of inadvertent climate modification by the Soviet Union. The policy history of global warming spans 5 presidents. In general, climate-relevant policy has been

Trade-offs in sulfur emission trading in Europe

Abstract: How to implement emission trading is one question in the current negotiations on a new sulfur protocol in Europe. Whereas the current protocol stipulates a 30 percent uniform reduction, national emission ceilings included in the proposed new protocol imply differentiated reductions. In addition, emission and fuel standards are proposed. This paper examines the costs and environmental impacts of emission trading. Emission trading combined with regulations is a new element in the paper. Calculations using the RAINS (Regional Acidification INformation and Simulation) model suggest that overlaying emission trading on regulations not only reduces the cost savings but has beneficial impacts as well: ecosystem protection is not changed and significant decreases in environmental benefits for countries are largely avoided. Emission trading can also be used to decrease emissions and increase ecosystem protection. If combined with existing legislation, emission trading minimizes losses in expected environmental benefits for some countries, and most countries gain. However, the initial distribution of emission ceilings has to be used so that some countries are not confronted with higher costs. Trade-offs appear to exist between the use of emission trading to achieve cost savings on the one hand, and ecosystem protection and distributional equity on the other.

On the Glivenko-Cantelli Problem in Stochastic Programming: Linear Recourse

Abstract: Integrals of optimal values of random linear programming problems depending on a finite dimensional parameter are approximated by using empirical distributions instead of the original measure. Uniform convergence of the approximations is proved under fairly broad conditions allowing non-convex or discontinuous dependence on the parameter value and random size of the linear programming problem.

Marine systems analysis and modeling

Abstract: Oceanography and marine ecology have a considerable history in the use of computers for modeling both physical and ecological processes. With increasing stress on the marine environment due to human activities such as fisheries and numerous forms of pollution, the analysis of marine problems must increasingly and jointly consider physical, ecological and socio-economic aspects in a broader systems framework that transcends more traditional disciplinary boundaries. This often introduces difficult-to-quantify, “soft” elements, such as values and perceptions, into formal analysis. Thus, the problem domain combines a solid foundation in the physical sciences, with strong elements of ecological, socio-economic and political considerations. At the same time, the domain is also characterized by both a very large volume of some data, and an extremely datapoor situation for other variables, as well as a very high degree of uncertainty, partly due to the temporal and spatial heterogeneity of the marine environment. Consequently, marine systems analysis and management require tools that can integrate these diverse aspects into efficient information systems that can support research as well as planning and also policy- and decisionmaking processes. Supporting scientific research, as well as decision-making processes and the diverse groups and actors involved, requires better access and direct understanding of the information basis as well as easy-to-use, but powerful tools for analysis. Advanced information technology provides the tools to design and implement smart software where, in a broad sense, the emphasis is on the man-machine interface. Symbolic and analogous, graphical interaction, visual representation of problems, integrated data sources, and built-in domain knowledge can effectively support users of complex and complicated software systems. Integration, interaction, visualization and intelligence are key concepts that are discussed in detail, using an operational software example of a coastal water quality model. The model comprises components of a geographical information and mapping system, data bases, dynamic simulation models, and an integrated expert system. An interactive graphical user interface, dynamic visualization of model results, and a hyper-text-based help-and-explain system illustrate some of the features of new and powerful software tools for marine systems analysis and modeling.

Overland Transportation Networks: History of Development and Future Prospects

Abstract: The basic technologies for overland transportation are symbolized by their infrastructures: canals, railways, roads, and airways. They integrate spatially distinct locations into mutually interrelated entities and are structured as networks. Nodes are different locations with interaction potential, such as urban and industrial centers. Links are individual transport infrastructures such as canals, railways, and roads and the related modes e.g., ships, trains, and automobiles. In time, they gradually replace one another; old system are substituted by the new ones. Each individual infrastructure evolves according to a particular scheme, the so-called technology “life cycle.” It starts with an early development phase marked with a high degree of experimentation, develops through a phase of growth characterized by standardization and pervasive diffusion, and eventually enters the last phase of saturation where the technical and economic potentials and thus, further growth prospects are exhausted. This leads to a structural change and transition to the next generation of transport systems.