Abstract
Enhanced weathering through basalt application on agricultural land represents a proposed strategy for the removal of carbon dioxide from the atmosphere. It has been shown that enhanced weathering is principally feasible on a global scale, but there is still uncertainty with respect to the predicted drawdown in a given timeframe. This information is however vital to evaluate, if enhanced weathering should be further considered as a factor to alleviate the impact of the climate crisis. With this in mind, this article reviews of the current state of research and estimates the CO 2 drawdown for scenarios using basalt powders of different particle size distribution (<100 μm, <10 μm and <1 μm). Calculated with a modified shrinking core model, the amount of powder dissolved within a timeframe of 10 years is approximately 16% (<100 μm), 55% (<10 μm) and 99.9% (<1 μm). This corresponds to a gross CO 2 removal of 0.045 t CO 2 t −1 of rock (<100 μm) and 0.153 t CO 2 t −1 of rock, (<10 μm). We evaluate our results on regional scale through a case study for Austria, including emissions from mining, comminution, application and transport. Assuming an average distance of 300 km from mine to field, the net CO 2 drawdown decreases to approximately 0.027 t CO 2 t −1 of rock (<100 μm) or 0.096 t CO 2 t −1 (<10 μm), when rail transport is used. For truck transport, the numbers are reduced to −0.030 t CO 2 t −1 of rock (<100 μm) or 0.039 t CO 2 t −1 (<10 μm), respectively. Accordingly, at the current CO 2 intensity, transport related emissions may cancel out any drawdown if grain sizes (<100 μm) are used. Our estimates suggest that enhanced weathering will only significantly contribute to net CO 2 drawdown if grain sizes (<10 μm) are used. Under these conditions the large-scale application of particles with a diameter <10 μm may remove about 2% of Austria's annual Greenhouse gas emissions. We discuss challenges towards this goal, including the enormous amounts of rock needed and the energy requirement related to grinding, as well as uncertainties related to actual field weathering rates. Those uncertainties hinder the precise quantification of CO 2 drawdown as of now. While enhanced weathering remains a promising path for climate change mitigation, further research at laboratory and field scale is required to put this technology to optimal use.
Originalsprache | Englisch |
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Aufsatznummer | 128178 |
Seitenumfang | 13 |
Fachzeitschrift | Journal of Cleaner Production |
Jahrgang | 315 |
DOIs | |
Publikationsstatus | Veröffentlicht - 15 Sept. 2021 |
Bibliographische Notiz
Funding Information:We thank Sylke Hilberg for valuable comments on this manuscript. Diego Bedoya-Gonz?lez and Timo Kessler are thanked for their help with creation of the map. Kayla Iacovino is thanked for providing an excel sheet for plotting TAS diagrams on her website (www.kaylaiacovino.com). We also thank Zhifu Mi and Jing-Li Fan for editorial handling of this manuscripts. 4 anonymous reviewers are thanked for their help in the improvement of this manuscript. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Systematik der Wissenschaftszweige 2012
- 105 Geowissenschaften