Metrolinx: Mainstreaming climate risk assessment across a vast organization

The implementation of the PIEVC Protocol across Metrolinx, Canada’s largest transit authority, identified extreme heat impacts on rail lines and an increased risk of ice on passenger platforms as freeze-thaw cycles increase. The assessment supported the development of an organization-wide adaptation strategy and a commitment to the ongoing understanding of climate change impacts of specific interest to the organization.


Metrolinx is the Ontario government agency responsible for public transport across Toronto, Hamilton, and Ottawa. It is one of the largest crown corporations in the country, running the GO Transit commuter rail and bus system, the Union Pearson Express airport rail link, and the Presto card fare system for 11 different municipalities, as well as overseeing subway development in Toronto.

In 2013, the agency suffered two climate-related disasters back-to-back: a flooded train in July with two washouts along the tracks, and an ice storm in December in which some stations went without power for a week. Metrolinx decided it was time to take climate adaptation seriously. They brought in climate risk expert Quentin Chiotti, creating a new managerial position dedicated solely to the question of climate adaptation.

Climate Risk Assessment

To understand where they might be vulnerable, Chiotti and a “dream team”, as he describes them, of risk science experts applied the PIEVC Protocol to six of the agency’s assets that were representative of Metrolinx as a whole. They chose a representative selection of infrastructure to assess with the PIEVC Protocol and the lessons from those assessments informed an organization-wide climate adaptation strategy.

The assessment of risk caused by an increasing frequency of hot days has led Metrolinx to change the temperature threshold at which they lay new rail track, and re-assess the number of days that are likely to face “slow-go” orders.

Another risk identified by the assessment is the increasing frequency of freeze-thaw cycles (days when the air temperature fluctuates between freezing and non-freezing temperatures). The freezing, melting, and re-freezing of water can damage infrastructure and have negative impacts on vehicle and passenger safety.

As shown on this graph of the hottest day, the hottest day in the past was in the low 30s (on average). The projections for the decades surrounding the 2020s indicate that the average hottest day has likely already increased to the mid 30s and that in the decades around the 2050s (in medium and higher emissions scenarios) it could increase to about 40. This has implications for the steel tracks.

When continuous welded rail tracks are installed in a corridor, they first have to be stressed according to a regionally-appropriate rail laying temperature. Across Canada, this temperature has traditionally been 32.2°C. Sustained air temperatures above 32°C can cause what are called “sun kinks” in steel rails. This poses a safety issue if trains pass over them too quickly. The climate-induced increase in the average summertime daily temperature has prompted Metrolinx to adopt a higher temperature for rail laying, of 37.7°C for all new track.

Slow-go orders are imposed when temperatures exceed 30°C. Train speeds are cut by 24 km/h, which can add about 10 minutes to the average trip. As these hot temperatures are occurring more often, there will be an increased number of “slow-go orders” and corresponding travel delays.

Figure 2. Freeze-Thaw Days

Increases in freeze-thaw cycles, in which snow melts and then re-freezes as ice, can lead to bus collisions and slips and falls on outside platforms. This in turn has knock-on considerations: should Metrolinx install heating systems to melt snow on platforms? This is not cheap, and would have a negative impact on greenhouse gas emissions, as they use natural gas boilers. How does this compare to improved salting of platforms?

These decisions, and many other policy, planning, and strategic questions were brought to the fore by the climate risk assessment process. This is part of the value of applying the PIEVC Protocol, through which historical climate data, future climate projections, and multi-disciplinary stakeholder input is evaluated to identify climate risks and make informed adaptation decisions.

Risk Assessment Conclusion

The assessment found that climate risks pose a threat to on-time performance, customer complaints and reputation, working conditions, and health and safety. While these risks may not result in infrastructure failure, they still create a profound threat to the organization over time. Passengers get frustrated with such annoyances or modest dangers when compared to what we imagine efficient, well-run transit should look like.

“You’ll notice that a lot of these aren’t exactly what you’d call catastrophic risk,” says Quentin.  He thinks there has been too much of a focus on catastrophic risk in the adaptation sector. “These are real concerns, but organizations like Metrolinx also need to ask themselves: ‘How does this impact our day-to-day?’ It’s not just about hurricanes and wildfires.”

Teasing out these interlocking relationships is complex work. For example, a number of snow-related contracts are tied to a set start of the winter season, but the season start is changing now. It sounds banal, but there are hundreds of such issues. Quentin says he’s lucky that there is buy-in for taking climate vulnerability seriously across the organization, especially at the executive level, and that Metrolinx has staff like him dedicated solely to the task of assessing climate risks. His team is now producing monthly internal climate risk reports. “Climate risk now has a direct sightline to senior management, which keeps it fresh and on people’s radar. The next few years for this stuff will be absolutely crucial.”

Key Takeaways

  • Existing and future transit infrastructure need to be designed and built with consideration for the fact that the climate has already changed and that those changes will continue into the future.
  • Some aspects of infrastructure will be at risk, not just to extreme events, but to impacts of changing average conditions.
  • Decision making processes and strategic planning need to account for current and future climate risk.