It is vital that we build healthier towns and cities

The World Bank estimates that half of the global population is living in cities today. This number is set to more than double by 2050, at which point nearly seven out of 10 people will live in urban areas.

The World Bank also states that the expansion of urban land consumption is outpacing population growth by 50%, which is expected to add 1.2m sq km of new development to the planet by 2030. With this pressure on land and natural resources, cities must clearly play a vital role in tackling both climate and biodiversity crises.

Building liveable cities that are green (and blue!), climate resilient and inclusive is therefore no longer an aspiration but a necessity, requiring policy coordination and investment choices. I want to unpick some of the recent international and UK plans for environmental improvement and reflect upon a recent study that provides scientific evidence for building healthy cities.

Policy landscape

In December, we saw world leaders agree the Montreal-Kunming global biodiversity framework at the COP15 summit in Canada. As a signatory, the UK must now protect and restore 30% of our land and water for nature conservation by 2030.

This 30% is generally considered to be protected sites, such as nature reserves and sites of special scientific interest (SSSI). However, prior to the meeting in April 2022, the British Ecological Society reported that the UK will miss this target.

The UK must protect what it has, but the new framework is also an opportunity to invest in ecological restoration

Not only does the UK not have enough protected areas, only half of our existing SSSI sites are in favourable condition. Post COP15, the UK must protect what it has, but the new framework is also an opportunity to invest in ecological restoration; enhancing existing habitats is likely to be more effective than creating new habitats.

The state of our existing SSSI sites also means that we need to do more than avoid negatively impacting them if the UK is actually to reverse nature decline.

So, given that the UK also needs to produce food, secure natural resources for manufacturing, generate energy and provisions for urban expansion, how (or where) do we meet biodiversity targets and build in climate resilience?

In the urban setting, this is where the UK’s biodiversity net gain policy can help make gains. Last week saw the eagerly anticipated release of the government’s environmental improvement plan (EIP), building upon its 25-year environment plan. In it we begin to see how developers and private finance will be expected to lead on the reversal of biodiversity decline in our cities through biodiversity net gain and local nature recovery networks.

The EIP provides a welcome roadmap, but it lacks detail, will often rely on voluntary action, and begs the question who will enforce and monitor restoration actions? And who will pay?

Green infrastructure has often been presented as a concept requiring government investment, however funding for the EIP is anticipated to come from private investment following the implementation of the green finance strategy, which will coincide with the update to the national planning policy framework (a new land use framework and the third national adaptation programme expected in 2023).

The green finance strategy is designed to direct private investment into green infrastructure that utilises and improves nature, rather than counting on investors to identify these opportunities themselves. The EIP includes a goal to raise at least £500m per year of private finance into nature’s recovery by 2027 and more than £1bn by 2030.

A further EIP goal is that everyone should live within 15 minutes’ walk of a green or blue space. This will be measured through the government’s green infrastructure framework (GIF), also launched last week by Natural England. The GIF embeds five standards for new developments to increase the extent and connectivity of nature-rich habitats. These are a green infrastructure strategy, accessible green space, urban nature recovery, an urban greening factor and urban tree canopy cover.

These standards have been developed by a 70-strong advisory group for developers and local planning authorities, but the benefits of urban nature will depend on the location and spatial configuration (network) of green infrastructure, including connectivity with new protected sites in rural areas.

The researchers found that 40% of deaths associated with the urban heat island effect could have been prevented by increasing tree cover in our cities up to at least 30%

The government’s EIP advocates local decision making and delivery, but there is not currently a role for national strategic planning to ensure connectivity of habitats (to act as species stepping stones) or representation across habitat types.

Local authorities are likely to know where their socially-deprived areas are, but they may not be able to prioritise nature-depleted areas. And who will enforce good green infrastructure design and long-term monitoring of nature-based solutions to ensure they are delivering for communities and nature recovery networks?

Healthy cities

Increasingly we are told that nature is good for our mental health, with the NHS now prescribing a “dose of nature” for improving mental health outcomes and reducing health inequalities. Nature’s physical risks have now also been quantified in a recent scientific study.

Last week The Lancet published a study on cooling cities through urban green infrastructure following the assessment of heat-related deaths across 93 European countries during the summer months. The researchers found that 40% of deaths associated with the urban heat island (UHI) effect could have been prevented by increasing tree cover in our cities up to at least 30%.

To put this in context, UHI can cause London to be up to 10°C warmer than neighbouring rural areas when the sun’s rays are absorbed by hard surfaces rather than vegetation such as trees, plants and grass. Even single trees provide cooling properties through water transpiration.

With the joint-hottest summer on record occurring in 2022, the challenge to develop infrastructure with an emphasis on cooling the UK’s cities, towns, streets and homes is touched on in the EIP. Expressly, the use of nature-based solutions is a key aim for managing heat, delivering co-benefits for biodiversity goals and human wellbeing.

Our communities will be relying on this nature for both their mental wellbeing and their physical health

With the widening understanding of the UHI effect for example, local planning authorities and community groups may seek to understand how developments will worsen the climate impact in a localised area. As environmental and social governance (ESG) and nature-related financial disclosures are increasingly required of organisations, developments will be forced to consider not only the environment, biodiversity and climate, but also the social ramifications on local communities.

Land is finite and, as the World Bank has said, “once a city is built, its physical form and land use patterns can be locked in for generations”. We need to be designing and building with nature in mind now – both strategically across cities and integrated into buildings – because it takes time for nature to mature.

As the government hands the baton to developers and private investors to fund and action delivery to meet the aims of the EIP, our communities will be relying on this nature for both their mental wellbeing and their physical health.

Samantha Deacon is a principal and biodiversity specialist ar Ramboll. This article was drafted in collaboration with Joseph Young, a graduate environmental consultant at Ramboll.