Article by Olivia Mann
With climate change bringing more intense rainfall and increasing temperatures, we need to adapt our towns and cities, putting into place features to ease the effects of these challenging weather events. Urban gardens can provide all sorts of really useful functions to help with this, for example moderating extreme temperatures, reducing flooding, improving water and air quality, and recycling water and organic waste. As gardeners, by carefully choosing specific features for our gardens, we can have a really positive impact on our urban environments.
Firstly, towns and cities are huge sources of air pollution, which, of course, is really bad for our health. We often hear about congestion charges being introduced to improve air quality, but what about the impacts of trees and plants? Plants absorb carbon dioxide and release oxygen. They directly absorb pollutant gases through pores in their leaves and provide a massive surface area for capturing and filtering out airborne pollutant particles. By maximising plant cover in our gardens, using layers of trees, shrubs, perennial plants and climbing plants, we can have indirect benefits on the health of every one of us living in urban environments.
The effects of global warming and increasing temperatures can be more extreme for those of us that live in built up areas. This is due to the heat island effect, where buildings, roads and other paved surfaces absorb and hold on to a lot of that extra heat. However, increasing the amount of plant cover in towns and cities, including in our gardens, can provide a cooling effect. When plants get hot, they transpire cooling water vapour through pores in their leaves. This cooling action increases during hot weather, naturally balancing temperatures during hot weather. Of course, increasing tree cover can provide shade, with additional cooling effects. So again, maximising plant cover in our gardens, including those all important trees, along with layers of other plants, can be massively beneficial, making our cities more tolerant of heat waves which are bound to become more frequent in the future. The shelter and insulation from the wind provided by trees can also help to warm our homes and reduce energy bills in the colder months- a year-round service provider!
Another significant problem facing urban areas is the increasing threat of flooding. Images of the floods both here in the UK and around the world, have shown the devastating effects of intense rainfall. The threats of flooding are made worse in towns and cities due to the large areas covered by pavements, roads and other solid surfaces that prevent water from being able to naturally soak away. However, the plants and soil within our gardens can absorb water, reducing flood risk. Gardens filled with plants – whether trees, shrubs and perennials or a simple lawn – are all helping to soak up these flood waters that are sadly predicted to increase with our changing climate. Yet another reason for us to rave about urban gardening!
With cities like New York and London being described as concrete jungles, we can all acknowledge that our cities are often at odds with nature. The lack of greenery and clean air often puts me off living in urban areas. However, given that our gardens make up a considerable amount of the green space available in cities, they provide an excellent opportunity for us to shape the future of our cities, for cleaning up the air and reducing the impacts of heavy rainstorms. From adding plants to our windows sills, to having an oasis in our back gardens, we can all help contribute to bringing more of the natural world into our towns and cities, for the health of the environment and of ourselves. Given that the number of us living in towns and cities is only increasing, I think it is vital that we all play our part.