<prompt> Carbon credits are issued in the terms of units of Ceified Emission Reduction CER. Each CER is equivalent to -1 kg of CO2 reduction10 kg of CO2 reduction100 kg of CO2 reduction1 ton of CO2 reduction  <response>: The offset ceificates issued by the clean development mechanism CDM are the ceified emission reductions CERs. Each CER is equivalent to one tonne of carbon dioxide CO2 avoided or removed from the atmosphere. By using CERs, emissions are offset Ref: Internet 