A voluntary emission reduction is an emission reduction that has been achieved outside of compulsion. In other words, the person carrying out the activity was not obliged to do so but choose to do so voluntarily. 'Voluntary Emissions Reductions (VERs) are carbon credits developed by carbon offset providers which are not certified.
Certification of carbon credits (Certified Emissions Reductions) are backed by an international framework and institutions, for example under the UN's Clean Development Mechanism, to ensure that real greenhouse gas emission reductions take place, as well as providing a clear audit trail. Voluntary offset schemes can be defined as those aimed at generating GHG emissions reductions not required by Kyoto Protocol’s derived regulation. Through these schemes, industries and individuals voluntarily compensate their emissions or provide an additional contribution to mitigating climate change.