•We present narrative descriptions of future societal development associated with the shared socioeconomic pathways.•We describe the methods used to develop the narratives and how they produce ...particular combinations of challenges to mitigation and adaptation.•The narratives describe plausible future changes in demographics, human development, economy, institutions, technology, and environment.•The narratives span an uncertainty space in terms of socioeconomic challenges to adaptation and mitigation of climate change.•The narratives relate to Sustainability, Regional Rivalry, Inequality, and Fossil-fueled Development, and a Middle of the Road pathway.
Long-term scenarios play an important role in research on global environmental change. The climate change research community is developing new scenarios integrating future changes in climate and society to investigate climate impacts as well as options for mitigation and adaptation. One component of these new scenarios is a set of alternative futures of societal development known as the shared socioeconomic pathways (SSPs). The conceptual framework for the design and use of the SSPs calls for the development of global pathways describing the future evolution of key aspects of society that would together imply a range of challenges for mitigating and adapting to climate change. Here we present one component of these pathways: the SSP narratives, a set of five qualitative descriptions of future changes in demographics, human development, economy and lifestyle, policies and institutions, technology, and environment and natural resources. We describe the methods used to develop the narratives as well as how these pathways are hypothesized to produce particular combinations of challenges to mitigation and adaptation. Development of the narratives drew on expert opinion to (1) identify key determinants of these challenges that were essential to incorporate in the narratives and (2) combine these elements in the narratives in a manner consistent with scholarship on their inter-relationships. The narratives are intended as a description of plausible future conditions at the level of large world regions that can serve as a basis for integrated scenarios of emissions and land use, as well as climate impact, adaptation and vulnerability analyses.
Future energy demand is likely to increase due to climate change, but the magnitude depends on many interacting sources of uncertainty. We combine econometrically estimated responses of energy use to ...income, hot and cold days with future projections of spatial population and national income under five socioeconomic scenarios and temperature increases around 2050 for two emission scenarios simulated by 21 Earth System Models (ESMs). Here we show that, across 210 realizations of socioeconomic and climate scenarios, vigorous (moderate) warming increases global climate-exposed energy demand before adaptation around 2050 by 25-58% (11-27%), on top of a factor 1.7-2.8 increase above present-day due to socioeconomic developments. We find broad agreement among ESMs that energy demand rises by more than 25% in the tropics and southern regions of the USA, Europe and China. Socioeconomic scenarios vary widely in the number of people in low-income countries exposed to increases in energy demand.
•Greenhouse gas and air pollutant emissions and global land use could develop in very different directions based on societal trends in the energy system and agriculture.•A combination of resource ...efficiency, preferences for sustainable production methods and investment in human development could lead to lower anthropogenic greenhouse gas emissions and land-use in 2100 than in 2010.•The SSP1 storyline could be a basis for further discussions on how climate policy can be combined with achieving other societal goals.
This paper describes the possible developments in global energy use and production, land use, emissions and climate changes following the SSP1 storyline, a development consistent with the green growth (or sustainable development) paradigm (a more inclusive development respecting environmental boundaries). The results are based on the implementation using the IMAGE 3.0 integrated assessment model and are compared with a) other IMAGE implementations of the SSPs (SSP2 and SSP3) and b) the SSP1 implementation of other integrated assessment models. The results show that a combination of resource efficiency, preferences for sustainable production methods and investment in human development could lead to a strong transition towards a more renewable energy supply, less land use and lower anthropogenic greenhouse gas emissions in 2100 than in 2010, even in the absence of explicit climate policies. At the same time, climate policy would still be needed to reduce emissions further, in order to reduce the projected increase of global mean temperature from 3°C (SSP1 reference scenario) to 2 or 1.5°C (in line with current policy targets). The SSP1 storyline could be a basis for further discussions on how climate policy can be combined with achieving other societal goals.
•We present a global simulation model for the steel and cement industries.•Next decades see a rapid increase of global steel and cement demands.•Under baseline scenario production shifts slowly ...towards more efficient technologies.•Climate policy accelerates uptake of low-carbon technologies.•CCS is a key technology for achieving major emission reductions.
This paper presents a global simulation-model for the steel and cement industries. The model covers the full modelling chain from economic activity, to materials consumption, trade, technology choice, production capacity, energy use and CO2 emissions. Without climate policy, the future projections based on the SSP2 scenario show a rapid increase in the consumption of steel and cement over the next few decades, after which demand levels are projected to stabilize. This implies that over the scenario period, CO2 emissions are projected to peak in the next decades followed by a decrease below 2010 levels in 2050. There is considerable scope to mitigate CO2 emissions from steel and cement industries, leading to resp. 80–90% and 40–80% reduction below 2010 in 2050 for a high carbon tax of 100 $/tCO2+4%pa depending on the availability of Carbon Capture and Sequestration (CCS).
Abstract
Long-term mitigation scenarios developed by integrated assessment models underpin major aspects of recent IPCC reports and have been critical to identify the system transformations that are ...required to meet stringent climate goals. However, they have been criticized for proposing pathways that may prove challenging to implement in the real world and for failing to capture the social and institutional challenges of the transition. There is a growing interest to assess the feasibility of these scenarios, but past research has mostly focused on theoretical considerations. This paper proposes a novel and versatile multidimensional framework that allows evaluating and comparing decarbonization pathways by systematically quantifying feasibility concerns across geophysical, technological, economic, socio-cultural and institutional dimensions. This framework enables to assess the timing, disruptiveness and scale of feasibility concerns, and to identify trade-offs across different feasibility dimensions. As a first implementation of the proposed framework, we map the feasibility concerns of the IPCC 1.5 °C Special Report scenarios. We select 24 quantitative indicators and propose feasibility thresholds based on insights from an extensive analysis of the literature and empirical data. Our framework is, however, flexible and allows evaluations based on different thresholds or aggregation rules. Our analyses show that institutional constraints, which are often not accounted for in scenarios, are key drivers of feasibility concerns. Moreover, we identify a clear intertemporal trade-off, with early mitigation being more disruptive but preventing higher and persistent feasibility concerns produced by postponed mitigation action later in the century.
•The paper illustrates the importance of capturing cross-sectoral relationships between industries in IAMs.•Retrofitting and clinker to cement ratio is not sufficiently represented in ...IAMs.•Retrofitting can offer considerable energy savings in the short-term.•Reducing the clinker content in cement can offer significant energy savings.•Limited future fly ash availability reduces the potential for clinker substitution.
Although the cement industry emits around 6% of global CO2 emissions, most global Integrated Assessment Models (IAMs) barely represent this industrial subsector or do not cover all important processes. This study, describes the state-of-the-art of cement modelling in IAMs, suggests possible improvements and discusses the impacts of these on energy and greenhouse gas emissions (GHG) in the IMAGE global IAM.
It is found that two cement-sector specific GHG mitigation measures are often not explicitly accounted for in IAMs, namely: (i) retrofitting and (ii) reducing the clinker to cement ratio. For retrofitting, many measures are identified as cost-effective and when incorporating these in the IMAGE model overall energy use reduces between 2010 and 2035 by 9.8 and 11 EJ (4% and 5%) under the baseline and GHG mitigation scenarios, respectively. When incorporating the clinker to cement ratio by linking material availability to the activities in the steel industry and coal-fired power plants, the 2050 energy use reduces by 15% under the baseline scenario and increases by 9% under the GHG mitigation scenario as fewer coal-fired power plants are in operation. This is even more prominent in the long term. The 2100 energy use is 14% higher in the GHG mitigation scenario as even fewer coal-fired power plants are used drastically limiting the potential for clinker substitution with fly ash. These results highlight the importance of capturing cross-sectoral relationships between industries and of including sector specific mitigation measures in long-term energy models.
The residential sector plays an important role in the energy system of developing countries. In this paper we introduce a bottom up simulation model for household energy use. The model describes ...energy demand for several end-use functions based on a set of physical drivers, such as floor space and heating degree days. The model also recognizes different population groups: i.e. urban and rural households, each distinguishing five income quintiles. The model is applied to analyze possible future developments of residential energy use in five developing world regions: India, China, South East Asia, South Africa and Brazil. We find that in each of these regions cooking is currently the main end-use function, but that other functions, such as space heating, cooling and appliances become more important. At the same time, energy consumption slowly shifts towards modern fuels. The model also shows that climate policy can reduce residential energy emissions, but could also slow down the energy transition away from traditional fuels in low income classes.
► A bottom-up model for residential energy use was developed and applied to five developing regions. ► The model distinguishes five end-use functions and rural/urban income quintiles. ► Exploration of the drivers of residential energy use and consequent fuel use. ► Exploration of effects of 100$/tCO
2 tax on emission reduction. ► Emissions reduce due to power sector. Climate policy can affect household energy transition.
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