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Paper has shaped society for centuries and is considered one of humanity's most important inventions. However, pulp and paper products can be damaging to social and natural systems along their lifecycle of material extraction, processing, transportation, and waste handling. The pulp and paper industry is among the top five most energy-intensive industries globally and is the fourth largest industrial energy user. This industry accounts for approximately 6% of global industrial energy use and 2% of direct industrial CO 2 emissions. The pulp and paper industry is also the largest user of original or virgin wood, with deleterious impacts on both human health and local flora and fauna, including aquatic ecosystems. This critical and systematic review seeks to identify alternatives for mitigating the climate impacts of pulp and paper processes and products, thus making the pulp and paper industry more environmentally sustainable. This study reviews 466 studies to answer the following questions: what are the main determinants of energy and carbon emissions emerging from the pulp and paper industry? What are the benefits of this industry adopting low-carbon manufacturing processes, and what barriers will need to be tackled to enable such adoption? Using a sociotechnical lens, we answer these questions, identify barriers for the pulp and paper industry's decarbonization, and present promising avenues for future research. •This review identifies carbon-intensive processes in the pulp and paper industry. •Presents decarbonizing practices, potential transformations and innovations. •Presents promising avenues for future research. •No agreed consensus on the most promising technologies to achieve net-zero in the pulp and paper industry. •Pulp and paper products are associated with other sociotechnical systems that create compelling interdependencies among industries. [ABSTRACT FROM AUTHOR]

Rapidly increasing catastrophic environmental incidents and changes in global climate have compelled researchers to take proactive measures for climate change mitigation. Consequently, reducing greenhouse gas emissions has become one of the most significant global targets. The transportation sector has a massive carbon footprint accounting for 22% of the total carbon dioxide emissions. In this regard, road transport contributes the largest fraction of the total emissions within the transportation sector. Conversely, the railway which is the cleanest form of transportation contributes slightly more than 1% of the total emissions. Moreover, since most of the rail systems are operated by government or private companies, it is relatively convenient to implement policies and replace conventional technology with environmentally friendly ones. This could be achieved by taking certain measures from technical and operational viewpoints for conserving energy to lower the carbon intensity of all transport modalities. Hence, this review paper focuses on investigating the railway sector to encourage a modal shift to the least carbon-intensive option. This study provides a critical review of the past and present rail technologies in terms of the environmental, economic, social, and technical perspectives. Moreover, a comparative assessment of the various locomotive types has been performed. The results reveal that battery-hydrogen hybrid locomotives are the best choice to be considered as a future locomotive technology. Hydrogen locomotives have the potential to be a promising alternative to diesel railway locomotives. However, certain technical barriers need to be overcome to enhance the overall system's performance and reliability to further improve the viability of its deployment in the railway sector. [Display omitted] • A critical review of the various rail technologies is provided through different viewpoints. • The assessment constitutes environmental, economic, social, and technical perspectives. • A decision-support tool for comparison of four rail technologies is also developed. • Battery-hydrogen hybrid locomotive results in the highest score of 1.47. • Standalone hydrogen locomotive results in the second highest score of 1.38. [ABSTRACT FROM AUTHOR]

Concrete is the most highly used construction material globally. This is largely due to its durability, versatility and manufacture from inexpensive and readily available materials. Although concrete has become an essential and ubiquitous construction material for modern society, its use has significant environmental impacts. The full cement and concrete lifecycle, from production to final disposal, accounts for nearly 10% of global energy-related CO 2 emissions with the majority of these emissions produced from cement, which is the binding material that holds concrete together. The cement and concrete industry (CCI), which is integral to global infrastructure development, is therefore confronted with a growing need to decarbonize its operations and products, as well as to support the decarbonization of associated end-user sectors. This paper provides a systematic and critical review of more than 800 studies to highlight ways in which the CCI can decarbonize. A socio-technical perspective is used to understand the full range of industrial and economic activities where a decarbonized paradigm for cement and concrete production is relevant. This perspective is further used to assess key technical, economic, social and political factors that will drive a net-zero transition in the CCI over the long term. • Reviews the cement and concrete industry (CCI) decarbonization literature. • Describes the CCI's sociotechnical system and energy and environmental impacts. • Highlights barriers and opportunities for CCI decarbonization. • Outlines technologies and policies to mitigate negative CCI impacts. • Proposes gaps and future agendas for CCI decarbonization research. [ABSTRACT FROM AUTHOR]

Renewable energy plays a crucial role in both climate change mitigation and adaptation in highly climate-vulnerable nations such as Nepal. This paper reviews various types of renewable energy technologies and their status, potential for adoption, relationship to climate change, and mitigative and adaptive roles in Nepal. Nepal has installed micro-hydro projects, solar power, improved cooking stoves, biogas technology, improved water mills, and wind energy to mitigate and adapt to climate change. There is a growing potential for renewable energy development in Nepal, such as hydropower, solar, wind energy, biogas, and improved cooking stoves. Roughly 70% of Nepal's energy consumption is generated from traditional energy sources while renewable energy accounts for approximately three percent. The gradual increase in the use of renewable energy has reduced greenhouse gas emissions and enhanced carbon sequestration. By adopting renewable energy technologies, Nepal has reduced emissions by 221,129 tCO 2 e from 2017 to 2018. Nepal's second Nationally Determined Contribution targets a 15% increase in national energy use from renewables with a reduction of 23% of CO 2 emissions by 2030 using biogas and improved cooking systems. Furthermore, a significant increase in the adoption of renewable energy has become a pivotal strategy in adaptation to climate change in social, health, and economic sectors resulting in time savings, alternative income sources, improved health and educational status, local job opportunities, and the promotion of social capital. The benefits of adapting to climate change and mitigating CO 2 emissions via renewable energy are significant at the local, national, and international levels. This study recommends that the government of Nepal focus work on energy policy reviews to address local energy demand and climate change issues by utilizing renewable energy resources at the local level, which has global implications. • Suitable, potential renewable energy technologies in Nepal. • The relationship between energy and climate change. • Relevant data on energy and climate change in tables and figures. • Social, economic, and environmental benefits of renewable energy. • Climate change adaptation and mitigation via renewable energy. [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]