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Lucas, Paul

Publications and source records attributed to Lucas, Paul.

Advancing a toolkit of diverse futures approaches for global environmental assessments

Global Environmental Assessments (GEAs) support national and international policy making for sustainable development. They rely on quantitative scenarios produced by Integrated Assessment Models (IAMs) to assess alternative futures. IAM-based scenarios can provide a coherent assessment framework that integrates different subsystems and their interactions. However, these top-down approaches have limited ability to represent key local dynamics, unexpected events, or the role of diverse actors. Other methods, including participatory scenarios, can help co-create narratives that emphasize diverse contents with clear links to existing decision-making. However, these bottom-up approaches provide only limited insight into global processes and are not constrained by measurable parameters. In our review, we identify four key challenges for current GEA scenarios: surprise, scale, diversity and imagination. We illustrate how these challenges can be overcome by combining top-down and bottom-up scenario approaches and conclude with a call to action for future research to take on this trans-disciplinary challenge.

Pereira, Laura M.↗

Chapter 22 - Pathways Toward Sustainable Development

Model-based scenario analysis can help in identifying ways to achieve the environmental targets of the Sustainable Development Goals (SDGs) and related multilateral environmental agreements (MEAs) (well established). Target-seeking scenarios provide insight into the required level of effort, promising measures, and possible synergies and trade-offs between these measures and a range of targets. The usefulness of scenarios can be illustrated by the successful use of such scenarios in the literature on climate policy. Scenarios can be used to explore different pathways for achieving long-term targets and provide insights into the costs and benefits of these pathways. There are important interrelations (synergies and trade-offs) between the achievement of the various SDGs and related MEAs.. This means that strategies that aim to achieve sets of targets will have to take account for these interrelations. At the moment, scenarios that explore the fulfilment of a large set of SDG targets simultaneously are mostly lacking. An assessment of possible pathways must therefore rely on more narrowly focused scenarios in the literature. This does lead to a higher level of uncertainty and some clear knowledge gaps. {22.2}

Van Vuuren, Detlef↗

Chapter 21 - Future Developments Without Targeted Policies

Together with other tools, model-based scenario analysis provides a useful method to explore whether environment related targets of the Sustainable Development Goals (SDGs) and related Multilateral Environmental Agreements (MEAs) are going to be achieved (well established). Assessing whether current trends are leading to fulfilment of the selected targets outlined in Chapter 20 is complex: it requires insights into the interactions of different trends and systems, inertia and cross-scale relationships. A combination of qualitative storylines and quantitative scenario tools can help to explore possible futures trends, while taking the many complexities into account. While scenarios can never be forecasts, because surprises may occur, they can inform decision makers of the likely implications of current trends. {21.2}

Lucas, Paul↗

Future energy system challenges for Africa: Insights from Integrated Assessment Models

Although Africa’s share in the global energy system is only small today, the ongoing population growth and economic development imply that this can change significantly. In this paper, we discuss long-term energy developments in Africa using the results of the LIMITS model inter-comparison study. The analysis focusses on the position of Africa in the wider global energy system and climate mitigation. The results show a considerable spread in model outcomes. Without specific climate policy, Africa’s share in global CO 2 emissions is projected to increase from around 1-4% today to 3-23% by 2100. In all models, emissions only start to become really significant on a global scale after 2050. Furthermore, by 2030 still around 50% of total household energy use is supplied through traditional bio-energy, in contrast to existing ambitions from international organisations to provide access to modern energy for all. After 2050, the energy mix is projected to converge towards a global average energy mix with high shares of fossil fuels and electricity use. Finally, although the continent is now a large net exporter of oil and gas, towards 2050 it most likely needs most of its resources to meet its rapidly growing domestic demand. With respect to climate policy, the rapid expansion of the industrial and the power sector also create large mitigation potential and thereby the possibility to align the investment peak in the energy system with climate policy and potential revenues from international carbon trading.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

Understanding the contribution of non-carbon dioxide gases in deep mitigation scenarios

The combined 2010 emissions of methane (CH4), nitrous oxide (N2O) and the fluorinated gasses (F-gas) account for about 20-30% of total emissions and about 30% of radiative forcing. At the moment, most studies looking at reaching ambitious climate targets project the emission of carbon dioxide (CO2) to be reduced to zero (or less) by the end of the century. As for non-CO2 gases, the mitigation potential seem to be more constrained, we find that by the end of the century in the current deep mitigation scenarios non-CO2 emissions could form the lion’s share of remaining greenhouse gas emissions. In order to support effective climate policy strategies, in this paper we provide a more in-depth look at the role of non-CO2¬ emission sources (CH4, N2O and F-gases) in achieving deep mitigation targets (radiative forcing target of 2.8 W/m2 in 2100). Specifically, we look at the sectorial mitigation potential and the remaining non-CO2 emissions. By including a set of different models, we provide some insights into the associated uncertainty. Most of the remaining methane emissions in 2100 in the climate mitigation scenario come from the livestock sector. Strong reductions are seen in the energy supply sector across all models. For N2O, less reduction potential is seen compared to methane and the sectoral differences are larger between the models. The paper shows that the assumptions on remaining non-CO2 emissions are critical for the feasibility of reaching ambitious climate targets and the associated costs.

Gernaat, David↗