Greening our ci+es: rethinking the role of metrics, policy and prac+ce in innova+ve landscape-led design

Ian Mell^*

• The University of Manchester, Manchester, United Kingdom

Greening our ci+es: rethinking the role of metrics, policy and prac+ce in innova+ve landscape-led design As ci+es con+nue to expand to meet socio-economic needs a greater emphasis is being placed on ways in which planners can regulate environmental quality to ensure that urban areas are sustainable. This process includes a rethinking of how we incorporate nature within considera+ons of what type of places we are developing. Are these interac+ve, high-density, walkable, and greener places or are we persis+ng in planning for ideals associated with suburbanisa+on and individualism? Within this space Green Infrastructure (GI)foot_0 has come to the fore as an approach to urban planning that recognises the value of mul+-func+onal, (ecologically and socio-culturally) connected, and diverse landscape that explicitly support the designing-in of "nature" in its myriad forms. GI has been linked to improved health and well-being, suppor+ng personal mobility and connec+vity between people, nature, and places, addressing climate extremes, and supports economic development by crea+ng places that people want to live, work, and invest in. However, GI is a not a panacea to the problems caused by urbanisa+on but needs to be considered as a star+ng point for more nuanced conversa+ons about urban form, func+on and quality (Mell & WhiQen, 2023). Moreover, the ways in which GI is delivered is framed by an ongoing debate related to quan+ta+ve assessments of GI needs, i.e. m 2 investments and the use of metrics, poli+cal thinking within policy direc+ves, and the role environmental/design professionals to integrate the environmental and cultural principles associated with "urban greening" effec+vely into planning.Unpacking the links between, and value of, metrics, policy and design is complicated. All are imbued with bias towards specific approaches. For example, ParkScore is used in the USA to denote which city has the best parks system but may fail to take into account local context, whilst the Accessible Greenspace Standard (formerly ANGSt 2 ) embedded within the Na+onal GI Standard in England looks at size, distance and travel metrics but does not readily consider local socio-environmental factors in its analysis (Grace et al., 2025). We can also iden+fy comparable issues with policy aimed at addressing climate change, water management, health and well-being, or personal mobility where a lack of holism linking form-func+on is visible in planning discourse. This is not the case in all instances, but analysis of urban and GI policy interna+onally suggests a lack of con+nuity in the alignment of these thema+c areas. Finally, there are significant concerns with the use of GI to "greenwash" development (Gałecka-Drozda et al., 2021;de Freitas NeQo et al., 2020). High profile architects and landscape architects have employed GI in their work to enhance their ecological creden+als, but we could ask whether the ethos of GI, and ecological func+onality the form of provisioning, suppor+ng and regula+ng services more broadly, is central to such developments? Alterna+vely, we could argue that GI is used as an aQrac+ve screen -to detract planners from the problems inherent with new development. By analysing how we use metrics within the development process to provide scope for design to be "greener" we can assess the addi+onality they provide within praxis. We therefore need to consider the ongoing risk of plan+ng the wrong tree in the wrong place -especially in high density urban areas. Poor quality GI investment leads to mistrust in the planning process and a poten+al disloca+on between people and nature (Kendal et al., 2022). It can also reinforce poor design and management prac+ces that perpetuates infrastructure redundancy that subsequently require repeated adapta+ons to urban green and built infrastructure. Alterna+vely, by using metrics and landscape-led design within urban planning a more adap+ve approach to risk minimisa+on to climate change can be achieved (Grace et al., 2025;Van Oijstaeijen, Van Passel, & Cools, 2020). There is a growing recogni+on of the u+lity of metrics in GI planning. They provide guidance, and in some cases legisla+on, related to the type and quan+ty of investment needed providing clarity to developers. However, there is a threat that runs parallel as metrics can lead to a "race to the boQom" for investment. As Mell & WhiQen (2023) discussed framing GI from a technical perspec+ve adds certainty but metrics should not be viewed as a universal solu+on -a deeper engagement with the role of metrics within a specific GI/urban context is needed. The distance and size metrics associated with GI delivery in the UK, India and China for example don't effec+vely take into account local demographic diversity and needs, road layouts, travel/mobility op+ons, types of GI, but do show spa$ally where things are (Wang, Mell, & Saha, 2025). Furthermore, there is substan+al evidence illustra+ng the added societal value of networks of GI to personal mobility by ac+ng a catalyst to engage with nature in urban areas or to move freely by foot or bicycle via the establishment of connected networks of greenways and public rights of way (Hapriyanto & Azmi, 2025). Moreover, current discussion centred on how we deliver a 10% uplin in baseline ecology via Biodiversity Net Gain (BNG) illustrate the complexity of (a) seong a baseline, (b) designing in addi+onality for people and nature, and (c) the conflicts related to where and what type of GI is developed (Tait, Chapman, & Postlethwaite, 2024). BNG and other climate focussed future-proofing approaches, i.e., the use of na+ve species and an acknowledgement of the role of climate adap+ve species in design workcommonly viewed as nature-based solu+ons (NBS) -are thus proposed as core elements needed to support ecological resilience to change in urban areas.Therefore, although metrics offer a useful grounding to enhance the quan+ty of GI they cannot be used in isola+on to ensure quality delivery. The underpinning research of the Na+onal GI Standard in England examined an extensive range of UK and interna+onal metrics/standardsfoot_2 and found complimentary in terms of the use of travel +me, distance, and size metrics between countries. Moreover, the use of the Urban Greening Factor (UGF) in Malmo, Berlin and the UK offers a con+nuity of approach that can provide certainty in terms of what ecosystem services GI will deliver in a specific loca+on (Kruuse, 2011). Unfortunately, developing a green wall, plan+ng street trees, or developing in sustainable urban drainage system in London is not the same clima+c or urban context as we find in Melbourne, São Paulo, Singapore, or Toronto. Therefore, the ecological specificity of each loca+on requires a dual universal-bespoke knowledge of species viability to ensure clima+c resilient design (Matsler, Miller, & Groffman, 2021). A transferability of approach can thus be undermined if local context it not taken into considera+on to shape investment to a specific place.Does "green design" equal mul+-func+onal GI development?The designing-in of GI can be said to elevate the value of these places for all. However, urban greening is also associated with examples of gentrifica+on. Therefore, the planning of greener neighbourhoods or landmark projects need to consider the wider socio-cultural impact of investment on all communi+es. City planners though have historically thought big and bold in their use of GI, and looked to deliver neighbourhood or city-scale investment that have the widest reach. The High Line in New York and the Gardens by the Bay in Singapore both offer "wow" experiences but do they deliver an everyday connectedness to nature at a local scale (Black & Richards, 2020;Tan, Wang, & Sia, 2013)? Moreover, as nature has been commodified in planning discourses, we have been condi+oned to associate GI with progress rather than engaging with the ongoing commentary of who has access to these spaces. What GI gets developed and who the intended beneficiaries are needs careful considera+on. It is not enough to invest in more GI, but we need to understand what type of park, trees, water features or facili+es are needed. The choice of GI maQers clima+cally, ecologically, and socio-culturally and needs to respond directly to local condi+ons. There is also a cri+cal need to avoid the imposi+on of GI that skews exis+ng uses, users or func+ons. Cri+ques of Bloomingdale Trail/606 in Chicago highlight the lack of facili+es focussed on exis+ng community needs (Loughran, 2014), for example. Moreover, the publicity associated with Mayfield Park Manchester's "first public park in a century" failed to acknowledge that the park is a private space with permissive access (Kanellopoulou, Ntounis, & Millington, 2025). Thus, even when GI is created to meet an iden+fied need the inclusivity of such spaces can be inequitable. To effec+vely address the clima+c, economic and societal complexi+es of ci+es an integrated approach to urban development is needed. This can, and should, draw on the designing-in of nature into all urban areas via the use of horizontal and ver+cal greening to maximise the use of floor and frontage spaces, the repurposing of redundant built infrastructure as GI, and working towards the crea+on of spaces that are connected, biodiverse, mul+-func+onal, and accessible to all members of society. The portolio of GI op+ons available to planners, urban and landscape designers, transport specialists, environmental advocates, and developers thus provides scope to address mobility, biodiversity, health, and economic issues simultaneously. To achieve this the following need to be considered: -Integra+on of GI thinking into all areas of public policy with the passing of legisla+on that explicitly places nature/GI at the centre of development debates.-Engage with issues of infrastructure resilience via exper+se from across the built and natural environment to ensure that ecological, socio-economic, and structural issues are considered in all design/development.-Ensure that the financial value of GI to society is known and supported through appropriate and sufficient funding streams What -Develop nature-led GI plans for all urban development.-Embed an understanding of the mul+faceted func+ons and benefits associated with thema+c framings, i.e., climate change, health, biodiversity, or mobility, at the centre if praxis.-Considered GI as a mechanism to deliver mul+-scalar and mul+-func+onal enhancements in urban areas.-Work with the suite of GI typologies 4 to advocate for the right from/func+on of investment in the right place.-Plan purposefully to integrate networks of green and blue spaces of all sizes into urban areas to support access and mobility, as well as suppor+ng biodiverse habitats.