CO₂-removal News

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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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Peer-reviewed Publications

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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Peer-reviewed Publications

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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Peer-reviewed Publications

Rathnayake et al. (2024): Quantifying soil organic carbon after biochar application: how to avoid (the risk of) counting CDR twice?

Dilani Rathnayake, Hans-Peter Schmidt, Jens Leifeld, Diane Bürge, Thomas D. Bucheli, Nikolas Hagemann IN: Frontiers in Climate, https://doi.org/10.3389/fclim.2024.1343516

The objectives of this review are (1) to compare the physicochemical properties and the quantities of biochar and SOC fractions on a global and field/site-specific scale, (2) to evaluate the established methods of SOC and pyrogenic carbon (PyC) quantification with regard to their suitability in routine analysis, and (3) to assess whether double counting of SOC and biochar C-sinks can be avoided via analytical techniques.

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Peer-reviewed Publications

Næss et al. (2024): Bridging Quantitative and Qualitative Science for BECCS in Abandoned Croplands

Jan Sandstad Næss, Ida Marie Henriksen, Tomas Moe Skjølsvold IN: Earth’s Future 12 (3), e2023EF003849, https://doi.org/10.1029/2023EF003849

Bioenergy with carbon capture and storage plays a vital role in most climate change mitigation scenarios, where a solution for sustainable near-term bioenergy expansion is to grow energy crops such as perennial grasses on recently abandoned cropland. This study combines natural science insights anchored in quantitative bioenergy modeling with qualitative social science anchored in the multi-level perspective. Using these mixed methods enables a global-to-local-to-global level assessment of near-term bioenergy recultivation opportunities for abandoned cropland. Norway is the local case. 

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Peer-reviewed Publications

Wu et al. (2024): Operating optimization of biomass direct-fired power plant integrated with carbon capture system considering the life cycle economic and CO2 reduction performance

Xiao Wu, Ziteng Zhang, Xuan Zhang IN: Renewable Energy 225, 120294, https://doi.org/10.1016/j.renene.2024.120294

Biomass direct-fired power plant integrated with carbon capture system can achieve negative CO2 emission during the power generation, which provides an important technology pathway for the transformation of energy system towards carbon neutrality. Understanding the economic competitiveness and CO2 reduction potential of the plant, and identifying the optimal operating mode are the key to fully exert the advantages of the technology. For this reason, this paper develops life cycle economic and CO2 emission assessment models for the biomass direct-fired circulating fluidized bed boiler power plant integrated with solvent-based post-combustion carbon capture system. 

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Peer-reviewed Publications

Xu et al. (2024): Durability and micromechanical properties of biochar in biochar-cement composites under marine environment

Weijian Xu, Yuying Zhang, Muduo Li, Fulin Qu, Chi Sun Poon, Xiaohong Zhu, Daniel C.W. Tsang IN: Journal of Cleaner Production 450, 141842, https://doi.org/10.1016/j.jclepro.2024.141842

Integrating biochar into traditional construction materials presents a promising avenue to reduce carbon emissions from the construction industry. While recent research has focused on the performance of biochar-cement materials, limited attention is given to the durability of biochar in cementitious materials. This study investigated the alterations in the structural, chemical, and mechanical properties of biochar in the cementitious system and marine environment. 

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Peer-reviewed Publications

Block et al. (2024): Analysing direct air capture for enabling negative emissions in Germany: an assessment of the resource requirements and costs of a potential rollout in 2045

Simon Block, Peter Viebahn, Christian Jungbluth IN: Frontiers in Climate 6, https://doi.org/10.3389/fclim.2024.1353939

The aim of this paper is to analyse and comparatively classify the resource consumption (land use, renewable energy and water) and costs of possible DAC implementation pathways for Germany. The paths are based on a selected, existing climate neutrality scenario that requires the removal of 20 Mt of CO2 per year by DACCS from 2045. The analysis focuses on the so-called “low-temperature” DAC process, which might be more advantageous for Germany than the “high-temperature” one.

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Peer-reviewed Publications

Nature – Macintosh et al. (2024): Australian human-induced native forest regeneration carbon offset projects have limited impact on changes in woody vegetation cover and carbon removals

Andrew Macintosh, Don Butler, Pablo Larraondo, Megan C. Evans, Dean Ansell, Marie Waschka, Rod Fensham, David Eldridge, David Lindenmayer, Philip Gibbons, Paul Summerfield IN: Communications Earth & Environment, https://doi.org/10.1038/s43247-024-01313-x

The authors analysed the performance of one of the world’s largest nature-based offset types: human-induced regeneration projects under Australia’s carbon offset scheme. The projects are supposed to involve the human-induced regeneration of permanent even-aged native forests through changes in land management. They analysed 182 projects and found limited evidence of regeneration in credited areas. Changes in woody vegetation cover within the areas that have been credited also largely mirror changes in adjacent comparison areas, outside the projects, suggesting the observable changes are predominantly attributable to factors other than the project activities. 

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