Carbon dioxide surface, warming the surface and the lower atmosphere. Less energy reaches the upper atmosphere, which is therefore cooler because of this absorption. Increases in atmospheric concentrations of and other long-lived greenhouse gases such as methane, nitrous oxide and ozone have correspondingly strengthened their absorption and emission of infrared radiation, causing the rise in average global temperature since the mid-20th century. Carbon dioxide is of greatest concern because it exerts a larger overall warming influence than all of these other gases combined and because it has a long atmospheric lifetime (hundreds to thousands of years). Not only do increasing carbon dioxide
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