This is slightly old news, as BoingBoing mentioned it last week, but it's very world-changing: Cornell chemists have invented a plastic made from orange rinds and CO2. As the Cornell University News Service reports, the researchers' breakthrough was developing a catalyst that makes an oil extracted from orange rinds (which is currently used for things like "giving household cleaners their citrus scent") react with carbon dioxide to form a polymer. The resulting polymer is similar to polystyrene--not usable for structural applications like PVC, but good for packaging and cloth-fibers.

They do not mention whether the plastic will be biodegradable (and this is not a given--some nylon is made primarily out of castor bean oil, and is not biodegradable), but even if not, it's a potential reduction of oil-dependence and sequesters CO2 at the same time. As Prof. Geoffrey Coates, the team leader, said: "If you can get away from using oil and instead use readily abundant, renewable and cheap resources, then that's something we need to investigate."