STANFORD (US) — Seaport officials are unsure how best to protect their facilities from rising sea levels and more frequent Katrina-magnitude storms, two possible consequences of global warming.
“Part of the problem is that science says that by 2100, we’ll experience anywhere from 1.5 to 6 feet of sea level rise,” says Austin Becker, a PhD candidate in environment and resources at Stanford University. “That’s a huge range.”
Port have to make tough financial decisions when it comes to funding infrastructure and need accurate information about what to expect, so that they can plan accordingly. Building a structure to withstand a 6-foot sea level rise would cost much more than trying to accommodate a 1.5-foot rise, Becker says.
In 2009, Becker distributed 160 surveys to members of the International Association of Ports and Harbors and the American Association of Port Authorities – the first worldwide survey of port authorities to address climate change adaptation.
A total of 93 agencies representing major seaports on every continent, except Antarctica, responded, ranking sea level rise and increased storm events associated with climate change high on their list of concerns.
However, only 6 percent reported they intend to build hurricane barriers within the next 10 years, and fewer than 18 percent had plans to build dikes or other storm protection structures.
Results from the survey are published in the journal Climatic Change.
“As we saw with Katrina in 2005, storm and flood damage can devastate a regional economy for years after an event and have national impacts,” Becker says. Katrina, a Category 5 hurricane, caused an estimated $1.7 billion of damage to Louisiana ports.
Scientists are forecasting a doubling of Category 4 and 5 hurricanes in the Atlantic Ocean by 2100, so it is imperative to start thinking about adapting port infrastructures now, Becker says.
Threat of violent storms
Sea level rise and more frequent violent storms resulting from climate change threaten to take a tremendous toll on all types of infrastructure, especially along the coasts, says study co-author Martin Fischer, professor of civil and environmental engineering.
Fischer and Becker are developing computer models to help port authorities and other government agencies make more informed decisions about adapting to climate change as they plan for the next generation of infrastructure.
“Look around at any seaport today and you will see structures that were built 100 years ago,” says Fischer. “And the buildings that we are building today will be around when sea level rise begins to reshape the coast.”
The problem on a global scale is that ports may start scrambling all at once to adapt their structures to changing environmental conditions. “It could potentially exceed our capacity for construction worldwide.”
Fischer and his colleagues have developed a model that demonstrates how a rapid, simultaneous push to fortify the world’s seaports could drive up demand for construction materials and equipment.
The model, called Sebastian, uses a Google Earth platform to simulate the costs and time required for building dikes around 200 of the world’s most active seaports. Sebastian knows the shape of the ocean floor at each location and tailors the structure to each site to produce an estimate of the materials, labor, and equipment that would be needed to fortify the port against sea level rise.
“Sebastian allows us to run different scenarios based on different levels of sea rise, and see how the ports are affected,” Fischer explains. Using criteria in the Army Corps of Engineers manual, the model calculates the resources needed for each variation of the structure as a way to calculate big-picture, worldwide demand, that also gives managers more reliable information about how much survivability they are buying when they invest in different types of protective structures.
Lack of oversight
Another difficult challenge in preparing for climate change at seaports is that no single agency or individual has sole authority over any given port. Some ports are privately owned, some are public and some are a mixture of both.
And a broad range of entities, including transportation companies, insurance companies, and the Environmental Protection Agency, have some stake in how they are managed, complicating ports’ efforts to budget and plan for the future.
“By the end of the century, quite a few ports will be in trouble, even if you are using the most conservative estimates for sea level rise,” Fischer says. “And if you use the estimates at the top of the range, all of them will be in trouble.”
More news from Stanford University: http://news.stanford.edu/