Carbon dioxide equivalent of "emissions" or rate of greenhouse gas emission—a "flow" into the atmosphere—rather than the instantaneous value of the radiative forcing of the "stock" (concentration) of greenhouse gases "in the atmosphere" described by e. The carbon dioxide equivalency for a gas is obtained by multiplying the mass and the GWP of the gas. The following units are commonly used: For example, the GWP for methane over 100 years is 34 and for nitrous oxide 298. This means that emissions of 1 million metric tonnes of methane and nitrous oxide respectively is equivalent to emissions of 34 and 298 million metric tonnes
Chicago Climate Exchange were intended to still be facilitated. Until July 2010, CCX was operated by the public company Climate Exchange PLC, which also owned the European Climate Exchange. Richard Sandor, creator of the Sustainable Performance Group, founded the exchange and has been a spokesman for it. The exchange traded in emissions of six gases: carbon dioxide, methane, nitrous oxide, sulfur hexafluoride, perfluorocarbons, and hydrofluorocarbons. CCX started trading in October 2003, prior to the commencement of trading in the European Union through the ETS system. IntercontinentalExchange (), a leading operator of regulated global futures exchanges, clearing houses and over-the-counter (OTC) markets, announced in