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Afforestation and reforestation can contribute to the mitigation of climate change by increasing forested areas that can actively sequester carbon dioxide from the atmosphere through photosynthesis. The purpose of this study was to assess the potential for carbon sequestration in the ecosystem and in harvested wood products, and associated greenhouse gas (GHG) emission mitigation, following the application of afforestation/reforestation strategies on unproductive lands in the Province of Quebec over an 80-year long period (2021–2101), using the Carbon Budget Model of the Canadian Forester Sector 3. Afforestation/reforestation scenarios without harvesting and scenarios based on establishment of fast-growing species such as hybrid poplar showed the greatest short-term (2020–2040) carbon sequestration potential. Over the 80-year simulation period, plantations without harvesting generated a greater potential for carbon sequestration in ecosystems; after each harvesting event, several decades were necessary to regain any ecosystem carbon loss, which could be compensated only if a proportion of the harvested wood is converted to long-lived wood products, with high substitution effects in other sectors. In the northern boreal zone of Quebec, significant mitigation potential can be expected from the afforestation of open woodlands and poorly regenerated burns, both with or without harvesting. In the southern zone, the need for better data on vegetation succession and carbon accumulation on abandoned farmlands in the absence of plantations was highlighted by this study. This study increases the understanding of carbon sequestration by plantations, and their role as a mitigation strategy to contribute to national GHG emission reduction targets and net-zero carbon objectives. [ABSTRACT FROM AUTHOR]

Bauxite residue or Red Mud (RM) is a by-product from alumina refineries. It has a high pH of 11–13 and accumulates globally at 200 million tons yearly, totalling about 4.6 billion tons. Being an alkaline anthropogenic geomaterial, its adsorption properties and reactivity with acidic gases make it a potential sink for CO 2 and SO X emissions from the aluminium industry. It offers both research challenges and opportunities for its utilisation at an industrial scale. In particular, carbon capture and mineralisation (CCM) within RM has been demonstrated in situ and waste disposal areas through direct air trapping of atmospheric CO 2. The RM-CO 2 system is also operated in ex-situ conditions in various physical states, such as powder, wet cakes, and slurry, with yields of carbonates as CaCO 3 , Na 2 CO 3 , and FeCO 3. Our contribution as a review illuminates significant advancements made and challenges for enhancing the mineral carbonation potential of RM, thereby delineating areas necessitating further exploration. Although, researchers have primarily focused on accelerating the CCM process in RM through slurry carbonation techniques. Recent advancements in filter press technologies have favoured soda recycling and wet cake disposal of RM, creating artificial mountains of RM stacks. With changing disposal trends for RM, it is vital to understand the mechanisms that govern long-term atmospheric CO 2 trapping in RM disposal areas. Recent investigations of techniques, hydrothermal treatment and dual-stage calcification-carbonation methods have expanded the domain of CCM in RM. Given the global need to reduce CO 2 emissions, CCM using RM does offer promising insights on account of its unique physicochemical and mineralogical properties. We, although presume that RM alone will not fully offset the CO 2 emissions of the aluminium industry. Enhanced weathering and mineral carbonation could reduce over 50% of refinery emissions. Uncertainties persist regarding methods of CO 2 sequestration potential and techno-economic feasibility when tested at a field scale. Moreover, contrasting results are revealed, primarily regarding changing disposal trends, variabilities in mineralogy, and limited knowledge of micro-mechanisms of the CCM process in RM. This work elucidates existing knowledge on synthesising CO 2 mineralisation, pathways, and mechanisms under various states associated with leveraging RM as a significant carbon sink in current and future climate change mitigation efforts. [Display omitted] • Illustrates RM mineral carbonation process and mechanistic models for CCM methods (slurry, semi-dry, atmospheric). • CCM potential is studied along with mechanisms using hydrothermal treatment, siderite formation and calcification-carbonation method. • Guidelines for RM sample extraction methods based on its physico-geochemical changes in BRDA with atmospheric CO 2. • Current and future research directions are discussed. [ABSTRACT FROM AUTHOR]

Summary: The world is setting aggressive targets for climate change mitigation and most pathway models require negative emission technologies (NETs) to meet these targets. Direct air capture (DAC) is a promising NET that captures carbon dioxide (CO2) from the atmospheric air; however, indirect and embodied emissions to power and build DAC systems must be considered when exploring NET options. Wind energy has experienced rapid cost reductions in the past few years and experts predict a significant continued decline in offshore wind energy costs. Here, we develop a conceptual design and conduct an energy assessment of two dominating DAC designs to show the potential of offshore wind to meet the DAC energy demand for two different scenarios capturing 3.3 GtCO2/y (10%) and 11 GtCO2/y (33.3%) of current global CO2 emissions covering a range of estimates for future NETs required to meet net‐zero goals. Energy assessment showed that the estimated energy requirement for the Carbon Engineering based design is higher as compared with Climeworks based design owing to the high temperature (900°C) requirement in the calcination step required for the desorption of CO2. However, conceptual design revealed that area requirements for DAC configurations are much less for Carbon Engineering based design comparatively. Employing offshore wind energy can eliminate indirect emissions associated with meeting DAC energy demands, facilitative modular NET deployment globally, be positioned geographically to avoid competition with grid decarbonization and take advantage of otherwise stranded offshore wind resources. Large‐scale offshore wind energy integrated DAC systems, therefore, deserve development efforts and deployment alongside other mitigation and NET options. [ABSTRACT FROM AUTHOR]

CO 2 concentration in the atmosphere has crossed an unprecedented level of 420 ppm, causing catastrophic events like climate change. Climate change mitigation via carbon capture is crucial for reducing CO 2 emissions. Among various CO 2 capture technologies, adsorption is considered one of the most efficient and promising techniques. In recent times, substantial research has been conducted on producing cost-effective and efficient adsorbents for CO 2 capture via the thermal and chemical treatments of biomass. In this review, we discuss key scientific results to give broad insight into the recent progress in biomass conversion to activated porous carbon (APC). The effects of various chemical and thermal treatments on the textural properties and CO 2 adsorption capacity of APC are comprehensively discussed. CO 2 adsorption mechanism based on interaction with the surface functionality is thoroughly explained. The economic aspects of APC synthesis and post-combustion CO 2 capture using APC are systematically reviewed. [Display omitted] • Use of biomass based activate porous carbon (APC) for CO 2 capture is reviewed. • CO 2 adsorption mechanism on APC surface is thoroughly explained. • APC surface functionalization via metal doping and heteroatom doping is discussed. • Economics of APC synthesis & large-scale CO 2 capture on APC is critically reviewed. [ABSTRACT FROM AUTHOR]