Critics wonder if emissions trading will work to actually reduce GHGs by By SATOSHI KOREEDA FROM The Olympian

There are two types of programs:

"One is a cap-and-trade program, in which European Union nations set a ceiling on companies' emissions, and firms whose emissions exceed their caps can purchase emission allowances from other firms whose emissions fall below their caps. The other is the Clean Development Mechanism, which allows industrialized countries to invest in environmental projects in developing countries, and the consequent emission cuts made in developing nations are regarded as the investors' cuts."