Enhanced chemical weathering as a geoengineering strategy to reduce atmospheric carbon dioxide, supply nutrients, and mitigate ocean acidification

Abstract

[1] Chemical weathering is an integral part of both the rock and carbon cycles and is being affected by changes in land use, particularly as a result of agricultural practices such as tilling, mineral fertilization, or liming to adjust soil pH. These human activities have already altered the terrestrial chemical cycles and land-ocean flux of major elements, although the extent remains difficult to quantify. When deployed on a grand scale, Enhanced Weathering (a form of mineral fertilization), the application of finely ground minerals over the land surface, could be used to remove CO 2 from the atmosphere. The release of cations during the dissolution of such silicate minerals would convert dissolved CO 2 to bicarbonate, increasing the alkalinity and pH of natural waters. Some products of mineral dissolution would precipitate in soils or be taken up by ecosystems, but a significant portion would be transported to the coastal zone and the open ocean, where the increase in alkalinity would partially counteract "ocean acidification" associated with the current marked increase in atmospheric CO 2 . Other elements released during this mineral dissolution, like Si, P, or K, could stimulate biological productivity, further helping to remove CO 2 from the atmosphere. On land, the terrestrial carbon pool would likely increase in response to Enhanced Weathering in areas where ecosystem growth rates are currently limited by one of the nutrients that would be released during mineral dissolution. In the ocean, the biological carbon pumps (which export organic matter and CaCO 3 to the deep ocean) may be altered by the resulting influx of nutrients and alkalinity to the ocean. This review merges current interdisciplinary knowledge about Enhanced Weathering, the processes involved, and the applicability as well as some of the consequences and risks of applying the method.

The Carbon Dioxide Removal Model Intercomparison Project (CDRMIP): rationale and experimental protocol for CMIP6

“…Enhanced weathering ideas have been proposed for both the terrestrial environment (Hartmann et al, 2013) and the ocean (Köhler et al, 2010;Schuiling and Krijgsman, 2006). We focus on the alkalinization of the ocean given its capacity to take up vast quantities of carbon over relatively short time periods and its potential to reduce the rate and impacts of ocean acidification (Kroeker et al, 2013).…”

Prospects of Stabilization of the Global Surface Atmocpheric Temperature at an Acceptable Level

“…Несомненными преимуществами обладает метод, основанный на внесении в почву, в речную или морскую воду силикатных минералов типа оливина ((Mg,Fe) 2 SiO 4 ) или альбита (NaAlSi 3 O 8 ) в виде порошка тонкого размола (Schuiling, de Boer, 2010;Hartmann et al, 2013). Образующаяся в результате растворения СО 2 угольная кислота нейтрализуется силикатами, обладаю-щими щелочными свойствами, с образованием нерастворимых карбонатов и диоксида кремния.…”

Moratoria for Global Governance and Contested Technology: The Case of Climate Engineering

“…47 CDR's risks mainly depend on where and how the captured carbon is disposed. They include disruption of ma- 42 49 and induced seismicity or re-release of stored material from geological sequestration. 50 These risks would be present even with ideally competent and prudent CE deployment.…”