For a hint of what Toronto's climatic future might look like, many climate change experts point to July 8, 2013, when a month's worth of rain fell in a matter of hours.

That much water overwhelmed the city's storm sewer system. The Don River, which flows into Lake Ontario through the city's east end, flooded.

A commuter GO Train was inundated on its tracks through the Don Valley. A downtown subway station flooded, as did basements in parts of the city.

Then an ice storm hit just before Christmas. Tree branches loaded with ice broke off and took out power lines, plunging thousands of homes into cold and darkness for days.

Toronto ice storm

A worker from Stacey Electric, which was subcontracted to assist with restoring power following an ice storm in Toronto, works to free a power line on Dec. 23, 2013. (Matthew Sherwood/Canadian Press)

Those storms are just a taste of what's in store for the city, University of Waterloo environmental sciences professor Blair Feltmate says.

"As a result of climate change and extreme weather events, in short form, Toronto is going to become hotter, wetter and wilder in terms of weather," he said.

Feltmate heads Waterloo's Intact Centre on Climate Adaptation, which helps municipalities, businesses and homeowners find ways to protect themselves from the effects of changing climate.

'Toronto is going to become hotter, wetter and wilder in terms of weather.' — Blair Feltmate, University of Waterloo

He preaches an adapt-or-perish message.

"We still have, there's no question about it, a little bit of a management-by-disaster mentality," Feltmate said.

"We wait till the disaster occurs and everybody gets interested in how do we address it in the short term," he said. "We have to be proactive and ahead of the curve. Not acting is simply not an option. Every day we don't adapt is a day we don't have."

But Toronto has begun to adapt, he adds. His list of the city's efforts includes:

  • Expanding storm sewer capacity in areas susceptible to flooding.
  • Creating storage above and below ground for storm water.
  • Providing subsidies to homeowners to install basement sump pumps and valves to stop sewers from backing up.
  • Aggressively trimming trees to get branches away from power lines.

These are all good efforts, says environmentalist Gabriella Kalapos, but not nearly enough.

Kalapos, who studies climate change adaptation for the Clean Air Partnership, a Toronto-based environmental group, says the city also needs to look at how to handle water from future storms naturally.

River systems, marshes and parkland already do this on the outskirts of the city, but Kalapos says the challenge downtown comes from too much concrete and asphalt that can't soak up water.

"I think we have to figure out a way in our urban high-growth areas to recreate, almost engineer, these natural systems so they can serve a role for us into the future," she says.

New York Bioswale

While Toronto seeks solutions to its water issues, New York City is installing bioswales, small wetlands, on its streets to help handle rainwater when storm sewers can't. (NYC Environmental Protection)

Kalapos points to a program in New York City to make the urban landscape more permeable and better able to handle rainfall by creating micro-marshes on city streets.

"New York is digging out the parking spots which you are not allowed to use in front of the fire hydrant and building these marshy areas," she says.

Feltmate and Kalapos say one plan Toronto hopes to implement will go a long way toward helping the city deal with its stormier future.

Decades ago, the mouth of the Don River was turned into a concrete-lined channel. Authorities plan to "naturalize" the mouth by bringing back the river's curves and turning the part that flows into Lake Ontario back into a wide, marshy area.

This is part of a series of CBC News features on how climate change is affecting specific communities in Canada. Read the other stories in the series:

Take a look back at the 2013 ice storm