CO₂-removal News

Smetacek et al. (2024): Rectifying misinformation on the climate intervention potential of ocean afforestation

Victor Smetacek, Mar Fernández-Méndez, Franziska Pausch, Jiajun Wu IN: Nature Communications, 15, https://doi.org/10.1038/s41467-024-47134-6

The authors show that the green and golden tides of Ulva prolifera and Sargassum horneri, respectively, that build up dense mats of free-floating biomass in the millions-of-tonnes range in the eutrophic, central Yellow Sea are more appropriate “natural analogues” for future OAFF than the diffuse Great Atlantic Sargassum Belt (GASB). The dense Yellow Sea algal rafts demonstrate that disparate macroalgal species are capable of building up prodigious, free-floating, harvestable biomass at rates depending on the supplies of seeding stocks (from macroalgal thalli fragments) and nutrients (by eutrophication) that can serve as potential crops for seaweed farms based on artificial upwelling of nutrient-rich water in the vast spaces of the open ocean.

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Nature – Prütz et al. (2024): A taxonomy to map evidence on the co-benefits, challenges, and limits of carbon dioxide removal

Ruben Prütz, Sabine Fuss, Sarah Lück, Leon Stephan, Joeri Rogelj IN: Communications Earth & Environment, 5, https://doi.org/10.1038/s43247-024-01365-z

Recent exponential growth in literature is rapidly filling this gap but makes the synthesis of the evidence on carbon dioxide removal side effects increasingly challenging. Here the authors address this issue by mapping this literature and proposing a taxonomy to synthesize and compare evidence on carbon dioxide removal side effects. The expansive evidence warrants the use of machine learning to systematically select relevant research and provide an inventory of nearly 400 co-benefits, challenges, and limits.

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Anyaoha et al. (2024): Potentials for microalgae sequestration of carbon dioxide (CO2) from composting off-gas; a review

Kelechi E. Anyaoha, Roman Maletz, André Rückert, Christina Dornack IN: Resources, Conservation & Recycling Advances, 22, 200213, https://doi.org/10.1016/j.rcradv.2024.200213

This review examines the available information on composting off-gas dynamics, particularly CO2 evolution, and the challenges and prospects of CO2 use in microalgal cultivation, ensuring circularity in the composting process. This review recommends the utilization of CO2 from composting as alternative to direct air extraction. However, achieving higher CO2 concentration relative to oxygen is challenging. While efforts are made towards reduction in greenhouse gas emissions during composting, near zero oxygen concentration in the off-gas is essential to enhancing CO2 utilization in microalgae cultivation. This should be achieved without compromising compost quality such as germination index and chemical oxygen demand/heavy metals reduction efficiency.

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Jerden et al. (2024): The impact of geochemical and life-cycle variables on carbon dioxide removal by enhanced rock weathering: Development and application of the Stella ERW model

James Jerden, Meteb Mejbel, Antonio Nilson Zamunér Filho, Monica Carroll, Joanna Campe IN: Applied Geochemistry, 167, 106002, https://doi.org/10.1016/j.apgeochem.2024.106002

The carbon dioxide removal (CDR) potential of enhanced rock weathering (ERW) depends on dynamic interactions between several biogeochemical and life-cycle variables. This paper reports results from a systems model developed to account for key variable interactions and provide a computational tool for optimizing ERW applications. The authors discuss the model development, comparisons with laboratory and field test data, and results from a series of sensitivity analyses for several hypothetical ERW applications. 

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Murali & Wong (2024): A comprehensive review of biochar-modified concrete: Mechanical performance and microstructural insights

G. Murali, Leong Sing Wong IN: Construction and Building Materials, 425, 135986, https://doi.org/10.1016/j.conbuildmat.2024.135986

This review article comprehensively analyses biochar’s source and properties to evaluate its effectiveness as a cement substitute in cement-based materials and concrete. The review begins by exploring the different methods utilized in biochar production, focusing on how they influence its chemical properties. This review assesses the properties of fresh and hardened cement mortars and concrete, incorporating biochar while investigating their microstructural characteristics.

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Dahai et al. (2024): The application of magical microalgae in carbon sequestration and emission reduction: Removal mechanisms and potential analysis

He Dahai, Yin Zhihong, Qin Lin, Li Yuhong, Tian Lei, Li Jiang, Zhu Liandong IN: Renewable and Sustainable Energy Reviews, 197, 114417, https://doi.org/10.1016/j.rser.2024.114417

Based on the current status of microalgae research and application, this review focuses on the intrinsic mechanism of microalgae carbon sequestration and emission reduction as well as the influencing factors of microalgae cultivation and growth and further explores the potential of microalgae carbon sequestration and emission reduction and its application in terms of carbon sequestration and emission reduction efficiency, economic feasibility and practical application. To solve the current challenges of microalgae carbon sequestration and emission reduction applications, it is proposed that the anti-pollution ability and carbon sequestration efficiency of microalgae can be improved through genetic engineering and the construction of suitable microalgae cultivation systems, combined with the wastewater and waste gas treatment and microalgae multi-product biorefinery to reduce the energy inputs and greenhouse gas emissions.

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Nature – Sun et al. (2024): Nature-based Solutions can help restore degraded grasslands and increase carbon sequestration in the Tibetan Plateau

Jian Sun, Yingxin Wang, Tien Ming Lee, Xiaowei Nie, Tao Wang, Eryuan Liang, Yafeng Wang, Lin Zhang, Jun Wang, Shilong Piao, Fahu Chen, Bojie Fu IN: Communications Earth & Environment5, https://doi.org/10.1038/s43247-024-01330-w

Here, the authors investigated the rationale and urgency behind the implementation of Nature-based Solutions on sequestering carbon using literature review and meta-analysis. They also project the changes in terrestrial carbon sink of Tibetan Plateau grassland ecosystems using model simulations with different future emissions scenario.

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Everson et al. (2024): What is the potential of bioCCS to deliver negative emissions in Norway? From biomass mapping to a window of negative emissions potential

Nikalet Everson, Michaël Becidan, Simon Roussanaly, Rahul Anantharaman, Petronelle Holt, Roger Khalil IN: Sustainable Materials and Technologies, 40, e00912, https://doi.org/10.1016/j.susmat.2024.e00912

Ground-up approaches are necessary to better understand the realistic potential of negative emissions technologies at the national or continental level. Such an approach was applied in the present study to understand the potential of bioenergy with carbon capture and storage to deliver negative emissions in Norway, starting from mapping and quantification of biomass until the derivation of a window of negative emission potential.

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Han et al. (2024): Carbon sequestration potential of biochar in soil from the perspective of organic carbon structural modification

Lanfang Han, Cuiling Lu, Liying Chen, Fayuan Wang, Qi’ang Chen, Kuo Gao, Yuanyuan Yu, Chao Xu IN: Applied Soil Ecology, 198, 105389, https://doi.org/10.1016/j.apsoil.2024.105389

While there has been extensive research on the priming effect of biochar on the mineralization of native soil organic carbon (nSOC), its correlation with soil organic carbon (SOC) structural variations remains poorly understood. A series of incubation experiments with soils amended with biochar prepared at 300 °C, 450 °C, and 600 °C were performed to explore the shifts in nSOC structure and reveal the interconnections among soil properties, SOC structural variation, and the priming effect induced by biochar.

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Nature – Scott-Buechler et al. (2024): Communities conditionally support deployment of direct air capture for carbon dioxide removal in the United States

Celina Scott-Buechler, Bruce Cain, Khalid Osman, Nicole M. Ardoin, Catherine Fraser, Grace Adcox, Emily Polk, Robert B. Jackson IN: Communications Earth & Environment, 5, https://doi.org/10.1038/s43247-024-01334-6

Direct air capture has gained traction as a method for carbon dioxide removal. How and whether direct air capture can be deployed requires securing social license to operate, and increasingly demands environmental justice and just transition principles. Here the authors use a nationally representative survey to evaluate public perceptions of direct air capture, paired with focus groups to assess community perceptions across four communities in the United States: Houston, Texas; Monaca, Pennsylvania; Bakersfield, California; and Rock Springs, Wyoming. 

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