One foot of sea level rise puts thousands of miles of fiber underwater

by Steve Blum • , ,

Climate change poses a significant threat to telecommunications infrastructure. That’s the conclusion of a recently published paper by three researchers from the University of Oregon and the University of Wisconsin.

The authors took standard electronic map data – i.e. geographical information system/GIS files – showimg major fiber routes and overlayed it with coastal flooding predictions made by the National Oceanic and Atmospheric Administration. The data shows thousands of miles of long haul fiber at risk…

The results of our analysis show that climate change-related sea level incursions could have a devastating impact on Internet communication infrastructure even in the relatively short term. In particular, we find that 1,186 miles of long-haul fiber conduit and 2,429 miles of metro fiber conduit will be underwater in the next 15 years. Similarly, we find that 1,101 termination points will be surrounded by sea water in the next 15 years. Given the fact that most fiber conduit is underground, we expect the effects of sea level rise could be felt well before the 15 year horizon. Interestingly, we find that the risks over longer time scales do not increase significantly. Specifically, there is only a modest increase in the amount of additional Internet infrastructure that will be under water at the 6 ft. rise level (the 100 year projection) vs. the 1 ft. rise level (the 15 year prediction)…

Our results show that communication infrastructure in New York, Miami, and Seattle, respectively, are at highest risk. We also quantify the impact to individual service providers and find that CenturyLink, Intelliquent (formerly Tinet), and AT&T are at highest risk.

California also faces significant risk, according the authors. They list San Francisco, Palo Alto and Los Angeles in the top five of several risk categories, primarily because of the high concentration of telecoms assets.

It appears that the authors assumed that the fiber routes in their database are all underground. Some of that infrastructure is likely strung on utility pole routes, but the principle is pretty much the same: coastal flooding can disrupt fiber infrastructure, and it doesn’t matter much if it’s entire routes or just chunks.

The danger might not be as imminent as the authors assume – a one foot sea level rise in the next 15 years is a pretty aggressive forecast. Even so, it’s a factor that needs to be considered in planning new fiber construction, for redundancy as much as for additional capacity, and in maintenance budgets for existing routes.