Tag Archives: climate change

Water Over the Bridge

A professor of American studies is helping port communities worldwide understand how rising sea levels and other impacts of climate change affect shipping and coastal infrastructures.

More than 14,000 vehicles cross the Herbert C. Bonner Bridge every day — a lifeline for the people of Ocracoke and Hatteras islands, connecting them to the Northern Outer Banks. Below the bridge, tides from the Atlantic Ocean push into the widening Oregon Inlet, breaking through to the Pamlico Sound.

The Bonner Bridge Replacement Project began on March 8, 2016. The new structure is designed to withstand 100 years of ocean currents, built with high-durability concrete and reinforced stainless steel. But it comes after years of failed attempts to create a durable bridge and countless arguments over environmental concerns.

The path forward, according to Rachel Willis, involves infrastructure and ports (like the Cape Fear Memorial Bridge and Port of Wilmington in the background) that work with sea-level rise, rather than against it. (photo by Alyssa LaFaro)

Beach erosion, severe weather and heavy traffic have taken their toll on the bridge since it was first built in 1963. In 1990, in the middle of the night, a dredge rammed into the bridge during a brutal nor’easter, causing a 400-foot section to collapse into the waves below. For more than three months, Hatteras Island could be accessed only by boat or plane. In 2013, safety concerns closed the bridge for 12 days when routine sonar scanning showed that substantial sand erosion had compromised the support structure. And in summer 2017, construction crews struck major underground electrical cables, knocking out power to Ocracoke and Hatteras islands for a week.

Since the bridge’s original construction, more than $300 million has been spent to protect and repair it.

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Rachel Willis watches the bridge construction from the water’s edge on Hatteras Island. She sighs.

“The ocean wants to open that inlet,” she says. “But we have put all this development and coastal infrastructure in a fixed place — and nature keeps taking it back. How are we preparing to protect the people in these communities? The answer is not ignoring the signs that nature gives us.”

Willis’ research examines the intersection of transportation infrastructure and sea-level rise. How does a labor economist end up studying climate change?

The answer is not one you’d expect: socks.

The Herbert C. Bonner Bridge connects Ocracoke and Hatteras islands to the Northern Outer Banks. The bridge is in the middle of a major replacement project after decades of severe weather, heavy traffic and beach erosion have taken their toll. (photo by Alyssa LaFaro)

The Herbert C. Bonner Bridge connects Ocracoke and Hatteras islands to the Northern Outer Banks. The bridge is in the middle of a major replacement project after decades of severe weather, heavy traffic and beach erosion have taken their toll. (photo by Alyssa LaFaro)

Knitting global social fabric

In the early 1990s, Willis and her students compiled data from every child care center in North Carolina — research that contributed to the development of Smart Start legislation. In 1994, while presenting this research at a conference, she met a sock manufacturer who would eventually introduce her to an industry specialist who created training programs for factories and workers.

In the 10 years that followed, Willis followed the lifecycle of socks around the world. She traveled to Italy, China and the Czech Republic to study sock-knitting machines and business practices. In North Carolina, she visited more than 200 sock factories and interviewed thousands of workers, owners, supervisors and suppliers.

But it wasn’t just about socks.

“The purpose of this research was, really, to find out the future of manufacturing, which was obviously declining in the United States. It quickly became clear that cost-effective land transportation was vital to global competitiveness.”

By land or by sea?

When you drive into Morehead City, you can follow the train tracks all the way to the port, thanks to the city’s namesake, John Motley Morehead, who as governor oversaw their construction in the 19th century. Today, boats still arrive at the port and load goods onto the trains, which make deliveries to local factories and villages along the corridor.

But this kind of infrastructure is the exception. “We’ve undervalued trains as a transportation method in this country,” Willis says. “It’s all about the interstate system here.”

Here’s why Willis believes the nation must put goods on railcars and then get railcars to ports: It costs about 80 cents per mile to move one metric ton of freight on an airplane. It costs 27 cents to move it by truck. It costs 2 cents by rail. “It costs one penny by water,” Willis stresses. These numbers don’t just represent product cost — they are a proxy for the amount of carbon put into the atmosphere to move goods around the planet.

Willis (front row, far right) poses with students from her “Global Impacts on American Waters” class atop the Maritime Museum in Beaufort, N.C.

Willis (front row, far right) poses with students from her “Global Impacts on American Waters” class atop the Maritime Museum in Beaufort, N.C. (photo by Alyssa LaFaro)

The search for a solution

The Dutch have a famous saying: “God built the world, but the Dutch built Holland.” About one-fifth of the Netherlands lies below sea level and 60 percent is vulnerable to flooding — startling statistics that the Dutch have learned to live with. Unlike most of the world, they have always worked to maintain a symbiotic relationship with the water.

Willis has always been fascinated by Dutch resiliency. And with good reason.

In the 13th century, the Dutch were already reclaiming land lost to flooding through the construction of dikes. Two hundred years later, the invention of the rotating turret windmill not only pumped water out of permanently flooded lands, it provided an energy source. Fast forward to the 1980s, when the Dutch began the largest land reclamation project and erected the grandest flood barrier that the world has ever seen.

The barrier, called Maeslantkering, is equivalent in size to two Eiffel Towers placed horizontally on the water in the Hook of Holland. In 2015, Willis decided she had to see it for herself. “If you’re looking for an insane field trip, go see where these solutions are in full force,” she advises.

“The Dutch spend the same percentage of their national income on infrastructure related to water management as the U.S. spends on the military,” Willis says. “Because fighting the water is their national defense.”

Willis returned to the Netherlands this past summer to interview local experts on their refocused efforts to work with nature to provide coastal protection. In 2011, they used 21 million cubic meters of sand to form a hook-shaped peninsula called the “sand engine,” which enables the forces of the ocean to deposit sand along the North Sea coast.

Willis realizes that these solutions are not financially possible for most of the world’s coastlines. “The costs are astronomical for all but the wealthiest communities and countries,” she says.

Willis points toward Hatteras Island as the ferry nears the docks. She’s been studying alternative means of passenger transportation since she was on the board of the Triangle Transit Authority (now GoTriangle) in the 1990s, and became interested in the same concept for freight near the end of that decade. But even before then, she spent her childhood riding trains and boats across Europe and Asia, having lived in both Germany and Japan. (photo by Alyssa LaFaro)

Optimism and education

Approximately 50 percent of the world’s population will live within 30 miles of the coast by 2050, according to Willis. How do we prepare people for threats from more intense storms? More importantly, what happens to communities that are at risk now?

“I have great optimism about finding solutions,” Willis says. “Because I’ve seen extraordinary examples of them.” She stresses that working toward solutions involves seeing the whole picture.

“Our goals are not American — our goals are global. … The problem is not going away. It’s water over the bridge. We need to look at infrastructure in the short run that is adaptable to these floodwaters, but we need to use policy and incentives to stop building at the edge.”

Story and photos by Alyssa LaFaro, a writer for Endeavors magazine. The print version of this story was written before the hurricanes that hit the Southeast.

 

Isolated coral reefs are not healthier

A colony of elk horn coral, Acropora palmata, which is listed as threatened under the U.S. endangered species act. This species once dominated Caribbean reefs but has been virtually wiped out by disease and climate change. (From Akumal, Mexico, in 2014. Photo by John Bruno)

A colony of elk horn coral, Acropora palmata, which is listed as threatened under the U.S. endangered species act. This species once dominated Caribbean reefs but has been virtually wiped out by disease and climate change. (From Akumal, Mexico, in 2014. Photo by John Bruno)

For the world’s coral reefs, the picture keeps getting gloomier. Although it’s widely assumed that both local and global factors are contributing to their decline, new research shows that isolated reefs far from human activities are in fact not healthier than those in more densely populated areas.

The work, led by John Bruno, a UNC professor of biology, marks the first global test of the hypothesis that isolated reefs are suffering from less damage.

“We often mythologize isolated coral reefs as pristine and safe from harm,” said Bruno. “In fact, coral loss on some of our isolated reefs is just as dramatic as coral decline on reefs adjacent to more densely populated islands.”

Bruno and co-author Abel Valdivia (a former UNC-Chapel Hill graduate student, currently a research scientist for the Center for Biological Diversity in Oakland. Calif.), analyzed data from 1,708 reefs around the world from the Bahamas to Australia collected from 1996 to 2006.

The research, reported online in the Nature journal Scientific Reports, shows that local management efforts to mitigate impacts of activities like fishing and tourism cannot alone restore coral reef populations.

One striking example is the massive bleaching of hundreds of kilometers on the northern and central Great Barrier Reef in Australia, Bruno said.

“Our work illustrates the truly far-reaching effects of global warming and the immediate need for drastic and sustained cuts in carbon emissions,” he said.

Read more.

Watch a video of graduate student Laura Mudge surveying recovering reefs in Mexico.

Caterpillars respond to climate change

Two related species of sulphur butterflies in Colorado and California are evolving to adapt to climate change. (photo courtesy of Heidi MacLean)

Two related species of sulphur butterflies in Colorado and California are evolving to adapt to climate change. (photo courtesy of Heidi MacLean)

Research by a team of UNC biologists and graduate student shows that some caterpillars are already evolving to cope with climate change. Caterpillars of two species of butterflies in Colorado and California have evolved to feed rapidly at higher and at a broader range of temperatures in the past 40 years, their study shows.

“To our knowledge, this is the first instance where we show changes in physiological traits in response to recent climate change,” said Joel Kingsolver, Kenan Distinguished Professor of Biology.

Caterpillars can eat and grow only when it’s not too cold and not too hot, explained Kingsolver. But when temperatures are ideal, caterpillars eat with reckless abandon and can gain up to 20 percent of their body weight in an hour.

The Brush Creek, Colorado, field site.

The Brush Creek, Colorado, field site.

Jessica Higgins, a graduate student in Kingsolver’s lab who spearheaded the study, worked with fellow UNC graduate student Heidi MacLean, former UNC faculty member Lauren Buckley and Kingsolver to compare modern caterpillars to their ancestors from 40 years ago. Their results show that the two related species of sulphur butterflies have adapted in two ways:

  • broadened the range of ideal feeding temperatures.
  • shifted their optimal feeding temperature to a higher one.

In their work, the researchers measured changes in climate at the two study sites and then examined changes in the caterpillars feeding rates using current and historical data from the 1970s, collected by Kingsolver’s graduate adviser Ward Watt.

Although they found little change in the average air temperature at both study sites, they noticed that the frequency of hot temperatures — that is, temperatures that exceeded 82 degrees Fahrenheit –— increased two-fold in Colorado and four-fold in California over the past 40 years.

In response to these temperature fluctuations, modern caterpillars in Colorado ate faster at higher temperatures than their 1970s counterparts. In California, the modern caterpillars ate faster at both high and low temperatures than did their ancestors, but their optimal feeding temperatures did not change.