The Importance of Green Spaces in Building Climate Resilient Cities

2021-11-23

 |  Science & The Environment

The need for more public green spaces became apparent at the beginning of the COVID-19 Pandemic and there are so many more important reasons why cities need more greenery. Not only does it provide space for public gathering, it  improves mental health, and it makes cities more climate resilient. The Centre for Climate and Energy Solutions defines climate resilience as “the ability to anticipate, prepare for, and respond to hazardous events, trends, or disturbances related to climate” (C2ES, 2021). Green space doesn’t just mean parks. It can also be tree lined streets, green roofs, urban gardens, or living walls. All of which will help combat climate related challenges cities will be facing at an increasing rate. Urban greening projects will make cities more livable and sustainable in a number of ways.

Combating the Heat Island Effect

Canada has been experiencing more severe heat waves and cities are consistently warmer than the surrounding area. This is because of the heat island effect, a phenomenon where concrete buildings and streets absorb then re-emit heat resulting in hotter city air temperatures. This past summer BC experienced record breaking heat waves with temperatures reaching 49.6 degrees celsius and close to 600 heat related deaths. Climate change will only increase these occurrences.  Having more vegetation in cities can greatly decrease temperatures. It has been shown that streets lined with trees can be 11-25 degrees celsius cooler than those without.

Increasing Rainwater Retention

Eastern Canada has seen more frequent flooding due to increased rainfall and snow melting at a faster rate. Our city’s current infrastructure quickly gets overwhelmed with large amounts of water resulting in flooding. Once again, green spaces can help with this. The soil around the plants allows water to be absorbed into the ground instead of running down concrete streets and sidewalks into overflowing water systems. Planting vegetation around and on buildings reduces the amount of water in the streets. Green roofs alone can retain 40-60% of rainwater.

Improving Air Quality

Air quality in cities is a big concern because 88% of urban populations are exposed to air pollution that exceeds the World Health Organization’s Air Quality Guidelines. One of the largest sources of poor air quality is transportation, therefore we need alternative modes of transportation. More greenery however,  can help improve air quality. Plants help in two ways, they disperse and deposit the harmful particulate matter in the air so humans are less likely to breathe them in. Plants really can make a big difference as recent study from The American Heart Association shows that more green spaces reduce heart disease-related deaths.

Maintaining Biodiversity

Biodiversity is being threatened globally, especially in cities. Urban sprawl is reducing and fragmenting natural habitat for countless plants and animals. A recent report claims that up to one million species could be extinct by 2050. Biodiversity is incredibly important for the overall health of people and the planet. Bringing back biodiversity in cities is as simple as creating more wild green spaces. Rewilding projects are happening all over the world. In Germany one green space resulted in 67 bee species and countless songbirds and butterflies being spotted in cities where they weren’t previously. 

Maintaining Building Temperature

Approximately 16% of global CO2 emissions are from heating and cooling buildings, as well as providing hot water. Green spaces can lower overall cities temperatures, but installing green roofs and walls can help insulate buildings. This natural insulation can keep buildings cooler in the summer and warmer in the winter. It can reduce energy consumption by 25% in the summer and 10% in the winter therefore reducing CO2 emissions. 

It is clear that urban greening can make cities more climate resilient. There are countless benefits from reducing temperatures to improving air quality. Simply incorporating more parks, trees, gardens, green roofs, and green walls in city design can make a huge impact on the overall health of the planet and its inhabitants. It is also important to note, often these greening projects happen in richer areas of the city leaving neighbourhoods with lower incomes, primarily comprised of people of colour, without the benefits. As we move forward in creating more green spaces in cities we need to make sure we are doing it equitably so everyone enjoys the benefits of a more climate resilient city.