After 2nd major flooding event in 11 years, Toronto must adapt better to changing climate

In 2013, Toronto was hit with a massive storm. In just 90 minutes, the city received 126 millimetres of rain.

Roads flooded, with drivers abandoning their cars, and stairs leading to subway stations became urban waterfalls. The Don Valley Parkway (DVP), the main north-south thoroughfare into the city, was closed as the adjacent Don River overran its banks, spilling onto the roadway. A GO Transit commuter train was stranded with 1,400 passengers on board. Nearly 300,000 residents were left without power.

And on Tuesday — 11 years and eight days after that historic flood — it's déjà vu for the largest, most populous city in Canada. 

This time, the rain started in the morning around 9 a.m., catching many commuters off guard. It eased up for a bit until another, much more potent storm system moved in less than an hour later, lasting until the afternoon. Shortly after, power outages began to pop up across the city.

Once again, images and videos inundated social media: Toronto's Union Station was flooded, as was the DVP and city streets; GO Transit halted service temporarily; cars were abandoned. 

Following the 2013 flood, talk abounded about how Toronto needed to better adapt, as climate change was likely to make these heavy rain events more frequent and more severe. And while it's too early to attribute Tuesday's rainfall to climate change, by all appearances, the city still seems unprepared for a major rainfall event.

As greenhouse gases continue to be pumped into our atmosphere, the effects of climate change will continue to be felt across Canada and the world.

"Climate change is not going anywhere.… These events are going to continue to increase in frequency and severity," said Kathryn Bakos, managing director of finance and resilience at the University of Waterloo's Intact Centre on Climate Adaptation.

"As temperatures continue to rise, you're going to have more moisture in the system. So with more moisture and energy, you're going to have bigger storms, larger precipitation events, with more water coming down over shorter periods of time," she said, "so storms are going to come down with even greater force.

"And that's exactly what we're seeing all across the GTA and across Canada, as well."

But it's not just about climate change that's exacerbating these events, she said. 

"Climate change isn't the only driver in the system. You're seeing aging municipal infrastructure, infrastructure that never incorporated adaptation," she said. "It's also not taking the increase the influx of people. We have more people utilizing the infrastructure."

It's also the concrete jungle effect, she noted.

Over time, Toronto has removed natural infrastructure like wetlands, grasslands and forested areas, which act like natural sponges. Instead, concrete roadways, driveways and buildings stand in their place.