Climate change threatens many facets of modern human life, from eroding coastlines, climbing temperatures, and ocean acidification. But these problems extend beyond our natural world—they affect our digital world as well.
“Our findings are clear,” Paul Barford, a computer science professor and the University of Wisconsin-Madison told Seniorhelpline. “A good deal of internet infrastructure will be underwater in the next 15 years.”
In a study, that more than 4,000 miles of buried fiber optic cable may be underwater and 1,100 nodes may be surrounded by water in just 15 years. To put that in perspective, New York City, one of the most at-risk metropolitan areas, would lose nearly 20 percent of its metro conduit and 32 percent of its long-haul conduit to rising sea levels. That's enough to cripple internet access in the area.
What We Could Lose
To come to this concerning conclusion, researchers compared two datasets. One was the Internet Atlas, a map charting the physical location of the internet. This map geocodes infrastructure from more than 1,500 internet service providers around the world.
The researchers focused on two kinds of infrastructure: buried conduit, which includes long-haul and metro fiber; and nodes, including landing points where deep sea transoceanic fiber comes ashore, data centers, colocation facilities, and points of presence that house servers, routers, and other hardware. On the outside, nodes can look like small huts and nondescript buildings, but on the inside they are the points where buried cables terminate.
The other piece of data was the National Oceanic and Atmospheric Administration’s projection of sea level rise inundation. NOAA’s data refashions the world and its coastlines 100 years in the future, drawing on published research to describe a range of best- and worst-case scenarios. The data they use predicted a best-case rise of one foot and a worst-case rise of eight feet. Barford and his team used a range between one foot and six feet.
What they found wasn’t good. In the near term, internet infrastructure would experience a “devastating impact.” That’s because nodes are often clustered at low-elevations around dense populations. In fact, the study found that most of the damage could occur within 15 years, regardless of the scenario.
“Since the inundation models project sea level rise over a 100-year period, I expected the effects to be spread out somewhat evenly,” Barford says. But that wasn’t the case.
New York, as well as Miami and Seattle, remain especially at risk, and three major companies will suffer most of the damage—CenturyLink, Intelliquent, and AT&T. The researchers limited their analysis to the U.S., but of course this threat faces the entire world.
The Effects of Underwater Fiber
Fiber buried on land is not armored and rubber clad like the deep-sea cables that connect the continents. Instead, conduit on land is often sheathed in PVC tubes with jelly surrounding the fibers. They are water- and weather-resistant, but not designed to be submerged. Some of this infrastructure is more than 20 years old.
“It's not clear what will happen when those points are inundated,” Barford says. “The bottom line is that these points are not meant to be surrounded by or under water so steps will need to be taken.”
Even tiny cracks in the weather-proofing around cables can allow water molecules to embed in the strands and attenuate the signal. Even if the effect is not as flashy as a toaster in a bathtub, flooding large swathes of U.S. internet infrastructure could affect communications around the country and the rest of the world.
Hurricanes Sandy and Katrina provide stunning examples of devastating flooding of conduit and nodes, and of service outages and restoration. Immediately following Katrina, for example, 8 percent of Louisiana’s and one-third of Mississippi’s routed networks were out. Mississippi was slow to recover, with 5 to 10 percent of its networks still out 10 days later. But the impact on the global internet was minimal.
“In my opinion, we can expect similar due to sea level rise, but only if we plan carefully,” Barford says.
But rising water is only one threat due to a warming world. In 1929 The Grand Banks earthquake struck the edge of Newfoundland, triggering undersea landslides that snapped 12 transoceanic telegraph cables.
As the climate warms, frozen slopes will thaw and landslides and avalanches may become a greater hazard to deep-sea fiber, says Hermann Fritz, a professor of civil and environmental engineering at Georgia Institute of Technology in Atlanta. He recalled this 90-year-old Canadian earthquake after reading the results of Barford’s study.
“Seafloor cables are very vulnerable,” Fritz adds. "A gravitational landslide on the seafloor could go on for hundreds of miles.” Even when the landslide halts, currents suspend ground rock and carry it in a turbidity current that’s like an underwater dust storm.
Turbidity currents broke telegraph cables after Grand Banks, Fritz points out. One method of clocking the speed of turbidity currents is by analyzing the cables it breaks along its path.
“We’re extremely dependent on technology but at the same time it’s also quite vulnerable to any kind of environmental or climate change issues,” Fritz says.
So Are We Prepared?
Barford’s paper raises serious questions in need of answers.
“From our experience, this is an area that needs more attention at the regional, national, and even global levels,” says Duane Verner, a specialist in resilient infrastructure assessment at Argonne National Laboratory in Argonne, Illinois.
Through his work, Verner knows what could be at stake if nothing is done in preparation of climate change’s most devastating effects. Argonne conducted an assessment of the resiliency of data centers on the East coast for the Department of Homeland Security in 2015. An average of 50-70 percent of global internet traffic flows through those data centers, Verner says.
Representatives of CenturyLink, one of the three companies with the most to lose, say they can handle the problem. The company takes climate change into consideration when fortifying its fiber optic cables, and the company’s networks are designed with redundancy and can divert traffic to alternate routes when infrastructure goes down, a CenturyLink representative told Seniorhelpline.
That’s a good answer, says Ramakrishnan Durairajan, a co-author of the paper. He and Barford are looking into the ways that ISPs can prepare for the potential disaster, and redundancy in the network is one of the best strategies available.
ISPs should be aware that climate change threatens their investment, Durairajan says. Then they should take changing weather and sea levels into account when deploying new conduit and building new nodes. Digging up old conduit to move it or shield it might not be possible.
Instead ISPs should examine data from NOAA and other sources to identify the regions that will be at risk, then strategically deploy new infrastructure that can reroute traffic and pick up slack if a region goes down.
CenturyLink and others will also need to prevent a cascading failure, where one section of the network collapses and drags down otherwise healthy sections overworked by the increased traffic load.
“It's good to start thinking about these things now because we don't have 50 years to come up with strategic locations for deployments,” Durairajan says.
Because within 15 years, climate change could be a threaten humanity—online and IRL.