It'll cost less now to prepare for the effects of climate change on public transportation infrastructure than it will to fix them later, the Financial Accountability Office (FAO) found in a new report.

It's the second time the FAO has estimated climate change impacts on Ontario's bottom line. There will be one more, about water infrastructure, plus a final summary report.

In both reports, the message is clear: act now, or pay the price — literally.

READ MORE: FAO maps out billions in climate change costs to government buildings

Ontario's transportation infrastructure, including roads, bridges, culverts and rail tracks, have a value of $330 billion, the FAO found. Municipalities own 82 per cent (mostly because they own all the roads, which make up two-thirds of the total cost) and the other 18 per cent is owned by the province.

The FAO found that if the climate were stable, it would still cost a lot — about $11 billion per year — to keep all this infrastructure in a state of good repair until 2030.

"I joke with folks that, you know, maybe the Jetsons had it right," FAO head Peter Weltman told reporters at Queen's Park on Thursday, referring to the cartoon family that lived in a futuristic city with flying cars.

Extreme weather like heavy rainfall, high heat and freeze-thaw cycles tack on an extra $1.5 billion per year on average, adding $14 billion in extra costs in that time frame.

Estimating costs longer-term depends on how bad climate change gets.

In the "medium emissions" scenario, which many experts have put forward as a realistic goal, global emissions will peak in the middle of the 21st century before declining. If that's the case, without proactive adaptation, infrastructure maintenance costs in Ontario would rise by $2.2 billion per year, totalling $171 billion in extra costs by 2100, the FAO found.

If emissions keep rising throughout this century, the cost goes up to $4.1 billion per year, or $322 billion in extra spending by the 22nd century.

There's no way to avoid climate change altogether — it's already happening, the FAO noted.

There were an average of four days per year with temperatures above 30 C between 1976–2005. The number is expected to increase to 34 days between 2071–2100. A one-in-100-year rainfall event was defined as 103mm of rain in 24 hours in the earlier period. That definition is expected to be 158mm in the latter period.

The good news is Ontario can be proactive, the FAO said. It would cost more upfront to make infrastructure more climate-resilient now. But the FAO found it would be less expensive overall, and put Ontario in a much better place to start the next century.

Public infrastructure has a long service life, which is why it's important to make these types of decisions now, Weltman said.

FAO.

The FAO didn't estimate the economic impact climate impacts on transportation networks to people and businesses, but said it "would be a useful area of future research."

"These costs would be material and if added, would likely show further benefits of adapting public transportation infrastructure," the FAO said in its report.

And the report only looks at the cost of repairing infrastructure — not broad economic disruption from climate change events, Weltman noted.

"We're not estimating the economic impact of having that road washed out. Kind of like we saw in B.C. last year with the road washed out, supply chains were disrupted, folks were cut off from the mainland," he said.

Weltman said the report could give municipalities data to "make your pitch" to the province to do more on climate, since those costs could be downloaded to local governments if action isn't taken now.

Opposition parties said the report shows the Ford government isn't taking climate change seriously.

Interim NDP leader Peter Tabuns said the PCs' focus on building highways is mortgaging the province's future.

Premier Doug Ford "is actually increasing the risk of flooding with his approach to public infrastructure, by allowing his developer buddies to pave over farmlands and wetlands. And Mr. Ford is teaming up with climate change deniers like William van Wijngaarden to fight young people in court who are advocating for a livable future," he said in a statement.

Green Leader Mike Schreiner repeated his call for a "real climate plan" that would cut pollution in half by 2030.

"Our pocketbooks depend on our action. Our lives and livelihoods depend on climate action. And our future and our children's future depend on climate action," he told reporters at Queen's Park.

Act now on infrastructure climate adaptation to avoid spending billions more down the line: FAO

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