News | Oct 2023
The world’s cities face the intense, overlapping challenges of environmental and demographic change, which are expected to grow over the coming decades. It is estimated that by 2050, 70 per cent of us will live in cities, and that 75 per cent of the infrastructure that will exist to meet the needs of these growing populations is yet to be built. Climate change poses the greatest threat to the health and security of city dwellers – causing more frequent, intense and longer-lasting extreme weather events, particularly floods and heatwaves. These and other disasters exacerbate existing urban health burdens and inequalities.
As cities expand, effective planning will mean the difference between achieving the aims of Sustainable Development Goal 11 – make cities and human settlements inclusive, safe, resilient and sustainable – or not. Likewise, Target 12 of the Kunming-Montreal Global Biodiversity Framework commits countries to enhance urban green and blue spaces. Central to this will be ensuring that land and other natural resources within and beyond cities are strategically used to not only meet the needs of economic development, but also to sustain biodiversity and ecosystem services such as clean air and water, carbon sequestration and flood storage – which bring the benefits of improved health, recreation and wellbeing for people.
However, development finance is not structurally well-equipped to deliver sustainable urban infrastructure, nor solutions that deliver long-term benefits to urban people. In part, this is due to the perceived competing pressures of economic development and environmental protection and restoration. To bring about the economic transformation needed to secure urban sustainability, current approaches to the financing of urban planning must change. The multiple values of nature will need to be incorporated into urban decision making.
To mark World Cities Day, the UN Environment Programme World Conservation Monitoring Centre (UNEP-WCMC) considers how to achieve this year’s theme of “unlocking investment for sustainable urban planning”.
There is increasing recognition of the importance of sustainable infrastructure development. Scaling up the deployment of nature-based solutions (NbS) has enormous potential across urban environments, and is underpinned by a growing body of supporting guidance, including with contributions from UNEP-WCMC. Nature-based solutions – which now have a globally agreed definition – are actions that protect, conserve, restore, sustainably use and manage ecosystems and in doing so address a range of social, economic and environmental challenges. Examples of NbS include creating green areas around the city, managing wetlands to reduce flood risk, enhancing urban forests and street trees, and installing green roofs and rain gardens. They can be more cost-effective and deliver a wider range of benefits than investing purely in grey infrastructure solutions, and when used in combination with grey infrastructure can be highly effective within a shorter time period.
NbS can build resilience and reduce disaster risk while delivering many other benefits for cities and their residents: climate adaptation and mitigation, clean water and air, cooler streets, and access to green public spaces for recreation and physical, mental and spiritual wellbeing. NbS also bring economic benefits, such as creating job opportunities, reducing water utility companies’ operation and maintenance costs, reducing infrastructure costs, and avoiding costs related to prevented disasters.
Despite growing acceptance of the benefits of sustainable planning and NbS, urban planners and policymakers often struggle to effectively integrate nature into their processes.
Guidance produced by UNEP-WCMC identifies four key barriers:
To overcome these barriers and realise the benefits of NbS for sustainable urban development, various tools have been created to raise awareness of the benefits of NbS and help decision-makers take them into account. Moreover, for long-term integration of nature into decision-making processes, urban planners and policymakers require regular and consistent information on the local state of nature and the benefits of NbS in local contexts.
Urban ecosystem accounting (EA) is an approach used to assess the status of urban nature and track the local benefits it can bring. Urban EA enables the multiple benefits of NbS to be captured and valued, and for perceptions of boosting nature in cities to be considered as an investment rather than a cost. UNEP-WCMC has contributed to resources that explain how ecosystem accounting can help to integrate and scale up NbS in city planning. While not yet commonly used by city planning institutions, in recent years some important EA pilots have been run in urban areas.
Aiming to build capacity in the use of urban EA to better integrate nature in cities and municipalities across China, UNEP-WCMC has produced two handbooks setting out the concepts and implementation of urban EA and its applications in China, the UK, Canada, and Norway.
In Oslo, for example, urban ecosystem accounting has been used across a range of local initiatives. One of these analysed trees in the Norwegian capital as a “stock”, for which asset accounts were compiled for 2011-17. Remote sensing and modelling were used to determine the number of trees across the built area and their condition; in one area alone, researchers at the Norwegian Institute for Nature Research found that trees were valued at approximately USD 100 million in 2017, based on the “regulating services” they provided, such as climate regulation, flood management and water filtration.
On a broader scale, urban EA is being tested in a number of Chinese cities that are pioneering the integration of nature and application of NbS in support of sustainable urban planning. In Shenzhen, total gross ecosystem services of green infrastructure in 2020 were valued at approximately USD 19 billion.
The economic principle for sustainable urban development has been established and the financial arguments for ensuring sustainability in urban planning are becoming clear. However, urban EA and urban NbS are still new approaches to many urban decision makers. Capacity needs to be developed across municipal governments to incorporate nature into cities and understand how urban ecosystem accounts can help make the business case for NbS and sustainable infrastructure. Decision makers also need to understand the range of options for applying urban EA to identify what will work best in local contexts in order to reach their city’s sustainability goals.
As the use of urban EA and NbS grows, more resources are being created to help make the most of their benefits. UNEP-WCMC has contributed to or led the development of many of these; find out more about our work on Nature-Based Solutions and the Nature Economy.
The world now needs construction and development corporations, city planners and their funders to embrace these methods in earnest and in doing so create the climate-resilient, socially just cities that are so desperately needed.
Main image: Adobe Stock