A recent Guardian article revealed a survey showing that

Some 55% of survey respondents had either never heard of carbon offsetting, or had heard the name but didn’t know anything about it. When asked which term best described carbon offsetting, 66% were unable to give an accurate definition.

One in five said it was “the release of carbon dioxide into the atmosphere” while 19% selected “a chemical process which neutralises carbon dioxide gas before it is released into the atmosphere”. Some 2% of respondents thought carbon offsetting was a “new technique that eases trapped wind caused by carbonated/fizzy drinks”.

it may be good news though that:

Only 1% of Britons told researchers they had ever paid into a carbon offsetting programme.

With more and more use of carbon off putting schemes being used in the built environment to archive zero carbon status, one wonders what the level of understanding really is. (Maybe a survey in Building, Phil)