ENGAGE Summary for Policymakers

As the world faces the risks of dangerous climate change, policymakers, industry and civil society leaders are counting on Integrated Assessment Models (IAMs) to inform and guide strategies to deliver on the objectives of the Paris Agreement (PA) and subsequent agreements. The Exploring National and Global Actions to Reduce Greenhouse Gas Emissions (ENGAGE) project has responded to this challenge by engaging these stakeholders in co-producing a new generation of global and national decarbonization pathways

Forum on Scenarios for Climate and Societal Futures: Meeting Report

The second Scenarios Forum took place in June 2022 in Laxenburg, Austria. The goal of the second Scenarios Forum was to bring together the diverse set of communities using or developing scenarios in climate change and sustainability analysis to exchange experiences, ideas, and lessons learned; identify opportunities for synergies and collaboration between communities; reflect on the use of scenarios; and identify knowledge gaps for future research. The Scenarios Forum 2022 brought together over 500 researchers onsite and online to share experiences to date on progress toward this goal. The Forum confirmed that the SSP-RCP framework is being widely and increasingly used across a variety of research communities and assessment processes in the climate and biodiversity communities. Key discussions on future needs during the Scenarios Forum included the need for expansion of the solution space to facilitate a wider diversity of response strategies, broadening the labeling of scenarios to facilitate connection to other communities, initiating a discussion on high-end community scenarios and the tension in the scenarios framework between providing building-blocks for scientists and identifying key community-level scenarios

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

Urban and rural energy use and carbon dioxide emissions in Asia

The process of urbanization has been shown to be important for economic development, environmental impacts and human wellbeing, particularly in developing countries. In this paper we compare structure data sources and scenario results of four integrated assessment models that are capable of analyzing different aspects of urbanization. The comparison focuses on residential sector energy use and related CO2 emissions based on a set of urbanization scenarios for China and India. Important insights from this model comparison include that (i) total fossil fuel and industrial CO2 emissions at the regional level are not very sensitive to alternative rates of urbanization and are largely dependent on the linkage between urbanization and economic growth via differentiated labor productivity in urban and rural areas, (ii) alternative urbanization pathways may yield different results for the share of solid fuels in residential energy use, thereby affecting the number of people relying on these fuels and the associated adverse health impacts, and (iii) alternative economic growth scenarios can only be assessed for their welfare implications if urban and rural household are distinguished, even though that distinction does not always strongly affect aggregate outcomes which is often due to two effects that compensate each other in total. It can be concluded that urbanization and heterogeneity of households and consumers are clearly relevant for distributional effects and associated health and social impacts

Porosity of human mandibular condylar bone

Quantification of porosity and degree of mineralization of bone facilitates a better understanding of the possible effects of adaptive bone remodelling and the possible consequences for its mechanical properties. The present study set out first to give a three-dimensional description of the cortical canalicular network in the human mandibular condyle, in order to obtain more information about the principal directions of stresses and strains during loading. Our second aim was to determine whether the amount of remodelling was larger in the trabecular bone than in cortical bone of the condyle and to establish whether the variation in the amount of remodelling was related to the surface area of the cortical canals and trabeculae. We hypothesized that there were differences in porosity and orientation of cortical canals between various cortical regions. In addition, as greater cortical and trabecular porosities are likely to coincide with a greater surface area of cortical canals and trabeculae available for osteoblastic and osteoclastic activity, we hypothesized that this surface area would be inversely proportional to the degree of mineralization of cortical and trabecular bone, respectively. Micro-computed tomography was used to quantify porosity and mineralization in cortical and trabecular bone of ten human mandibular condyles. The cortical canals in the subchondral cortex of the condyle were orientated in the mediolateral direction, and in the anterior and posterior cortex in the superoinferior direction. Cortical porosity (average 3.5%) did not differ significantly between the cortical regions. It correlated significantly with the diameter and number of cortical canals, but not with cortical degree of mineralization. In trabecular bone (average porosity 79.3%) there was a significant negative correlation between surface area of the trabeculae and degree of mineralization; such a correlation was not found between the surface area of the cortical canals and the degree of mineralization of cortical bone. No relationship between trabecular and cortical porosity, nor between trabecular degree of mineralization and cortical degree of mineralization was found, suggesting that adaptive remodelling is independent and different between trabecular and cortical bone. We conclude (1) that the principal directions of stresses and strains are presumably directed mediolaterally in the subchondral cortex and superoinferiorly in the anterior and posterior cortex, (2) that the amount of remodelling is larger in the trabecular than in the cortical bone of the mandibular condyle; in trabecular bone variation in the amount of remodelling is related to the available surface area of the trabeculae