America has over 600,000 bridges. Steel girder bridges, among the most common, could face serious infrastructure problems thanks to man-made climate change.

Rising temperatures would mean increased thermal expansion, which would put increased pressure on joints keeping the bridges in place. That makes a collapse more likely.

America’s infrastructure as a whole needs serious work.

Rising temperatures due to man-made climate change could present a major challenge to American infrastructure. A new study from Colorado State University looking at America’s steel bridges shows that while current temperatures don’t present a challenge, nearly 25 percent could see a section collapse in the next 21 years. The numbers move upwards after that, going to 28 percent by 2060 and 49 percent by 2080. Disturbingly, nearly all of the bridges studied set to fail by 2100.

The team, comprised of engineers Hussam Mahmoud and Susan Palu, looked at 89,089 “simply supported steel girder bridges,” a common design in the country post-World War 2. These bridges are made up of longitudinal beams which span two piers. These bridges are not perfect. They regularly suffer from debris clogging their expansion joints, which keep the bridge steady as the temperatures make the steel expand and contract. When debris clogs these joints, the bridges need regular maintenance.

It’s a recipe for disaster, the pair of engineers argue.