Agent-based integrated assessment modelling: the example of climate change

Current approaches to deal with the socio-economic implications of climate change rely heavily on economic models that compare costs and benefits of different measures. We show that the theoretical foundations underpinning current approaches to economic modelling of climate change are inappropriate for the type of questions that are being asked. We argue therefore that another tradition of modelling, social simulation, is more appropriate in dealing with the complex environmental problems we face today.     

Participatory integrated assessment of adaptation to climate change in Alpine tourism and mountain agriculture

Winter tourism and mountain agriculture are the most important economic sectors in a major part of the Swiss Alps. Both are highly sensitive to changing climatic conditions. In the framework of the CLEAR project, results from climate impact research in the field of tourism and agricultural production were used to investigate the perception of climatic change by stakeholders and to assess possible adaptations. We used a participatory integrated assessment (PIA) to involve the knowledge, values and experiences of the various social actors in tourism and agriculture (e.g., skiers, tourism managers, farmers) in the research process. Whereas climate change may have various severe direct impacts on the tourism industry, depending on the region, agricultural production may generally benefit from changed climatic conditions. But because of the dependence of farmers on “off-farm” income, the loss due to declining winter tourism in specific areas may cause more important indirect effects. However, the two sectors may adapt actively by choosing from a variety of strategies, and the loss of income from the tourism industry may support the re-evaluation of the various functions agriculture plays in mountain regions, beyond the production of food. The study demonstrates the suitability of the PIA approach to elucidate the interactions between different stakeholders and their perception of the climate change phenomena. A similar participatory approach could be a useful tool to transfer research results and expert knowledge to the political process addressing adaptations to climate change. This revised version was published online in July 2006 with corrections to the Cover Date.     

INASUD project findings on integrated assessment of climate policies

This communication summarizes the main findings of INASUD, an European-wide research project on integrated assessment of climate policies. The project aimed at improving the framing of climate policy analysis through the parallel use of various existing integrated assessment models. It provides a comprehensive examination of the link between uncertainty regarding damages and inertia in economic systems. Results show that the Kyoto targets and timing are consistent with the precautionary principle but offers little insurance for longer-term climate protection. Flexibility mechanisms offer potentials for cooperation with developing countries, and are necessary to tap the environmental and economic benefits of joint carbon and sulfur emissions abatement.     

Scientist–stakeholder collaboration in integrated assessment of climate change: lessons from a case study of Northwest Canada

Research on the climate change issue has generally focused on uncertainties in climate projections and calculation of mitigation costs. Most integrated assessment (IA) efforts have been directed at the mitigation component. The problem of climate change, however, is really about the potential effects on ecosystems, resources, and societies that depend on them. As illustrated by experiences from the Mackenzie Basin Impact Study, a case study from Northwest Canada, these effects will be unique to each region and country. Many of these will be indirect, including region specific thresholds, vulnerabilities and adaptations which may not be included in sectoral analyses. Science can define some of the “What if” aspects of climate change, but the regional “So what” and “What should be done” questions are largely unanswered and subject to intense debate in various political fora. IA needs to recognize the multiobjective and multistakeholder aspects of vulnerabilities, risks, and potential responses to climate change. IA could provide a more holistic analysis of the regional impacts dimension of climate change by including both modeling and non‐modeling approaches, and incorporating institutional and stakeholder issues that do not readily lend themselves to economic analyses.     

Environmental water demand assessment under climate change conditions

Measures taken to cope with the possible effects of climate change on water resources management are key for the successful adaptation to such change. This work assesses the environmental water demand of the Karkheh river in the reach comprising Karkheh dam to the Hoor-al-Azim wetland, Iran, under climate change during the period 2010–2059. The assessment of the environmental demand applies (1) representative concentration pathways (RCPs) and (2) downscaling methods. The first phase of this work projects temperature and rainfall in the period 2010–2059 under three RCPs and with two downscaling methods. Thus, six climatic scenarios are generated. The results showed that temperature and rainfall average would increase in the range of 1.7–5.2 and 1.9–9.2%, respectively. Subsequently, flows corresponding to the six different climatic scenarios are simulated with the unit hydrographs and component flows from rainfall, evaporation, and stream flow data (IHACRES) rainfall-runoff model and are input to the Karkheh reservoir. The simulation results indicated increases of 0.9–7.7% in the average flow under the six simulation scenarios during the period of analysis. The second phase of this paper’s methodology determines the monthly minimum environmental water demands of the Karkheh river associated with the six simulation scenarios using a hydrological method. The determined environmental demands are compared with historical ones. The results show that the temporal variation of monthly environmental demand would change under climate change conditions. Furthermore, some climatic scenarios project environmental water demand larger than and some of them project less than the baseline one.     

Integral assessment of climate impact on the transboundary Mesta River flow formation in Bulgaria

The present work considers the section of the Mesta River on Bulgarian territory using the integral method for evaluation of climate and anthropogenic impact on the river flow. The level of this impact is determined by the index K _i (flow module), the coefficient C _i for the deviation of the average annual water volume Q _i from the flow norm Q _o and the index h _i for the deviation of the average annual rainfall volume H _i from the average multi-annual rainfall volume H _o . The dynamics of the average annual flow Q _i at two typical hydrometric stations – Yakoruda and Khadzhidimovo, as well as the dynamics of the average annual rainfall for the Yakoruda station was examined for the period 1955–2003. The data for the considered period 1955–2003 exhibit a decreasing trend of the average annual water volumes dynamics for both stations due to the impact of climate changes in the Mesta River catchment.     

Retrospective assessment of dryland soil stability in relation to grazing and climate change

Accelerated soil erosion is an aspect of dryland degradation that is affected by repeated intense drought events and land management activities such as commercial livestock grazing. A soil stability index (SSI) that detects the erosion status and susceptibility of a landscape at the pixel level, i.e., stable, erosional, or depositional pixels, was derived from the spectral properties of an archived time series (from 1972 to 1997) of Landsat satellite data of a commercial ranch in northeastern Utah. The SSI was retrospectively validated with contemporary field measures of soil organic matter and erosion status that was surveyed by US federal land management agencies. Catastrophe theory provided the conceptual framework for retrospective assessment of the impact of commercial grazing and soil water availability on the SSI. The overall SSI trend was from an eroding landscape in the early drier 1970s towards stable conditions in the wetter mid-1980s and late 1990s. The landscape catastrophically shifted towards an extreme eroding state that was coincident with the “The Great North American Drought of 1988”. Periods of landscape stability and trajectories toward stability were coincident with extremely wet El Niño events. Commercial grazing had less correlation with soil stability than drought conditions. However, the landscape became more susceptible to erosion events under multiple droughts and grazing. Land managers now have nearly a year warning of El Niño and La Niña events and can adjust their management decisions according to predicted landscape erosion conditions.     

Modeling economy-wide climate change impacts on Egypt: A case for an integrated approach

This study looks at the role of biophysical sectors and world markets on an integrated economic assessment of climate change impacts on Egypt. Using the outcome from Global Circulation Models (GCMs) and a global model of world food trade (the Basic Linked System; BLS) — changes in crop yields; crop water demands; water and land resource availability; and world market prices were applied to a dynamic, computable general equilibrium model of Egypt (the Standard National Model of the BLS). Modeling results consistently showed that the net effect of climate change on the macro indicator of per capita GDP was not great — regardless of the level of integration. This outcome was only realized through autonomous economic adjustments which implied significant socio-economic and structural change. Including or excluding certain biophysical sectors and world markets influenced the development path and the nature of the autonomous adjustments. The importance of a particular biophysical sector or of world markets was also dependent upon the specific climate change scenario.     

Regional impact analysis of climate change on natural and managed forests in the Federal State of Brandenburg, Germany

A methodology for regional application of forest simulation models has been developed as part of an assessment of possible climate change impacts in the Federal state of Brandenburg (Germany). Here we report on the application of a forest gap model to analyse the impacts of climate change on species composition and productivity of natural and managed forests in Brandenburg using a statistical method for the development of climate scenarios. The forest model was linked to a GIS that includes soil and groundwater table maps, as well as gridded climate data with a resolution of 10 × 10 km and simulated a steady-state species composition which was classified into forest types based on the biomass distribution between species. Different climate scenarios were used to assess the sensitivity of species composition to climate change. The simulated forest distribution patterns for current climate were compared with a map of Potential Natural Vegetation (PNV) of Brandenburg.In order to analyse the possible consequences of climate change on forest management, we used forest inventory data to initialize the model with representative forest stands. Simulation experiments with two different management strategies indicated how forest management could respond to the projected impacts of climate change. The combination of regional analysis of natural forest dynamics under climate change with simulation experiments for managed forests outlines possible trends for the forest resources. The implications of the results are discussed, emphasizing the regional differences in environmental risks and the adaptation potentials of forestry in Brandenburg.     

Environmental impacts of climate change adaptation

Climate change adaptation reduces adverse effects of climate change but may also have undesirable environmental impacts. However, these impacts are yet poorly defined and analysed in the existing literature. To complement this knowledge-gap, we reviewed the literature to unveil the relationship between climate change adaptation and environmental impact assessment, and the degree to which environmental impacts are included in climate change adaptation theory and practice. Our literature review showed that technical, social and economic perspectives on climate change adaptation receive much more attention than the environmental perspective. The scarce interest on the environmental impacts of adaptation may be attributed to (1) an excessive sectoral approach, with dominance of non-environmental perspectives, (2) greater interest in mitigation and direct climate change impacts rather than in adaptation impacts, (3) a tendency to consider adaptation as inherently good, and (4) subjective/preconceived notions on which measures are good or bad, without a comprehensive assessment. Environmental Assessment (EA) has a long established history as an effective tool to include environment into decision-making, although it does not yet guarantee a proper assessment of adaptation, because it is still possible to postpone or even circumvent the processes of assessing the impacts of climate adaptation. Our results suggest that there is a need to address adaptation proactively by including it in EA, to update current policy frameworks, and to demand robust and reliable evaluation of alternatives. Only through the full EA of adaptation measures can we improve our understanding of the primary and secondary impacts of adaptation to global environmental change.     

Integrated assessment of potential health impact of global environmental change: Prospects and limitations

Estimating the future health impact of global environmental change requires scientific methods that extend beyond conventional health risk assessment in relation to existing exposures. The dynamic and non‐linear nature of these changes in large complex biophysical systems, the interactions between them, and the reference to future scenarios all contribute uncertainty. Potential health impacts can be estimated from historical analogues, by mathematical modelling, or by reasonable foresight (especially in relation to social and economic disruptions). Integrated assessment methods draw upon all these techniques. In particular, integrated mathematical modelling techniques are evolving, as scientists (and policy‐makers) come to terms with this complex scenario‐based impact assessment task.     

Determining the global significance of local and regional mitigation strategies: Setting the scene with global integrated assessment models

Because of the importance and complexity of the processes involved in the response of land cover and land use to changing environmental conditions, other approaches are required to evaluate the effectiveness of mitigation options. One such approach is provided by the global integrated assessment model, IMAGE 2. This article presents the structure and some of the underlying assumptions of IMAGE 2, which illustrates the importance of feedback processes in evaluating the effectiveness of mitigation options with respect to land use. Although models such as IMAGE 2 are unsuitable for local and national mitigation evaluations, they can be used to define the regional and global constraints of the smaller scale assessments.     

Environmental health implications of global climate change

This paper reviews the background that has led to the now almost-universally held opinion in the scientific community that global climate change is occurring and is inescapably linked with anthropogenic activity. The potential implications to human health are considerable and very diverse. These include, for example, the increased direct impacts of heat and of rises in sea level, exacerbated air and water-borne harmful agents, and--associated with all the preceding--the emergence of environmental refugees. Vector-borne diseases, in particular those associated with blood-sucking arthropods such as mosquitoes, may be significantly impacted, including redistribution of some of those diseases to areas not previously affected. Responses to possible impending environmental and public health crises must involve political and socio-economic considerations, adding even greater complexity to what is already a difficult challenge. In some areas, adjustments to national and international public health practices and policies may be effective, at least in the short and medium terms. But in others, more drastic measures will be required. Environmental monitoring, in its widest sense, will play a significant role in the future management of the problem.     

Environmental impact assessment of a mixed tropical hardwood integrated pulp and paper mill— a case study

An overview of the environmental impact assessment (EIA) for a mixed tropical hardwood integrated pulp and paper mill in Sabah, Malaysia, is presented. The EIA before the mill construction included, among other things, a detailed baseline study and also environmental impact predictions based on certain mill design and pollution abatement measures. Subsequent to mill construction (during the operational stage), data were gathered to determine the quality of the ambient air as well as the effluent and the receiving bay water quality. These post-construction monitoring results were then compared with the earlier impact predictions, and showed, in general, a good correspondence.     

Including the temporal change in PM2.5 concentration in the assessment of human health impact: Illustration with renewable energy scenarios to 2050

This article proposes a new method to assess the health impact of populations exposed to fine particles (PM_2.5) during their whole lifetime, which is suitable for comparative analysis of energy scenarios. The method takes into account the variation of particle concentrations over time as well as the evolution of population cohorts. Its capabilities are demonstrated for two pathways of European energy system development up to 2050: the Baseline (BL) and the Low Carbon, Maximum Renewable Power (LC-MRP). These pathways were combined with three sets of assumptions about emission control measures: Current Legislation (CLE), Fixed Emission Factors (FEFs), and the Maximum Technically Feasible Reductions (MTFRs). Analysis was carried out for 45 European countries. Average PM_2.5 concentration over Europe in the LC-MRP/CLE scenario is reduced by 58% compared with the BL/FEF case. Health impacts (expressed in days of loss of life expectancy) decrease by 21%. For the LC-MRP/MTFR scenario the average PM_2.5 concentration is reduced by 85% and the health impact by 34%. The methodology was developed within the framework of the EU's FP7 EnerGEO project and was implemented in the Platform of Integrated Assessment (PIA). The Platform enables performing health impact assessments for various energy scenarios.     

Optimisation analysis and integrated models of the enhanced greenhouse effect

The issues surrounding the anticipated impacts of the enhanced greenhouse effect are likely to form a significant part of the research activities in the coming years. In this paper we have adopted a control theoretic approach to the analysis of one of the world's best known integrated models of the enhanced greenhouse effect: the Dutch IMAGE 1.0 (Integrated Model to Assess the Greenhouse Effect) model. The paper demonstrates that optimisation methodologies can be applied to integrated models to enhance their interpretative power. This is accomplished by providing a mechanism whereby optimal emission allocation strategies can be formulated from existing models. One result of particular interest is that the analysis confirms that the earlier human input into the climate system can be stabilised, the higher the levels of CO₂ emissions can be permitted and still achieve specific long-term environmental target.     

Representing uncertainty in climate change scenarios: a Monte-Carlo approach

Climate change impact assessment is subject to a range of uncertainties due to both incomplete and unknowable knowledge. This paper presents an approach to quantifying some of these uncertainties within a probabilistic framework. A hierarchical impact model is developed that addresses uncertainty about future greenhouse gas emissions, the climate sensitivity, and limitations and unpredictability in general circulation models. The hierarchical model is used in Bayesian Monte-Carlo simulations to define posterior probability distributions for changes in seasonal-mean temperature and precipitation over the United Kingdom that are conditional on prior distributions for the model parameters. The application of this approach to an impact model is demonstrated using a hydrological example. This revised version was published online in July 2006 with corrections to the Cover Date.