How Climate Change Is Accelerating Bridge Deterioration: An In-Depth Look at America’s Aging Infrastructure

Climate change is rapidly transforming how we live and interact with our environment. While much focus is on the visible effects like rising sea levels and wildfires, one pressing issue has largely gone unnoticed: the alarming rate at which bridges are deteriorating due to extreme weather. Engineers warn that America’s aging bridges are increasingly at risk, with the dual threat of extreme heat and increased flooding causing them to deteriorate faster than ever before.

This article delves into the serious implications of climate change on bridge safety, the hidden costs to the economy, and the steps being taken to mitigate this growing crisis.

How Extreme Heat and Flooding Threaten Bridge Integrity

Bridges, a quarter of which were built before 1960, were already due for repair. However, engineers point out that climate change is accelerating their decay. According to experts like Dr. Paul Chinowsky, a civil engineering professor at the University of Colorado Boulder, extreme heat and flooding are pushing these structures beyond their limits. In 2023, extreme heat caused New York City’s Third Avenue Bridge to get stuck in the open position, while a steel railroad bridge connecting Iowa and South Dakota collapsed due to floodwaters.

These events are becoming alarmingly common. Materials used in bridges, primarily concrete and steel, are susceptible to expansion and contraction during extreme heat, causing cracks and weakening the overall structure. “It’s getting so hot that the pieces that hold the concrete and steel, those bridges can literally fall apart like Tinkertoys,” says Dr. Chinowsky. 

The Economic Cost of Bridge Failures

Bridge failures have far-reaching economic consequences, particularly for supply chains. For instance, when a 30-foot section of the Interstate 10 bridge on the California-Arizona border was washed away in 2022, it added an estimated $2.5 million per day to trucking costs. The need for detours not only increases fuel consumption but also reduces the number of deliveries truck drivers can make. Dan Murray, senior vice president of the American Transportation Research Institute, highlights how these closures can lead to significant inflationary pressure as trucking companies pass on their costs to consumers.

How Bridge Age Compounds the Problem

Age is often a key predictor of structural weakness. Many of America’s bridges, designed to meet the climate conditions of decades past, are not equipped to handle the temperature extremes of today. Studies show that one in four steel bridges in the United States could collapse by 2050 due to extreme weather conditions. This is particularly concerning given that a significant portion of the nation’s infrastructure is already over 50 years old.

Some newer bridges are also unexpectedly vulnerable. For example, bridges in Colorado, designed only 10 to 20 years ago, are already showing significant signs of wear. This premature deterioration has caught engineers by surprise, underscoring the unpredictable effects of climate change on infrastructure.

How Bridges Are Affected by Bridge Scour and Pavement Buckling

Another critical issue linked to climate change is “bridge scour,” the erosion of soil around bridge foundations due to increased precipitation and flooding. According to studies, bridge scour is the leading cause of bridge failures in the U.S. For instance, in Vermont, heavy rainfall has caused significant damage to an estimated 100 bridges in the last two years alone.

On top of that, the phenomenon of pavement buckling is becoming more frequent as temperatures swing between extremes. Steel bridges, which are designed to bend slightly under heavy loads, are stiffening as clogged joints prevent them from distributing weight evenly. This additional strain can lead to cracking and, in some cases, structural collapse.

How the U.S. Government and States Are Responding to Bridge Vulnerabilities

To address the growing risks posed by climate change, the Biden administration has taken action through the 2021 bipartisan infrastructure law, which allocated $110 billion for bridge and road repair. The law also established the PROTECT program, which provides $7.3 billion to states for making infrastructure more resilient to extreme weather.

Vermont is one state that has begun rebuilding its bridges to withstand future floods and extreme heat, with wider spans and deeper foundations. Colorado, one of the first states to factor climate resilience into its bridge designs, has implemented stricter standards after suffering $700 million in damages from a 2013 flood. However, these improvements are costly. Vermont estimates that flood-resistant bridges cost 30 to 40 percent more to build, putting a significant strain on already limited budgets.

How Future-Proofing Bridges Remains a Complex Challenge

While progress is being made, scientists and engineers agree that building climate-resilient bridges remains a “moving target.” Climate change is evolving rapidly, and its effects on infrastructure are difficult to predict. Jim Tymon, executive director of the American Association of State Highway and Transportation Officials, emphasizes that while steps are being taken to fortify bridges, future weather events could bring new challenges.

Studies conducted by Dr. Hussam Mahmoud at Colorado State University suggest that smaller bridges with lighter loads are particularly vulnerable. His research found that many bridges in the Northern Rockies, Plains, and Midwest could soon be at risk of collapse due to extreme heat. Yet, despite these alarming findings, some states, like North Dakota and Oklahoma, have been slower to acknowledge the link between climate change and infrastructure deterioration.

The Urgency of Climate-Resilient Infrastructure

The growing vulnerability of America’s bridges underscores the need for urgent action. While federal and state governments are taking steps to address the issue, the gap between available funding and the need for resilient infrastructure remains wide. As climate change continues to push temperatures higher and increase the frequency of extreme weather events, ensuring the safety and longevity of the nation’s bridges will be one of the most critical challenges in the coming decades.