Conventionally, platform chemicals are produced from fossil feedstock. In recent years, the production of chemicals from renewable feedstock has been considered. One possible renewable carbon source is biomass. Another option is carbon dioxide (CO2). A rigorous comparison of processes employing renewable carbon sources is missing today. We therefore identify the environmentally most beneficial process routes for platform chemicals. All processes are integrated into a single superstructure, which is analyzed using linear optimization minimizing global warming impacts. The optimal solutions exploit synergies between the different process routes and feedstocks.