The global climate change issue has experienced a gradual metamorphosis over the past several decades from an issue focused primarily on scientific concerns to one now focusing on selection of mitigation and carbon removal options. A broad range of technological options exist to reduce emissions of greenhouse gases or to capture and dispose of carbon from emissions sources or from the atmosphere. A range of factors need to be considered in choosing appropriate mitigation and disposal options, including how soon each option can be expected to be available, the volume of emissions that could be reduced or offset, the cost, and other technical, social, and political factors. The disposal of carbon dioxide in geological structures appears to be an important option because of the volume of potential disposal sites, permanence of disposal, potential low cost, and the prospect of safely extending the use of cost-effective fossil fuels to allow time for the development of alternatives. We examine some of the technical issues surrounding the geological disposal of carbon dioxide and highlight opportunities for research and development to realize the potential of this valuable option.