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[Display omitted] • Contribution variations of various policies to PM 2.5 deaths are quantified by period and region. • Carbon and pollution controls can enable 79% to reside in low PM 2.5 areas by 2060. • Population aging could double PM 2.5 deaths by 2060 if other factors remain constant. • A joint effort for carbon and pollution could prevent 2.15 million PM 2.5 deaths by 2060. • Pollution controls can greatly reduce PM 2.5 before 2030, but climate policy becomes crucial after. To confront the challenges posed by air pollution and climate change, China has undertaken significant initiatives to develop strategies that address both issues concurrently. However, the health benefits of these initiatives have not been clearly articulated. In this study, the dynamic changes in health impacts under air pollution and carbon reduction actions in China are evaluated by employing the latest concentration–response models and projected PM 2.5 concentrations under future scenarios. From 2020 to 2060, the enforcement of clean air and climate mitigation policies is expected to increase the percentage of the population living with PM 2.5 concentrations meeting the 10 μg/m3 standard by 79 %. Without the implementation of relevant mitigation measures, PM 2.5 -associated deaths are projected to double due to an aging population. In comparison to the 2060 reference scenario, the joint implementation of clean air and carbon neutrality measures is expected to reduce nationwide PM 2.5 -associated mortality by 62 %, equivalent to 2.15 (95 % CI: 1.80–2.48) million deaths. Stringent pollution controls are crucial for reducing PM 2.5 -associated deaths before 2030, after which carbon neutrality actions become increasingly significant from 2030 to 2060. The challenges of mitigating future PM 2.5 -associated deaths vary greatly across regions, showing a critical response to pollution control and carbon reduction. The research proves the effectiveness of China's future air pollution control and carbon reduction policies in mitigating PM 2.5 -associated deaths. [ABSTRACT FROM AUTHOR]

Climate aid is a form of official development assistance that addresses climate change mitigation and adaptation and plays a crucial role in combating climate change. However, existing empirical evidence does not suggest a clear link between climate aid and carbon lock-in. Based on country-level panel data from 77 countries spanning the period 2002–2020, this paper empirically examines the impact of climate aid on carbon lock-in and the four sub-indicators of carbon lock-in. Moreover, we investigate the mediating role of technological progress and potential impact mechanisms. We find that (1) climate aid has a significant restraining effect on carbon lock-in, and is an effective means of inhibiting the four aspects of carbon lock-in, namely, the lock-in of industry, institution, technology, and social behavior. (2) Technological progress not only directly leads to carbon lock-in eradication, but also synergizes with climate aid, suggesting that the combined influence of technological progress and climate aid can enhance the efficacy of efforts to mitigate carbon lock-in. (3) Climate aid promotes carbon lock-in mitigation by accelerating energy structure transition and industrial structure transition, which are two internal impact mechanisms in the nexus between climate aid and carbon lock-in. These findings offer concrete and practical policy implications to facilitate the development of climate aid and carbon lock-in eradication. • This paper estimates the impact of climate aid on carbon lock-in. • Climate aid significantly mitigates carbon lock-in and its four dimensions. • Technological progress can further strengthen the inhibiting effect of climate aid on carbon lock-in. • Climate aid indirectly affects carbon lock-in by promoting energy structure transition and industry structure transition. [ABSTRACT FROM AUTHOR]

Petrochemical producers both rely upon and generate some of the most problematic substances in the current age of socioecological crisis: fossil fuels and plastics. With mounting calls to cap fossil fuel extraction as well as plastics production, the industry appears to be caught between a rock and a hard place. Nonetheless, betting on continuously increasing global plastic demand, petrochemical production is expanding significantly. This predicament raises the question of how the industry attempts to square increasing petrochemical production with the need to address environmental issues. In recent years, leading actors in and around the industry have promoted notions of carbon circularity as a desirable mitigation strategy. In this paper, we examine this strategy, using discourse analysis to uncover what we refer to as the imaginary of circular carbon. We highlight how the circular carbon imaginary risks delaying climate mitigation by rendering alternative mitigation pathways undesirable. It does so by reconciling increased production, carbon neutrality, and circular economy in a vision of a circular carbon economy, framing the climate crisis as an issue of carbon management. In the circular carbon economy, carbon dioxide, petrochemicals, and plastics all fit as mere flows of carbon. The circular carbon imaginary thereby helps future-proof the petrochemical industry in legitimizing its carbon-intensive practises essential to the fossil world order and the plastic crisis. • We explore the circular carbon imaginary as promoted by the petrochemical industry. • It is a mitigation strategy centred around circular and diversified carbon flows. • That relies on largely unproven technologies and frames out short-term mitigation pathways. • By doing so, it risks delaying climate mitigation. [ABSTRACT FROM AUTHOR]

• We examine the impacts of personal social capital and national carbon dependency on citizens' response to climate change in 22 European countries. • We utilize individual-level data from the 2016 European Social Survey and corresponding country-level data from multiple sources. • We conduct multilevel regression for analyses. • People with higher social capital are more likely to have climate-mitigation behavioral intention and show support for climate policy. • Greater national carbon dependency tends to inhibit public response to climate change. Climate change is one of the most challenging issues facing the world today, and it is important to have effective policies to address its impact. One critical factor in shaping climate policy is public response to climate change. In this study, we theoretically and empirically focus on examining the impacts of personal social capital and national carbon dependency on citizens' response to climate change in 22 European countries. Utilizing individual-level data from the 2016 European Social Survey and corresponding country-level data from multiple sources, we conduct multilevel regression analyses. Findings show that in these 22 European countries people with higher social capital are more likely to have climate-mitigation behavioral intention and show support for climate policy, while greater national carbon dependency tends to inhibit public response to climate change. We conclude by discussing this study's contributions to the literature and policy implications and offer suggestions for future research. [ABSTRACT FROM AUTHOR]

• Carbon efficiency and abatement costs of the PLEEZ are estimated. • The regional heterogeneity among the three major types of functional zones in the PLEEZ are analyzed. • Major agriculture production zone has a higher carbon efficiency and lowest abatement costs in the PLEEZ. • The global non-radial directional distance function and its dual model are used. In this paper we investigate the carbon efficiency and abatement cost for different main functional regions in China, to test whether major agriculture production zone has higher carbon efficiency and abatement cost than other functional regions. For this purpose, we use a global non-radial distance function to examine the efficiency and abatement cost of carbon emissions and take China's Poyang Lake Ecological Economics Zone (PLEEZ), one of China's national strategy for sustainable development, as an empirical study. By using the non-radial efficiency model, the carbon emissions efficiency indicator can be constructed. By employing the dual model of the non-radial directional distance function, the shadow prices of carbon emissions, which is interpreted as marginal abatement cost can be derived. County level data from 2009 to 2013 of the PLEEZ is used as the empirical investigation. Empirical results show that the CO 2 emissions of the PLEEZ are not performing efficiently and the CO 2 emissions efficiency remains at a very low level with an average value of 0.279. Meanwhile, the shadow prices of CO 2 emissions are calculated, with a mean value of 11.867 yuan per ton, which is relatively low compared with other previous studies of different regions or industry and indicate that carbon emissions are not strictly regulated. Moreover, significant heterogeneities in the carbon efficiency and abatement cost are found among three major functional zones in the PLEEZ remain. Major agriculture production zone shows better carbon efficiency than key ecological function zone, but lower than key economic development zone. It is also found carbon abatement cost of major agriculture production zone is lower than key economic development zone indicating the less pressure under climate change mitigation. [ABSTRACT FROM AUTHOR]

This study adapts the Faustmann model (1849) to include the effects of carbon-based payments for environmental services on the optimal rotation length of forest plantations. We assume payments occur at the end of the harvesting cycle and are based on the additional average carbon stock over the rotation length relative to an optimal management scenario without carbon incentives. We present numerical applications of our model based on the four most planted tree species in the world: Eucalyptus sp., Acacia sp., Pinus sp. and Tectona sp. Simulations were performed to quantify the impact of different payment levels (USD Mg CO 2 −1) on optimal rotation lengths and carbon stocks. We find diminishing sequestration returns to increasing carbon payments. Overall, our results suggest that targeting plantations with longer rotations, associated with slow-growing species, is a more cost-effective strategy to retain additional forest carbon stored (USD Mg CO 2 −1). However, such a strategy results in lower proportional increases in carbon stocks (Mg CO 2 ha−1) compared to faster-growing species, which benefit the most from the carbon incentives. As a result, increasing payments for additional carbon stored could change the choice of which tree species to produce and ironically promote plantations with lower total carbon stocks. • PES are based on the additional average carbon stock over the rotation length. • We find diminishing sequestration returns to increasing carbon payments. • Carbon payments may change the choice of which tree species to produce. [ABSTRACT FROM AUTHOR]

• Global carbon inequality rising from 2005 to 2015. • Top income group in developing economies surpassed the peers in developed economies in 2014. • Most developed economies had declining carbon footprints with expanding carbon inequality. • Most developing economies had rising footprints with different trend in carbon inequality. • Mitigation efforts could raise carbon inequality. Carbon inequality is the gap in carbon footprints between the rich and the poor, reflecting an uneven distribution of wealth and mitigation responsibility. Whilst much is known about the level of inequality surrounding responsibility for greenhouse gas (GHG) emissions, little is known about the evolution in carbon inequality and how the carbon footprints of socio-economic groups have developed over time. Inequality can be reduced either by improving the living standards of the poor or by reducing the overconsumption of the rich, but the choice has very different implications for climate change mitigation. Here, we investigate the carbon footprints of income quintile groups for major 43 economies from 2005 to 2015. We find that most developed economies had declining carbon footprints but expanding carbon inequality, whereas most developing economies had rising footprints but divergent trends in carbon inequality. The top income group in developing economies grew fastest, with its carbon footprint surpassing the top group in developed economies in 2014. Developments are driven by a reduction in GHG intensity in all regions, which is partly offset by income growth in developed countries but more than offset by the rapid growth in selected emerging economies. The top income group in developed economies has achieved the least progress in climate change mitigation, in terms of decline rate, showing resistance of the rich. It shows mitigation efforts could raise carbon inequality. We highlight the necessity of raising the living standard of the poor and consistent mitigation effort is the core of achieving two targets. [ABSTRACT FROM AUTHOR]

Abstract Understanding carbon emissions embodied in trade is an important prerequisite for the effective formulation of climate mitigation policies. Based on input–output analysis and panel regression models, this study proposes a multi-step forecasting procedure to simulate carbon emissions embodied in bilateral trade. We calculate carbon emissions embodied in the trade between China and Australia during 2000–2014 and forecast the same for the period 2015–2022 under four different development scenarios. The results show that, during 2000–2014, net carbon outflow from China to Australia increased from 2.2 to 15.5 Mt CO 2 , concentrated in textile and heavy manufacturing sectors. The simulation results show that, the forecasts of "R&D focus" and "GDP focus" scenarios constitute the lower and upper bounds of embodied emissions, and the latter is more than two times of the former in 2022 both for embodied emissions in Australia's exports and China's exports. Finally, conclusions are drawn and policy implications are discussed. Highlights • A multi-step forecasting procedure of carbon emissions embodied in trade is proposed. • Carbon emissions embodied in China–Australia trade during 2000–2014 are analyzed. • A scenario analysis is conducted for emissions embodied in China–Australia trade. [ABSTRACT FROM AUTHOR]

Indigenous communities (ICs) have emerged as important players in global efforts to reduce forest carbon emissions, in part because they are viewed as conscientious stewards of the forest lands to which they have legal title. Yet ICs tend to be located in remote areas where deforestation would be limited regardless of who manages them. Therefore, to determine whether IC management actually cuts forest carbon emissions, it is important to control for such confounding factors. To that end, we use propensity score matching and regression to analyze the effects on 2001–2013 deforestation and forest carbon emissions of IC management in the Amazon regions of Bolivia, Brazil, Ecuador and Colombia. We find that IC management reduces both deforestation and forest carbon emissions in Bolivia, Brazil and Colombia. We are not able to discern a statistically significant effect in Ecuador. These findings suggest that IC management can, in fact, help combat climate change. [ABSTRACT FROM AUTHOR]

Highlights • Driving forces behind behaviors and their carbon intensities are different. • Highly populated areas have lower reduce emissions in domains of high lock-in. • Income, household size, heating source and refurbishment trends should be regarded. • Top-down incentives are needed to tackle emissions for air travel and fossil fuels. • Car-ownership is a significant carbon lock-in even at low travel distances. Abstract As climate policy needs to address all feasible ways to reduce carbon emissions, there is an increasing focus on demand-side solutions. Studies of household carbon footprints have allocated emissions during production to the consumption of the produced goods, and provided an understanding of what products and consumer actions cause significant emissions. Social scientists have investigated how attitudes, social norms, and structural factors shape salient behavior. Yet, there is often a disconnect as emission reductions through individual actions in the important domains of housing and mobility are challenging to attain due to lock-ins and structural constraints. Furthermore, most behavioral research focuses on actions that are easy to trace but of limited consequence as a share of total emissions. Here we study specific alternative consumption patterns seeking both to understand the behavioral and structural factors that determine those patterns and to quantify their effect on carbon footprints. We do so utilizing a survey on consumer behavioral, attitudinal, contextual and socio-demographic factors in four different regions in the EU. Some differences occur in terms of the driving forces behind behaviors and their carbon intensities. Based on observed differences in mobility carbon footprints across households, we find that the key determining element to reduced emissions is settlement density, while car ownership, rising income and long distances are associated with higher mobility footprints. For housing, our results indicate that changes in dwelling standards and larger household sizes may reduce energy needs and the reliance on fossil fuels. However, there remains a strong need for incentives to reduce the carbon intensity of heating and air travel. We discuss combined effects and the role of policy in overcoming structural barriers in domains where consumers as individuals have limited agency. [ABSTRACT FROM AUTHOR]

Biochar products that hold and release water within a stable carbonised porous structure provide many opportunities for climate mitigation and a range of applications such as for soil amendments. Biochar that are produced from various organic feedstocks by pyrolysis can provide multiple co-benefits to soil including improving soil health and productivity, pH buffering, contaminant control, nutrient storage, and release, however, there are also risks for biochar application in soils. This study evaluated fundamental biochar properties that influence Water Holding Capacity (WHC) of biochar products and provides recommendations for testing and optimising biochar products prior to soil applications. A total of 21 biochar samples (locally sourced, commercially available, and standard biochars) were characterised for particle properties, salinity, pH and ash content, porosity, and surface area (with N 2 as adsorbate), surface SEM imaging, and several water testing methods. Biochar products with mixed particle size, irregular shapes, and hydrophilic properties were able to rapidly store relatively large volumes of water (up to 400% wt.). In contrast, relatively less water (as low as 78% wt.) was taken up by small-sized biochar products with smooth surfaces, along with hydrophobic biochars that were identified by the water drop penetration test (rather than contact angle test). Water was stored mostly in interpore spaces (between biochar particles) although intra-pore spaces (meso-pore and micropore scale) were also significant for some biochars. The type of organic feedstock did not appear to directly affect water holding, although further work is needed to evaluate mesopore scale processes and pyrolytic conditions that could influence the biochemical and hydrological behaviour of biochar. Biochars with high salinity, and carbon structures that are not alkaline pose potential risks when used as soil amendments. [Display omitted] • Optimisation of biochar surface structure will also enhance WHC. • Increase in meso-porosity increases WHC and decreases hydrophobicity. • Considering inter-particle porosity is critical for biochar WHC. • Surface angularity and roughness of biochar enhances its WHC. • Modified methods for key biochar characterisations for soil application are provided. [ABSTRACT FROM AUTHOR]

Latin America is one of the most urbanized region in the world, where patterns of urbanization are disorganized and disjoint from urban planning, with unknown effects for ecosystem services (ES). We evaluated the ES in Bogota and Santiago for a 30-year period. Using remote sensing data, models and census data we quantified carbon regulation, climate mitigation and recreation potential. We assessed ES provision changes and their spatio-temporal patterns using landscape metrics. Urban vegetation patterns differ between the two cities because of climate variability and greening policies. Bogota stored more carbon than Santiago given to climate effects, differences within city were the result of different policies and management. Climate mitigation showed similar behavior for both cities, influenced by global climate, densification and urban sprawling. Recreation potential increased in the inner-city and decrease at the outskirts, reflecting unplanned urban sprawling and increase population. Areas of high ecosystem services connected for Bogota and fragmented for Santiago. Bogota improved its environmental condition, as evaluated by ES provision, while Santiago worsens, even there was an increased in vegetation cover. Vegetation cover was not a sufficient indicator for ecosystem services and the distribution of it becomes highly relevant for informing mismatches between services and vegetation. [ABSTRACT FROM AUTHOR]

Replacing fossil fuels by logging-residue-based bioenergy has been proposed as a way to mitigate climate change. If residues are combusted for energy, their carbon content is released immediately. Residues, that are not combusted, decompose and emit carbon gradually. The relative harmfulness of bioenergy emissions therefore depends on how strongly we prefer the slow release of carbon to an immediate one. Two factors affect this judgment: (1) our time preference and (2) our expectations regarding the relative harmfulness of future carbon emissions. Neither aspect is included in established biomass emission factors. The Effective Emission Factor (EEF), outlined in this study, includes both aspects in a transparent and tractable way. We demonstrate the concept by deriving the EEFs for the logging residues of three Nordic tree species: Norway spruce (Picea abies), Scots pine (Pinus sylvestris) and silver birch (Betula pendula). We also examine the sensitivity of the results to variation in time preference and damage expectations. The derived factors can be used to compare the harmfulness of carbon emissions from residue-based bioenergy and fossil fuel combustion and to organize bioenergy carbon taxation consistently with the taxation of fossil fuels. [ABSTRACT FROM AUTHOR]

So far, research has insufficiently addressed the long-term effectiveness of business responses to climate change in delivering actual outcomes. The aim of this article is therefore to analyze the determinants of such strategies and their influence on firms' financial and carbon performance over time. It is argued that corporate carbon strategies have three main objectives: carbon governance, carbon reduction and carbon competitiveness. To assess the complex interactions between these strategic objectives, their determinants and outcomes, an integrative structural equation model is developed and empirically tested. Data are sourced from a global sample of 45 leading enterprises from the steel, cement and automotive sector, including some of the largest GHG emitters in the world. In order to account for the long-term impacts of strategies, the firm-level change in financial and carbon performance is calculated by comparing two different points in time, namely 2008 and 2013. The results provide empirical evidence for the positive effect of institutional and stakeholder pressure on emission reduction activities. Proof for a positive impact of carbon pressure on organizational capabilities and corporate competitiveness in the context of climate change cannot be established. Surprisingly, the results also indicate no relationship between carbon reduction activities and long-term improvements in carbon performance. However, such measures are linked to long-term financial gains. Advancements in carbon performance, in turn, are not found to be associated with economic benefits. [ABSTRACT FROM AUTHOR]

Urban parks are considered as an effective, sustainable, and affordable heat mitigation strategy. At present, there is a lack of understanding of the carbon saving potential of urban parks in the context of urban warming. Here we provide a simple approach to estimate the potential carbon savings due to heat mitigation based on analysis of 1510 parks in 26 major urban areas of the years 2017–2021 within the Yangtze River Economic Belt (YREB), China's largest sustainability experiment. On average, an urban park with 26.9 ± 1.5 ha in the YREB could avoid 23.7 ± 1.6 t CO 2 (1.08 ± 0.03 t CO 2 /ha) in emissions due to heat mitigation per summer day. Considered altogether, the 1510 urban parks can offset 5.37% of the daily fossil fuel emissions in the YREB. To boost carbon saving efficiency, lush vegetation should be first considered and the coupled green and blue infrastructures are always advocated. The total parks carbon saving of cities gradually improved along the Yangtze River from west to east, among which Shanghai city (in the east of the YREB) is with the largest amount (4341 t CO 2). The strategies using exquisite landscape design for improving carbon saving may differ across different climate zones. These findings can inform decision-making for urban sustainable development and climate change mitigation, which may benefit China's movement toward carbon neutrality. [ABSTRACT FROM AUTHOR]

China’s commitment to the UNFCCC to peak its emissions by 2030, or sooner, signaled a long anticipated shift in China’s model of development with far reaching consequences. Cities in China, and particularly the residential sector in cities, will be charged with making significant reductions in emissions growth even as rates of urbanization continue to climb. Focusing on Beijing and Shanghai, this paper carries out a measures-based economic analysis of low carbon investment opportunities in the residential sector. Results find significant opportunity: between 2015 and 2030, BAU levels of CO 2 emissions could be reduced by 10.2% in Beijing and 6.8% in Shanghai with the adoption of economically attractive low carbon measures. While these headline results underline the case for low carbon investment in the residential sectors of these megacities in China, a closer analysis provides insights for understanding the economics of decarbonisation in cities more generally. [ABSTRACT FROM AUTHOR]

There is evidence that the replacement of carbon-intensive products with bio-based substitutes (‘material substitution with biomass’) can be highly efficient in reducing greenhouse gas (GHG) emissions. Based on two case studies (CS1/2) for Austria, potential benefits of material substitution in comparison to fuel substitution are analysed. GHG savings are calculated according to default IPCC approaches (Tier 2 method assuming first-order decay) and with more realistic approaches based on distribution functions. In CS1, high savings are achieved by using wood residues for the production of insulating boards instead of energy. The superiority of material substitution is due to the establishment of a long-term carbon storage, the high emission factor of wood in comparison to natural gas and higher efficiencies of gas-fired facilities. The biomass feedstock in CS2 is lignocellulosic ethanol being used for bio-ethylene production (material substitution) or replacing gasoline (fuel substitution). GHG savings are mainly due to lower production emissions of bio-ethylene in comparison to conventional ethylene and significantly lower than in CS1 (per unit of biomass consumed). While CS1 is highly robust to parameter variation, the long-term projections in CS2 are quite speculative. To create adequate incentives for including material substitution in national climate strategies, shortcomings of current default accounting methods must be addressed. Under current methods the GHG savings in both case studies would not (fully) materialize in the national GHG inventory. The main reason is that accounting of wood products is confined to the proportion derived from domestic harvest, whereas imported biomass used for energy is treated as carbon-neutral. Further inadequacies of IPCC default accounting methods include the assumption of exponential decay and the disregard of advanced bio-based products. [ABSTRACT FROM AUTHOR]

• Global forest sector model intercomparison of 81 future pathway scenarios. • Socioeconomic drivers have strongly influence forest sector model estimates. • Global forests could sequester 1.2–5.8 GtCO2e/yr over the next century. • Improved management can increase carbon and harvests without expanding forest area. • Climate policy assessments could better represent forest markets and management dynamics. Deforestation has contributed significantly to net greenhouse gas emissions, but slowing deforestation, regrowing forests and other ecosystem processes have made forests a net sink. Deforestation will still influence future carbon fluxes, but the role of forest growth through aging, management, and other silvicultural inputs on future carbon fluxes are critically important but not always recognized by bookkeeping and integrated assessment models. When projecting the future, it is vital to capture how management processes affect carbon storage in ecosystems and wood products. This study uses multiple global forest sector models to project forest carbon impacts across 81 shared socioeconomic (SSP) and climate mitigation pathway scenarios. We illustrate the importance of modeling management decisions in existing forests in response to changing demands for land resources, wood products and carbon. Although the models vary in key attributes, there is general agreement across a majority of scenarios that the global forest sector could remain a carbon sink in the future, sequestering 1.2–5.8 GtCO2e/yr over the next century. Carbon fluxes in the baseline scenarios that exclude climate mitigation policy ranged from −0.8 to 4.9 GtCO2e/yr, highlighting the strong influence of SSPs on forest sector model estimates. Improved forest management can jointly increase carbon stocks and harvests without expanding forest area, suggesting that carbon fluxes from managed forests systems deserve more careful consideration by the climate policy community. [ABSTRACT FROM AUTHOR]

There is increasing interest in the potential of cities to contribute to climate mitigation. Multiple assessments have evaluated the scale and composition of urban GHG emissions, while others have evaluated some aspects of urban mitigation potential. However, assessments of mitigation potential tend to be broadly focused, few if any have evaluated urban mitigation potential on a measure-by-measure basis, and fewer still have considered the economic case for investing in these measures. This is a significant knowledge gap as an economic case for action could be critical in building political commitment, strengthening institutional capacities, securing large-scale finance and targeting investment and implementation in cities. In this paper, we conduct a comparative analysis of the results of five recently completed studies that examined the economic case for investing in low-carbon measures in five cities: Leeds in the UK, Kolkata in India, Lima in Peru, Johor Bahru in Malaysia and Palembang in Indonesia. The results demonstrate that there is a compelling economic case for cities in both developed and developing country contexts to invest, at scale, in cost-effective low-carbon measures. The results suggest that these investments could generate significant reductions (in the range of 15–24% relative to business-as-usual trends) in urban carbon emissions over the next 10 years. Securing these savings would require an average investment of $3.2 billion per city, which if spread over 10 years equates to 0.4–0.9% of city GDP per year. However, the savings generated in the form of reduced energy bills would be equivalent to between 1.7% and 9.5% of annual city-scale GDP, and the average payback period of investments would be approximately 2 years at commercial interest rates. We provisionally estimate that if these findings were replicated and similar investments were made in cities globally, then they could generate reductions equivalent to 10–18% of global energy-related GHG emissions in 2025. While the studies offer some grounds for optimism, they also raise important questions about the barriers to change that prevent these economically attractive options from being exploited and about the scope for mitigation based on the exploitation of only the economically attractive options. We therefore discuss the institutional capacities, policy environments and financing arrangements that need to be developed before even these economically attractive opportunities can be exploited. We also demonstrate that, in rapidly growing cities, the carbon savings from such investments could be quickly overwhelmed – in as little as 7 years – by the impacts of sustained population and economic growth. We conclude by highlighting the need to build capacities that enable the exploitation not only of the economically attractive options in the short term but also of those deeper and more structural changes that are likely to be needed in the longer term. [ABSTRACT FROM AUTHOR]

Carbon farming in agricultural landscapes may provide a cost-effective mechanism for offsetting carbon emissions while delivering co-benefits for biodiversity through ecosystem restoration. Reforestation of landscapes using native tree and shrub species, termed environmental plantings, has been recognized as a carbon offset methodology which can contribute to biodiversity conservation as well as climate mitigation. However, far less attention has been paid to the potential for assisted natural regeneration in areas of low to intermediate levels of degradation, where regenerative capacity still remains and little intervention would be required to restore native vegetation. In this study, we considered the economics of carbon farming in the state of Queensland, Australia, where 30.6 million hectares of relatively recently deforested agricultural landscapes may be suitable for carbon farming. Using spatially explicit estimates of the rate of carbon sequestration and the opportunity cost of agricultural production, we used a discounted cash flow analysis to examine the economic viability of assisted natural regeneration relative to environmental plantings. We found that the average minimum carbon price required to make assisted natural regeneration viable was 60% lower than what was required to make environmental plantings viable ($65.8 t CO 2 e −1 compared to $108.8 t CO 2 e −1 ). Assisted natural regeneration could sequester 1.6 to 2.2 times the amount of carbon possible compared to environmental plantings alone over a range of hypothetical carbon prices and assuming a moderate 5% discount rate. Using a combination of methodologies, carbon farming was a viable land use in over 2.3% of our study extent with a low $5 t CO 2 e −1 carbon price, and up to 10.5 million hectares (34%) with a carbon price of $50 t CO 2 e −1 . Carbon sequestration supply and economic returns generated by assisted natural regeneration were relatively robust to variation in establishment costs and discount rates due to the utilization of low-cost techniques to reestablish native vegetation. Our study highlights the potential utility of assisted natural regeneration as a reforestation approach which can cost-effectively deliver both carbon and biodiversity benefits. [ABSTRACT FROM AUTHOR]

Estimates of biofuel carbon intensity are uncertain and depend on modeled land use change (LUC) emissions. While analysts have focused on economic and agronomic assumptions affecting the quantity of land converted, researchers have paid less attention to how models classify land into broad categories and designate some categories as ineligible for LUC. To explore the effect of these land representation attributes, we use three versions of a global human and Earth systems model, GCAM, and compute the "carbon intensity of land-use change" (CI-LUC) from increased U.S. corn ethanol production. We consider uncertainty in model parameters along with the choice of land representation and find the latter is one of the most influential parameters on estimated CI-LUC. A version of the model that protects 90% of non-commercial land reduced estimated CI-LUC by an average of 32% across Monte Carlo trials compared to our baseline model. Another version that mimics the GTAP-BIO-ADV land representation, which protects all non-commercial land, reduced CI-LUC by an average of 19%. The results of this experiment demonstrate that land representation in biofuel LUC models is an important determinant of CI-LUC. [Display omitted] • Models of biofuel-induced land use change differ in how they categorize land. • Biofuel effects modeled with alternate land representations in a single model, GCAM. • Land representation affects estimates of climate change mitigation by biofuels. [ABSTRACT FROM AUTHOR]

• Embodied energy and embodied carbon as a tool for climate change mitigation. • A keyword analysis regarding EE and EC was carried out. • Bibliometric analysis and literature maps were developed. • 1003 documents were found in the Scopus database for the 1981–2019 period. • Current building material research claims for EE and EC standardization. Climate change mitigation is a recurrent consciousness topic among society and policymakers. Actions are being adopted to face this crucial environmental challenge, with a rising concern with a big impact on the building sector. Construction materials have a high carbon footprint as well as an energy-intensive activity. To measure the environmental damage and effects, life cycle assessment (LCA) is the methodology most widespread. However, the LCA methodology itself and the assumptions done to carry it out leads to a generalized burden to compare the case studies outcomes. LCA method and for instance geographical location are incompatibilities also revealed in embodied energy and embodied carbon assessments. Urgent actions are needed to clarify the confusions arisen in the research, considering a detailed study on the embodied energy and embodied carbon values. From a material level point of view, this paper aims to illustrate the chronological overview of embodied energy and embodied carbon through keywords analysis. Moreover, to support and corroborate the analysis, an organized summary of the literature data is presented, reporting the range of embodied energy and embodied carbon values up to now. This systematic analysis evidences the lack of standardization and disagreement regarding the assessment of coefficients, database source, and boundary system used in the methodology assessment. [ABSTRACT FROM AUTHOR]

The building industry is expanding its ability to mitigate the environmental impacts of buildings through the application of life cycle assessment (LCA). Most building LCA studies focus on core and shell (C&S) and rarely assess mechanical, electrical, and plumbing (MEP) and tenant improvements (TI). However, C&S typologies in the commercial sector pose particular challenges to achieving net zero carbon due to the numerous renovations these building undergo through during their service life. MEP and TI are installed multiple times over the lifetime of commercial buildings leading to cumulative environmental impact caused by increasing material quantities and embodied carbon (EC). This study aimed to establish a preliminary range of material quantities and embodied carbon impacts for MEP and TI components, focusing on commercial office buildings in the Pacific Northwest. The first research stage involved quantifying material quantities while a second stage aimed to calculate Embodied Carbon Coefficients (ECC) and LCA impacts using different data sources. The embodied carbon estimates ranged from 40 to 75 kg CO 2 e/m2 for MEP and 45–135 kg CO 2 e/m2 for TI. However, with recurring instalments during a life span of 60 years the impacts become comparable to known impacts of core and shell systems. [ABSTRACT FROM AUTHOR]

The Paris Agreement on climate change has calls for urgent, radical, and transformative actions in mitigation and adaptation, particularly in terms of reducing greenhouse gas (GHG) emission. There are many terms used to describe the process of reducing GHGs, including decarbonization, low carbon development (LCD) or low carbon transition (LCT). The conceptualization of these terms remains puzzling and there has not been any consensus to explain the meaning and their interrelationship. Clearer definition and conceptual boundaries are necessary to improve the coherence of overarching practices to cut CO 2 emission. The paper aims to review key concepts related to climate change mitigation related to the reduction of CO 2 and efforts toward net-zero emission in the academic literature, by (1) examining progress of the literature over time, (2) identifying geographical locus and sectoral focus of the literature, (3) determining the interrelationships between the key concepts. We use a Systematic Literature Review (SLR) method for data collection by selecting peer-reviewed literature from Scopus and analyzing the data with content analysis and bibliometric analysis. The findings are, firstly, the publications of the literature are influenced by global and national climate change policies and the interest of scholars affiliated to institutions from major emitter countries. Therefore, the literature is mostly originating from countries that emit the most CO 2 while also implement mitigations to reduce CO 2 emission. Secondly, China is the country where studies are mostly focused and also where the authors are affiliated/located. However, publications from the United Kingdom are cited the most. Thirdly, there are three clusters of literature found, namely that LCD and LCT are the terms used to identify visions for climate mitigation, while decarbonization is the actions and processes to achieve either LCD or LCT (as the visions). • The dynamic of climate change policies influence the literature trend. • The literature is mostly originating from major CO 2 emitter. • Low carbon development and low carbon transition are visional terms. • Decarbonization indicates the processes of decoupling CO 2 to achieve the visions. [ABSTRACT FROM AUTHOR]

Combating global climate change calls for all countries to accelerate emissions reductions, and equity is an important guiding principle. A new indicator – the carbon Palma ratio, extended from the income Palma ratio and defined as the ratio of the total emissions of the top 10% emitters to those of the bottom 40% – is proposed, which provides a new perspective to inform the international community and the public of the distribution inequality of carbon emissions among individuals. The ratio is quantified within and across countries, by applying an elastic relationship between individual emissions and income. Results show that the carbon Palma ratios within most developing countries are overall high, suggesting them to focus more on coordinating regional and income differences and mainly guide high emitters to mitigate, so as to improve emissions and income equity simultaneously. The carbon Palma ratios within developed countries are comparatively smaller; however, the greater historical responsibilities to warming suggest them to substantially reduce emissions of all citizens, so as to enhance national mitigation contributions systematically. At a global scope, the current carbon Palma ratio is observably higher than within any country, reflecting an extremely severe inequality when looking at individual emissions beyond territorial limitations. The regional decomposition of emitters further suggests developed countries to take the lead in the post-Paris era in ratcheting up mitigation and climate finance ambition. Image 1 • Carbon Palma ratio is proposed to measure individual emissions inequality. • The ratio provides a new perspective to quantify and inform inequality. • The ratios in developed countries are overall lower than in developing countries. • The global ratio reflects an extremely severe inequality across the world. • Decomposition suggests developed countries to enhance mitigation and finance. [ABSTRACT FROM AUTHOR]