CO₂-removal News

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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Nature – Corbett et al. (2024): Organic carbon source controlled microbial olivine dissolution in small-scale flow-through bioreactors, for CO2 removal

Thomas D. W. Corbett, Marcus Westholm, Anna Rosling, Tullia Calogiuri, Reinaldy Poetra, Harun Niron, Mathilde Hagens, Alix Vidal, Jan Willem Van Groenigen, Jens Hartmann, Ivan A. Janssens, Lukas Rieder, Eric Struyf, Michiel Van Tendeloo, Siegfried E. Vlaeminck, Sara Vicca, Anna Neubeck IN: npj Materials Degradation, 8, https://doi.org/10.1038/s41529-024-00454-w

Here the authors are investigating the importance of the organic carbon feedstock to support silicate mineral weathering in small-scale flow through bioreactors and subsequent CO2 sequestration. They combine two bacteria and two fungi, widely reported for their weathering potential, in simple flow through bioreactors (columns) consisting of forsterite and widely available, cheap organic carbon sources (wheat straw, bio-waste digestate of pig manure and biowaste, and manure compost), over six weeks.

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E et al. (2024): Effect of waste leather dander biochar on soil organic carbon sequestration

Tao E, Cheng Ji, Ying Cheng, Shuyi Yang, Liang Chen, Daohan Wang, Yuanfei Wang, Yun Li IN: Journal of Environmental Chemical Engineering, 12, 3, 112633, https://doi.org/10.1016/j.jece.2024.112633

In order to determine the carbon sequestration content of waste leather dander biochar (W-BC) at different pyrolysis temperatures and its effect on soil organic carbon mineralization, waste leather dander (WLD) was prepared into BC-300, BC-400 and BC-500 at different temperatures (300, 400 and 500 °C).

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Nature – Hasegawa et al. (2024): Careful selection of forest types in afforestation can increase carbon sequestration by 25% without compromising sustainability

Tomoko Hasegawa, Shinichiro Fujimori, Akihiko Ito, Kiyoshi Takahashi IN: Communications Earth & Environment, https://doi.org/10.1038/s43247-024-01336-4

Here, the auhtors used an integrated assessment model to quantitatively demonstrate how the selection of forest type to use in afforestation could increase global carbon sequestration without compromising global food and land sustainability. Our findings indicate that if a carbon-intensive forest type is selected, afforestation would increase carbon sequestration by 25% compared to the level assuming the native forest type. At the same time, if implemented inappropriately at a large scale, afforestation would worsen the economy, food, and land systems due to decreased land efficiency in carbon removal compared to bioenergy with carbon capture and storage, leading to increased land expansion for carbon removal, higher food prices, and increased risk of hunger.

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Tang & Qiu (2024): CO2-sequestering ability of lightweight concrete based on reactive magnesia cement and high-dosage biochar aggregate

Yihong Tang, Jishen Qiu IN: Journal of Cleaner Production, 451, 141922, https://doi.org/10.1016/j.jclepro.2024.141922

In this study, lightweight concretes based on reactive magnesia cement (RMC) and high amount of biochar aggregates (up to 508 kg/m3, 61 vol% of the concrete) are developed. The new material demonstrates the ability to sequestrate massive amounts of CO2 from ambient air, and thus has the potential to be used for greener non-structural applications. The CO2 sequestration during curing under high-concentration CO2 (10 %), which is mainly via the RMC carbonation, is determined by acid digestion. The CO2 sequestration during service under ambient CO2 concentration (0.1%, or 1000 ppm), which is via the continued carbonation of RMC and the adsorption of biochar, is determined by monitoring the removal of CO2 in situ; particularly, the CO2 sequestrations by the RMC and the biochar are determined separately. The effect of varying biochar content and CO2 curing time on the overall CO2 sequestering ability of the concrete are studied, together with the variation of the local CO2 sequestration with carbonation depth in the concrete.

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Chen et al. (2024): Effect of Biochar Types and Rates on SOC and Its Active Fractions in Tropical Farmlands of China

Mingwan Chen, Daquan Liu, Xujie Shao, Shoupeng Li, Xin Jin, Jincun Qi, Hong Liu, Chen Li, Changjiang Li, Changzhen Li  IN: Agronomy, https://doi.org/10.3390/agronomy14040676

This study aimed to determine the impact of different types and rates of biochar applied in tropical farmlands on so SOC and its active fractions. The SOC, microbial biomass carbon (MBC), dissolved organic carbon (DOC), and soil mineralizable carbon (SMC) in the 0–30 cm soil layers under rice hull (R) and peanut shell (P) biochar treatments were measured. The results showed that the application of R and P biochar increased the contents, stocks, and cumulative stocks of SOC, MBC, and DOC in the 0–10 cm, 10–20 cm, and 20–30 cm soil layers. 

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Forest carbon’s back-end durability problem

by Zeke Hausfather, on theclimatebrink.com, March 19, 2024

„The natural world is a key ally in combating climate change. Studies estimate that reforestation – restoring areas where forests have been removed or fragmented – could remove upwards of 300 gigatons of CO2 (GtCO2) from the atmosphere. Even more could be removed by protecting existing forests and allowing to recover and maturity. The world needs to invest more in protecting the forests we have and restoring those that have been degraded. However, the way we have chosen to finance it – by selling offsets into voluntary or compliance markets – introduces unintended consequences that could undermine our ability to stabilize global temperatures and achieve our climate goals.“

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Liang et al. (2024): Synergistic advantages of volcanic ash weathering in saline soils: CO2 sequestration and enhancement of plant growth

Bing Liang, Jianbing Wei, Shangyu Wu, Heyang Hao IN: Science of The Total Environment, 925, 171825, https://doi.org/10.1016/j.scitotenv.2024.171825

The scientific premise of this study is that CO2 sequestration in agriculturally relevant, organically-deficient saline soil can be achieved by incorporating alkaline earth silicates. Volcanic ash (VA) was used as a soil amendment for CO2 removal from saline soil by leveraging enhanced silicate rock weathering (ERW). The study pursued two primary objectives: first, the authors aimed to evaluate the impact of various doses of VA, employed as an amendment for organically-deficient soil, on the growth performance of key cultivated crops (sorghum and mung bean) in inland saline-alkaline agricultural regions of northeastern China. Second, they aimed to assess alterations in the physical properties of the amended soil through mineralogical examinations, utilizing X-ray diffraction (XRD) and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) analyses, quantifying the increase in inorganic carbon content within the soil.

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Nuterman & Jochum (2024): Impact of marine carbon removal on atmospheric CO2

Roman Nuterman, Markus Jochum IN: Environmental Research Letters, 19, 3, DOI 10.1088/1748-9326/ad26b7

A computer simulation of Earth’s climate is used to study if marine carbon removal will lead to a reduced atmospheric carbon dioxide concentration, and if there are potential secondary impacts on marine life and chemistry. The authors find that for stationary carbon removal plants the ocean cannot supply sufficient carbon rich water to allow a meaningful reduction of atmospheric CO2. This also means that outside the location of carbon removal there is no noticeable impact on plankton concentrations. It can be speculated that putting carbon removal plants on ships would lead to a significant increase in removal efficiency, although the engineering and energy aspects of this approach would need to be investigated.

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