Category Climate Change

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Modelling Global Change: The Art of Integrated Assessment Modelling

Janssen, M.A. 1998
Edward Elgar Publishers, Cheltenham UK/ Northampton, MA, USA.

Meeting Targets: Tools to Support Integrated Assessment Modelling of Global Change

Janssen, M.A. 1996
PhD Dissertation, University Maastricht ISBN 90-9009908-5

Journal Articles

On our rapidly shrinking capacity to comply with the planetary boundaries on climate change

Mathias, J-D., J.M. Anderies and M.A. Janssen

2017 Scientific Reports 7: 42061.


The planetary boundary framework constitutes an opportunity for decision makers to define climate policy through the lens of adaptive governance. Here, we use the DICE model to analyze the set of adaptive climate policies that comply with the two planetary boundaries related to climate change: (1) staying below a CO2 concentration of 550 ppm until 2100 and (2) returning to 350 ppm in 2100. Our results enable decision makers to assess the following milestones: (1) a minimum of 33% reduction of CO2 emissions by 2055 in order to stay below 550 ppm by 2100 (this milestone goes up to 46% in the case of delayed policies); and (2) carbon neutrality and the effective implementation of innovative geoengineering technologies (10% negative emissions) before 2060 in order to return to 350 ppm in 2100, under the assumption of getting out of the baseline scenario without delay. Finally, we emphasize the need to use adaptive path-based approach instead of single point target for climate policy design.


Urban resilience efforts must consider social and political forces

Eakin, H., L. Bojórquez-Tapia, M.A. Janssen, M. Georgescu, D. Manuel-Navarrete, E.R. Vivoni, E.R., A.E. Escalante, A. Baeza-Castro, M. Mazari-Hiriart and A.M. Lerner

2017 Proceedings of the National Academy of Sciences USA 114(2): 186-189.

Food security in the face of climate change: Adaptive capacity of small-scale social-ecological systems to environmental variability

Perez, I., M.A. Janssen and J.M. Anderies

2016 Global Environmental Change 40: 82-91.


Improving the adaptive capacity of small-scale irrigation systems to the impacts of climate change is crucial for food security in Asia. This study analyzes the capacity of small-scale irrigation systems dependent on the Asian monsoon to adapt to variability in river discharge caused by climate change. Our study is motivated by the Pumpa irrigation system, a small-scale irrigation system located in Nepal that is a model for this type of system. We developed an agent-based model in which we simulated the decisions farmers make about the irrigation strategy to use according to available water flow. Given the uncertainty associated with how climate change may affect the Asian monsoon, we simulated the performance of the system under different projections of climate change in the region (increase and decrease in rainfall, reduction and expansion of the monsoon season, and changes in the timing of the onset of the monsoon). Accordingly to our simulations, farmers might need to adapt to rainfall intensification and a late onset in the monsoon season. The demands for collective action among farmers (e.g. infrastructure repair, meetings, decisions, etc.) might increase considerably due to climate change. Although our model suggests that investment in new infrastructure might increase the performance of the system under some climate change scenarios, the high inequality among farmers when water availability is reduced might hinder the efficiency of these measures due to a reduction of farmers’ willingness to cooperate. Our modeling exercise helps to hypothesize about the most sensitive climate change scenarios for smallscale irrigation farming in Nepal and helps to frame a discussion of some possible solutions and fundamental trade-offs in the process of adaptation to improve for food and water security under climate change.

Keywords: Adaptation; Agent-based model; Climate change; Common-pool resources; Irrigation systems; Resilience


Sequential optimization of integrated climate change models

Janssen, M.A.

2001 Mathematics and Computers in Simulation 54(6): 477-489.


A sequential optimization approach is applied to optimize the behavior of a complex dynamical system. It sequentially solves a large set of mathematical equations and next optimizes the behavior of a reduced-system, fixing certain variables of the larger original problem. These two steps are repeated till convergence occurs. The approach is applied to the problem of identifying response strategies for climate change caused by antropogenic emissions of different trace gases. The convergence properties are analyzed for this example.

Keywords: Sequential optimization; Sequential reduced-system programming; Dynamical system.


Greenhouse gas emissions in an equity-, environment- and service-oriented world: an IMAGE-based scenario for the 21st century

Vries, B. de, J. Bollen, L. Bouwman, M. den Elzen, M. Janssen, E. Kreileman and R. Leemans

2000 Technological Forecasting and Social Change 62 (2/3):137-174.


This article describes a greenhouse gas (GHG) emissions scenario for a world that chooses collectively and effectively to pursue service-oriented economic prosperity while taking into account equity and environmental concerns, but without policies directed at mitigating climate change. After peaking around 2050 at 2.2 times the 1990 level of primary energy use, a number of factors lead to a primary energy use rate at the end of the next century that is only 40% higher than the 1990 rate. Among these factors are a stabilizing (and after 2050, declining) population, convergence in economic productivity, dematerialization and technology transfer, and high-tech innovations in energy use and supply. Land use-related emissions show a similar trend. Total CO2 emissions peak at 12.8 CtC/yr around 2040, after which they start falling off. Other GHG emissions show a similar trend. The resulting CO2-equivalent concentration continues to rise to about 600 ppmv in 2100. Present understanding of climate change impacts suggest that even in this world of high-tech innovations in resource use in combination with effective global governance and concern about equity and environment issues, climate policy is needed if mankind is to avoid dangerous interference with the climate system.


Climate change policy targets and the role of technological change

Janssen, M.A. and H.J.M. de Vries

2000 Climatic Change 46 (1/2): 1-28.


In this paper, we present results of simulationexperiments with the TIME-model on the issue ofmitigation strategies with regard to greenhouse gases.The TIME-model is an integrated system dynamics worldenergy model that takes into account the fact that the systemhas an inbuilt inertia and endogenouslearning-by-doing dynamics, besides the more commonelements of price-induced demand response and fuelsubstitution. First, we present four scenarios tohighlight the importance of assumptions on innovationsin energy technology in assessing the extent to whichCO2 emissions have to be reduced. The inertia ofthe energy system seems to make a rise ofCO2 emissions in the short term almostunavoidable. It is concluded that for the populationand economic growth assumptions of the IPCC IS92ascenario, only a combination of supply- anddemand-side oriented technological innovations incombination with policy measures can bring the targetof CO2-concentration stabilization at 550 ppmv bythe year 2100 within reach. This will probably beassociated with a temporary increase in the overallenergy expenditures in the world economy. Postponingthe policy measures will be more disadvantageous,and less innovation in energy technology will happen.


Perspectives on global energy futures: simulations with the TIME model

Vries, H.J.M. de, M.A. Janssen and A. Beusen

1999 Energy Policy 27(8): 477-494.


Many uncertainties and controversies surround the future of the global energy system. The Targets Image Energy (TIME) model of which a concise description is given, is used to explore the consequences of divergent assumptions about some uncertain and controversial issues. The IPCC-IS92a Conventional Wisdom scenario is used as a reference and, in combination with two other scenarios, discussed in the context of other recently published global energy scenarios.

Keywords: Global energy scenarios; Energy modelling; Climate change.


Use of complex adaptive systems for modeling global change

Janssen, M.A.

1998 Ecosystems 1(5): 457-463.


Global modeling has been used for decades to assess the possible futures of humanity and the global environment. However, these models do not always satisfactorily include the adaptive characteristics of systems. In this article, a general approach is used to simulate change and transition at a macrolevel due to adaptation at a microlevel. Tools from complex adaptive systems research are used to simulate the microlevel and consequently determine parameter values of the equation-based macrolevel model. Two case studies that applied this approach are reviewed. The first study assessed the efficacy of efforts to control malaria, whereas the second study used an integrated model to construct climate change scenarios by using various possible views on the nature of the climate system.

Key words: complex adaptive systems; global change; climate change; malaria; multiagent modeling; adaptation; coevolution; genetic algorithms.


The battle of perspectives: a multi-agent model with adaptive responses to climate change

Janssen, M.A. and H.J.M. de Vries

1998 Ecological Economics 26(1): 43-65.


To evaluate possible futures with regard to economy, energy and climate, a multi-agent modelling approach is used. Agents hold different perspectives on how the world functions (worldview) and how it should be managed (management style) and this is implemented in a simple dynamic model of the economy-energy-climate system. Each perspective is supported by a proportion of the agents, but this proportion changes in response to observations about the real world. In this way the totality of agents learn from their observations. It is concluded that this approach is a good illustration of how adaptive behavior can be included in global change modelling. Some exploratory experiments are done to address the consequences of surprises.

Keywords: Global change; Integrated assessment modeling; Perspectives; Multi-agent modeling.


The Interactive Scenario Scanner (ISS): A Tool to Support the Dialogue between Science and Policy on Scenario Analysis

Berk, M and M.A. Janssen

1998 Change  42: 11-13.


Workers at the Dutch National Institute of Public Health and the Environment (RIVM) have recently developed a new comput­ er tool called the Interactive Scenario Scanner (ISS). The tool enables users to interactively construct global greenhouse gas emission scenarios and evaluate their likely climate change impacts. In this way, the tool can be used to support a dialogue between scientists and policy makers on scenario development and help in selecting scenarios to be analysed with more sophisticated modelling tools, like RIVM’s IMAGE 2 model.


Uncertainty, Climate Change and Adaptive Management

Peterson, G., G.A. De Leo, J. Hellmann, M.A. Janssen, A. Kinzig, J.R. Malcolm, K. O'Brien, S.E. Pope, D. Rothman, E. Shevliakova, and R. Tinch

1997 Conservation Ecology 1(2):4.

Modeling malaria as a complex adaptive system

Janssen, M.A. and W.J.M. Martens

1997 Artificial Life  3(3): 213-237.


As the resistance of the malaria parasite to antimalarial drugs continues to increase, as does that of the malarial mosquito to insecticides, the efficacy of efforts to control malaria in many tropical countries is diminishing. This trend, together with the projected consequences of climate change, may prove to exacerbate substantially the significance of malaria in the coming decades.

In this article we introduce the use of an evolutionary modeling approach to simulate the adaptation of mosquitoes and parasites to the available pesticides and drugs. By coupling genetic algorithms with a dynamic malaria-epidemiological model, we derive a complex adaptive system capable of simulating adapting and evolving processes within both the mosquito and the parasite populations.

This approach is used to analyze malaria management strategies appropriate to regions of higher and lower degrees of endemicity. The results suggest that adequate use of insecticides and drugs may reduce the occurrence of malaria in regions of low endemicity, although increased efforts would be necessary in the event of a climate change. However, our model indicates that in regions of high endemicity the use of insecticides and drugs may lead to an increase in incidence due to enhanced resistance development. Projected climate change, on the other hand, may lead to a limited reduction of the occurrence of malaria due to the presence of a higher percentage of immune persons in the older age class.


Optimization of a non-linear dynamical system for global climate change

Janssen, M.A.

1997 European Journal of Operations Research 99(2): 322-335.


We regard the global climate system as a controlled dynamic system, with controls corresponding to economic activities causing emissions of greenhouse gases. Previous optimization studies for climate change have used descriptions of the environmental system which are found to be too unrepresentative of what is known in the scientific community. In this paper an approach is applied which tries to include a more sophisticated model of the environmental system. The resulting continuous dynamic control problem is solved by the application of a set of non-linear optimization techniques to find optimal response strategies to maximize the discounted sum of future consumption while adhering to certain environmental constraints.

Keywords: Non-linear optimization; CO2; Climate change.


Climate change: optimization of response strategies

Janssen, M.A., J. Rotmans, and O.J. Vrieze

1995 International Transactions in Operational Research 2(1): 1-15.


The development of climate change response strategies is expected to remain an important issue in the next few decades. The use of optimization techniques might serve as a helpful guide in this process. Although, in recent years, a number of studies have focused on optimization techniques, the optimization models do not fully employ the dynamics of climatic and economic systems. In this paper a heuristic is introduced that combines an integrated simulation model and an optimization technique (local search). This approach may be considered as a first step towards a more comprehensive and systematic analysis of climate change response strategies in a dynamic setting described by a simulation model. Results of a number of experiments in which the heuristic is applied to the integrated global assessment model TARGETS are discussed.


Allocation of fossil CO2 emission rights quantifying cultural perspectives

Janssen, M.A., and J. Rotmans

1995 Ecological Economics 13(1): 65-79.


Cultural perspectives play an important role in framing international climate policy. The concept we have introduced is designed to enable quantification of the influence of such cultural perspectives on the allocation of fossil CO2 emission rights. A model is presented which allocates future emission rights to world regions. An emission budget which incorporates an historical component is defined for the specific period which is required if climate change policy targets are to be met. Allocation of the budget to regions is based on a weighted mix of indicators such as population size, GNP and energy consumption. Subtracting historical emissions results in future regional emission rights. Uncertainties in the selection of parameter values for the model and in generating scenarios of future developments are here regarded as being related to cultural perspectives. We have assumed that cultural perspectives can be quantified by reference to distributions of preferred parameter values and preferred future scenarios. Distributions of regional emission rights biased towards preferred allocations as determined by the perspectives can thus be described. In fact, the proposed approach envisages an uncertainty analysis based on the characteristics of cultural perspectives.

Keywords: Climate change; CO2; Cultural perspectives; Allocation of emission rights.


Allocating the remaining global carbon budget based on international and intergenerational equity throughout a sustainable world

Elzen, M.G.J. den, M.A. Janssen, J. Rotmans, R.J. Swart and H.J.M. de Vries

1992 International Journal of Global Energy Issues 4(4): 287-301.


The feasibility of an effective international response to anticipated climate change is dependent on the recognition of the present and historical inequities between developing and industrialized countries. Developing countries should be enabled and supported to continue their development towards higher standards of living in a fashion that is consistent with the sustainability of the global biosphere. This paper evaluates long-term climate strategies by which the burden of mitigating climate change by controlling CO2 emissions is shared equitably. Here we use as a possible criterion of equity, that every human being, past or future, is allowed to emit the same carbon quotum on an annual basis, which, as a theoretical concept, could provide for intergenerational and international equity throughout the world. In order to do this we first define the global carbon budget as the cumulated CO2 emissions over the period 1800 till 2100, from 1990 described by an emission scenario. This budget determines the permitted CO2 emissions per capita using past and future population estimates. Next, we introduce the concept of ’emission debt’, defined by the difference between the cumulated allowed CO2 emissions, based on the permitted emission quota per capita, and the actual historical CO2 emissions. Finally the remaining carbon budget, described as the global carbon budget (1800-2100) minus the actual cumulated CO2 emissions (1800-1990) is allocated to the different world regions, taking into account the regional past CO2 emissions. This gives the future emission quota per capita. The results show that past industrialisation has coincided with a large relative contribution of the rich regions to the rise in CO2 concentration, an estimated 40 per cent for the European Community and North America, which have built up an emission debt of 36 GtC and 75 GtC, respectively, using recent World Bank projections of population growth. The developing countries, however, have built up an emission credit of 24 GtC. These regional emisson debts and credits increase the future per capita budget for the developing regions till 0.2-0.8 ton C/cap yearly, whereas North America and the EC end up with a negative future carbon budget of 0.4 to 1.5 ton C/cap yearly. Even if the IPCC Business-as-Usual scenario is considered as reference, the future emission quota of most industrialized countries are lower than their present per capita emissions, i.e, North America has a negative future carbon budget of 0.3 tC/cap yearly.

Keywords: future emissions allocation; carbon dioxide; CO2; carbon emissions; emission debt; global carbon budget; global warming; Integrated Model to Assess the Greenhouse Effect; IMAGE; sustainable climate strategies; sustainable temperature targets; sustainability; sustainable development.


Book Chapters

Impact of Diverse Behavioral Theories on Environmental Management: Explorations with Daisyworld

Janssen, M.A.

2016 In Proceedings of the 2016 Winter Simulation Conference , edited by T.M.K. Roeder, P.I. Frazier, R. Szechtman, E. Zhou, T. Huschka, and S.E. Chick, 1690-1701, IEEE.


Our understanding of human behavior is limited and consequently lacks a standard formal model of human behavior that could represent relevant behavior in social-ecological systems. In this paper we explore the consequences of alternative behavioral models using a simple dynamic system of agents of harvesting daisies in the well-known Daisyworld model. We explore the consequences of different behavioral assumptions and derive optimal tax policies that lead to sustainable outcomes for each of the theories.


A future of surprises

Janssen, M.A.

2002 In Panarchy: Understanding Transformations in Human and Natural Systems, edited by L. Gunderson and C.S. Holling, pp. 241-260, Island Press.

Modeling human dimensions of global environmental change

Janssen, M.A.

2002 In Encyclopedia of Global Environmental Change, edited by T. Munn, Vol. 5: Social and economic dimensions of global environmental change, by P. Timmerman (ed.), pp. 394-408, John Wiley and Sons Ltd, London, UK.

An evolutionary integrated modelling approach: a case study for climate change

Janssen, M.A.

1999 In Complex Problem Solving: Methodological Support for Societal Policy Making, edited by D.J. DeTombe & E.A. Stuhler, pp. 130-139,  Rainer Hampp Verlag, Munchen u. Mering.


Addressing global change demands an integrative consideration of interactions between humans and the environment on a world wide scale. An assimilative integrated system approach seems to be appropriate for investigation of this complex global problem. In this paper an integrated modeling approach is proposed that is based on an evolutionary view on global change. A case study is worked out where images of the future using a multi-agent model are assessed, and where agents differ in their world view and thus also in their preferred management style. The perspective of agents may change due to new information they derive from the system. A simple model is constructed to illustrate the consequences of this approach on climate change scenarios.


Global modelling: managing uncertainty, complexity and incomplete information

Janssen, M.A. and H.J.M. de Vries

1999 In Validation of Simulation Models, edited by  Cor van Dijkum, Dorien DeTombe and Etzel van Kuijk, pp. 45-69, Amsterdam: SISWO.


Human activities change the environment on a global level. Global modelling is used to derive insights in the interactions between humans and their environment. However, the possibility to validate those global models is limited. In fact, too little information is available, many subjective assumptions are made and a single model cannot cover all relevant scale levels and processes. These limitations already appeared in the early seventies. Current global modelling activities still deal with the same dilemma’s, often in the same way as the strongly criticised world models of the early seventies. We sketch some recent developments which can help to manage the persistent dilemma’s. We focus on the use of different modelling paradigms and on the use of different world views to analyse the consequences of subjective assumptions to be made in global models.

Keywords: global modelling, validation, complexity, uncertainty.


The safe landing approach: risks and trade-offs in climate change

Swart, R, M.M. Berk, M.A. Janssen, G.J.J. Kreileman and R. Leemans

1998 In Global Change Scenarios of the 21th century - results from the IMAGE 2.1 model, edited by J. Alcamo, R. Leemans and G.J.J. Kreileman, pp. 193-218, Elsevier Science, London.


The safe landing analysis has been devel­ oped to link short-term greenhouse gas emission targets to longer-term climate protection goals. The analysis was applied to the climate policy goals proposed by the European Union. This application and sev­eral presentations of the analysis during the negotiations on the Kyoto Protocol led to critical but constructive discussions. In this paper we discuss some of the key questions such as policy relevance, scien­tific credibility, use and adequacy of global indicators todetermine impact levels, tech­nological feasibility and economic aspects. The results from the safe landing analysis were generally accepted by the policy community because it bridges the gap between policy needs and the under­standing derived from complex but scienti­fically rigorous integrated assessment models.The selected indicators of the safe landing analysis are evaluated. It is shown that the indicators describing rates of change are as important for defining impacts and response policies as those describing only cumulative or absolute change. Lower levels of climatic change generally coincide with lower impact levels. However, only the lowest rates and levels of climate change allow natural eco­systems to adapt. It is further shown that the level of additional energy expenditures needed to meet such low impact levels strongly depends on the assumed techno­logical development rates.


An application of optimization to the problem of climate change

Filar, J.A., P.S. Gaertner and M.A. Janssen

1996 In State of the Art in Global Optimization: Computational Methods and Applications, edited by C.A. Floudas and P.M. Pardalos, pp. 475-498, Kluwer Academic Publishers, Dordrecht/Boston/London.


The objective of this paper is to demonstrate a methodology whereby reductions of greenhouse gas emissions can be allocated on a regional level with minimal deviation from the “business as usual emission scenario”. The methodology developed employs a two stage optimization process utilizing techniques of mathematical programming. The stage one process solves a world emission reduction problem producing an optimal emission reduction strategy for the world by maximizing an economic utility function. Stage two addresses a regional emission reduction allocation problem via the solution of an auxiliary optimization problem minimizing disruption from the above business as usual emission strategies. Our analysis demonstrates that optimal CO2 emission reduction strategies are very sensitive to the targets placed on CO2 concentrations, in every region of the world. It is hoped that the optimization analysis will help decision-makers narrow their debate to realistic environmental targets.



The IMAGE User Support System: Global Scenarios from IMAGE 2.1

Leemans, R. E. Kreileman, G. Zuidema, J. Alcamo, M. Berk, G.J. van den Born, M. den Elzen, R. Hootsmans, M. Janssen, M. Schaeffer, S. Toet and B. de Vries
1998 RIVM Publication 4615006, Bilthoven, the Netherlands, (CD-ROM).

The Interactive Scenario Scanner: a Tool to Support the Dialogue between Science and Policy on Scenario Development

Berk, M.M. and M.A. Janssen
1997 RIVM Report No. 481508005, Bilthoven, the Netherlands.


In order to explore long-term policy options for controlling climate change, there is a need to develop and evaluate long-term emission scenarios. If these scenarios are to be policy relevant, they should, account for differences between world regions with respect to their contribution to the problem, their stage of economic development, their vulnerability to climate change and their ability to control emissions. The scenarios should also deal with the question of fair distribution of future emission budgets. Therefore it is important to involve policy makers in the development of these scenarios. On the basis of requests and comments from policy makers participating in the Delft Science Policy Dialogue workshops, a new software tool, called the Interactive Scenario Scanner (ISS), has been constructed at RIVM. ISS is a computer model that assists in the interactive construction and evaluation of long- term emission scenarios using the parameters of the Kaya Identity to define scenarios and the climate indicators of the Safe Landing Approach to scan their likely consequences for global climate change and its impacts. This tool can be used to construct proto-scenarios, which can then be further elaborated and analysed with such sophisticated energy and climate change models as IMAGE 2. Recent experiences with the application of ISS indicate that it indeed can be a useful tool to involve policy makers in the development of emission scenarios. Moreover, ISS has also been shown useful in educating policy makers on the complexity of the problem and enhancing communication between, and among, scientists and policy makers.

Keywords: Science/Policy Dialogue, Climate Change, Integrated Assessment Models, Scenario Development


`Global Energy Futures: An integrated perspective with the TIME-model’

Vries de, H.J.M. and M.A. Janssen
1996 GLOBO Report Series no. 18, RIVM, Bilthoven, the Netherlands.


This report contains an integrated analysis of the Targets/IMage Energy (TIME) model. In a previous report (De Vries and Van den Wijngaart, 1995) the five submodels of the energy model were described in detail. Here, we describe a number of applications with the (stand-alone) TIME model.

After the introduction and a brief outline of the TIME framework in Chapter 2, Chapter 3 describes the calibration of the world version for the period 1900-1990. Given the exogenous drivers like population size and economic activities, the energy demand, fuel mix, fuel prices, energy investments- and C02 emissions are calculated and compared with observed values. We discuss what assumptions had to be made to derive a suitable fit with the observed values.

Chapter 4 present the methodology for scenario construction. Furthermore, we discuss uncertainties

and assumptions on structural change, energy efficiency improvements, long-term supply cost curves of fossil fuel resources and technology in energy supply options.

An application of the methodology of Chapter 4 is discussed in Chapter 5 where a reference scenario is constructed based on the IS92a scenario of the IPCC. In Chapter 6 some scenarios from other institutions are investigated by assessing their outcomes in terms of the underlying assumptions. In Chapter 7, we will discuss energy futures according to alternative perspectives or world views. Finally, in Chapter 8, we give some results of optimized mitigation strategies using the CYCLES module of TARGETS to assess the impacts of scenarios. We specially address the role of technological change in meeting climate change policy targets.


`The Safe Landing Approach: Risks and Trade-offs in Climate Change’

Swart, R., M. Berk, E. Kreileman, M. Janssen, J. Bollen, R. Leemans and B. de Vries
1996 paper presented at a special session at the occasion of the 2nd Conference of Parties to the Framework Convention on Climate Change and the Ad Hoc Group on the Berline Mandate.

Sex, Drugs and Climate Change: Modelling Malaria as a Complex Adaptive System

Janssen, M.A. and W.J.M Martens
1995 GLOBO Working Paper 95-2, RIVM, Bilthoven, the Netherlands.


As the resistance of the malaria parasite to antimalarial drugs continues to intensify, as does that of the malarial mosquito to insecticides, efforts to adequately control the malaria situation in many tropical countries are coming under strain. This, together with a projected climate change may substantially increase malaria risks in the coming decades. In this paper we introduce genetic algorithms to simulate the adaptation (development of resistance) of mosquitoes and parasites. By coupling genetic algorithms with a dynamic malaria-epidemiological model we derive a complex adaptive system which is used to analyze strategies of malaria management for high and low endemic regions. Our results show that control programs can be used successfully in low ondemic regions although increased effort will be necessary in case of a climate change. However, in high endemic regions the inefficient use of insecticides and antimalarial drugs may eventually increase the incidence of malaria by decreasing the high levels of natural immunity of the population in these regions.

Keywords: malaria, climate change, genetic algorithms, adaptation


The Battle of Perspectives

Janssen, M.A.
1995 GLOBO Working Paper 95-3, RIVM, Bilthoven, the Netherlands.


Current (integrated) modelling efforts aimed at scanning the future do not allow for the learning and adaptive behaviour of agents in a world of uncertainty. In this paper, a framework is presented which might prove to provide a starting point in scanning the feasibility of coping with the dynamics of an ever-evolving interaction between the global system and the relevant agents, whereby the latter are assumed to view the global system from various perspectives. These perspectives may change over time in the event of surprises appearing in the observations. The agents’ favoured management styles, which are assumed to be related to the perspectives, may therefore likewise change over time. Incorporation of the ‘battle of perspectives’ enables us to embark modelling the interaction of decision-making with the complex global system in a world of uncertainty.

The example which is worked out here is the climate change issue, whereby a simple dynamic system for the economy and the climate system is used. This enables us to derive images of the future which take the notion of learning and adaptation into account.

Keywords: climate change, integrated assessment modelling, perspectives, learning behaviour, surprises


Allocating CO2-Emissions by Using Equity Rules and Optimization

Janssen, M.A., M.G.J. den Elzen and J. Rotmans
1992 RIVM, Report nr. 222901012, Bilthoven, The Netherlands.


In order to reduce the risks of a climate change, a major problem in developing an effective international policy, is the allocation of the responsibility for reducing green­ house gas emissions among regions.

This report presents two approaches to provide for the allocation problem of emission reductions of the most important greenhouse gas C02. The first deals with a description of the emission debt concept. We use an equity rule by which all past and future dwellers on earth are permitted to emit an equal C02 quotum per year. Furthermore, the level of the equal emission quotum is dependent on the policy related C02-equivalent concentration targets. The regional emission debt is the amount of C02, based on a equal share per capita, emitted in a region in the past exceeding the amount allowed. The resulting initial allocation of emission rights may be used as a start for a concept of tradable emission rights.

In the second approach the allocation problem is formulated as an optimization problem. This contains an ‘optimal’ trade off between rough estimates for social and economic consequences of reducing fossil C02-emissions in order to meet policy targets, as expressed in a C02-equivalent concentration level. The optimization algorithm developed is a first attempt in solving the optimization problem, where restrictions are dependent on simulation runs with IMAGE (an Integrated Model to Assess the Greenhouse Effect). The algorithm is used to find an allocation of regional fossil C02-emissions in order to maximize welfare of future generations, given a maximum allowable concentration level.

Results of both approaches indicate that if the world community is to accept constraints on C02-emissions, industrialized regions will have to take the main responsibility in reducing C02-emissions either by reducing emissions in their own regions and in developing regions.


Historical and Future Regional Emission Paths of Carbon Dioxide: Allocation and Optimization Mechanisms

Janssen, M.A.
1992 Master Thesis, Department of Operations Research, Erasmus University of Rotterdam.

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