Sarah Phillips

Six years ago, the United States government was seriously considering a $1 trillion budget proposal to strengthen deteriorating infrastructure across the country, especially its vulnerable bridges, which had recently received a C+ from the American Society for Civil Engineering (Jordan).  Today, the issue of bridge collapses continues to accelerate, thanks, in large part, to global warming (Jordan).  Many bridges, both in the United States and around the world, are constructed with expansion joints, which are designed to allow portions of a bridge to expand and contract with changing temperatures without damaging the structure (“University”).  However, these joints can be pushed beyond their limits in extreme heat, particularly when clogged with debris (“University”).  Thus, as global temperatures continue to rise, more frequent and more thorough maintenance of the world’s bridges is necessary if they are to remain stable (Grossman).  Unfortunately, though, “standard risk assessments” are often not sufficient to identify vulnerable bridges, and “complicated natural factors make accurate damage estimates hard to come by” (Jordan).

And it is not only high heat that is weakening bridges.  Many other environmental factors often contribute to a collapse – and most can be traced back to human activity (Genuchten).  Accelerated microorganism activity, for instance, fueled by higher air humidity and carbon concentrations in the atmosphere, can speed of the corrosion of metals and concrete; deforestation means loosened soil and unstable bases (Genuchten).  The more than 500,000 United States bridges that span water (for context, there were roughly 600,000 total bridges in the country in 2019) are at particular risk due to heavier rains, higher water levels, strained drainage capacities, and an increased frequency in extreme waves (Jordan, Genuchten, Grossman). 

On a positive note, because they are so clearly visible, failing bridges might be acting as an alarm bell to individuals still apathetic about the environmental crisis.  The recent I-95 bridge collapse in the Philadelphia area, for example, has been widely covered by the media (“Biden”).  Just over a month later, when a bridge in Qianzhou, China buckled, apparently due to extreme heat – it was over 40 °C (104 °F) in the region that day – a video of its collapse soon began to circulate rapidly around social media (“Watch”). 

Though nobody was injured in the Qianzhou bridge collapse, it was just one of many to come, and it is no longer possible to hope that nobody will be hurt in the future.  Colorado State University researcher and engineer Hussam Mahmoud, together with his team, has estimated that, in just over 20 years, 25% of United States bridges will fail (Scully).  And nearly all should fail in less than 70 years – assuming, of course, that climate action continues at its current pace (Scully). 

Works Cited

“Biden Takes Helicopter Tour of I-95; Shapiro Says It Will Re-Open within Two Weeks.” WHYY, Accessed 5 Aug. 2023.

Genuchten, Dr Erlijn van. “30 Ways Climate Change Affects the Safety of Bridges.” The Environment, 12 Jan. 2023, Accessed 2 Aug. 2023.

Grossman, David. “Climate Change Could Wreck a Quarter of Steel Bridges in 21 Years.” Popular Mechanics, Popular Mechanics, 25 Oct. 2019, Accessed 2 Aug. 2023.

Jordan, Rob. “When Bridges Collapse.” Stanford Earth, 28 Apr. 2017, Accessed 2 Aug. 2023.

Scully, Ruby Prosser. “Climate Change May See One in Four US Steel Bridges Collapse by 2040.” New Scientist, 2019, Accessed 2 Aug. 2023.

University, Colorado State. “Climate Change Could Hasten Deterioration of US Bridge Infrastructure.”, Accessed 2 Aug. 2023.

“Watch | Bridge Collapses as China Experiences Record-Breaking Heat.” WION, Accessed 2 Aug. 2023.