Agence France-Presse: The global market in CO2 emission rights could be worth two trillion euros (3.14 trillion dollars) by 2020 if the United States joins the scheme, analysis group Point Carbon said on Thursday. The United States, which has not ratified the Kyoto Protocol that calls for the mechanism, could in 2020 account for 67 percent, or 1.25 trillion euros, of emissions rights if it decided to introduce a US emissions trading system, the Point Carbon study said. Carbon dioxide (CO2) is one of …