Author name: Eric H. Oelkers

Asurvey of the global carbon reservoirs suggests that the most stable, long-term storage mechanism for atmospheric CO2 is the formation of carbonate minerals such as calcite, dolomite and magnesite. The feasibility is demonstrated by the proportion of terrestrial carbon bound in these minerals: at least 40,000 times more carbon is present in carbonate rocks than in the atmosphere. Atmospheric carbon can be transformed into carbonate minerals either ex situ, as part of an industrial process, or in situ, by injection into geological formations where the elements required for carbonate-mineral formation are present. Many challenges in mineral carbonation remain to be resolved. They include overcoming the slow kinetics of mineral–fluid reactions, dealing with the large volume of source material required and reducing the energy needed to hasten the carbonation process. To address these challenges, several pilot studies have been launched, including the CarbFix program in Iceland. The aim of CarbFix is to inject CO2 into permeable basaltic rocks in an attempt to form carbonate minerals directly through a coupled dissolution– precipitation process.

Human and industrial development over the past hundred years has led to a huge increase in fossil fuel consumption and CO2 emissions, causing a dramatic increase in atmospheric CO2 concentration. This increased CO2 is believed to be responsible for a significant rise in global temperature over the past several decades. Global-scale climate modeling suggests that the temperature increase will continue, at least over the next few hundred years, leading to glacial melting and rising sea levels. Increased atmospheric CO2 also leads to ocean acidification, which will have drastic consequences for marine ecosystems. In an attempt to solve these problems, many have proposed the large-scale sequestration of CO2 from our atmosphere. This introductory article presents a summary of some of the evidence linking increasing atmospheric CO2 concentration to global warming and ocean acidification and our efforts to stem this rise though CO2 sequestration.