Are you ready for Biodiversity Net Gain?

But wherever you are in the world, the impact of construction on nature is an increasingly hot topic with some significant emerging issues to get to grips with, as calls to put nature at the heart of development continue to increase.

New requirement

From January 2024 developers in England will be required to deliver a 10% biodiversity net gain (BNG) when building large new housing, industrial or commercial developments. The same requirement for small sites (those under 1 hectare with fewer than 10 dwellings or 1000 square metres of commercial floorspace) will be introduced from April 2024 and implementation for Nationally Significant Infrastructure Projects is planned for 2025. 

Biodiversity net gain is an approach to development that aims to leave the natural environment in a measurably better state than before. BNG will be measured using Defra’s biodiversity metric and habitats must be secured for at least 30 years to ensure the net gain is delivered. 

This new requirement, delayed from November 2023, will apply to new planning applications for major development made after January 2024 and will not be applied retrospectively. BNG originates from the Environment Act 2021, and some developments are already delivering a biodiversity net gain either voluntarily or due to local requirements.

Why is biodiversity net gain important?

Biodiversity or ‘biological diversity’ is the variety of all life on earth. It includes all living organisms, the variety of species of animals, plants, fungi and micro-organisms, genetic diversity within species, and the variety of ecosystems and natural habitats in which they occur. Together this diversity, and all the interactions within it, create a delicate balance ensuring the continuation of the services nature provides to support our wellbeing such as provision of oxygen, fresh water, natural resources, medicines, pollination, and food.

According to the State of Nature Report 2023, the UK, like most other countries worldwide, has experienced a significant loss of biodiversity. As a result, the UK is now one of the most nature-depleted countries on Earth.

Resources to support BNG

There are a wide range of tools and resources to support the implementation of BNG. If you haven’t already done so, you could start by checking out some of the CPD available on this topic, for example Members can find an introductory session on Biodiversity Net Gain in Construction on the CIOB Academy. 

Long awaited Government guidance for developers, released at the end of November, details how to Meet Biodiversity Net Gain requirements. 

The UK Green Building Council, which the CIOB is a member of, has a set of three checklists and a number of factsheets which are extremely accessible resources for growing your knowledge.

An interesting development has been the emerging role of Artificial Intelligence (AI). It is anticipated that there will be a shortage of competent people to support the new requirement, as it rapidly increases demands on a fixed supply of qualified professionals. This has driven the development of AI tools for initial site assessment, mapping habitat types, and measuring and monitoring change over time. Examples include:

Gentian, which uses high resolution satellite images together with fully trained AI algorithms to recognise and separate different habitat types remotely and autonomously.

Map Impact's Biodiversity View, which provides on-demand indications of biodiversity condition every 50 metres across England, using metrics derived from satellite imagery.

The BNG Screening Tool, which uses nationally available datasets to quickly understand the BNG implications of a site for development. 

These tools are best understood as resources to support ecologists, rather than replace them, as there can be no substitute for ‘boots on the ground’ given the complexity of accurately assessing habitat condition and the consequences of incorrect assessments. 

What about the devolved nations?

Environmental policy is a devolved issue and therefore BNG is dealt with differently between the devolved nations. For example, Scotland's approach to addressing biodiversity in development is through the planning system, and is based on enhancement rather than gain, with no nationally set minimum level of biodiversity enhancement and no national metric. In Wales, the Future Wales: National Plan 2040 introduced a requirement for development to deliver a ‘net benefit for biodiversity’ (NBB): “strategic planning and individual development proposals must avoid loss in the extent of biodiversity and incorporate measures to appropriately maintain and enlarge existing habitats, especially where extent is small or declining through habitat restoration and creation with adjoining and nearby areas, green infrastructure features and networks”. 

Global perspective

According to the Business and Biodiversity Offsets Programme, No Net Loss or Biodiversity Net Gain are policy goals in many countries and businesses. Almost 70 governments have requirements on the mitigation hierarchy that include biodiversity offsets and the number rises to over 100 if you include those currently developing them. However, my own experience of working in a global business which was an early adopter in mandating biodiversity net gain for development projects suggests that in some geographies awareness of the concept remains low.

Embodied biodiversity impacts

Biodiversity net gain offers an approach to addressing the direct impact of construction and development at site level. However, this does not fully address the impact of construction on nature. For example, the production and processing of construction materials, such as timber, sand, and minerals including gravel, iron ore and rocks, also impacts heavily on biodiversity. 

The embodied biodiversity impacts of a project, i.e. the impacts on biodiversity resulting from the processes that take place throughout a material’s lifecycle, from extraction to end of life disposal, are not covered by Biodiversity Net Gain. Expedition Engineering highlighted this issue in a recent report which calls on the industry to develop capabilities in the choice and specification of materials that minimise impact on nature.