Home to over half of the planet’s population, urban areas are responsible for a significant proportion of global greenhouse gas emissions.
What is green infrastructure and why is it important?
Green infrastructure is defined as a “planned network of natural and semi-natural areas with other environmental features designed and managed to deliver a wide range of ecosystem services”. This term incorporates a huge variety of different ecosystems from parks, playing fields and woodlands to community gardens, green roofs and street planters. These spaces facilitate physical activity, relaxation and can be a refuge from the noisy city. Green spaces help to foster biodiversity and provide safe routes for people walking and cycling through the city thus contributing positively to population health. In fact, estimates show that physical inactivity, linked to poor walkability and lack of access to recreational areas, accounts for 3.3% of global deaths.
There is robust evidence to support the claim that green space has a positive impact on people’s wellbeing with features such as parks, rivers and trees creating more liveable and pleasing urban environments. Research has shown that having access to green space can reduce health inequalities, improve well-being and aid in the treatment of mental illness.
Importantly, green spaces also help to regulate the impacts of harmful emissions in the city. Trees absorb carbon dioxide and help to filter out harmful pollution while urban waterways such as lakes, rivers or even fountains moderate temperature and together with vegetation, play a vital role in cooling cities. In some areas, it has been estimated that evapotranspiration (the process of converting water in leaves to water vapor which is then transpired through the trees) can reduce peak summer temperatures by 5°C. Additionally, green spaces provide areas where runoff interception can occur, thus reducing the likelihood of flooding, an issue particularly pertinent to Scotland where winter rainfall is expected to increase between 10-35% in some areas.
Supporting the development of green infrastructure is becoming an even more prominent part of urban policymaking across the world. From street planters to citizen gardening, the following section describes a couple of examples in which local authorities in Scotland are helping to create healthier, greener cities.
- High-tech street planters, Glasgow
In June 2017 two CityTrees arrived in central Glasgow. At £20,000 each, these high-tech pieces of street furniture are 4 meters tall, nearly 3 meters wide, 2 meters deep and are covered in a mixture of moss cultures that filter harmful pollutants out of the air. The chosen mosses have a much greater leaf surface area than thus capture more pollutants. In fact, the creators of CityTree have found that these designs have the environmental benefit of up to 275 urban trees with each unit removing around 12.2kg of particulate matter and 240 metric tons of CO2 annually. Glasgow is ranked as one of the cities with the worst air pollution in the UK, so addressing this issue has become a serious public health concern in recent years and the Council is a member of the Scottish Government’s Cleaner Air for Scotland Strategy. These high-tech street planters are part of Glasgow City Council’s effort to create healthier and liveable streets.
- Edinburgh Canal Strategy, Edinburgh
The Union Canal in Edinburgh runs 16km between Ratho and Fountainbridge. A navigable waterway for boating, this stretch of water is also an important wildlife habitat, a walking, jogging and cycling route, and a focus for new canal-side development and for local community use. After extensive consultation with communities and stakeholders the Union Canal Strategy was published by in 2011. The Strategy, which is a collaboration between the City of Edinburgh Council and Scottish Canals, aims to maximise the use of the 200-year-old waterway by locals and visitors to the city through a wide range of projects and events. The award-winning strategy identifies seven hubs for development in key sites along the canal and is structured around four key areas of opportunity:
- Access to the Union Canal
This area covers issues such as improving local use, access and visual connections to the canal as well as managing competing canal users such as commercial drafts, rowers, canoeists, cyclists, anglers and walkers. This section also covers opportunities focusing on issues of safety and maintenance.
- Development and environment
Under this section opportunities and projects are identified surrounding the improvement and development of facilities such as toilets, seating and lighting. It also covers opportunities for businesses, employment and housing on sites along the canal. An important part of this is to develop new waterspaces and moorings (both residential and commercial) with the aim of building a stronger community.
- Community, recreation and tourism
Chances to develop green space and recreational facilities are key to this section that identifies projects aimed at improving the relationship with surrounding communities and local use of the waterway. Here the canal is identified as ‘a catalyst to community regeneration’ and opportunities are identified to raise awareness and improve the appeal of the canal to locals and tourists.
- Infrastructure, drainage and climate change
This section explores the canal as a water resource and covers opportunities to improve water quality, drainage and flood risk management. It also considers how the canal can contribute to supporting climate change, carbon reduction and Environmental Sustainability. Important in this is ensuring the balance between increased use of the waterway and protecting the ecosystems and local communities.
These innovative approaches to Green infrastructure has the capacity to improve a city’s physical environment and benefit the quality of people’s lives.