Some colleagues and I have a Comment piece that has come out today in Nature. The article outlines the risks associated with using offsets to achieve pre-existing commitments, such as those to which nations have committed under the Convention on Biological Diversity and the World Heritage Convention.
We recommend that while it is often appropriate for offsets to create and manage new protected areas, these outcomes should be accounted for separately from progress towards existing commitments such as the Aichi targets, in order to avoid offsets simply replacing government funding for protected areas. We argue that future international agreements should require separate accounting of conservation gains that were possible only because of equivalent losses, and benefits from the new protected areas funded by offsets should always be reported alongside the losses that triggered their protection.
Here is the link to the article: http://www.nature.com/news/conservation-stop-misuse-of-biodiversity-offsets-1.18010.
Citation: Maron, M., Gordon, A., Mackey, B. G., Possingham, H. P. and Watson, J. E. M. 2015. Stop misuse of biodiversity offsets. Nature 523, 401–403; doi:10.1038/523401a
In addition the ABC has written an article on this topic which you can see here: http://www.abc.net.au/science/articles/2015/07/23/4278534.htm