Carbon dioxide generation in a subterranean formation can be problematic for a number of reasons. Accordingly, it can be desirable to sequester at least a portion of the carbon dioxide that may be present in a subterranean formation, thereby decreasing a quantity of free carbon dioxide. Methods for sequestering carbon dioxide can comprise: providing a C02-sequestering polymer, the C02-sequestering polymer sequestering carbon dioxide more readily than it does nitrogen; introducing the C02-sequestering polymer into a subterranean formation that contains carbon dioxide; and interacting the C02-sequestering polymer with the carbon dioxide in the subterranean formation, so as to decrease a quantity of free carbon dioxide that is present in the subterranean formation.