Carbon trading systems will soon be a reality across Canada.Such a system is already up and running in Alberta. The federal government is also in the process of setting up its own system, as are the governments of BC, MB, ON and QC.Under a carbon trading system, companies earn “offset credits” for reducing their greenhouse gas (GHG) emissions below designated caps. They can then trade or sell these credits to regulated companies that need them to meet their own GHG emission reduction targets. In some systems, companies can also trade or sell unused emissions allowances issued by the government. Each offset credit or emissions allowance is generally equal to one metric tonne of GHG expressed in carbon dioxide (CO2) equivalents.