Geoengineering Potential of Mineral Weathering Schemes

For instructors who include a module on climate geoengineering, there is a very good new article in the Proceedings of the National Academy of Science of the United States on the carbon dioxide removal option of mineral sequestration, Mineral sequestration is a geoengineering approach that contemplates acceleration of the natural weathering process, producing a reaction between silicate rocks and carbon dioxide that forms solid carbonate and silicate materials. The reaction consumes one carbon dioxide molecule for each silicate molecule, with storage of carbon as a solid mineral.  The PNAS article focuses on silicate weathering of the mineral olivine.

Among the article’s take-aways:

  1. Enhanced silicate weathering by dissolution of olivine in the humid tropics, an optimal area to effectuate this scheme, could store approximately 1 Pg of carbon per year. This is 20% less than estimated in some previous studies;
  2. Another complementary option would be to dissolve olivine powder in open ocean surface waters. This could increase sequestration to a maximum of 5 Pg of carbon annually. This could reduce warming by 0.6-1.1K
    • The increase of riverine input of silicic acid into the world’s oceans might also enhance the marine biological pump, ultimately enhancing oceanic sequestration of carbon dioxide
  3. Environmental impacts need to be further assessed , including potential increases in alkalinity and silic acid in soils and aquatic ecosystems.

Be Sociable, Share!