Guest essay by Eric Worrall
According to a study by Arizona State University, global warming will accelerate deterioration of roads because the original asphalt won’t cope with the anticipated rapid temperature rise.
Study Says Climate Change Could Lead to Rougher Roads
By Don Jergler | September 28, 2017
A study by professors at Arizona State University shows that global warming could add billions of dollars to the nation’s transportation budget for pavement costs alone.
“Transportation infrastructure is built to last decades, but engineering protocols in the United States assume climate stationarity, which may result in accelerated degradation and, consequently, increased costs,” a study out from academics at ASU states.
According to the study, if the standard practice for material selection is not changed to adapt to rising average temperatures, it could add up to $21.8 billion to pavement costs by 2070 under the same moderate global warming scenarios that predict average global temperature increases of 1.8 C.
The standard practice for selecting materials to build roads is based on average temperatures from 1966 to 1995, which differs from averaged based on data studied from 1985 to 2014, according to Shane Underwood, an assistant professor of civil engineering at ASU and one of the authors of the study.
“That may not be applicable going forward,” Underwood said. “That’s largely a decision on expectations that the future will look at lot like the past. That uncertainty can lead to higher costs.”
The abstract of the study;
Increased costs to US pavement infrastructure from future temperature rise
B. Shane Underwood, Zack Guido, Padmini Gudipudi & Yarden Feinberg
Roadway design aims to maximize functionality, safety, and longevity. The materials used for construction, however, are often selected on the assumption of a stationary climate. Anthropogenic climate change may therefore result in rapid infrastructure failure and, consequently, increased maintenance costs, particularly for paved roads where temperature is a key determinant for material selection. Here, we examine the economic costs of projected temperature changes on asphalt roads across the contiguous United States using an ensemble of 19 global climate models forced with RCP 4.5 and 8.5 scenarios. Over the past 20 years, stationary assumptions have resulted in incorrect material selection for 35% of 799 observed locations. With warming temperatures, maintaining the standard practice for material selection is estimated to add approximately US$13.6, US$19.0 and US$21.8 billion to pavement costs by 2010, 2040 and 2070 under RCP4.5, respectively, increasing to US$14.5, US$26.3 and US$35.8 for RCP8.5. These costs will disproportionately affect local municipalities that have fewer resources to mitigate impacts. Failing to update engineering standards of practice in light of climate change therefore significantly threatens pavement infrastructure in the United States.
Read more (paywalled): https://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3390.html
I’m not questioning Professor Underwood’s expertise with civil engineering, his ability to calculate the impact on existing materials of given arbitrary temperature changes, but an assumption that materials will remain static in coming decades is highly questionable.
There is huge ongoing investment into improving the durability of road paving materials, and increasingly robotic means of laying roads. To assume these advances will not significantly reduce road maintenance costs, to assume unlikely worst case climate scenarios like RCP 8.5, in my opinion is alarmist and absurd.