Enhanced Weathering of Minerals
During Earth’s 3.7 billion-year journey, rocks have sequestered many trillions of tons of carbon dioxide. Natural rock weathering removes approximately 1 billion tons of atmospheric carbon dioxide annually. Various types of silicate rock on the surface of the earth are weathered by carbon dioxide and dissolved in rainwater, which transforms the carbon dioxide into inorganic carbonates. These carbonates find their way into streams, rivers, and oceans, eventually becoming calcium carbonate.
Enhanced weathering of minerals refers to technologies that hasten this process sustainably. One type of silicate that would work well is olivine, a greenish mineral, rich in magnesium and iron. Enhanced weathering would involve mining and milling olivine and then applying the resulting rock powder to land and water, so that the soil, oceans, and biota can act as “reactors” for accelerated weathering.
The rock powder could be strategically distributed over various landscapes, using existing infrastructure for the management of farm and forest soils. Agricultural land in the tropics, where soils are warmer and wetter and have fewer minerals that would inhibit dissolution, are ideal. If applied to one-third of tropical land, olivine could lower atmospheric carbon dioxide by 30 to 300 parts per million by 2100.
fluctuations in the annual carbon cycle: NASA. Orbiting Carbon Observatory-2 (OCO-2). https://oco.jpl.nasa.gov.
“basalts…unlimited storage capacity”: Mooney, Chris. “They May Save Us Yet: Scientists Found a Way to Turn Our Carbon Emissions into Rock.” Washington Post. November 18, 2016.
Additional Background Sources
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Köhler, Peter, Jens Hartmann, and Dieter A. Wolf-Gladrow. “Geoengineering Potential of Artificially Enhanced Silicate Weathering of Olivine.” Proceedings of the National Academy of Sciences 107, no. 47 (2010): 20228-20233.
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Renforth, Phil. “The Potential of Enhanced Weathering in the UK.” International Journal of Greenhouse Gas Control 10 (2012): 229-243.
Renforth, Philip, PAE Pogge von Strandmann, and G. M. Henderson. “The Dissolution of Olivine Added to Soil: Implications for Enhanced Weathering.” Applied Geochemistry 61 (2015): 109-118.
Schuiling, R. D., and P. Krijgsman. “Enhanced Weathering: An Effective and Cheap Tool to Sequester CO2.” Climatic Change 74, no. 1 (2006): 349-354.
Full models and technical reports coming in late 2017.