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• Current national policies are not sufficient to meet the Paris Agreement goals. • Collective increase in climate action is needed to stabilize warming at safe levels. • Good practice policies can bridge the emissions gap to a below 2 °C world. • These policies can create a bridge trajectory in key major-emitting countries. One key aspect of the Paris Agreement is the goal to limit the global average temperature increase to well below 2 °C by the end of the century. To achieve the Paris Agreement goals, countries need to submit, and periodically update, their Nationally Determined Contributions (NDCs). Recent studies show that NDCs and currently implemented national policies are not sufficient to cover the ambition level of the temperature limit agreed upon in the Paris Agreement, meaning that we need to collectively increase climate action to stabilize global warming at levels considered safe. This paper explores the generalization of previously adopted good practice policies (GPPs) to bridge the emissions gap between current policies, NDCs ambitions and a well below 2 °C world, facilitating the creation of a bridge trajectory in key major-emitting countries. These GPPs are implemented in eleven well-established national Integrated Assessment Models (IAMs) for Australia, Brazil, Canada, China, European Union (EU), India, Indonesia, Japan, Russia, South Korea, and the United States, that provide least-cost, low-carbon scenarios up to 2050. Results show that GPPs can play an important role in each region, with energy supply policies appearing as one of the biggest contributors to the reduction of carbon emissions. However, GPPs by themselves are not enough to close the emission gap, and as such more will be needed in these economies to collectively increase climate action to stabilize global warming at levels considered safe. [ABSTRACT FROM AUTHOR]

[Display omitted] Mitigation of climate change by reducing the anthropogenic CO 2 emissions has recently gained huge momentum. A prime pathway to achieve it in the short-medium term lies within capturing CO 2 from industries' flue gases. Post-combustion CO 2 capture (PCC) is the most mature methodology for large-scale CO 2 capture and closest to market. However, the conventional chemical absorption-based PCC process implies high regeneration energy requirements, constituting the majority of the energy load when adding PCC to the plant from which the CO 2 is going to be captured. As such, reducing the overall parasitic load of the conventional process is of interest. Changing the solvent or improving the process flowsheet are two main methodologies to achieve higher energetic efficiency and lower exergy losses. As there are several reviews dealing with novel solvents, this review critically evaluates the progress in improving the conventional PCC process through modifications of process configurations and shadowed by solvent replacements as drop-in solutions. The process configurations were grouped into absorption and stripping enhancement categories. A comparative analysis was conducted between the different available schemes in the literature and interactions between solvents and process configurations were showcased, highlighting the advantages and shortcomings of some of them. The review reveals the need for standardized framework and optimization algorithms using exergo-economic performance indicators for integrated solvent and process synthesis. [ABSTRACT FROM AUTHOR]

[Display omitted] • A bi-level joint-probabilistic programming approach is developed. • It can handle leader–follower issues and joint-probabilistic constraints. • The proposed approach is applied to China's multi-regional energy system model. • The optimal schemes during 2021–2050 under three mitigation scenarios are obtained. • Results are helpful to achieve low-carbon goals in multi-regional energy system. Climate change mitigation and renewable resources utilization are becoming particularly urgent for energy system management. In this study, a bi-level joint-probabilistic programming (BJPP) method is developed for planning multi-regional energy system under different mitigation policies and uncertainties. BJPP can handle leader–follower issues in decision-making process as well as examine the risk of violating joint-probabilistic constraints. Based on the BJPP method, a China's multi-regional energy system (named as BJPP_CMES) model is formulated to provide optimal scheme for energy system planning of China over a long-term horizon (2021–2050) by synergistically minimizing carbon dioxide (CO 2) emission and system cost. A series of scenarios associated with different carbon capture and storage (CCS) levels and violation risks of energy-demand constraints are examined. Results reveal that: (i) the share of non-fossil energy in China's energy supply would keep increasing in 2021–2050, and the highest growth of the renewable supply would occur in Ningxia (rising 47.7%); (ii) Sichuan, Inner Mongolia, and Gansu would be the top three suppliers of renewable electricity; (iii) the CO 2 emission of China would reach a peak of [44.3, 54.8] billion tonnes during the period of 2026–2030; Shandong, Inner Mongolia, and Shanxi would be main contributors of CO 2 emission in the future; (iv) compared with the single-level model, the CO 2 emission from the BJPP_CMES model would reduce by [2.7, 5.7]%; (v) among developed regions, the individual probability level of Jiangsu-Zhejiang-Shanghai is the most significant parameter for both CO 2 emission and system cost. The findings are helpful for decision makers to optimize multi-regional energy system (MES) with a low-carbon and cost-effective manner, as well as to provide useful information for renewable energy utilization and regional sustainable development. [ABSTRACT FROM AUTHOR]

• Method was established to model building stock composition in adopted technologies. • Stock model can estimate the baseline development of building stock. • Building stock energy models can be constructed to use building stock data. • The Japanese technology deployment trend can significantly reduce CO 2 emissions. • Efficiency measures help avoid the increase in electricity demand by electrification. A significant improvement in the building stock energy efficiency is imperative to mitigate climate change. Building stock energy models (BSEMs) that employ reference building models are useful for mitigation analysis. However, most existing BSEMs developed for commercial building stock focus on limited building systems and energy conservation measures, and technology deployments are suggested based on simple vintage-driven scenarios. These approaches are insufficient, particularly for regions where improvements to building insulation performances can have a modest impact. This study aims to establish a BSEM framework to overcome this issue and to validate the framework via its application to the Japanese commercial building stock. The framework develops statistical models for estimating the selection probabilities of system alternatives and utilizes them to disaggregate building stocks. A reference building model is developed for each stock segment. The results show that this approach facilitates the use of multiple technological options considering various factors that affect technological deployments, and it also helps estimate the baseline development of building stocks. Furthermore, the developed model well represents the observed distributions in energy use intensity and estimates the aggregated energy consumption of building stocks with a reasonable accuracy. The baseline development was estimated to reduce the CO 2 emission by 18% by 2030 from 2013. Efficiency measures can help avoid the increase in electricity demand caused by electrifying the heat source of heating, ventilating, and air-conditioning and water heating systems. The framework could help extend the scope of BSEM application because BSEM development is not information intensive. [ABSTRACT FROM AUTHOR]

The world needs to rapidly reduce emissions of carbon dioxide (CO 2) emission to stave off the risks of disastrous climate change. In particular, decarbonizing U.S. manufacturing industries is particularly challenging due to the specific process requirements. This study estimates the potential for future CO 2 emission reductions in this important sector. The analysis is a detailed accounting exercise that relies on estimates of emission-reduction potential from other studies and applies those potentials to the manufacturing sector using a bottom-up approach. The actions are grouped into four "pillars" that support deep decarbonization of manufacturing (DDM): Energy Efficiency, Material Efficiency, Industry-Specific, and Power Grid. Based on this bottom-up approach, the analysis shows that an 86% reduction in carbon dioxide emissions from the Reference Case is feasible. No single pillar dominates DDM, although opportunities vary widely by sub-sector. The analysis shows that a strategy incorporating a broad set of elements from each pillar can be effective instead of relying on any single pillar. Some pillars, such as Energy Efficiency and Material Efficiency, have wide applicability; others have key niche roles that are Industry-Specific; the Power Grid pillar requires interaction between grid decarbonization and industry action to switch from fossil fuels to zero-carbon electricity where appropriate. [Display omitted] • Four technological strategies ("pillars") for deep decarbonization of U.S. manufacturing are investigated. • Seven energy-intensive and one non-energy-intensive industries are examined separately. • An 86% reduction in energy related CO 2 emissions is feasible in U.S. manufacturing by 2050. • No single pillar dominates implying a diversified approach to decarbonization is needed. • Some emissions remain in select industries, in particular chemicals. [ABSTRACT FROM AUTHOR]

In recent years, wood has received increased interest in Europe as a multi-storey building material. The trend is driven by the recognition that wood, as an environment friendly material, can contribute bioeconomy development and the achievement of sustainable development goals. In Lithuania, multi-storey wood-based building is still at the level of policy and political discussions. Therefore, the presented research focuses on quantification and comparison of the sustainability impacts of both wood- and concrete-based building materials value chains and provides applied scientific knowledge relevant to decision makers and in this way contributes to mitigation of the climate change. In detail, study covers the production value chain – from raw material extraction to manufacturing using the same method, while documenting and assessing the material sourcing stages transparently and consistently. In our study glue laminated timber and sawn timber building materials represented renewable material value chains, while site-cast concrete and precast reinforced concrete building materials represented non-renewable materials value chains. In discussion with study partners in the BenchValue project and during a project stakeholder workshop, twelve environmental, social and economic indicators were selected to perform the sustainability impact assessment of selected building materials. Building materials were compared by using a decision support tool ToSIA. The relevant data was gathered from local, well-known companies in the national and international arena. Our results revealed that glue laminated timber and sawn timber value chains compared to site-cast concrete and precast reinforced concrete value chains have more positive sustainability impacts. This is especially true when analysing environmental indicators: GHG emissions , Energy use , Generation of wastes and Water use. Analyses also revealed more positive socio-economic impacts of wood-based building materials. The socio-economic advantage of wood could increase competitiveness of the regions and contributes to their sustainable development. Our paper is in line with the applied research. Since it is a case study, the presented results are country specific, because the estimation of indicators was done by applying local data. The presented research is relevant to policy experts and decision makers in the context of the reduction of CO 2 emissions. Also, this paper is relevant to the companies and architects who want to build and compare various building materials. Partially, results of this paper could be applied in other countries with comparable to Lithuania economic development level, having in mind the possible shortcomings already highlighted. • Sustainability impact assessment of building materials are critical for decision makers and influence the choice of materials. • SIA of wood- and concrete-based building materials production value chains (A1-A3) were compared. • A decision support tool ToSIA was applied. • Wood-based value chains showed more positive sustainability impacts compared to concrete-based value chains. • Wood could be the key component in increasing the sustainability of the national construction sector. [ABSTRACT FROM AUTHOR]

Governments foster voluntary actions within households to mitigate climate change. However, the literature suggests that they may not be as effective as expected due to rebound effects. We use a dynamic economy–energy–environment computable general equilibrium (CGE) model of the Catalan economy to simulate the effect of 75 different actions on GDP and net CO 2 emissions, over a 20-year period. We also examine how a carbon tax could counteract the carbon rebound effects. We find energy rebound effects ranging from 61.77% to 117.49% for voluntary energy conservation actions, depending on where the spending is redirected, with similar carbon rebound values. In our main scenarios, where energy savings are redirected to savings and all non-energy goods proportionally, the rebound is between 64.47% and 66.90%. We also find, for these scenarios, that a carbon tax of between 2.4 and 3.6 €/ton per percentage point of voluntary energy reduction would totally offset carbon rebound effects. These results suggest that voluntary actions in households need additional measures to provide the expected results in terms of energy use reduction and climate change mitigation. [ABSTRACT FROM AUTHOR]

• Infrastructure is essential to meet basic needs but require carbon intensive materials. • I assess the material/carbon impact of reaching in 2030 high access to 5 basic infrastructure. • Global material demand is the lowest for water and the highest for transportation. • Providing high sanitation and transportation access conflicts with low-carbon pathways. Access to infrastructure services is essential to meet human basic needs. However, infrastructure construction requires carbon-intensive materials, first and foremost cement and steel. In this paper, I assess if high level of access to 5 basic infrastructure services – electricity, water, shelter, sanitation and transportation – can be provided at the global scale in 2030 and until 2050 without compromising climate mitigation targets. Following historical patterns, I first quantify the cement and steel requirements in each country associated with providing high access levels. I then estimate the production-based carbon dioxide emissions related to manufacturing the cement and steel needs. To do so, I model influencing factors such as national production technologies mix, trade structure and mitigation actions in the cement and steel industries. Global cumulative material demand (central values) to reach high access level in 2030 is the lowest for water with 8 Gt of cement and 1 Gt of steel and the highest for transportation with 50 Gt of cement and 6 Gt of steel. Most of the cement and steel demand is concentrated in Asia, Middle-East and Africa. I show for all infrastructure services that achieving high access level in 2030 and until 2050 induces cumulative carbon dioxide emissions well below the carbon budgets related to Paris Agreement targets, with central values under baseline scenario from 10 to 53 Gt CO 2 depending on the infrastructure service. However, I find providing high sanitation and transportation access in Middle-East and Africa conflicts with existing low-carbon pathways. This calls for on one side implementing material efficiency and substitution towards less carbon-intensive construction materials, and on the other side strengthening mitigation efforts in wealthiest countries to leave enough 'carbon space' for basic infrastructure development in emerging countries. [ABSTRACT FROM AUTHOR]

• The EDGAR dataset provides decades-long time series of GHG emissions for all world countries. • The EDGAR V5.0 updates CO 2 emissions data to 2018 and non-CO 2 to 2015. • EDGAR shows an overall upward trend for global GHG emissions. • A detailed overview of emission trends and features is provided by gas, by activity sector and by geographical areas. Over the last three decades, socio-economic, demographic and technological transitions have been witnessed throughout the world, modifying both sectorial and geographical distributions of greenhouse gas (GHG) emissions. Understanding these trends is central to the design of current and future climate change mitigation policies, requiring up-to-date methodologically robust emission inventories such as the Emissions Database for Global Atmospheric Research (EDGAR), the European Commission's in-house, independent global emission inventory. EDGAR is a key tool to track the evolution of GHG emissions and contributes to quantifying the global carbon budget, providing independent and systematically calculated emissions for all countries. According to the results of the EDGAR v.5.0 release, total anthropogenic global greenhouse gas emissions (excluding land use, land use change and forestry) were estimated at 49.1 Gt CO 2eq in 2015, 50 % higher than in 1990, despite a monotonic decrease in GHG emissions per unit of economic output. Between 1990 and 2015, emissions from developed countries fell by 9%, while emissions from low to medium income countries increased by 130%, predominantly from 2000 onwards. The 27 Member States of the European Union and the United Kingdom led the pathway for emission reductions in industrialised economies whilst, in developing countries, the rise in emissions was driven by higher emissions in China, India, Brazil and nations in the South-East Asian region. This diversity of patterns shows how different patterns for GHG emissions are and the need for identifying regionally tailored emission reduction measures. [ABSTRACT FROM AUTHOR]

• Prior beliefs and demographics affect reading accuracy and knowledge gains from scenarios. • In contrast, effects from different visualization formats analyzed are relatively minor. • Graphs with steep slope are disadvantageous over tables and graphs with gradual slope. • Tailoring formats to demographic and country differences to some extent reduces adverse effects. While scenarios are used extensively for communication about climate change mitigation, little is known about the interpretation of these scenarios by citizens. We conducted a cross-country empirical evaluation of scenario visualizations for global mitigation, using online surveys in Germany (N = 379), Poland (N = 223), and France (N = 225). Each respondent received visualizations of the required changes in global carbon dioxide emissions and composition of electricity supply (fossil fuels, nuclear, and renewable sources) for limiting global warming to 1.5 °C. We evaluated the effects of respondents' demographics, prior beliefs, numeracy, and graph literacy on the reading accuracy and knowledge gains from the visualizations. We also included an experimental between-groups design on visualization format, where four groups received different graph formats (steep or gradual graphs with depictions of uncertainty ranges or scenario ensembles) and the fifth group received a table. Results showed that higher education level, numeracy, and graph literacy increased reading accuracy in all countries, while age reduced them. Respondents with prior beliefs about climate change mitigation that matched the information in the visualizations had also higher reading accuracy and knowledge gains. While the effects of different visualization formats were comparatively minor, customizing formats according to demographic and country differences was used to reduce adverse effects from these differences. These results emphasize the need to design visualizations that match characteristics of the intended audience and could inform better communication of climate change mitigation scenarios to non-expert audience. [ABSTRACT FROM AUTHOR]

• We estimated economic value of sequestered carbon in California's coastal habitat. • Lack of site-specific carbon sequestration data hampers current valuation efforts. • Sub-national blue carbon policy can help countries keep Paris Agreement commitments. • Valuation of sequestration helps governments meet commitments to greenhouse gas goals. The emissions reduction pledges made by individual countries through the 2015 Paris Agreement represent the current global commitment to mitigate greenhouse gas emissions in the face of the enduring climate crisis. Natural lands carbon sequestration and storage are critical for successful pathways to global decarbonization (i.e., as a negative emissions technology). Coastal vegetated habitats maintain carbon sequestration rates exceeding forest sequestration rates on a per unit area basis by nearly two orders of magnitude. These blue carbon habitats and their associated carbon sequestration benefits are vulnerable to losses from land-use change and sea-level rise. Incorporation of blue carbon habitats in climate change policy is one strategy for both maintaining these habitats and conserving significant carbon sequestration capabilities. Previous policy assessments have found the potential for incorporation of coastal carbon sequestration in national-level policies, yet there has – to date – been little inclusion of blue carbon in the national-scale implementation of Paris commitments. Recently, sub-national jurisdictions have gained attention as models for pathways to decarbonization. However, few previous studies have examined sub-national level policy opportunities for operationalizing blue carbon into climate decision-making. California is uniquely poised to integrate benefits from blue carbon into its coastal planning and management and its suite of climate mitigation policies. Here, we evaluated legal authorities and policy contexts addressing sequestration specifically from blue carbon habitats. We synthesized the progressive action in California's approaches to mitigate carbon emissions including statutory, regulatory, and non-regulatory opportunities to incorporate blue carbon ecosystem service information into state- and local-level management decisions. To illustrate how actionable blue carbon information can be produced for use in decision-making, we conducted a spatial analysis of blue carbon sequestration in several locations in California across multiple agencies and management contexts. We found that the average market values of carbon sequestration services in 2100 ranged from $7,730 to $44,000 per hectare and that the social cost of carbon sequestration value was 1.3 to 2.7 times the market value. We also demonstrated that restoration of small areas with high sequestration rates can be comparable to the sequestration of existing marshes. Our results illustrate how accessible information about carbon sequestration in coastal habitats can be directly incorporated into existing policy frameworks at the sub-national scale. The incorporation of blue carbon sequestration benefits into sub-national climate policies can serve as a model for the development of future policy approaches for negative emissions technologies, with consequences for the success of the Paris Agreement and science-based decarbonization by mid-century. [ABSTRACT FROM AUTHOR]

There is a lack of studies on assessing long-term impacts of different sectors on shrinking global carbon budget. Present study focuses on assessing contribution of electric vehicles (EVs) with improving electricity grids' efficiency (EGs) and minimizing 'transmission and distribution' (T&D) losses in reducing carbon dioxide (CO 2) emissions and fulfilling emission targets for 2030 and 2050. Eleven different scenarios are articulated with estimated uncertainties for Mumbai Metropolitan Regions' (MMRs') passenger transportation using data extracted from MMR's Comprehensive Mobility Plan's transportation model. A novel methodology is developed to estimate local carbon budget targets from global targets between 2018 and 2050. The estimations indicate that carbon emissions in 'business as usual' scenario are 252%, 505%, and 55% above the targets for 2 °C, 1.5 °C, and Intended Nationally Determined Contributions (INDC), respectively. Study also shows that introducing EVs in MMR without simultaneously improving EGs will generate more net CO 2 emissions than BAU. EVs with EG and T&D improvements are not enough to meet the estimated targets. However, their combined contribution significantly reduces CO 2 emission by half and reaches peak emission by 2025 from post-half-century. • Developed a novel methodology to estimate local carbon budget. • Transport emissions assessment with electric vehicle, electricity grid (EG), and T&D losses. • Interventions are unable to achieve carbon budget targets of 2 °C, 1.5 °C, and INDC. • Electric vehicles are not suitable without improving EG efficiency, and T&D losses. [ABSTRACT FROM AUTHOR]

Global climate change is a key concern in today's world, especially with the growth of population and industrial activities. One of the biggest sources of climate change is anthropogenic greenhouse gas emissions. In Canada, buildings are the third largest emitter of greenhouse gases, contributing to 12% of the country's equivalent Carbon dioxide emissions. These emissions have various negative impacts on the planet, which impede the transition towards a cleaner environment and more sustainable communities. Attention has now shifted towards Carbon dioxide reduction in addition to the currently practiced energy efficiency improvements and source switching, which is also important in achieving Canada's 2030 climate action goals. The current study attempts to address the above gap by investigating the feasibility of installing carbon capturing unit at building level, based on the perceptions of building managers in both multi-unit residential buildings and non-residential buildings. A Modified Digital Logic approach was used to identify the key factors that determine the acceptability of the unit, based on experts' input. Six primary criteria were identified to design a questionnaire and structured interviews to evaluate the acceptability of building level carbon capturing unit to stakeholders. The findings indicated that around 50% of non-residential building managers were interested in installing the carbon capturing unit, whereas none of the multi-unit building managers were in favor of the unit installation. The lack of interest is attributed to different factors such as unit scalability, inability to accurately estimate the short and long-term economic benefits, and other alternate plans to reduce carbon dioxide emissions. Specifically, when establishing relationship between cost and unit scalability, 82% of residential unit managers and 50% of non-residential managers opined that the unit should be capable of being upgraded to accommodate a larger area and capture more emissions in order to justify the proposed cost of the unit. The findings provide important insights for policy makers in understanding the acceptability of carbon capturing unit at building level and to further develop and promote this emerging technology in the market. [Display omitted] [ABSTRACT FROM AUTHOR]

Climate aid refers to official development assistance relevant for mitigation and adaptation, and it is an important guarantee for action against climate change. Meanwhile, evidences suggesting that a large portion of climate aid flows to energy areas and the resulting energy restructuring is highly associated with carbon emissions in recipient countries. Focusing on the complicated relations among climate aid, energy structure and carbon emissions in recipient countries, we aim to investigate the influencing mechanism of climate aid. According to the theoretical analysis, we suppose that climate aid has both direct and indirect carbon reduction effects on recipient countries. And on the empirical analysis, based on the national panel data of 52 recipient countries from 1980 to 2016, the mediation model is used to empirically-test the above dual carbon reduction mechanism. In the direct path, climate aid can directly reduce carbon emissions by monitoring their implementation effect and increasing carbon reduction resources in recipient countries. As for the indirect effect, climate aid with low-carbon technology attribute can promote the gradual substitution of clean energy for traditional fossil energy to optimize energy structure, and ultimately reduce the carbon emissions in recipient countries. This study provides useful enlightenments for fulfilling the climate aid commitments, better utilizing climate aid, building low-carbon energy systems, and exploring broader environmental benefits. • We study the influence mechanism of climate aid on carbon emissions. • Climate aid has both direct and indirect carbon reduction effects. • The implementation of climate aid projects ensures the direct reduction effect. • Climate aid indirectly reduces emissions through reducing fossil energy consumption. [ABSTRACT FROM AUTHOR]

With the deepening of the global division of labor, it is significant to analyze the impact of global value chain participation on embodied carbon emission intensity. It provides implications for countries to address climate issues and improve development quality. The present work uses a multi-region input-output table provided by World Input Output Database to calculate the global value chain participation and the embodied carbon emission intensity of 42 different countries, for the period between 2000 and 2014. In addition, we decompose the carbon emission intensity into the carbon emission intensity embodied in domestic demand and foreign exports demand, and the carbon emission intensity of foreign exports demand is further divided into three types of embodied carbon emission intensity. Then, we analyze how global value chain participation affects the embodied carbon emission intensity, and examine different impacts across different development countries and different types of embodied carbon emission intensity. We also explore the different impacts under different embodied carbon emission intensity distributions. The results show that global value chain participation has a significantly negative impact on the embodied carbon emission intensity. Compared with the developed "north" countries, the global value chain participation of developing "south" countries have a larger negative impact of embodied carbon emission intensity. From the perspective of different types of demand, the impact of global value chain participation on carbon emission intensity embodied in foreign exports demand is greater than that embodied in domestic demand. The quantile regression results show that the global value chain participation at the high quantiles has a greater impact on the embodied carbon emission intensity, which indicates countries with higher embodied carbon emission intensity should participate in the global value chain to expand the production scale while reducing carbon emissions. These results provide relevant material and insights to countries about how their participation in the global production fragmentation affects their greenhouse gas emission profile, which can be used to elaborate structured political measures to address, at the same time, global market inclusion and climate change mitigation. • We construct a model to decompose the embodied carbon emission intensity (CEI) into four types of CEI. • We estimate the impact of global value chain participation (GVCP) on embodied CEI. • GVCP has significant negative impact on the embodied CEI and is greater for CEI embodied in foreign exports demand. • Compared with the developed "north" countries, the GVCP of developing "south" countries have a larger negative impact. • The GVCP at the high quantiles has a greater impact on the embodied CEI. [ABSTRACT FROM AUTHOR]

• Incorporate the emission inventory into an improved emission spatial mapping model. • Provide an estimate of emission characteristics and spatial distribution in cities. • Conduct the driving forces and emission reduction targets based on Paris Agreement. • Localized reduction policies are the keys to achieving low carbon city development. The identification of CO 2 emissions in megacities is vitally important to promote a transition to low-carbon city. This study aims to analyze the CO 2 emission characteristics and spatial distribution in megacities among different countries, which is important for climate change mitigation. In this study, 12 megacities from China, Japan, and South Korea were selected as typical case studies for analysis. Results show that Chinese cities' CO 2 emissions are among the top four cities studies and are much higher when compared to the other sample cities in Japan and South Korea. Chongqing, Incheon, Tianjin, and Shanghai were the top four cities with the highest carbon intensity. The spatial distribution of urban carbon emissions varies widely. In Seoul, Tokyo Metropolis, and Beijing, 90% of carbon emissions are concentrated on 74.17%, 55.95% and 8.93% of the land area, respectively. The results of the driving forces and emission reduction targets analysis indicate that the three countries face different challenges and there are different action plans in each city accordingly. This study proposed the carbon emissions reduction targets and countermeasures in different industrial sectors, including an increased rate of the standardization of city CO 2 emission accounting systems and the decarbonization of the power industry, among others. These countermeasures will not only contribute to the analysis of CO 2 emissions but will also promote to the low-carbon city development and encourage the realization of urban sustainable development goals. [ABSTRACT FROM AUTHOR]

Carbon capture and storage (CCS) is one of the most promising mitigation strategies for reducing the emissions of carbon dioxide (CO 2) to the atmosphere and may substantially help to decelerate global warming. There is an increasing demand for CCS sites. Nevertheless, there is a lack of knowledge of the environmental risk associated with potential leakage of CO 2 from the storage sites; and even more, what happens when the seepage stops. Can the environment return to the initial equilibrium? Potential effects on native macrofauna were studied under a scenario of a 50-day CO 2 leakage, and the subsequent leak closure. To accomplish the objective, Trondheim Fjord sediments and clams were exposed to an acidified environment (pH 6.9) at 29 atm for 7 weeks followed by a 14-day recovery at normal seawater conditions (pH 8.0, 29 atm). Growth and survival of clams exposed to pressure (29 atm) and reduced pH (6.9) did not significantly differ from control clams kept at 1 atm in natural seawater. Furthermore, bioaccumulation of elements in the soft tissue of clams did not register significant variations for most of the analysed elements (Cd, Cr, Pb, and Ti), while other elements (As, Cu, Fe, Ni) had decreasing concentrations in tissues under acidified conditions in contrast to Na and Mg, which registered an uptake (Ku) of 111 and 9.92 μg g−1dw d−1, respectively. This Ku may be altered due to the stress induced by acidification; and the element concentration being released from sediments was not highly affected at that pH. Therefore, a 1 unit drop in pH at the seafloor for several weeks does not appear to pose a risk for the clams. Image 1 • Acidification and recovery were assessed with high-pressure bioassays. • No mortality was reported for Astarte sp. for a pH 7.0 scenario. • Normal growth of shell length was recorded after CO 2 exposure and a recovery period. [ABSTRACT FROM AUTHOR]

• Establishes a comprehensive framework to explore the multiple-effects exerted by urbanization on future building carbon emissions. • Constructs a carbon emission dynamic scenario simulation model by combining the extended Kaya identity and Monte Carlo simulation. • The building sector will reach its peak at 3.09 (±0.36) Bt CO 2 in 2037 (±4). • Rural residential building sector will be the first to reach its energy and emission peak. • Economic urbanization and space urbanization exert major promoting effects on the peaking time and emission peaks of building carbon emissions. The accelerating urbanization has posed great challenges to China's carbon-mitigation efforts and global climate change response. However, how does the urbanization process impact the peak of future carbon emissions from buildings is still unclear. This study first establishes a comprehensive urbanization framework from three dimensions. Then, a dynamic scenario simulation model is innovatively constructed by combining the extended Kaya identity and Monte Carlo simulation approach to explore future dynamic evolution trajectory, possible peaks and peaking time of China's building carbon emissions from 2000 to 2050, considering the uncertainties of factors. Finally, dynamic sensitivity analysis is performed to investigate the contributions of different dimensions of the urbanization. Results show that under the business-as-usual scenario, the rural residential building sector will be the first to reach its energy peak in 2027. Dynamic scenario simulation shows that the building sector will peak at 3.09 (±0.36) Bt CO 2 in 2037 (±4). Specifically, the urban residential building sector will peak at 1.27 (±0.18) Bt CO 2 in 2040 (±4), while the rural residential building sector will peak at 0.51 (±0.03) Bt CO 2 in 2021 (±4) and the commercial building sector will peak in 2038 (±4) at 1.41 (±0.30) Bt CO 2. Dynamic sensitivity analysis indicates that rural–urban migration will exert promoting effect on the peaking time and emission peaks of building carbon emissions through the concomitant effects of the urbanization process, i.e., the economic urbanization and space urbanization. Overall, this study can provide a better insight into the impact of urbanization on carbon emission peak and can support governments and decision-makers to formulate effective carbon-mitigation strategies. [ABSTRACT FROM AUTHOR]

Sweden and Finland have national goals to reach net negative greenhouse gas emissions before mid-century. Achieving these ambitious goals could employ negative emission technologies, such as bioenergy with carbon capture and storage, but it is unclear how this technology could be realized in an energy transition. Sweden and Finland stand out for having a large share of substantial point source emissions of biogenic carbon dioxide, in the production of pulp, heat and power. In the European Pollutant Release and Transfer Register, Sweden and Finland reported 64% and 51% biogenic emissions, respectively, in facilities emitting over 100 kt of carbon dioxide in 2017, while the corresponding collective figure for all European states in the database is 6%. This qualitative study highlights company actors' perspectives on bioenergy with carbon capture and storage within a Nordic regional context and explores their perspective on emerging tensions in the energy transition. Semi-structured interviews were conducted with 20 of the 24 companies with the largest point sources of biogenic emissions. The results are framed around four emerging tensions regarding bioenergy with carbon capture and storage from companies' perspectives in this study: (1) absence of reliable long-term policies; (2) limits to companies' climate change responsibility; (3) technical trade-offs of carbon capture; and (4) lack of customer demands for negative emissions. According to most of the companies, it is technically feasible to capture carbon dioxide, but it could be a challenge to determine who is responsible to create a financially viable business case, to enact supporting policies, and to build transport and storage infrastructure. Company representatives argue that they already contribute to a sustainable society, therefore bioenergy with carbon capture and storage is not their priority without government collaboration. However, they are willing to contribute more and could have an increasing role towards an energy transition in an international context. • BECCS discussions are on the horizon, but few companies are first movers. • Large-scale deployment of BECCS would require political and financial support. • Swedish and Finnish companies lack customer demand for negative emissions. • There are trade-offs between energy efficiency and carbon capture. • Companies consider BECCS as one of many climate change mitigation measures. [ABSTRACT FROM AUTHOR]

• EBSR divides responsibility for emissions in trade between producers and consumers. • EBSR goes beyond consumption-based (CBA) and production-based (PBA) accounting. • Responsibility is proportional to economic benefits from emitting free of charge. • With EBSR, China is attributed higher responsibility for emissions than in CBA. • Lower responsibility is attributed to both the US and the EU. How to share responsibility for greenhouse gas emissions between consumers and producers is a highly sensitive question in international climate policy negotiations. Traditional 'Production-Based Accounting' (PBA), which assigns responisibility to the region where emissions are released, has frequently been challenged by 'Consumption-Based Accounting' (CBA) schemes that suggest that greenhouse gas emissions generated to produce traded goods and services should be attributed to their final consumers. PBA and CBA both lack a sound foundation in economic theory as they do not consider the economic benefits accruing to producers or consumers if carbon emissions do not carry a price that reflects their social costs. We build on well-established economic theory to derive how to share responsibility for trade-related emissions between producers and consumers and apply this novel approach for the most prominent bilateral trade relationships using multi-regional input–output data. We propose an 'Economic Benefit Shared Responsibility' (EBSR) scheme, in which China is attributed significantly higher responsibility for emissions than in CBA, while lower emissions and responsibility are attributed to both the US and the EU. [ABSTRACT FROM AUTHOR]

The carbon footprint (CF) has emerged as an important yardstick to understand the total contribution of countries, sectors and individuals to climate change. In contrast to conventional emissions accounting which captures only territorial or local production activities, the CF includes the emissions imposed by consumption across global supply chains for goods and services. Recent interest has grown in the application of CF assessment for municipalities owing to their large contribution to global carbon emissions and the limited coverage of existing data to monitor their climate pledges. By linking household-level consumer surveys to a global supply chain database, spatially-explicit CF assessment is possible at a district and household scale. To date, such technique has exposed otherwise unforeseen differences in consumer carbon footprints in developed countries. Within this study we calculate and compare the household carbon footprints 623 districts in India, based on micro consumption data from 203,313 households and explain their variation by economic, cultural and demographic factors. We show the eradication of extreme poverty does not conflict with ambitious climate change mitigation in India. However, our analysis suggests CF reduction policies within India need to target high-expenditure households which are responsible for nearly seven times the carbon emissions than low-expenditure households (living on $1.9 consumption a day). These vast disparities between the carbon footprint of citizens in India highlights the need to differentiate individual responsibilities for climate change in national and global climate policy. [ABSTRACT FROM AUTHOR]