The facts about nature loss are startling. One million of the planet’s estimated eight million species of plants and animals face probable extinction. Three quarters of the planet’s land surface has been significantly affected by human activity. Decades of development, heedless of nature’s importance, have led to the need for a radically different mindset. 

As an approach, biodiversity net gain is a way to contribute to the recovery of nature while developing land. It aims to ensure that the habitat for wildlife is in a better state than it was before development. England is leading the way in its use of environmental and planning regulation to promote biodiversity and the protection of nature. The issue of damage to nature is relevant across the globe, so it’s a good moment to see what can be learned from the experience here in the UK, and think about what it means to achieve in practice. 

With the English BNG regulations coming into effect in February 2024, many clients have spoken to us, looking for clarity about both what it means for their operations or the projects they invest in, and to understand what benefits can be accrued. With parallel goals like net zero and emissions reduction already commanding a lot of mental bandwidth in boardrooms, I thought it would be useful to relay a few principles that our biodiversity net gain specialists have developed from Arup’s work in the field to date. 

Principle 1: Start with a robust and honest definition of the stakes

Every project contains different implications for nature and biodiversity, meaning a degree of initial research and exploration is required. Understandably, many developer clients might not be aware about which practices really deliver lasting natural benefits on the ground. They want to invest wisely and effectively, in this just as any other dimension of a project, be it a public highway redevelopment or a commercial mixed-use site. The net ‘net gain’ is important here. It means being transparent about every element of a project’s impact on nature, negative and positive, if the reporting at the end is to be credible and honest.

Principle 2: Nature isn’t numbers (but you still have to measure).

Regulation typically requires numerical claims somewhere in the process and, understandably, governments want to see quantifiable benefits. However, our underlying goal here is delivering a better state of nature and biodiversity, both complex systems requiring nuanced and thoughtful consideration. A green wall on an office building might be a big win according to the numbers, but if wholly isolated from other biodiverse spaces and neglected following installation, the plants may have died by winter. The lesson here is that biodiversity net gain is meaningless without endurance and a sense of connection to wider natural systems.

Principle 3: Prioritise the local

In the past many big polluters or emitters have bought carbon and nature offsets, investing in the reforestation efforts in the Amazon, for example, while building a new manufacturing facility in their home country. Leaving aside the wider debate about the honesty and effectiveness of offsets, it makes more sense, intuitively, to prioritise the nature on your doorstep. Not only will it improve the local area and community, it also reconnects an organisation to the impacts of its activities, which is central to any responsible business or operation. 

Biodiversity net gain is meaningless without endurance and a sense of connection to wider natural systems.

Neil Harwood

Associate Director, Arup

What does ‘net gain’ look like?

Our team works on biodiversity net gain and nature positive outcomes in a wide variety of contexts, a range that keeps growing. To give you some idea of what’s involved, we could look at three typical scenarios.

Firstly, many UK and global organisations are in the process of making public commitments to delivering biodiversity net gain and/or developing their own nature recovery strategies. For an organisational strategy to become truly embedded, manufacturers or entities with complex global supply chains need to dive deeply into every element of their operations and ensure that virtue in one place isn’t undone by old practices elsewhere. So the initial requirement is an open-mindedness to new ways of working, and thinking, and perhaps a few unfamiliar conversations.

A second example, consider a new office building in a city environment. Here, proposed designs often look like a biodiversity net gain could be achieved quite simply, at least, on paper. Often, the site’s pre-existing natural value may be low to non-existent, and so the addition of some basic green space provisions (a handful of terrace planters and a peripheral strip of sedum green roofing) counts as a significant improvement. However, we need to ask ourselves whether this level of ‘do the minimum’ ambition is still appropriate and whether the proposal is genuinely delivering a better outcome for biodiversity, for people (think urban heat) and nature, despite what the numbers might say.

We could instead adopt a systems thinking approach to the building. That means integrating biodiversity considerations with those of climate and building resilience, flood attenuation, and the urban heat island effect in a single design. This could be achieved with a multi-level biodiverse green roof, sat beneath elevated solar panels, that holds and stores water before flowing down into a ground-level rain garden or similar sustainable drainage (SuDS) provision, surrounded by pockets of trees to provide shade. The end result is greater positive impact on biodiversity and a far more appealing and sustainable asset for users and owners alike

In a different context, UK local authorities, who are frequently under-resourced and without specialist capability in-house, are being asked to develop Local Nature Recovery Strategies for their jurisdictions. In many areas, these strategies are at best embryonic and there is a vacuum of knowledge and understanding about how to develop and deliver these in line with the local plan framework. The best way to help authorities is to set out a place-based strategy that will allow developers and other stakeholders to contribute to and invest in nature in locations and ways that really deliver optimal outcomes on the ground.

A better future

Once biodiversity net gain becomes a planning norm, we might perhaps wonder what we were doing in the past. In essence the shift allows us to listen to what the planet needs tomorrow and act on it today. It’s a stronger, more robust definition of socially useful and environmentally conscious design. Now is a good time to reflect on what it means for all of us who work in the built environment industry.