Tag: Climate Change

Climate Change Threatens U.S. Bridges

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Key Findings from a Recent Study

A recent study published in PLOS ONE, authored by Susan Palu and Dr. Hussam Mahmoud, highlights the growing vulnerability of deteriorating U.S. bridges due to climate change. This research, conducted at Colorado State University, focuses on how rising temperatures and clogged expansion joints could jeopardize the structural integrity of thousands of bridges across the country.

The Researchers Behind the Study

Susan Palu was a master’s student in civil engineering when the study was conducted, bringing fresh academic insight into the challenges of aging infrastructure. Dr. Hussam Mahmoud, a professor at Colorado State University and the George T. Abell Professor in Infrastructure, is a renowned expert in sustainable infrastructure and community resilience. With a Ph.D. from the University of Illinois at Urbana-Champaign and over 300 publications to his name, Mahmoud’s research focuses on making infrastructure systems more resilient to natural hazards, including climate change​.

The Aging U.S. Bridge Infrastructure

As U.S. infrastructure ages, many bridges are approaching or exceeding their intended design life. Approximately 40% of U.S. bridges are over 50 years old, with around 54,560 classified as structurally deficient. While bridges have been inspected and maintained regularly, this study sheds light on a specific issue: malfunctioning expansion joints, small but critical components responsible for allowing bridge expansion and contraction during temperature changes.

Impact of Climate Change on Bridges

he study examines the effects of climate change on steel-span bridges, which were mass-produced during the highway boom of 1950s to 1970s, when the interstate highway system was being developed. These bridges, when subjected to higher future temperatures, are at risk of developing dangerous levels of thermal stress, especially when their expansion joints are clogged.

When debris builds up in these joints, it prevents the bridge from expanding as temperatures rise. This blockage causes axial pressure on the girders, which, combined with the weight of vehicles, could lead to structural fatigue, cracks, and even failure.

Researchers also studied how temperature changes during bridge construction impact their strength.
They looked at four scenarios: building bridges in winter, spring, summer, or fall. They found that:

  • If built in winter, 100% of bridges might be too weak.
  • If built in spring, 97% might be too weak.
  • If built in summer, 83% might be too weak.
  • If built in fall, 95% might be too weak.

Most Vulnerable Regions

The study identifies bridges in the Northern Rockies, Upper Midwest, and Northwest as the most vulnerable, particularly in states like North Dakota and South Dakota. These regions are likely to experience more severe temperature variations, exacerbating the effects of clogged joints and adding stress to already aging structures.

A Call for Action

With over 89,000 simply supported steel girder bridges analyzed, the study advocates for immediate attention to maintaining and clearing bridge expansion joints. It emphasizes that neglecting to address these climate-related challenges could lead to substantial economic and social costs. Prioritizing repair and maintenance will be essential to ensure the safety and longevity of U.S. infrastructure in the face of climate change.

Summing Up

This groundbreaking study, conducted by Susan Palu and Dr. Hussam Mahmoud at Colorado State University, offers critical insights into how climate change is accelerating the deterioration of U.S. bridges. Without intervention, the impact on national infrastructure could be catastrophic. Policymakers, engineers, and transportation authorities are urged to take immediate steps to mitigate these risks and protect public safety.

By staying ahead of these challenges, the U.S. can safeguard its infrastructure from the growing threat of climate change.

Source: Palu, S., & Mahmoud, H. (2019). Impact of climate change on the integrity of the superstructure of deteriorated U.S. bridges. PLOS ONE, 14(10), e0223307. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0223307.

Three Out of the Past Five Julys Were the Hottest on Record

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By Johnny Wood, Senior Writer, Formative Content, World Economic Forum (Public License)

  • July temperatures in 2016, 2019, and 2020 were the hottest ever.
  • The last fully intact ice shelf in Canadian Arctic collapsed in July’s heatwave.
  • Climate change could double the area of central Europe affected by severe drought by the second half of the century.

The July just gone was the third-hottest ever recorded, according to the Copernicus Climate Change Service. This isn’t the result of a one-off heatwave or freak weather front, but part of an alarming trend that has seen three of the hottest July months ever recorded – peaking in 2016, followed by 2019 – occurring within the past five years.

Have you read?

  • A climate scientist explains what the melting Arctic means for the world
  • The shrinking Arctic ice protects us all. It’s time to act
  • 2020 is predicted to be the hottest year on record, according to NASA

June 2020 saw the joint-hottest average temperatures for this month, together with 2019. Both Junes had average global temperatures 0.5C above the 1981-2010 average.

For more temperate parts of the world, hotter summers are concerning. But what happens when summers get hotter in already very hot places?

Too hot to survive without air conditioning

This summer, Iraq’s capital Baghdad has endured some of the hottest days ever, with temperatures in excess of 50C, during a heatwave that has hit much of the Middle East. While the region is used to hot weather, countries including Israel and Lebanon have experienced unusual heat extremes, a sign of things to come as climate change continues to heat up the planet.

Humans could face a future that’s too hot to survive without air conditioning. Exposure to extreme heat can stress the body to the point where organs shut down, presenting potentially life threatening conditions for many people living in developing countries.

Photo by Andre Klimke on Unsplash

But hot weather is only part of the climate crisis story.

Warming temperatures make extreme weather events, such as floods, storms and droughts, both more likely and potentially more intense.

Warming temperatures could make extreme droughts as much as seven times more likely, according to new research. This means the area of cropland affected by extreme drought across central Europe could double in the second half of this century, to more than 40 million hectares (approximately 400,000 square kilometres), the Guardian reported.

Using precipitation and temperature data from records from as far back as 1766 to inform climate change computer models, researchers from the UFZ-Helmholtz Centre for Environmental Research in the German city of Leipzig forecast that moderate reductions in greenhouse gas emissions could reduce the drought-affected area of central Europe by 40%.

Sinking islands

In the icy wilds of remote northern Canada, the threat of droughts isn’t a consideration, but the region is no less affected by climate change.

At the periphery of Ellesmere Island sits the Milne Ice Shelf, the last fully intact ice shelf in the Canadian Arctic. July’s extreme heat caused two-fifths of this natural wonder to break up in just two days.

“This was the largest remaining intact ice shelf, and it’s disintegrated, basically,” Luke Copland, glaciologist at Canada’s University of Ottawa, told Reuters, explaining that summer temperatures in the Canadian Arctic this year climbed 5C above the 30-year average.

“You feel like you’re on a sinking island chasing these features, and these are large features. It’s not as if it’s a little tiny patch of ice you find in your garden.”

Infographic: Lowest Arctic Ice Cover for July in Recorded History | Statista
Infographic: Lowest Arctic Ice Cover for July in Recorded History | Statista

Extreme July temperatures have hit the entire Arctic region, which scientists say is warming more than twice as fast as the rest of the planet. The 2020 summer melt produced the lowest recorded ice cover for the month of July since records began in 1981.

While the impact of global warming is clear to see, it’s not too late to curb emissions and tackle the climate crisis, but urgent action is needed to accelerate the journey toward net-zero emissions.