Protection of subterranean water infrastructure in an abrupt sunlight reduction scenario

An abrupt sunlight reduction scenario (ASRS) could result from a nuclear war, supervolcanic eruption, or asteroid/comet impact, reducing global temperatures for over a decade and leaving subterranean water pipes vulnerable to freezing. This paper builds on previous work assessing the extent of vulnerable water pipes in a severe ASRS, and assesses the feasibility of two methods of pipe protection: (i) piling soil above the pipes, and (ii) installing electrical resistive heat cables around pipes. Total vulnerable pipe length is expected to be 5.4-8.8 million km affecting over 2 billion people, with peak freeze depths exceeding 30 m. In several assessed scenarios, soil piling is expected to take 113-141 days and leave 0.32-0.64 million km of pipelines damaged, affecting 161 million people. Heat cables could be installed where soil piling is impractical, such as where pipes are beneath critical roads, but heat cable production is expected to be sufficient for less than 1% of vulnerable pipes. Implications for local, national, and international response planning are discussed, and potential directions for future research are identified, including improved quantification of the extent of subterranean infrastructure, analysis of direct damage from an ASRS-causing event, and exploration of alternative infrastructure protection methods.