Domestic gardens, parks, and woodlands give numerous benefits to human urban populations as well as critical habitats for animals. The presence of green areas can improve the health and welfare of people living and working in cities by enhancing physical fitness and reducing depression. Green spaces also have an indirect impact on human health by increasing air quality and reducing urban temperatures, which helps to mitigate the effects of heat waves. Furthermore, urban greenery helps to prevent climate change by storing carbon and reducing flood risk by storing surplus rainwater.
In 2014, around 54% of the world’s population lived in towns and cities, with this figure expected to rise to nearly 70% by the middle of the century. Almost two-thirds of the urban area that will exist by 2030 has yet to be created, thus we must seize the chance to create and preserve healthy and sustainable urban settings.
Health & Wellbeing
Access to green space benefits our mental health, lowering the need to treat anxiety and other mental health issues. Depressive disorders are currently the leading cause of disability in middle- and high-income nations, and they can be precursors to chronic physical health problems. Green spaces promote physical activity by offering a pleasant environment in which to exercise; linear woodland pathways encourage walking and cycling, while huge sports and community parks promote more formal physical activity. In Europe, about 1 in every 15 deaths is linked to a lack of physical activity. Only one-third of the UK population meets the recommended amount of physical activity, and the impact on our health is predicted to cost £1 billion every year.
Temperature & Climate Change
Urban green spaces mitigate the UHI effect by providing shade and cooling the air through the evapotranspiration process. The sun’s energy is used to move water from plant leaves into the atmosphere during evaporation and transpiration. Metropolitan green spaces are roughly 1oC cooler than built-up areas in the same town or city during both the day and night, and this cooling impact can extend beyond the green space itself, into the surrounding urban areas. This may lessen the requirement for air conditioning and associated energy use in surrounding buildings during the summer.
The urban heat island effect is reduced the most in large parks with numerous trees and extensive canopies, as well as minimum paving. Woodland areas that are maintained to minimize tree mortality and do not require extensive irrigation or fertilizer use are the largest carbon sinks.
The effects of trees and shrubs on air quality are numerous. They can improve air quality by removing particles and gases from the air; particles adhere to the surface of the leaves, while gases are absorbed through pores on the leaf surface. Trees with complex, ridged, or hairy leaves tend to trap more particles than trees with broader, smoother leaves. However, plants send gases into the atmosphere that, under certain conditions, can result in the creation of O3. Exposure to poor ambient air quality is estimated to cause roughly 3.7 million deaths each year around the world. On a local level, particle air pollution is thought to cause 350 early deaths in Leeds each year, and 29,000 in the UK.
Flooding & Water Quality
Rain does not absorb and remains on the surface in metropolitan environments due to the impermeable materials used for roads and pavements. This water collects during periods of heavy rainfall, and when the drainage capacity of the land is exceeded, flooding occurs. Vegetated surfaces, on the other hand, can capture and store water, limiting the volume of rainfall run-off. Individual tree benefits are maximized when they are planted in tree pits with permeable soils that may absorb additional water or structural soils that let tree roots develop beneath pavements and roads.
Another effect of large levels of surface water run-off is that rainwater washes pollutants away from the surfaces it falls on, carrying them into water courses. This can harm water quality in streams, rivers, and lakes, as well as result in excessive pollution loads at water treatment plants.
Wildlife & Habitats
Our cities are generally thought to have a less variety of vegetation, animals, and birds than nearby rural areas. However, many of the same species that are more often associated with rural environments, including those that are uncommon or threatened, can be found in urban green spaces. For some species, urban environments can provide better habitat than the intensively farmed countryside, implying that cities can contribute significantly to national conservation efforts. Urban green spaces can serve as “wildlife corridors,” connecting larger parks and connecting rural areas on the fringes of cities. This allows animals, birds, and insects to move freely between various green spaces, avoiding fragmentation and isolation of biodiversity.
The creation, maintenance, and administration of green space also creates jobs, and it may have indirect economic advantages by promoting more investment and property development in the area.
An evaluation of the Mersey Forest, a tree-planting program that has grown into a 1300-square-kilometer network of woodlands and green areas across Cheshire and Merseyside, found that every £1 invested in the project was more than doubled. This was mostly due to tourism expenditure, the development of forestry-related jobs, estimated societal cost savings, and well-being benefits such as people’s perceptions of greater biodiversity and improved visual quality of the environment. The review determined that the location of green space is critical; to reap the greatest benefits, green space must be easily accessible to both locals and tourists, or at the very least visible from their houses or when traveling.
- Matthew H.E.M.Browning, AlessandroRigolon, OliviaMcAnirlin, Hyunseo (Violet)Yoon. Where greenspace matters most: A systematic review of urbanicity, greenspace, and physical health. [online]. Available at: https://www.sciencedirect.com/science/article/pii/S0169204621001961 [Accessed date: 14/06/2022].
- Dhanapal G. and Dr. Pradeep Chaudhry (Mar 13, 2012). Open Spaces for Urban Sustainability [online]. Available at: http://sustainabilityoutlook.in/content/open-spaces-urban-sustainability [Accessed date: 15/06/2022].