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Is biodiversity net gain the answer to sustainable development?

The recent State of Nature report (2023) says “The UK is now one of the most nature-depleted countries on Earth.” UK wildlife is in crisis, so politically, socially, morally and environmentally, sustainable development is high on the agenda.

Come January 2024, when biodiversity net gain legislation comes into effect, all land developers must “leave biodiversity in a measurably better state than before” in a move that feels like a no-brainer if we’re going to support people and the planet.

Biodiversity plays a vital role in supporting the healthy ecosystems that give us clean air and water, food and flood protection. But with biodiversity declining at an alarming rate, due to habitat loss and fragmentation, climate change and pollution, we can’t just stand by. Something has to change if we have a hope of reversing this trend.

But does this need to be legislated? Could developers be trusted to do the right thing by nature and the environments they’re working in without government intervention? Here, we dig into the future of biodiversity net gain (BNG).


What is biodiversity net gain?

With increasing evidence of the poor state of UK biodiversity ( for example the State of Nature Report) the government created legislation on biodiversity gain. This was then developed by the government regulator, Natural England into a highly prescriptive metric that requires developers to create or improve habitats on the development site or to purchase additional biodiversity units from local landowners

BNG requires developers to have an ecologist assess land earmarked for development. Developers must then show how the completed development will gain at least 10 percent biodiversity onsite. If onsite biodiversity is not possible, they must declare, first, the biodiversity units they will buy from landowners who have created biodiversity units specifically to sell to developers or, as last resort, the biodiversity credits they will buy from government.

The BNG metric scores higher those habitats that support richer biodiversity than those with a lower level of biodiversity. For example, a hectare of modified grassland, which has very few plant species and carries little biodiversity, scores two. A hay meadow, with its abundance of grasses and flowers, has rich biodiversity, so it scores eight.

The metric could make it prohibitive to develop high biodiversity plots – such as hay meadows – so they may be left undeveloped. Although BNG is prescriptively defined by habitat types, it should have wide-ranging benefits:

  • improving habitats for wildlife
  • preserving areas of high biodiversity from development
  • helping to reverse the long decline in biodiversity
  • creating more biodiverse and greener neighbourhoods
  • linking with carbon credits so carbon sequestration and biodiversity creation can work together
  • providing critical habitats for endangered species
  • providing nature-based solutions to climate change
  • helping to improve water and air quality
  • helping humans access nature and wellbeing

While BNG will not in itself make everything better, it can “contribute to the recovery of nature while developing land. It is making sure the habitat for wildlife is in a better state than it was before development.”1

What does BNG look like in practice?

Provided they can deliver at least 10 percent net gain in accordance with the statutory metric and sustain it for 30 years, developers can be as imaginative, innovative or conservative as they want. The key here is to ensure projects have a positive impact on the natural world and contribute to sustainable development. In addition to the legal requirements to create biodiversity, developers can look at other ideas to enhance the environment.

Environment-enhancing approaches:

  • add green spaces with native plants to a new housing development to provide habitat for wildlife and improve air and water quality
  • build a new road with wildlife crossings to help animals move around safely
  • restore the habitat around a renewable energy project in an already-degraded area
  • incorporate green roofs and walls in design and build
  • mount bat boxes, bird feeders, swift bricks to encourage wildlife to thrive
  • create planted walkways and cycle paths to encourage active commutes
  • plant street trees and use flower boxes in road design
  • set aside wildflower meadows

Why is the BNG legislation happening now?

In 2021, government passed the Environment Act 2021, making BNG mandatory for all new developments in England from January 2024. BNG is a relatively new concept, but it is already gaining global traction as a way to address the biodiversity crisis and promote sustainable development.

Why do we need BNG legislation?

Biodiversity net gain is a valuable tool and an important component of sustainable development, but it is not the sole answer. Sustainable development is a complex and multifaceted concept that involves balancing economic, social and environmental considerations to meet the needs of the present without compromising the ability of future generations to meet their own needs. BNG primarily addresses the environmental aspect of sustainability, specifically biodiversity conservation.

What alternatives are there to BNG?

It’s important to note that BNG is not a silver bullet for sustainable development. It could all too easily become a box-ticking exercise and lose its potency when planning and implementing new developments. For example, BNG should not be used to justify developments that have a significant negative impact on other environmental factors, such as air or water quality.

Integration with other environmental goals: BNG is just one piece of the sustainability puzzle and needs to integrate with broader objectives of reducing greenhouse gas emissions, conserving water resources and promoting social equity.

Holistic economic and social aspects: Beyond BNG, for sustainable development, we need to create jobs, reduce poverty, improve access to education and healthcare and promote economic growth that benefits all members of society. It’s not enough to focus solely on one aspect – it’s about finding synergies and trade-offs between all elements.

Global and long-term perspective: BNG, mandated by the UK government, primarily addresses local or site-specific biodiversity concerns. Ideally, we would explore ways for it to fit into a wider commitment with a global and long-term perspective and consider the interconnectedness of ecosystems, economies and societies worldwide.

Biodiversity net gain is a valuable tool for addressing biodiversity conservation in the context of development projects – it’s certainly a positive step towards environmental sustainability and a more sustainable and equitable world. But for true sustainable development, it must be part of a broader, more comprehensive effort that considers economic, social and environmental factors at local, regional and global scales.


Are you eager to learn more about how you can be ready for the new legislation coming into effect in 2024? Then read our blog post:

Biodiversity net gain: How can land developers be ready for January 2024? 

Article originally published by Landmark Information Group.