Climate Change Threatens U.S. Bridges

September 15, 2024 / activist360

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.

New Study Shows West Antarctic Ice Sheet Might Be Safer from Collapse This Century

August 25, 2024 / activist360

Glacier breaking edge in the Lemaire Canal. The Lemaire Canal is a narrow ship passage. It separates the island of Booth from the Antarctic Peninsula. Credit: W. Bulach, CC BY-SA 4.0, via Wikimedia Commons, December 8, 2005.

Some Climate Threats May Be Less Urgent, But Action Is Still Needed to Protect Ice Sheets

A recent study led by researchers at Dartmouth College brings some good news about the West Antarctic Ice Sheet, particularly Thwaites Glacier. Scientists have found that this massive ice sheet might be less likely to collapse during the 21st century than we previously feared. This discovery could mean that the threat of rapidly rising sea levels is not as immediate as some had thought.

What Is MICI and Why Does It Matter?

MICI stands for Marine Ice Cliff Instability. It’s a big concern in the world of climate science. The idea is that if the floating ice shelves around Antarctica collapse, they could expose tall ice cliffs. These cliffs might break apart quickly, leading to more ice melting and causing sea levels to rise around the world. Previous studies suggested that MICI could cause the West Antarctic Ice Sheet to collapse, leading to significant sea level rise by the end of this century.

How This Study Was Done

Scientists from several universities used advanced computer models to simulate what might happen to Thwaites Glacier if its ice shelf collapses. They applied new methods to gain a clearer understanding of the ice sheet’s stability. These models are more detailed and realistic than the ones used in older studies.

The new methods took into account how the ice both bends and breaks. This made the models more realistic in showing how the ice sheet might behave if the ice shelves collapse and tall cliffs are exposed.

The study also used more advanced and detailed models. By using three different models (ISSM, STREAMICE, and Úa), the researchers made sure their results were not limited to just one type of model. This approach gave a clearer picture of how stable the West Antarctic Ice Sheet might be, especially concerning MICI.

Key Findings: Less Risk of Collapse

The study’s results are reassuring. Even in the worst-case scenarios, where the ice shelf collapses completely, the models show that the glacier would likely remain stable throughout the 21st century. The exposed ice cliffs wouldn’t be tall enough to cause the runaway collapse that was previously feared.

Two important factors help keep the glacier stable:

Faster Ice Movement: If the ice shelf collapses, the ice behind it would begin moving faster, which surprisingly helps prevent the cliffs from breaking apart.
Thinning Ice: The ice near the front would become thinner, making the cliffs less likely to reach dangerous heights.

Why This Matters for Sea Levels

This study suggests that the scenarios where sea levels rise quickly due to the collapse of the West Antarctic Ice Sheet might not happen as soon as we thought. However, the scientists warn that other processes could still cause the ice to melt over the long term. We shouldn’t assume everything is fine, but it’s a relief to know that we might have more time to address these challenges.

Call to Action

This study is a reminder that while some climate threats may be less urgent than we feared, we still need to take action. Ice sheets like the West Antarctic are still at risk in the long run.

Morlighem, M., Goldberg, D., Barnes, J. M., Bassis, J. N., Benn, D. I., Crawford, A. J., Gudmundsson, G. H., & Seroussi, H. (2024). The West Antarctic Ice Sheet may not be vulnerable to marine ice cliff instability during the 21st century. Science Advances, 10(eado7794).

Alaska’s Melting Permafrost: Unleashing Toxic Mercury into Our Ecosystem

August 18, 2024 / activist360

Photo of permafrost thawing with ominous darkening effect surrounding the photo.

New Research Unveils Risks of Mercury Mobilization in the Yukon River Basin Due to Permafrost Thaw

The Arctic is heating up faster than anywhere else on Earth, and this rapid warming is causing a lot of problems. One big concern is the melting of permafrost—ground that has been frozen for thousands of years. When this frozen ground thaws, it can release harmful substances into our environment. recent study published in Environmental Research Letters looked at how mercury, a toxic metal, is being released from permafrost in the Yukon River Basin in Alaska. This is bad news for the environment, and it could also affect our health.

Why Mercury in Permafrost is a Problem

Mercury is a dangerous metal that can poison living things, including humans. It’s especially harmful because it can build up in the food chain. For example, small fish absorb mercury from their environment, and when bigger fish eat those smaller fish, the mercury accumulates. If humans eat those bigger fish, they can get sick. Mercury has been locked away in permafrost for a long time, but as the Arctic warms and the permafrost melts, this mercury is being released.

What the Study Found

Researchers studied two areas in the Yukon River Basin: Huslia and Beaver. Here’s what they discovered:

Mercury in the Soil: The study found that the soil in these areas contains mercury—about 49 nanograms per gram in Huslia and 39 nanograms per gram in Beaver. This may not sound like much, but it’s enough to be concerning, especially as it spreads into the environment.
River Erosion Releases Mercury: As rivers in the Yukon River Basin move and change course, they erode the riverbanks, which releases mercury into the water. Some of this mercury gets washed away, while some gets redeposited in new locations. The study found that more mercury is released in some areas, like Beaver, while in others, like Huslia, more is deposited back into the ground.
Impact on Communities and Wildlife: The release of mercury is especially dangerous for people who live in the Arctic and rely on fishing for food. When mercury enters the water, it can turn into a form that is even more toxic, called methylmercury. This can then build up in fish, which is a major part of the diet for many Indigenous communities in Alaska. Eating fish contaminated with mercury can lead to serious health problems.

Why This Matters

This study shows how climate change is not just about warmer temperatures—it’s also causing toxic substances to be released into our environment. The Yukon River Basin is a major waterway, and what happens here can affect larger ecosystems and even the Arctic Ocean. If we don’t address this issue, the mercury released from permafrost could have far-reaching effects on both wildlife and people.

What We Can Do

Understanding how climate change is impacting our world is the first step in taking action. This study highlights the importance of monitoring these changes and finding ways to reduce the risks. We need to pay attention to what’s happening in the Arctic and support efforts to protect our environment.

Summing Up

The melting of permafrost in the Yukon River Basin is releasing mercury into our environment, which poses serious risks to both nature and human health. As climate change continues to accelerate, it’s crucial that we understand these impacts and work together to find solutions. By staying informed and taking action, we can help protect our planet for future generations.

Call to Action

If you care about the environment and want to learn more about how climate change is affecting our world, read our weekly articles and follow us on X.com. Together, we can make a difference.

Study referenced: Smith, M. I., Ke, Y., Geyman, E. C., Reahl, J. N., Douglas, M. M., Seelen, E. A., Magyar, J. S., Dunne, K. B. J., Mutter, E. A., Fischer, W. W., Lamb, M. P., & West, A. J. (2024). Mercury stocks in discontinuous permafrost and their mobilization by river migration in the Yukon River Basin. Environmental Research Letters, 19(8), 084041.