The rising atmospheric concentration of CO(2) has motivated researchers to seek routes for improved utilization, increased mitigation, and enhanced sequestration of this greenhouse gas. Through a combination of bioinformatics, molecular modeling, and first-principles quantum mechanics the binding of carbon dioxide to proteins is analyzed. It is concluded that acid/base interactions are the principal chemical force by which CO(2) is bound inside proteins. With respect to regular secondary structural elements, beta-sheets show a marked preference for CO(2) binding compared to alpha-helices. The data also support the inference that while either or both oxygens of CO(2) are generally tightly bound in the protein environment, the carbon is much less "sequestered." First principles and more approximate modeling techniques are assessed for quantifying CO(2) binding thermodynamics.