Natural solutions

20th May 2024

What is the role for nature in the Climate Change Act? Sophie Mairesse reports

At the end of last year, Chris Stark, the former chief executive of the Climate Change Committee (CCC), gave a talk at the UK Environmental Law Association (UKELA) annual Garner Lecture. The speech was about the Climate Change Act (CCA) 2008, how it started and has driven changes, and what is left to do. Coincidentally, 2023 was the 15th year anniversary of the Act.

There were some important points made, including that, while the UK has made progress toward its net-zero target and the electricity sector - which had the highest emissions - has decarbonised significantly, the UK still needs to massively reduce emissions to limit and curb global warming and its effects. The sectors which have a key role to play include:

  • Surface transport
  • Manufacturing, construction and fuel supply
  • Buildings
  • Electricity supply
  • Agriculture and land use
  • Aviation and shipping
  • Waste and fluorinated greenhouse gases (F-gases)
  • Removals (of carbon from the atmosphere)

Analysis on how much decarbonisation investment is required shows that the return on investment will (in the future) exceed input. The surface transport sector will have the highest return of all sectors. The UK path to net zero will require four broad actions:

  • Reduction and efficiency on the demand for carbon intensive activities
  • Expending the low-carbon electricity supply
  • Adopt low-carbon solutions (electrification, bioenergy, hydrogen and carbon capture)
  • Offsetting emissions using land-based removal methods and engineered greenhouse gas removal.

While IEMA members can contribute to all of these in the work they do, the last one is particularly interesting as it is the one where biodiversity net gain (BNG) and ecosystem services through natural capital can play a major role.

Degraded habitats generally do not store as much carbon and can even leak it back to the atmosphere. They perform less well when it comes to storing water, soil stability, resilience to disease, stress, and so on. By creating more blue and green spaces as well as enhancing habitat conditions we will not only provide better habitats for species but also help with removing and storing carbon.

In 2021, Natural England reviewed scientific evidence on semi-natural habitats’ carbon capture rate and published ‘Carbon Storage and Sequestration by Habitat 2021’[1]. BNG has become mandatory in England as of 12th of February 2024, and choosing the ‘right’ habitats to be created or enhanced will be dictated by several factors: human planned use of the habitat, geographical location, soil type, costs, time, connectivity, species distribution, ecosystem services provided, amenity value, etc. As a result, the carbon capture rate might well become a measurement that will need to be considered and reported on more.

However, this is not currently the norm for most projects. The trade-off between competing priorities and environmental impacts are normally looked at when considering environmental net gain (ENG). BNG is one element of ENG with 10% BNG gain a pre-request for ENG.

To achieve the CCA target of net zero by 2050, carbon capture and removal is a key action and BNG is one of the tools at our disposal to help achieve it. However, this leaves us with some issues and challenges to consider.

BNG in England was already demanded by several local planning authorities yet its national roll out was delayed. Further, the choice of habitats to be enhanced or created on site can be explained as part of the BNG submission but there is no requirement to explain why a habitat was chosen over another or the pros and cons of choosing it in term of carbon storage or ecosystem services provided.

BNG as a tool has its limitations because it is very difficult to quantify nature and the metric only looks at habitats. However, it is a useful tool to direct people away from impacting the habitats which are generally the rarer, hardest, or the longest to create/recreate on site and yet there is still the option to impact those and then provide bespoke compensation, even though it is discouraged and may not be agreed.

When planning a development, nature-based solutions are still not widely used. Options such as having ‘dirt/grass’ or ‘grasscrete’ roads and parking spaces are not often considered and concrete still favoured even though it has little value for storing carbon, storing water run-off or getting BNG units. Furthermore, green walls and roofs are still not the norm even though they provide several ecosystem services and amenity value on top of adding more vegetation to help remove carbon and air particulates as well as storing some rainwater.

There is still a reticence for using softer engineering methods - they are often seen as more expensive, not as effective, requiring more land and less companies are able to offer those services. There are still too many streets with no vegetation which become too hot in summer. Maybe we could remove a parking space or some of the pavement here or there and add more trees or other vegetation to cool down those areas as well as provide additional carbon, biodiversity and amenity benefits. At a smaller scale, how can we discourage gardens to be concreted over and encourage hedgerows to replace some fences.

If we all consumed less products and/or if they lasted longer then there would be less need for resource extraction, production, manufacturing, energy, transportation, and waste disposal - all of which increase our carbon footprint. This is aimed to both food and other products. If we need to store carbon and get BNG credit through farmland conversion into wetland, woodland, or other habitats then better managing food waste would definitely help if we do not want to increase food import, thus increasing emission release through transportation.

There are many initiatives and tools to help professionals and companies understand what their carbon footprint is and how to reduce it. This includes disclosure of company carbon footprint emissions (with some scope exceptions) such as through the Taskforce on Climate-related Financial Disclosures (TCFD). There are also many ways to report or get an accreditation for carbon reductions. However, although we saw the publication of the Taskforce on Nature-related Financial Disclosures (TNFD) in 2023, mirroring the TCFD, there seems to be a lack of ways to report or get accreditation for nature reductions and coordination between carbon and biodiversity activities to adequately tackle climate change and carbon reduction at the scale we need within the timeframe we have.

What does the future hold in this area?

We need to see better and more joined up thinking. Nature-based solutions should be the first thing considered by organisations tackling not only their carbon footprint but also their nature and social key performance indicator targets (KPI). For BNG, planners and developers respectively might promote and seek to look at the habitats created and enhanced, and their benefits in term of carbon emissions reductions and achievability based on site conditions and planned used.

BNG and climate change targets are interlinked, and we need to be more cognisant that they to be considered as such in the design and implementation of our actions.

Sophie Mairesse is an ecologist and BNG lead for the Work Delivery/Minor Work team (Kent, Sussex and Wessex) at Network Rail. She has had this role for three years and works on a range of projects aimed at enhancing and/or creating habitats on Network Rail land. Sophie is a member of the IEMA Biodiversity and Natural Capital Network Steering Group.

[1] Carbon Storage and Sequestration by Habitat 2021 - NERR094 (


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