Is the World Trade Organisation blocking progress in the fight against climate change? This is the question at the origin of this legal analysis. Politicians often invoke the WTO as a powerful supranational institution that prevents them from taking any ‘market unfriendly’ measures. With this legal analysis we intend to correct this distorted picture of WTO rules, and demonstrate that WTO rules provide adequate flexibility for national policy makers to take bold and necessary measures to meet the climate change challenge.