Companies in the U.S. are already trading the right to emit more greenhouse gas pollution than the entire country of Germany: 540 million metric tons of carbon dioxide are being bartered on the Chicago Climate Exchange (CCX). In fact, if all U.S. emissions were to be so traded"including carbon dioxide from the tailpipes of cars as well as the smokestacks of coal-fired power plants"a $1-trillion market could be created by 2020, according to Eron Bloomgarden, country director of U.S. operations for EcoSecurities, PLC, a Dublin, Ireland"based company that creates offsets for globe-warming pollution. The CCX"a voluntary effort with legal commitments from its member companies to reduce emissions"and its founder, financial derivatives wizard Richard Sandor, have essentially invented "a new form of currency." The market is an example of carbon cap and trade, in which an overall cap is set (in the case of the CCX, 6 percent below an average of emissions over the period 1998 to 2001) and then companies trade to comply. Those that can reduce emissions more than the cap sell their reductions to those who cannot reduce their discharges as much. For example, one Minnesota dairy farmer received a check for $10,000 simply for capturing the methane wafting from the dung left behind by his cows. One hundred metric tons of carbon dioxide pollution was priced at $5.70 on the exchange as of March 27, according to Paula DiPerna, CCX's executive vice president for corporate recruitment and public policy. But will such prices on carbon dioxide pollution end up facilitating the development of cleaner energy alternatives? "The answer is no," argues economist Michael Grubb of the University of Cambridge who is also chief economist for The Carbon Trust, a London consultancy that helps companies transition away from greenhouse gas pollution. "Carbon prices will not drive the innovation that we require." Government policies will be needed for that, particularly in encouraging the conservative energy industry to transition to more innovative forms of power generation, such as new nuclear power and coal-fired generation that captures and stores the carbon it would otherwise emit, along with renewables like wind- and solar-derived energy. "Nothing alone is enough," DiPerna admitted. But "price transparency""knowing how much it will cost a given company to release greenhouse gases into the atmosphere""is very critical."