Integrated Modeling of Sustainable Behaviour
Integrated Assessment Models (IAMs) are used to look into avoiding particular futures, but also how to avoid climate change (in line with 2°C and 1.5°C targets). The key aspect of these models is that different technologies can be compared to each other based on costs. The results are framed in a certain way that certain solutions can be presented to policy makers (among others). In the models and in the IPCC report, climate change is mitigated by a combination of efficiency, changes in supply, renewable energy, bioenergy and carbon capture and storage, which are all valid solutions. Availability of resources (e.g. oil, solar, gas energy availability) are included dynamically in the model (e.g. if oil reserves are depleted, oil price increases due to scarcity). Yet, IAMs are less equipped to evaluate lifestyle changes dynamically, as it is unlikely that we can evaluate these actions based on costs (like we do with technology options). Therefore, these solutions are not included in the scenarios and not available for comparison. E.g. when becoming vegetarian, there isn’t a cost to society that is included in the model, so it’s difficult to compare these different options in the model. If and when we have included lifestyle changes, we only included these as exogenous inputs into the model, or very simply. For example, consumption patterns are purely dependent on income per capita and population in the models.
More recently, modellers did model lifestyle changes as options in IAMs, but mostly done in an abstract way (e.g. assumed that all people would adopt specific lifestyle changes and measured effects on scenarios), to at least show the impacts of the changes in reaching climate targets. This highlighted the need to understand the likelihood of this happening, and therefore in this research we seek to improve our assumptions. We acknowledge that outside of modelling there is a lot of work done on lifestyle changes. Furthermore, that this work can be used to improve our assumptions, what behaviour changes, where and when it would be possible/likely for the changes to happen, and thus make the modelling of lifestyle changes less abstract. Therefore, first, we would like to gain these insights from a larger group, and not just make these assumptions with a couple of modellers behind a desk. Secondly, we want to share and communicate our results with the larger sustainable lifestyles community to offer our expertise on emission levels and the activities that are consistent with climate targets.
More recently, modellers did model lifestyle changes as options in IAMs, but mostly done in an abstract way (e.g. assumed that all people would adopt specific lifestyle changes and measured effects on scenarios), to at least show the impacts of the changes in reaching climate targets. This highlighted the need to understand the likelihood of this happening, and therefore in this research we seek to improve our assumptions. We acknowledge that outside of modelling there is a lot of work done on lifestyle changes. Furthermore, that this work can be used to improve our assumptions, what behaviour changes, where and when it would be possible/likely for the changes to happen, and thus make the modelling of lifestyle changes less abstract. Therefore, first, we would like to gain these insights from a larger group, and not just make these assumptions with a couple of modellers behind a desk. Secondly, we want to share and communicate our results with the larger sustainable lifestyles community to offer our expertise on emission levels and the activities that are consistent with climate targets.
Analysing the Impact of Lifestyle Change
Earlier, we used the IMAGE integrated assessment model to provide insight into the potential for lifestyle change by prescribing alternative lifestyle patterns. This involves, for instance, different choices in use of transport modes, appliances and diets. Prescribing the outcomes of different lifestyle patterns in IMAGE allows us to analyze the contribution of different strategies in reducing greenhouse gas emissions in relation to other strategies. Recently, we used this approach to develop alternative scenarios aimed at contributing to the IPCC Special Report on 1.5 degrees. While many researchers, stakeholders and policy-makers have expressed considerable interest in this work, the assumptions made in this work are at the moment, however, very stylized.
In this work, we aim to combine information from detailed studies on consumer behavior and global mitigation models – by translating the outcomes of detailed studies into scenario inputs for the integrated assessment model IMAGE. The opportunity for scaling lifestyles mitigation strategies increases with this evidence-based clarification of the contribution of lifestyle interventions (in contrast to the stylized runs used so-far). The analysis allow us to estimate the environmental impact of sustainable behavior vis-à-vis business-as-usual using model studies and to engage IPCC and decision-makers as we develop the model. Using IMAGE also allows us to analyze the impacts of lifestyle change on staying within planetary boundaries in general (climate, biodiversity, land use, water). It will also improve our ability to provide a more realistic indication of the mitigation potential, the role of different actors and the rate at which strategies can be implemented. Together with the stakeholders, we will also improve understanding and communication on the possible impact of sustainable consumption patterns – both to show the effectiveness of lifestyle change oriented strategies and to use their feedback from action experiments in further improving the scenario set.
In this work, we aim to combine information from detailed studies on consumer behavior and global mitigation models – by translating the outcomes of detailed studies into scenario inputs for the integrated assessment model IMAGE. The opportunity for scaling lifestyles mitigation strategies increases with this evidence-based clarification of the contribution of lifestyle interventions (in contrast to the stylized runs used so-far). The analysis allow us to estimate the environmental impact of sustainable behavior vis-à-vis business-as-usual using model studies and to engage IPCC and decision-makers as we develop the model. Using IMAGE also allows us to analyze the impacts of lifestyle change on staying within planetary boundaries in general (climate, biodiversity, land use, water). It will also improve our ability to provide a more realistic indication of the mitigation potential, the role of different actors and the rate at which strategies can be implemented. Together with the stakeholders, we will also improve understanding and communication on the possible impact of sustainable consumption patterns – both to show the effectiveness of lifestyle change oriented strategies and to use their feedback from action experiments in further improving the scenario set.
Integrating Lifestyles into the Model
Global, model-based scenarios play a key role in exploring different strategies to mitigate climate change and reduce loss of global biodiversity. The results of them are directly used by decision-makers and the IPCC. This can be seen, for instance, in the references in the Paris Climate Agreement to reduction targets directly derived from model-based scenarios, the IPCC’s report Synthesis Report but also the emphasis on these scenarios in impact assessment of EU policies. Based on the need of simplifications, the models that are used describe decision-processes in terms of cost-optimal choice of different technologies. This approach provides a useful reference for describing decisions and mitigation strategies for energy supply (such as investments in large-scale power plants). On the “demand” side (future demand of energy, water and food), however, a more diffuse set of drivers plays a role related to behavior, technologies and activities. These factors are much more difficult to address in aggregated models.
Still, based on case-studies and some stylized scenario studies it is known that considerable potential exists for changing consumption and lifestyle patterns. For instance, calculations using the IMAGE model showed that lifestyle change could reduce emissions globally at by 10 GtCO2-eq by 2050. It is important to realize that very ambitious climate targets might be out-of-reach without considering these options. The fact that models typically do not cover these options results in a situation where too little attention is paid to them. At the same time, case studies have shown that such changes can be implemented.
Still, based on case-studies and some stylized scenario studies it is known that considerable potential exists for changing consumption and lifestyle patterns. For instance, calculations using the IMAGE model showed that lifestyle change could reduce emissions globally at by 10 GtCO2-eq by 2050. It is important to realize that very ambitious climate targets might be out-of-reach without considering these options. The fact that models typically do not cover these options results in a situation where too little attention is paid to them. At the same time, case studies have shown that such changes can be implemented.
