Supply versus use designs of environmental extensions in input–output analysis: Conceptual and empirical implications for the case of energy

Input–output analysis is one of the central methodological pillars of industrial ecology. However,the literature that discusses different structures of environmental extensions (EEs), that is, thescope of physical flows and their attribution to sectors in the monetary input–output table (MIOT),remains fragmented. This article investigates the conceptual and empirical implications of apply-ing two different but frequently used designs of EEs, using the case of energy accounting, whereone represents energy supply while the other energy use in the economy. We derive both exten-sions from an official energy supply–use dataset and apply them to the same single-region input–output (SRIO) model of Austria, thereby isolating the effect that stems from the decision for theextension design. We also crosscheck the SRIO results with energy footprints from the g lobalmulti-regional input–output (GMRIO) dataset EXIOBASE. Our results show that the ranking offootprints of final demand categories (e.g., household and export) is sensitive to the extensiondesign and that product-level results can vary by several orders of magnitude. The GMRIO-basedcomparison further reveals that for a few countries the supply-extension result can be twice thesize of the use-extension footprint (e.g., Australia and Norway). We propose a graph approachto provide a generalized framework to disclosing the design of EEs. We discuss the conceptualdifferences between the two extension designs by applying analogies to hybrid life-cycle assess-ment and conclude that our findings are relevant for monitoring of energy efficiency and emissionreduction targets and corporate footprint accounting

The 'High-with-Low' Scenario Narrative: Key Themes, Cross-Cutting Linkages, and Implications for Modelling

We define a global ‘High-with-Low’ scenario that delivers high wellbeing with low energy and material resource consumption while limiting global warming in line with Paris Agreement targets. The High-with-Low scenario comprises a rich thematic narrative and a quantitative framework for interpreting the narrative using systems and sectoral modelling tools at different scales. The three central themes of the High-with-Low scenario are decent living standards for all, innovation and granularity, and digitalization. Inter-linkages between these themes emphasize drivers of change towards a High-with-Low future that include decentralization, adaptability to local needs, accelerated diffusion through peer and network effects, and the management of complexity on shared infrastructures. However, the direction of change is not deterministic. The High-with-Low scenario envisages a set of specific and strong governance institutions for coordinating a highly distributed global sustainability transition. To help develop and enrich these narrative aspects, we also set out some guidelines and parameterisations for quantitative model interpretations of the High-with-Low scenario. These guidelines are not universally prescriptive but rather define a set of quantitative reference points against which model inputs, processes, and outputs can be iteratively tested for consistency. In particular, we emphasize the overall development pattern of the High-with-Low scenario as one of conditional convergence in which energy services for well-being increase substantially in the Global South catching up to levels maintained in the Global North, while associated resource use tends to converge, combining a contraction in the Global North with relatively modest increases in the Global South

How much infrastructure is required to support decent mobility for all? An exploratory assessment

Decarbonizing transport is crucial for achieving climate targets, which is challenging because mobility is growing rapidly. Personal mobility is a key societal service and basic need, but currently not available to everyone with sufficient quality and quantity. The basis for mobility and accessibility of desired destinations is infrastructure, but its build-up and maintenance require a substantial fraction of global resource use. The question arises, how much mobility and how much infrastructure are required to deliver decent, sustainable mobility. We explore the relations between mobility levels, mobility infrastructure and well-being. We synthesize definitions of decent mobility and assess mobility measurements and provide a novel estimate of mobility infrastructure stocks for 172 countries in the year ~2021. We then explore the relations between infrastructure, travelled distances, accessibility, economic activity and several ‘beyond GDP’ well-being indicators. We find that travelled distances and mobility infrastructure levels are significantly correlated. Above levels of ~92–207 t/cap of mobility infrastructure no further significant gains in well-being can be expected from a further increase of infrastructure. We conclude that high mobility in terms of distances travelled as well as build

MESSAGEix-Materials v1.0.0: Representation of Material Flows and Stocks in an Integrated Assessment Model

Extracting and processing raw materials into products in industry is a substantial source of CO2 emissions, which currently lacks process detail in many integrated assessment models (IAMs). To broaden the space of climate change mitigation options and to include circular economy and material efficiency measures in IAM scenario analysis, we developed MESSAGEix-Materials module representing material flows and stocks within the MESSAGEix-GLOBIOM IAM framework. With the development of MESSAGEix-Materials, we provide a fully open-source model that can assess different industry decarbonization options under various climate targets for the most energy and emissions-intensive industries: Aluminium, iron and steel, cement, and petrochemicals. We illustrate the model’s operation with a baseline and mitigation (2 degrees) scenario setup and validate base year results for 2020 against historical datasets. We also discuss the industry decarbonization pathways and material stocks of the electricity generation technologies resulting from the new model features

Unequal household carbon footprints in China

Households’ carbon footprints are unequally distributed among the rich and poor due to differences in the scale and patterns of consumption. We present distributional focused carbon footprints for Chinese households and use a carbon-footprint-Gini coefficient to quantify inequalities. We find that in 2012 the urban very rich, comprising 5% of population, induced 19% of the total carbon footprint from household consumption in China, with 6.4 tCO2/cap. The average Chinese household footprint remains comparatively low (1.7 tCO2/cap), while those of the rural population and urban poor, comprising 58% of population, are 0.5–1.6 tCO2/cap. Between 2007 and 2012 the total footprint from households increased by 19%, with 75% of the increase due to growing consumption of the urban middle class and the rich. This suggests that a transformation of Chinese lifestyles away from the current trajectory of carbon-intensive consumption patterns requires policy interventions to improve living standards and encourage sustainable consumption

Modeling Low Energy Demand Futures for Buildings: Current State and Research Needs

Buildings are key in supporting human activities and well-being by providing shelter and other important services to their users. Buildings are, however, also responsible for major energy use and greenhouse gas (GHG) emissions during their life cycle. Improving the quality of services provided by buildings while reaching low energy demand (LED) levels is crucial for climate and sustainability targets. Building sector models have become essential tools for decision support on strategies to reduce energy demand and GHG emissions. Yet current models have significant limitations in their ability to assess the transformations required for LED. We review building sector models ranging from the subnational to the global scale to identify best practices and critical gaps in representing transformations toward LED futures. We focus on three key dimensions of intervention (socio-behavioral, infrastructural, and technological), three megatrends (digitalization, sharing economy, and circular economy), and decent living standards. This review recommends the model developments needed to better assess LED transformations in buildings and support decision-making toward sustainability targets

High-resolution maps of material stocks in buildings and infrastructures in Austria and Germany

The dynamics of societal material stocks such as buildings and infrastructures and their spatial patterns drive surging resource use and emissions. Two main types of data are currently used to map stocks, night-time lights (NTL) from Earth-observing (EO) satellites and cadastral information. We present an alternative approach for broad-scale material stock mapping based on freely available high-resolution EO imagery and OpenStreetMap data. Maps of built-up surface area, building height, and building types were derived from optical Sentinel-2 and radar Sentinel-1 satellite data to map patterns of material stocks for Austria and Germany. Using material intensity factors, we calculated the mass of different types of buildings and infrastructures, distinguishing eight types of materials, at 10 m spatial resolution. The total mass of buildings and infrastructures in 2018 amounted to ∼5 Gt in Austria and ∼38 Gt in Germany (AT: ∼540 t/cap, DE: ∼450 t/cap). Cross-checks with independent data sources at various scales suggested that the method may yield more complete results than other data sources but could not rule out possible overestimations. The method yields thematic differentiations not possible with NTL, avoids the use of costly cadastral data, and is suitable for mapping larger areas and tracing trends over time

Scientists’ warning on affluence

For over half a century, worldwide growth in affluence has continuously increased resource use and pollutant emissions far more rapidly than these have been reduced through better technology. The affluent citizens of the world are responsible for most environmental impacts and are central to any future prospect of retreating to safer environmental conditions. We summarise the evidence and present possible solution approaches. Any transition towards sustainability can only be effective if far-reaching lifestyle changes complement technological advancements. However, existing societies, economies and cultures incite consumption expansion and the structural imperative for growth in competitive market economies inhibits necessary societal change

A review of trends and drivers of greenhouse gas emissions by sector from 1990 to 2018

Global greenhouse gas (GHG) emissions can be traced to five economic sectors: energy, industry, buildings, transport and AFOLU (agriculture, forestry and other land uses). In this topical review, we synthesise the literature to explain recent trends in global and regional emissions in each of these sectors. To contextualise our review, we present estimates of GHG emissions trends by sector from 1990 to 2018, describing the major sources of emissions growth, stability and decline across ten global regions. Overall, the literature and data emphasise that progress towards reducing GHG emissions has been limited. The prominent global pattern is a continuation of underlying drivers with few signs of emerging limits to demand, nor of a deep shift towards the delivery of low and zero carbon services across sectors. We observe a moderate decarbonisation of energy systems in Europe and North America, driven by fuel switching and the increasing penetration of renewables. By contrast, in rapidly industrialising regions, fossil-based energy systems have continuously expanded, only very recently slowing down in their growth. Strong demand for materials, floor area, energy services and travel have driven emissions growth in the industry, buildings and transport sectors, particularly in Eastern Asia, Southern Asia and South-East Asia. An expansion of agriculture into carbon-dense tropical forest areas has driven recent increases in AFOLU emissions in Latin America, South-East Asia and Africa. Identifying, understanding, and tackling the most persistent and climate-damaging trends across sectors is a fundamental concern for research and policy as humanity treads deeper into the Anthropocene

Material Cycles, Industry and Service Provisioning: A Review of Low Energy and Material Demand Modelling and Scenarios

Developing transformative pathways for industry’s compliance with international climate targets requires model-based insights on how supply- and demand-side measures affect industry, material cycles, global supply chains, socio-economic activities and service provisioning supporting societal wellbeing. Herein, we review the recent literature modelling the industrial system for Low Energy and Materials Demand (LEMD) futures, resulting in lowered environmental pressures without relying on negative emissions. We identify 77 innovative studies drawing on nine distinct industry modelling traditions and critically assess system definitions and scopes, biophysical and thermodynamic consistency, granularity and heterogeneity, and operationalization of demand and service provision. We find large potentials of combined supply- and demand-side measures to reduce current economy-wide material use by -56%, energy use by -40 to -60%, and GHG emissions by -70% to net-zero. We call for strengthening interdisciplinary collaborations between industry modelling traditions and demand-side research, to produce more insightful scenarios and discuss research challenges and recommendations