CCER is the short term of China Certified Emission Reduction, which means the certification and registration of emission reduction volume/amount of China domestic greenhouse gases from renewable energy sources, forestry carbon sink, methane utilization etc. projects by China Certified Emission Reduction Trading Registration System.　

In simple, CCER is an carbon emission offset mechanism, that is to say “emission-control” enterprises buying certified emission reduction volume/amount from “emission-offset” enterprises to offset itself emission volume/amount.