Europe's heatwave shows up climate risk to roads

LONDON • The historic heatwave that has smothered western Europe this summer has caused transportation chaos. Railroad tracks warped, airport runways failed and key roads buckled.

On July 18, the busy A14 highway in Cambridge, England, was shut down after developing a bizarre ridge that, while enticing to skateboarders, would be calamitous to fast-moving cars and their passengers.

As it happens, the same thing has been occurring across America, Australia, China and Africa.

With average temperatures rising and heatwaves becoming more frequent and intense, infrastructure and, in particular, roads are increasingly vulnerable to human-induced global warming.

A 2017 study assessing the impacts of the climate crisis on critical infrastructure found that by 2080, heatwaves would account for about 92 per cent of total hazard damage in Europe's transport sector alone, in large part because the roads were built for cooler times.

Another study looked at data from weather stations used to determine the proper composition of local roads. It estimated around 35 per cent of them used materials unsuited to the actual climate.

"The maximum temperatures that civil engineers have been using in design are now being surpassed much more frequently," said Dr Amit Bhasin, a director of the University of Texas Centre for Transport Research. "That's when the design starts falling apart."

The good news, though, is that the technology exists to sufficiently harden what is arguably the most critical of infrastructure.

The bad news is it will require government at all levels to spend a lot of money upfront.

Most, if not all, of the ways global warming has changed the climate are having a deleterious effect on roads everywhere.

Besides extreme heat, heavier rainfall and flooding triggered by the phenomenon can quickly erode highways and paved roads while obliterating those made of gravel and dirt.

The cost of repair can be steep: The devastating floods in Australia between 2010 and 2014 cost the government an estimated US$6.4 billion (S$8.8 billion) in repairs to the road network.

In traditionally colder places, the problem is thawing. According to a report from the Canadian Climate Institute, more than half of the country's winter roads in its northern regions, built on frozen lakes and rivers each autumn, may in 30 years become unusable or impossible to build. Nearly all could be gone by 2080, cutting off whole regions from critical services.

And a paper published in 2020 warned that those responsible for building and maintaining roads in permafrost areas in China face "significant engineering challenges". Huge cracks are already appearing in the roads, making them unusable.

According to Mr Claude Van Rooten, former president of the World Road Association, this summer's European heatwave is the latest reminder of the growing discrepancy between the planet's climate reality and what existing roadways can withstand.

He said that in order to weatherproof roads for a fast-warming future, government officials everywhere have to substantially rethink the way they are engineered.

"You try to make assumptions about what is going to happen, and climate change is changing those assumptions," Mr Van Rooten said.

If sufficient steps to mitigate against temperature and precipitation changes are not taken, the bill for repairing and maintaining roads worldwide will skyrocket.

Prevention - as is so often the case - would be the cheaper route. In Canada, for example, selecting base materials and road structures to withstand the climate decades into the future could reduce costs by over 90 per cent, saving as much as US$4.1 billion annually by the 2050s.

The cost of upkeep is only part of the economic threat: Disruptions across road networks can have huge implications for global commerce and development.

When the Leverkusen Bridge in Germany was closed between December 2012 and March 2013, the cost to the national economy was estimated at €80 million (S$112 million).

And the deadly 2018 collapse of the Morandi bridge in Italy cost the city of Genoa an estimated €6 million a day as freight traffic was disrupted.

The economic vulnerability posed by increased road damage is of particular concern in low-and middle-income countries, given the lack of resources and investment in wider networks.

According to Professor Stephen Muench of the Civil Engineering Department at the University of Washington, a key part of the solution is shifting design to incorporate predictive climate models.

Doing that will enable engineers to design something "more in line with what the roadway is actually going to endure".

BLOOMBERG