All of the carbon dioxide in the atmosphere passes through the surface ocean within 10 years. Most of the CO2 in the surface ocean is in the form of carbonate ions (components of alkalinity). Therefore, we are conducting research into alkalinity addition in order to understand how the ocean-atmosphere CO2 cycle behaved in the past and how it can be “geoengineered” in the future.
Through a range of laboratory experiments and feasibility studies we are developing the concept and initial work by Haroon Kheshgi (1995) and Tim Kruger, who propose to sequester atmospheric carbon dioxide by the addition of (hydr)oxide minerals into the open ocean. When dissipated across the surface ocean these minerals form a benign solution of calcium bicarbonate (which is already one of the main constituents of seawater). However, it is important to understand the localised environmental impacts during addition (which in small doses may include the amelioration of ocean acidification, and in large doses may produce excessively high pH).