Biodiversity Net Gain is a term that is becoming ingrained in the development process, particularly as it is set to become mandatory as part of the up and coming Environment Bill. However, the related concept of Environmental Net Gain is perhaps less well known, but is also entering the terminology of development projects in tandem.


What is Environmental Net Gain and how does it differ from Biodiversity Net Gain?


The Chartered Institute of Ecology and Environmental Management (CIEEM) has recently published a briefing paper that seeks to “provide a practical definition of the term and provide the legislative, policy and strategic context within which ENG [Environmental Net Gain] can be delivered” (CIEEM, April 2021).


Environmental Net Gain builds on Biodiversity Net Gain – defined as “development that leaves biodiversity in a better state than before” [1] – by seeking to benefit ecosystem services [2] and natural capital [3].


How can Biodiversity Net Gain contribute to Environmental Net Gain?

Essentially, Biodiversity Net Gain can also provide wider environmental benefits, for example, the creation of a wetland habitat can have multiple benefits for biodiversity, being of intrinsic value as well as supporting species of fauna; however, it can also benefit flood attenuation, be used as an educational resource and improve water quality, which are considered to have wider ecosystem services benefits.


How can Environmental Net Gain be delivered?

Similarly to Biodiversity Net Gain, there are a number of tools (guidance and frameworks) that can be used to aid the delivery of Environmental Net Gain. Initially, the mitigation hierarchy is used to achieve Biodiversity Net Gain and from there, the Environmental Net Gains can be determined and maximised.


CIEEM’s briefing note defines three levels of detail that can be considered for Environmental Net Gain: qualification, quantification, and monetisation of environmental benefits.


The successful delivery of Environmental Net Gain will likely require the involvement of a number of technical specialisms to ensure appropriate design and management of projects, and it is likely that in the future, Environmental Net Gain considerations will be flagged as part of ecology Preliminary Ecological Appraisals.


One of the major considerations of successful Environmental Net Gain is the long term maintenance of the benefits. CIEEM recommends that maintenance should be planned for at least thirty years. This can be achieved through means such as conditions and conservation agreements.


If you would like to discuss Biodiversity Net Gain (and Environmental Net Gain) requirements for your project, please get in touch.



[1] CIRIA, CIEEM, IEMA, 2016. Biodiversity Net Gain: Good practice principles for development.

[2] Ecosystem services are the benefits that people obtain from ecosystems. They include provisioning (e.g. food and fresh water), regulating (e.g. flood and climate regulation), and cultural services (e.g. educational and recreational), in addition to supporting services that are needed to maintain the other services (e.g. nutrient cycling and soil formation).

[3] The World Forum on Natural Capital defines natural capital as, “the world’s stocks of natural assets which include geology, soil, air, water and all living things. It is from this natural capital that humans derive a wide range of services, often called ecosystem services, which make human life possible”.