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Green roofs can mitigate climate change through various mechanisms, including carbon sequestration, thermal process regulation, and building energy savings. While those mechanisms have been well studied, it remains unclear how to quantify carbon dioxide reduction and design green roofs properly for optimal performance. This review summarizes the processes, factors, and quantitative methods for carbon dioxide reduction from peer-reviewed literature. Firstly, the processes that account for how green roofs reduce carbon dioxide directly (by absorbing ambient CO 2 and storing it in biomass and substrate) and indirectly (thermal process regulation reduces energy consumption) are focused. The factors affecting CO 2 reduction (i.e., vegetation, substrate, building environment, and maintenance) are then discussed to investigate how these factors impact the performance of green roofs. Lastly, quantitative methods, including field experiments and simulation models to evaluate direct and indirect CO 2 reductions from green roofs, are discussed considering different spatial scales. The review found that a better understanding of green roofs' carbon reduction mechanisms is needed. Recommendations also should be developed on customized green roof system designs for various climate conditions. Lastly, there is a lack of green roof decarbonization evaluation at multiple spatial and temporal scales to effectively implement green roofs in urban areas. Overall, this comprehensive review facilitates an understanding of how green roofs reduce CO 2 , the driving factors, and quantitative methods, which will advance research on designing and building green roofs as effective climate mitigation solutions in urban areas. • Analysis of the carbon sequestration and energy savings processes of green roofs. • Evaluation of factors affecting carbon sequestration and thermal performance. • Summarizing methods to quantify the carbon dioxide reduction services of green roofs. [ABSTRACT FROM AUTHOR]

The decarbonization of industry and industrial systems is a pressing challenge given the relative lack of low-carbon options available for "hard to decarbonize" sectors such as steelmaking, cement manufacturing, and chemical production. Carbon capture utilization and storage (CCUS) represents a promising and crosscutting solution to this formidable problem. This review takes a systematic and sociotechnical perspective to examine how CCUS can support industrial decarbonization and relevant associated technical, economic, and social factors. This includes a focus on the energy and climate impacts of carbon emitting activities, the role, and options for CCUS in global responses to climate change, technical aspects of capture, transport, storage, and utilization, as well as policy implications and areas requiring further research. In doing so, the Review examines hundreds of published studies on the topic over the previous twenty years to offer a state-of-the-art investigation on technical options for capture (including direct air capture), transportation (including pipelines, ships, and rail), storage (including biotic and abiotic), and utilization (including enhanced oil recovery and biochar). The Review also investigates the evidence base within the literature on enablers and barriers to CCUS, policy mechanisms, and international frameworks as well as themes such as geopolitics, trade, and future research gaps. We conclude with insights about future CCUS pathways and sociotechnical systems dynamics. [Display omitted] • Carbon Capture Utilization and Storage can play a critical role in climate change mitigation. • Ample emerging technologies are available with adequate capture capacities and biotic and abiotic forms of storage. • Utilization processes include enhanced oil recovery and biochar. • Carbon Capture Utilization and Storage deployment has been largely limited by social and economic barriers. • Policy driven solutions may help drive costs down, engender social acceptance, and increase CCUS deployment. [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]