Biodiversity offsetting provides a process where damage to habitats arising from a development can be compensated for by providing replacement habitats elsewhere. The Government set out proposals for biodiversity offsetting in a Green Paper in September 2013, including a prospective metric for calculating biodiversity gains and losses.
Arguably offsetting is an admission of failure in that it should only arise after alternative development sites or means of mitigating the environmental loss from development have been considered. A decision on the Government's offsetting proposals should not be made at this time. Offsetting pilots were set up in 2011 and these should be allowed to run their course and then be subjected to the independent evaluation previously promised by ministers. If that evaluation concludes that there are benefits in introducing an offsetting scheme, the Government should then bring forward revised proposals that reflect the concerns that we have raised in this Report.
If the Government nevertheless decides now to introduce offsetting, the current proposals need to be improved in several ways. The metric, which the Government estimates would take only 20 minutes to apply, is overly simplistic. A proper metric needs to reflect the full complexity of habitats, including particular species and 'ecosystem networks', and recognise the special status of ancient woodlands and sites of special scientific interest. Biodiversity assessments would need to be transparent and independent to command respect from developers, local authorities, environmental groups and local people.
Offsets have to be near enough to the development site that local people can still enjoy the types of habitat and wildlife being affected. Focusing the system at the lowest local planning authority level possible would allow the local authority to give full weight to both the loss and the gain under its jurisdiction. Any offsetting system must emphasise the continuing primacy of the 'mitigation hierarchy', where offsetting is only considered after alternative development sites or a means of mitigating the environmental loss in situ have been exhausted.
The Green Paper does not provide an evidence based analysis of how offsetting would deliver "biodiversity gain". The weighting of 'risk factors' must only be reduced when experience of offsetting in practice provides confidence that the environment overall has not been harmed.
The Government and Natural England must monitor any offsetting scheme to ensure that a balance of habitat types is provided overall, and if necessary the weighting factors applied in offset metrics must be adjusted to ensure that such a balance is delivered.
A mandatory, rather than voluntary, offsetting system would encourage a market to develop, which would in turn allow more environmentally and economically viable offset projects to be brought forward. The poor uptake in the pilots suggests that a mandatory system is needed, although the case for that has not yet been made and more analysis of the pilots is needed.