U.S. Coastal Internet Infrastructure at Risk

Thousands of miles of buried fiber optic cable in densely populated coastal regions of the U.S. may be inundated by rising seas in 15 years time, according to a new study by researchers at the University of Wisconsin–Madison and the University of Oregon.

Paul Barford, a UWisconsin–Madison professor of computer science, said: “Most of the damage that’s going to be done in the next 100 years will be done sooner than later,” says Barford, an authority on the buried fiber optic cables, data centers, traffic exchanges and termination points of the global information network. “That surprised us. The expectation was that we’d have 50 years to plan for it. We don’t have 50 years.”

Seawater inundation projected for New York City by 2033 and its effect on internet infrastructure. Anything in the blue shaded areas is estimated to be underwater in 15 years. Credit: Paul Barford

The study, conducted with Ramakrishnan Durairajan, now of the University of Oregon, and Carol Barford, who directs UWisconsin–Madison’s Center for Sustainability and the Global Environment, is the first assessment of risk of climate change to the internet. It suggests that by the year 2033 more than 4,000 miles of buried fiber optic conduit will be underwater and more than 1,100 traffic hubs will be surrounded by water. The most susceptible U.S. cities, according to the report, are New York, Miami and Seattle, but the effects would not be confined to those areas and would ripple across the internet, says Barford, potentially disrupting global communications.

The peer-reviewed study combined data from the Internet Atlas, a comprehensive global map of the internet’s physical structure, and projections of sea level incursion from the National Oceanic and Atmospheric Administration (NOAA). 

Much of this infrastructure is buried and follows long-established rights of way, typically paralleling highways and coastlines, says Barford. “When it was built 20–25 years ago, no thought was given to climate change.”

Many of the conduits at risk are already close to sea level and only a slight rise in ocean levels due to melting polar ice and thermal expansion as climate warms will be needed to expose buried fiber optic cables to sea water. Hints of the problems to come, says Barford, can be seen in the catastrophic storm surges and flooding that accompanied hurricanes Sandy and Katrina.

Buried fiber optic cables are designed to be water-resistant, but unlike the marine cables that ferry data from continent to continent under the ocean, they are not waterproof.

Risk to the physical internet, says Barford, is coupled to the large population centers that exist on the coasts, which also tend to be the same places where the transoceanic marine cables that underpin global communication networks come ashore. “The landing points are all going to be underwater in a short period of time,” he notes.

The impact of mitigation such as sea walls, according to the study, are difficult to predict. “The first instinct will be to harden the infrastructure,” Barford says. “But keeping the sea at bay is hard. We can probably buy a little time, but in the long run it’s just not going to be effective.”

In addition to looking at the risk to local and long-haul infrastructure in the nation’s coastal areas, the study examined the risk to the buried assets of individual internet service providers. It found the networks of CenturyLink, Inteliquent and AT&T to be at highest risk.

Barford says: “This is a wake-up call. We need to be thinking about how to address this issue.”