Biodiversity offsets are conservation activities that are designed to give biodiversity benefits to compensate for losses - ensuring that when a development damages nature (and this damage cannot be avoided) new, bigger or better nature sites will be created.
They are different from other types of ecological compensation as they need to show measurable outcomes that are sustained over time. The Government ran six two year pilot projects from 2012 on the biodiversity offsetting approach but have not yet published a report into their findings. A Green Paper consultation on options for biodiversity offsetting ran in late 2013, the results of this have not yet been published.
Biodiversity offsetting has been used as a voluntary and informal tool within the planning system for some time.
The more recent usage refers more specifically to the National Planning Policy Framework and the mitigation hierarchy. The mitigation hierarchy is Paragraph 118, and biodiversity offsetting is the compensation referred to:
"if significant harm resulting from a development cannot be avoided (through locating on an alternative site with less harmful impacts), adequately mitigated, or, as a last resort, compensated for, then planning permission should be refused;"
This paragraph suggests a more compulsory approach hence the Government pilots and consultation, yet no further national guidance has been forthcoming. This paragraph, and all of the National Planning Policy Framework, applies to different degrees according to Local Plan status. Developers and their agents should check with their Local Authority.
Defra has produced much background information including a biodiversity metric based on habitats. This was used in the pilot studies to guide how much habitat was to found as an offset for that lost.