In the paper "Developing the international carbon market beyond 2012", the focus is on controlling greenhouse gas emissions using emissions trading. The Kyoto Protocol set up a trading system until 2012 where countries could trade allowed emissions. Developing nations can join through the Clean Development Mechanism. The European Union also has its own emissions trading scheme for companies since 2005, regulating over 10,000 facilities emitting around 2 gigatonnes of CO2 annually. This shows how emissions trading is a big part of worldwide efforts to reduce carbon dioxide emissions.