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Seafloor cables carry over 95% of all digital data traffic worldwide, including financial trading information and social media communications.

However, how the Earth’s changing climate could impact this vast undersea network has been relatively understudied until now.

In a new global study published in the journal Earth-Science Reviews, an international team of researchers led by the UK’s National Oceanography Centre (NOC) worked to illuminate this problem by assessing how and where future climate change is likely to impact subsea cables and their shore-based infrastructure.

By analyzing published peer-reviewed datasets, the researchers identified regional climate change ‘hotspots’ where threats to subsea cables may become more intense.

These include areas off Taiwan where changes to tropical cyclone intensity and frequency have already increased cable damage and in polar latitudes where melting glacial and sea ice are profoundly changing ocean conditions more rapidly than many other places on Earth.

The new findings provide much-needed evidence to enable the design of resilient future cables and their routes, the researchers say.

“In our paper, we conducted the first comprehensive assessment of a range of climate related threats to seafloor cables across the globe and their landing stations,” says study co-author Thomas Wahl, an associate professor in UCFs Department of Civil, Environmental, and Construction Engineering.

“Our analysis clearly stresses the need to carefully plan cable routes and landing station locations factoring in a range of local hazards and how those are affected by climate change,” he says.

The researchers say that consideration should be given both to instantaneous events influenced by climate change, such as landslides and tropical cyclones, as well as longer-term, sustained impacts such as sea-level rise and changing seabed currents that circulate even in deep water.

When looking at Florida, there are at least 21 subsea telecommunications cables that connect to the Florida coastline, meaning that there is generally plenty of redundancy if a cable is damaged, the researchers say.

The state serves as an important hub in the global network, connecting North and South America and the Caribbean.

However, the study identifies the importance of assessing changing conditions, particularly where multiple cable systems share a landing point, as they may be affected by combinations of hazards that affect the low-lying Florida coastline, such as sea level rise, changes in storm activity and eroding sandy beaches.

Lead author Mike Clare, a researcher with NOC, says it is essential that researchers assess any potential future disruptions that may emerge as a result of climate change.

“Our reliance on cables that are no wider than a garden hose is a surprise to many, who regard satellites as the main means of communication,” Clare says. “But satellites simply don’t have the bandwidth to support modern digital systems. The ‘cloud’ is not in the sky – it is under the sea. This study and ongoing research will help mitigate any social and economic impacts that could arise if industry is not well-informed and prepared.”

Wahl’s role was primarily analyzing the effects of sea level rise and changes in storm surges and how those changes lead to increased risks for cable and landing stations.

Before joining UCF, Wahl was a Marie-Sklodowska Curie Fellow of the European Union at the University of Southampton, where he also had an office at the National Oceanography Centre and met many of the co-authors.

“It was great to be able to collaborate with them on this important topic, although I am now working on the other side of the Atlantic,” Wahl says. “Luckily, it is easy these days to collaborate remotely with colleagues across the globe, largely thanks to underwater cables and landing stations that are intact.”

The project was an international collaboration with the University of Southampton, U.S. Geological Survey, UCF, the Victoria University of Wellington in New Zealand and the International Cable Protection Committee. It was funded by the Natural Environment Research Council under the COP26 Adaptation and Resilience Scoping Call.

Wahl earned his doctorate in civil engineering from the University of Siegen, Germany, and joined UCF’s Department of Civil, Environmental and Construction Engineering, part of UCF’s College of Engineering and Computer Science, in 2017. He is also a member of UCF’s National Center for Integrated Coastal Research and Sustainable Coastal Systems faculty cluster.

Study title: Climate change hotspots and implications for the global subsea telecommunications network