Four ways parks help address climate change
September 26, 2019
By Jake Tobin Garrett, Policy and Planning Manager
As Park People staff prepare to participate in the climate strike this Friday, September 27th at the rallies in Toronto, Montreal, and Vancouver, we have turned our attention to the ways in which parks play into this conversation.
In addition to the social, health, and economic benefits of parks, our shared green spaces are powerful ecological forces worthy of increased investment.
Here are four ways parks help combat and mitigate the effects of climate change.
Parks reduce the urban heat island effect
Last year Montreal suffered from a devastating heat wave that left 66 dead. When the City plotted the deaths, they found that people who lived in neighbourhoods deemed heat islands—where temperatures rose higher than in other neighbourhoods—were twice as likely to die.
As the Toronto Star noted, the heat islands divided “the cool, treed areas from the hot concrete-covered ones.”
Urban areas can feel as much as 12 degrees hotter than rural areas due to pavement, brick, and concrete surfaces that absorb the sun’s heat. One Montreal city councillor said that urban greening projects such as tree planting and green walls can be a way to combat this effect, and help cool some of these particularly hot neighbourhoods.
How does this work? Think of green spaces as natural air conditioners.
Increasing the tree canopy increases shade, which helps shield surfaces from the sun, reducing their ability to absorb heat. Trees and other vegetation also help cool the air around them through a process called evapotranspiration, which is basically when plants sweat. Water evaporates into the air through the leaves, cooling the air around it in the process.
As temperatures continue to rise in cities across the country, features like tree-lined streets and well-tended parks to keep things cooler will become ever more important.
Parks mitigate flooding from extreme weather
Another devastating impact of climate change has been increasing extreme weather events such as heavy rainfalls, known, poetically, as cloud bursts. In these events, stormwater systems can be overwhelmed by too much rain in a short period of time, leading to flooding.
As we documented in our Canadian City Parks Report, flooding continues to impact Canadian cities.
Calgary’s Bow River overflowed due to heavy rainfall in 2013, causing widespread property damage and evacuations. Flooding caused 4 million dollars worth of damage to Oakville’s waterfront in 2017 — the same year high water and flooding caused millions of dollars in damage in Toronto, and the closing of the popular Toronto Islands park for the summer. And this past spring, heavy rainfall caused flooding in many communities in Ontario and Quebec. It goes on and on.
Sudden storms can also lead to the release of raw sewage into waterways. This is because cities were planned with systems that combined stormwater and sewage pipes into one. When those systems are overwhelmed by a sudden onslaught of stormwater they vent untreated water into nearby lakes, rivers, and oceans.
This impacts water quality. High E.coli readings at some beaches in Vancouver closed them this summer and Ontario’s environmental commissioner found that sewage flowed into southern Ontario waterways over 1,300 times in the year between April 2017 and March 2018.
The amount of paved surfaces in our cities only further contributes to flooding and overwhelmed stormwater systems, which is where parks, as soft landscapes capable of absorbing water, come into play.
As our Resilient Parks, Resilient City report noted, turning our streets, public spaces, and parks into sponges through green infrastructure can help address flooding. Green infrastructure includes engineered natural elements — rain gardens, bioswales, retention ponds — that help to store, soak up, and treat rainwater where it falls, rather than whisking it away through underground pipes.
Green infrastructure can relieve pressure on aging stormwater systems, but also contributes to more beautiful, biodiverse cities through the creation of more green space.
Despite that, our Canadian City Parks Report found that while Canadian cities were experimenting with small-scale green infrastructure projects, less than half had strategies for scaling the practice up across the city. That work is urgently needed.
There is some great work happening in Canada, though.
Toronto’s Corktown Common includes a flood protection berm and a wetland that helps to stop and soak up water. Vancouver’s Rain City Strategy coordinates green infrastructure projects across the city, including a new plaza built last year that can soak up water from over 1,000 square metres of impervious surfaces in the neighbourhood around it. And Calgary just finished the first phase of West Eau Claire Park along the Bow River, which safeguards neighbourhoods from flooding.
Parks suck up carbon from the air
While governments and oil companies experiment with technology that can capture carbon from the air and store it underground, we already have a natural, tested way of removing carbon from the air and storing it: trees.
Planting trees may seem like a small act, but reforestation is the most effective way to remove carbon from the atmosphere.
According to National Geographic, there’s enough land around the world to plant new forests to cut carbon by 25 percent. This would erase “nearly 100 years of carbon emissions.” Apparently, Canada has 78 million hectares that could be reforested. Not bad.
Trees and other plants capture carbon from the air through the act of photosynthesis, removing it from the air and storing it within themselves. The carbon is then only released if the plant is burned, which is why the recent spate of large forest fires in British Columbia and Alberta are so concerning–a trend that is only likely to get worse.
Forest fires release all the carbon sucked up by those trees back into the air. In fact, it was found that California’s 2018 wildfires released as much carbon into the air–68 million tons–as the state does in providing a year’s worth of electricity.
Cities across Canada have tree planting programs in place, with varying targets.
Mississauga is partway through a multi-year plan to plant one million trees in the city by 2032, having planted over 340,000 so far. Victoria has committed to a more modest, but still beneficial, 5,000 trees planted by 2020 as part of the United Nations Trees in Cities Challenge.
Vancouver is on track to reach its goal of planting 150,000 trees in the city by 2020. And in Ontario, the provincial government backed down from axing its tree-planting program after public protest in 2018, which has a goal of planting 50 million trees in the province by 2025 (it’s about halfway there).
So, hug a tree. Or better yet, plant one–lots of them.
Parks provide space to come together
This benefit doesn’t deal with the science of evapotranspiration or the engineering of green infrastructure, but instead with social capital and good ol’ fashioned meeting your neighbours.
With climate change being such a large and often intangible force in our lives that can cause anxiety, stress, and feelings of helplessness, the benefits of parks to provide a collective space to gather becomes even more crucial.
Take this recent example from Dartmouth, Nova Scotia, where, after being ravaged by a hurricane, community members gathered at a park bake oven to provide food and warmth for families without power. Other community park groups contribute to a cleaner environment by hosting park clean-ups, tree planting, and even zero-waste picnics.
An existential threat like climate change can spin us apart from one another or it can be a force to drive us together–and our parks and public spaces, as sites of gathering, will become only more important to ensuring that we join with our community in calling for action.
Join us and thousands of others at the Global Climate Strikes across the country on Friday, September 27. For more information on finding a rally near you, click here.