Global warming has been identified as one of the world's major environmental issues. While it is impossible to completely stop the effects of anthropological global warming, it is possible to mitigate these effects via a variety of options. One such option is the reduction of greenhouse gas emissions by the capture of carbon dioxide from flue gases followed by underground sequestration. For this technology to become widespread, new methods of capturing carbon dioxide must be devised. While capture of carbon dioxide with amine solvents is the most mature technology, another possible contender is gas separation membranes. This review will focus on novel materials for gas separation. In particular, polymeric gas separation membranes are examined. Possible design strategies, synthesis, fabrication and role of novel materials are discussed. (c) 2006 Elsevier B.V All rights reserved.