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Ethylene is one of the most important products in the emissions-intensive petrochemical industry. Decarbonizing the ethylene industry is thus important for achieving global carbon neutrality. This study is the first to explore future long-term zero-emissions production pathways for the ethylene industry in China, the world's biggest ethylene producer. An optimization model was built in the context of China's carbon neutrality target of 2060. Four scenarios were developed where the policy ambitions for climate mitigation and for plastic management including waste were varied. Based on this, authors assessed the cumulative total emissions, technology options, future geographical location of ethylene production, and policy challenges associated with each scenario. This is also the first time that scope 3 emissions from waste incineration are included, motivated by the short lifetime of most ethylene products. Results show the cumulative CO 2 emissions for the scenarios differ considerably, ranging from 4.3 to 7.8 Gt, even if carbon neutrality by 2060 is achieved in all scenarios. The results suggest that ambitious plastic focused policies can result in lower costs and less cumulative emissions compared to ambitious climate focused policies. The results demonstrate the importance of adopting CCS for waste incineration. This reduces cumulative CO 2 emissions by up to 2 Gt. However, reduced overall demand and increased recycling rates should be priority options due to CCS challenges. Results suggest Chinese ethylene industry should adopt a mixed portfolio of production technologies, where the share of emission-intensive coal-based methanol-to-olefins is limited. These findings on decarbonization pathways can contribute to achieving the Paris agreement. [Display omitted] • Ambitious plastic policies lead to 1.3 Gt less cumulative CO 2 than climate policies. • Cumulative CO 2 until 2060 can be reduced by 3.5 Gt compared to reference scenario. • Adopting CCS in incineration can reduce cumulative CO 2 emissions by 2 Gt. • Ethylene industry should adopt a mixed production portfolio due to uncertainties. • Coal-based MTO with CCS does not appear to be a cost-competitive option. [ABSTRACT FROM AUTHOR]

This study investigates the potential of utilizing carbon credits to finance innovative local energy communities in Europe, addressing a significant gap in academic literature. Despite the growing interest in voluntary carbon credits as a mechanism for offsetting carbon emissions, there is limited evidence connecting local energy systems to voluntary carbon markets. The study explores whether carbon credits could serve as a practical tool for funding the development of energy communities, contributing to sustainable energy transitions and climate mitigation strategies. The research employs a comprehensive methodology to assess the quality of carbon credit projects and examines ten innovative energy community projects in Europe. Key findings reveal there is potential for using carbon credits to finance energy community initiatives. However, challenges persist, particularly regarding financing barriers and the volatile nature of carbon markets. The study underscores the importance of policy support in establishing clear standards for voluntary markets and promoting the accessibility of carbon offsets. Furthermore, it suggests potential solutions such as pre-financing agreements and the utilization of carbon market derivatives to enhance project viability. Overall, the study offers insights into the intersection between voluntary carbon markets and local energy initiatives, providing a foundation for further research and policy development in the field of local sustainable development and climate change mitigation. [Display omitted] • Innovative local energy communities in Europe have significant carbon emissions reduction potential. • Carbon credit issuance could financially support the development of local energy initiatives. • Challenges persist in accessing financing and navigating volatile carbon markets. • Policy support is crucial in establishing clear standards for voluntary carbon markets. [ABSTRACT FROM AUTHOR]

This study investigates the climate emergency declaration (CED) movement in cities and its effects and synergies with local climate planning. Urban areas are experiencing a wide range of climate-induced extreme events, particularly those located in the Mediterranean hotspot. The focus is on Italian cities, which have only recently become key players in climate planning. The method is based on the collection, analysis, and comparison of data on CEDs and local climate plans (LCPs), integrated with information on city membership in climate networks, to extrapolate key performance indicators of the CED movement. The results show that the CED movement can motivate municipalities to become more ambitious in climate action. As of February 2021, the "climate emergency" movement was supported by 105 Italian cities geographically concentrated in the northern regions (66.7%). The motivation behind a CED is often attributable to local populations calling for concrete climate action (91.1% referred to the Fridays for Future movement) but also to a greater perception of the impacts of climate change (85.6% referred to the Special Report on Global Warming of 1.5 °C). Networking plays an important role (85 cities in the Covenant of Mayors). Interestingly, 36 cities (34.3%) were not engaged in local climate planning previously, but the CED shows now they see the urgency to act. 24.4% cities aim at carbon neutrality in their CEDs (most with local adaptation aspirations), with a much smaller fraction of cities doing so in LCPs and generally lower ambition in terms of greenhouse gas emission reduction targets. [Display omitted] • Case study: 105 IT cities that have declared climate emergency (66.7% in the north). • Motivation: 91.1% refer to the FFF movement, 85.6% to the 2018 IPCC Special Report. • Networking: 85 cities are members of CoM and 33 of the Italian Green City Network. • 34.3% of the CED cities had not previously a mitigation or adaptation plan. • 24.4% of CEDs aim at carbon neutrality, while LCPs have less ambitious GHG targets. [ABSTRACT FROM AUTHOR]

The residential sector has been targeted as the one with a huge potential for reducing carbon emissions. In order to determine the present carbon footprint and the potential for achieving carbon neutrality, the study examines electricity consumption in average households, whose electricity is supplied by their national power grids. 31 European countries (27 EU and 4 non-EU countries) were included in this analysis. Our results indicate that the annual carbon emissions of these average households range from 0.09 to 6.44 tCO 2 e (1.36 tCO 2 e on average), depending on a country. In addition, the calculated electricity costs per tCO 2 e emission for an average household vary significantly (from 94 to 10,135 EUR/tCO 2 e).Carbon offsetting is a mechanism which enables households to achieve carbon neutrality, i.e. households can compensate for the emissions caused by their electricity consumption by purchasing voluntary carbon offsets. This study also analyses the financial implications of purchasing voluntary carbon offsets. The results indicate that voluntary carbon offsets do not burden household budgets significantly because their share in total electricity costs is small. European households, particularly those in countries where electricity is more expensive, can comfortably achieve carbon neutrality with voluntary carbon offsets. In this way, they can contribute to global sustainable development. [Display omitted] • Average carbon footprint of grid-connected household in Europe is less than 2 tCO2e. • The cost of electricity per CO2 emissions varies from 94 to 10,135 EUR/tCO2. • Voluntary carbon offset costs in electricity costs vary widely across Europe. • Carbon offsetting is a practical solution for achieving a carbon-neutral household. [ABSTRACT FROM AUTHOR]

While feeding 20% of global population, China's agriculture is a large greenhouse gas (GHG) emitter, posing a major challenge to the country's carbon neutrality target. However, the pathways of agriculture towards carbon neutrality remain unclear. To address this knowledge gap, we conduct a comprehensive life-cycle assessment and show that valorization of sustainable biomass wastes (crop residues, forest residues, livestock manure, food waste, and sewage sludge) into biochar can contribute importantly towards agricultural carbon neutrality in China. The maximum potential of biochar production from these waste resources in 2018 is 145 Mt yr−1 with a corresponding GHG mitigation potential of 455.7 (405.5–572.4) Mt CO 2 -eq yr−1. This can fully offset the total CH 4 and N 2 O emissions from China's croplands (∼400 Mt CO 2 -eq yr−1), which are difficult to be entirely eliminated due to rice paddy irrigation and intensive use of fertilizers. Distribution of biomass waste varies across regions, and at the national level , crop residues (48.8%) and livestock manure (25.4%) and food waste (15.6%) are the main sources of biochar feedstocks and should be prioritized in biochar development. Forest residues have a marginal contribution due to competing uses from other sectors, and sewage sludge derived biochar is a net source of GHG emissions due to the large energy consumption required for sludge drying. The total GHG mitigation potential of biochar is greatly affected by pyrolysis temperature and the highest mitigation effect is observed under 300–500 °C. These results underscore the benefit of sustainable biochar production to agricultural carbon neutrality, and to maximize the climate benefit requires differential policies and pyrolysis technologies tailored to regional availability of biomass resources. • The GHG mitigation potential of sustainable biochar in China was analyzed. • The maximum mitigation potential can offset all CH 4 and N 2 O emission from croplands. • Biochar GHG mitigation potential is affected significantly by pyrolysis temperature. • Sustainable biochar can contribute toward agricultural carbon neutrality. [ABSTRACT FROM AUTHOR]

Biochar has received increasing attention in agricultural and environmental fields as an integrated solution to agricultural waste recycling, soil amendment, carbon sequestration, and greenhouse gas (GHG) reduction. However, obtaining the environmental benefits of biochar is limited by an inadequate number of soil applications. Currently, the willingness to use biochar in soil management is relatively low, which results from the insufficient understanding and promotion of the roles of biochar in soil management and climate change mitigation. This review article presents biochar applications based on carbon-neutral strategies in agricultural soil systems. The primary roles of biochar in soil improvement and remediation are discussed and the main soil application methods are introduced. The focus of this article is on biochar-based soil management strategies for contributing to carbon neutrality. Carbon sequestration using biochar is an application-dependent strategy, as the key to obtaining this ecological benefit is to store biochar products in soil via effective agricultural management. This article offers insights into biochar-based soil management strategies and their contribution to carbon neutrality in agricultural soil systems, with recommendations for appropriate government involvement in promoting biochar-based soil management and for incorporating biochar into the carbon trading market. • The non-CO 2 GHGs account for the majority of carbon emission via agricultural soil. • Incorporating biochar into the global carbon trading market is recommended. • Using biochar to help achieve carbon neutrality is an application-dependent strategy. [ABSTRACT FROM AUTHOR]

Pyrolysis can be used to produce renewable energy and offset greenhouse gas emissions. While the biopower potential of pyrolysis has been widely analyzed, agronomic and environmental benefits under competing pyrolysis modes have not been investigated and compared. This study reviews the properties and characteristics of major pyrolysis technologies including fast, intermediate, slow, gasification, and torrefaction, and then investigates and compares their biopower potential and the biochar-induced agronomic and environmental benefits so that the fundamental figures for future large-scale biopower development can be explored. The results indicate that (1) revenues from energy sale generally outweigh the agronomic and environmental benefits, but the extent depends on the commodity price and emission price; (2) if biochar is not used as an energy source, 10.58%–26.73% of biopower generation is decreased for fast pyrolysis and a 90%–97.44% decrease would occur for torrefaction; (3) biochar-induced agronomic benefits and emission offsets from torrefaction can greatly recover the loss of energy sales; and (4) with torrefaction the emission offset can be up to 2.82–3.19 tonnes carbon dioxide, on a per tonne biomass basis. We also discuss how biochar application might alleviate surface water eutrophication and groundwater pollution. • Mitigation potential of torrefaction is up to 3.19 MT per ton feedstock. • Without the use of biochar, power generation of fast pyrolysis declines by 26.73%. • Torrefaction benefits agronomic mostly but yields least biopower. • Changes in energy and emission prices would cause technology transitions. • Slow pyrolysis balances biopower production and mitigation effects. [ABSTRACT FROM AUTHOR]

Bioenergy is considered a promising alternative to achieve carbon neutrality and emission reduction. There is a debate over the role of bioenergy in climate change mitigation because of carbon emissions from the production and utilization of biofuels. Recently, studies on emissions of biogenic volatile organic compounds (BVOCs) have substantially increased as they have a significant impact on human health and climate change due to large emissions and high reactivity. A scientometric analysis of 2895 journal papers during 1991 and 2020 related to BVOC emissions from the Web of Science Core Collection was conducted by CiteSpace and Carrot2. Results showed that three main knowledge domains were BVOC emissions and drivers, BVOCs and their oxidation products in biosphere-atmosphere exchange, and soil BVOCs in plant-microbe interactions during the period under study. Generally, the relationships between plant BVOC emissions and environmental variables (e.g., temperature, drought, light solar radiation, humidity, availability of nutrients, carbon dioxide, ozone, etc.) can be investigated by measurement techniques (i.e., chamber) or models (i.e., Model of Emissions of Gases and Aerosols from Nature). Soils could work as both the sink and source of BVOCs through various processes that are affected by soil temperatures, pH, organic matter, and moisture. Anthropogenic activities might affect the emission of BVOCs and promote the formation of BVOC-derived pollutants (e.g., ozone, particles, etc.). Incorporating BVOC emissions and their relationships with pollutants, biomass, and energy into environmental management and decision-making is a promising direction. [Display omitted] • A scientometric analysis was conducted on the research evolution of BVOC emissions. • Ten clusters generated by CiteSpace were logically reclassified into three hotspots. • MEGAN is the most frequently empirical model for BVOC emission assessment. • BVOC-derived pollutants like SOA are likely affected by anthropogenic activities. • Soils in terrestrial ecosystems can act as both the source and sink of BVOCs. [ABSTRACT FROM AUTHOR]

About 3 billion people still rely on traditional sources of fuel. Biomass-based fuels were responsible for more than 4 million deaths in 2012. Household energy consumption is steadily increasing across cities due to the urbanization of rural areas, more economic and travel activities. In this review, Multiple Correspondence Analysis (MCA) and other bibliometric tools were applied to determine the conceptual structure and typological thematic areas of household emissions in urban areas. The current state of knowledge and opportunities towards creating carbon-neutral cities indicated that while most of the research was focussed on cities and regions of developed countries and China, the mitigation activities grouped under three broad heads - reducing emissions, consumption and impact of household emissions. Strong heterogeneity between the urban and rural areas, fuel options and human choices gave rise to fuel-stacking in developing countries. Integrated modelling and inclusion of environmental and human behavioural components into economic models were recognised as emerging fields oriented towards a systems approach. Accessibility and availability of clean energy and clean energy appliances were identified as the biggest challenges. To create carbon-neutral urban areas, integrated modelling should include categorization of carbon policy according to local conditions, analysis of feedback loops, embedded emissions, the global and regional impact of household consumption patterns, and uncertainty associated with mitigation measures. [Display omitted] • Carbon neutral cities should have access equality despite income inequality. • Multiple Correspondence Analysis indicated mitigation research focused on emissions, consumption and impacts. • Integrated modelling and general equilibrium models were the two emerging themes. • Risk, uncertainty, embedded emissions and feedback loops should be integrated into emission models. • Availability and accessibility to cleaner fuels is the biggest challenge for creating carbon-neutral cities. [ABSTRACT FROM AUTHOR]