• Energy Research

Mitigation scenarios that achieve the ambitious targets included in the Paris Agreement typically rely on greenhouse gas emission reductions combined with net carbon dioxide removal (CDR) from the atmosphere, mostly accomplished through large-scale application of bioenergy with carbon capture and storage, and afforestation. However, CDR strategies face several difficulties such as reliance on underground CO2 storage and competition for land with food production and biodiversity protection. The question arises whether alternative deep mitigation pathways exist. Here, using an integrated assessment model, we explore the impact of alternative pathways that include lifestyle change, additional reduction of non-CO2 greenhouse gases and more rapid electrification of energy demand based on renewable energy. Although these alternatives also face specific difficulties, they are found to significantly reduce the need for CDR, but not fully eliminate it. The alternatives offer a means to diversify transition pathways to meet the Paris Agreement targets, while simultaneously benefiting other sustainability goals.

Although nearly all 2 °C scenarios use negative CO2 emission technologies, only relatively small investments are being made in them, and concerns are being raised regarding their large-scale use. If no explicit policy decisions are taken soon, however, their use will simply be forced on us to meet the Paris climate targets.

The target of zero emissions sets a new standard for industry and industrial policy. Industrial policy in the twenty-first century must aim to achieve zero emissions in the energy and emissions int...

In this paper, we apply two global Integrated Assessment Models (IAMs) and one detailed European electricity system model to explore the consequences of different narrative-based low-carbon scenarios on the electricity system from the global to national scale. The narratives are based on insights from socio-technical transition analysis on niche-innovations. The main aim of this exercise is to examine the solution space in low-carbon scenarios for electricity supply from the global to national scale, which is largely neglected when focusing on cost-optimal solutions only. We show that taking into account insights from socio-technical transition analysis can have large impacts on the projected transition strategy, especially regarding relatively costly technologies that currently have a high momentum. For instance, we find that the share of offshore wind in electricity generation in Europe is less than 3% or up to 27% by 2050, depending on the underlying narrative. These ranges are useful input for policy-makers, as they show the degree of flexibility in mitigation options. Furthermore, our analysis shows that combining IAMs with more detailed sectoral models illuminates the challenges on a more detailed geographical scale, for instance regarding storage requirements and the need for interconnectivity across European borders.

Most model studies focus on technical solutions in order to meet the 2°C climate target, such as renewable, carbon capture and energy efficiency technologies. Such studies show that it becomes increasingly more difficult to attain the 2°C target with carbon price driven technical solutions alone. This indicates the need to focus more on non-economic and non-technological drivers of energy system transformations, which are generally not explicitly included in long-term scenario studies. This study implements a set of lifestyle change measures for residential energy use, mobility and waste management in the integrated assessment model IMAGE. We analyze the implications of these lifestyle changes in a business-as-usual and 2°C climate mitigation reference case. We find that lifestyle change measures included in this study mostly affect the end-use sectors. By 2050, the measures reduce CO2 emissions in the residential sector by about 13% and in the transport sector by about 35% compared to baseline emissions. The indirect implications in the industry and energy supply sectors were found to be negligible. In mitigation scenarios the contribution of lifestyle measures is dampened in end-use sectors as they overlap with more technical measures. Yet, as they may create opportunities to mitigate in sectors without more radical changes in (1) the energy infrastructure and (2) on the short term, it leads to a more cost-efficient mitigation strategy. Further research in how behavior can be internalized into integrated assessment studies is recommendable.

Recent studies show that lifestyle changes can provide an essential contribution to achieving the Paris climate targets. While some efforts have been made to incorporate lifestyle changes into model-based scenarios, the attempts are currently very stylised and included exogenously. This paper discusses current efforts to represent lifestyle change in models, and analyses potential insights from relevant scientific disciplines to improve the representation of lifestyle changes in models – including modelling specific behaviour changes, identifying cross-cutting lifestyle solutions, representing the intentions behind the changes and quantifying their impacts. As such, this research attempts to bridge the gap between qualitative and quantitative theories and methodologies. Based on the results of this literature analysis, we recommend defining lifestyle changes more harmoniously, exploring an expanded range of approaches, domains and transformative solutions, adopting a whole-systems approach, and addressing the trade-offs between the use of exogenous inputs and endogenous modelling.

Abstract Recent studies show that behaviour changes can provide an essential contribution to achieving the Paris climate targets. Existing climate change mitigation scenarios primarily focus on technological change and underrepresent the possible contribution of behaviour change. This paper presents and applies a methodology to decompose the factors contributing to changes in per capita emissions in scenarios. With this approach, we determine the relative contribution to total emissions from changes in activity, the way activities are carried out, the intensity of activities, as well as fuel choice. The decomposition tool breaks down per capita emissions loosely following the Kaya Identity, allowing a comparison between the contributions of technology and consumption changes among regions and between various scenarios. We illustrate the use of the tool by applying it to three previously-published scenarios; a baseline scenario, a scenario with a selection of behaviour changes, and a 2 °C scenario with the same selection of behaviour changes. Within these scenarios, we explore the contribution of technology and consumption changes to total emission changes in the transport and residential sector, for a selection of both developed and developing regions. In doing so, the tool helps identify where specifically (i.e. via consumption or technology factors) different measures play a role in mitigating emissions and expose opportunities for improved representation of behaviour changes in integrated assessment models. This research shows the value of the decomposition tool and how the approach could be flexibly replicated for different global models based on available variables and aims. The application of the tool to previously-published scenarios shows substantial differences in consumption and technology changes from CO2 price and behaviour changes, in transport and residential per capita emissions and between developing and developed regions. Furthermore, the tool’s application can highlight opportunities for future scenario development of a more nuanced and heterogeneous representation of behaviour and lifestyle changes in global models.

Integrated assessment models (IAMs) are computer-based instruments used to assess the implications of human activity on the human and earth system. They are simultaneously also used to explore possible response strategies to climate change. As IAMs operate simplified representations of real-world processes within their model structures, they have been frequently criticised to insufficiently represent the opportunities and challenges in future energy systems over time. To test whether projections by IAMs diverge in systematic ways from projections made by technology experts we elicited expert opinion on prospective change for two indicators and compared these with the outcomes of IAM studies. We specifically focused on five (energy) technology families (solar, wind, biomass, nuclear, and carbon capture and storage or CCS) and compared the considered implications of the presence or absence of climate policy on the growth and diffusion of these technologies over the short (2030) to medium (2050) term. IAMs and experts were found to be in relatively high agreement on system change in a business-as-usual scenario, albeit with significant differences in the estimated magnitude of technology deployment over time. Under stringent climate policy assumptions, such as the internationally agreed upon objective to limit global mean temperature increase to no more than 2 °C, we found that the differences in estimated magnitudes became smaller for some technologies and larger for others. Compared to experts, IAM simulations projected a greater reliance on nuclear power and CCS to meet a 2 °C climate target. In contrast, experts projected a stronger growth in renewable energy technologies, particularly solar power. We close by discussing several factors that are considered influential to the alignment of the IAM and expert perspectives in this study.