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Journal Articles

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.



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


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