A recent study from a Simon Fraser University think tank demonstrates that cities can achieve better value in restoring urban ecosystems over building additional infrastructure in the fight against climate change.
The Adaptation to Climate Change Team, which is based in the faculty of environment, highlighted potential environmental, financial, and health benefits gained from the restoration of Still Creek — one of just two daylit streams remaining in the city — from 1949 to 2014, through collaboration between the cities of Vancouver and Burnaby.
“Many cities around the world are considering ecosystem-based responses to climate change,” said Deborah Harford, the team’s executive director. “This is because ecosystems are cheaper to install, maintain, and upgrade, compared to traditional hard infrastructure solutions that are often more expensive and emissions intensive.”
Healthy ecosystems in urban settings are extremely valuable and much of urban development has overlooked their benefits in the past. While responding to flooding and extreme levels of heat can be expensive for a city, urban ecosystems have the power to stem the effects of climate change.
“Soil and vegetation absorb flood water and reduce heat, while asphalt and concrete amplify heatwaves and stormwater run-off,” explained Harford.
“Thermal imaging over cities shows how much heat concrete stores emit, causing heat bubbles known as urban heat islands,” she added. Ecosystem-based responses such as green roofs can help offset this impact.
It was awareness around ecosystem restoration in the area that prompted cities to re-evaluate waterways like Still Creek which has had a positive effect on environmental well-being, according to the study.
“Still Creek was extremely polluted by the 1970s, it was basically a wastewater channel,” said Harford.
The ecosystem revival also helps species that are struggling to adapt to climate change. For the first time in years, salmon came back to spawn in Still Creek in 2012, and have returned every year since, partly thanks to the restoration work.
The focus on urban ecosystems has also had success in other cities around the world. After Copenhagen, Denmark experienced a series of rainstorms several years running, their sewer system was overwhelmed, said Harford. Upgrading the sewer system would have interrupted the city for a significant length of time.
Instead, the city chose an ecosystem response, installing parks, swales — vegetated boxes in sidewalks —and trees to absorb stormwater and alleviate flooding. In the city’s analysis, not only was this a cheaper option, but it served to potentially boost the property values.
“Ecosystems offer as many values and benefits that are comparable to regular capital assets,” noted Harford. “It’s time we took into account the benefits associated with intact, healthy ecosystems, and the power cities have to make positive change when they collaborate across municipal boundaries.”