Drones carry electromagnetic sensors over Alaska's tundra to find where permafrost has thawed

The sensor measures how well the ground conducts electricity. Along the Arctic coast, conductivity is a useful stand-in for thaw because salty water that has not frozen conducts far better than ice-rich frozen ground ^[8]. The method is called very low frequency electromagnetic surveying ^[7]. It reads how the ground responds to signals from distant transmitters and never touches the surface, so a lightweight unit can be flown over wet tundra that is prone to thawing ^[7].

The alternative is drilling. Dense borehole grids are expensive, disruptive and extremely labor-intensive, the author wrote ^[6]. The grids also have to be dense, because ice and unfrozen water can differ sharply between spots a city block apart ^[5]. Wainwright looks stable from the air, but the frozen ground under the town holds large bodies of ice, and that ice is now exposed and melting along its eroding bluffs ^[17].

The author, a civil engineer who has spent a decade on Arctic permafrost and infrastructure ^[2], is open about the survey's limits. Its depth estimates can be uncertain ^[9]. The author claims only this much for it: "it can identify where subsurface conditions have changed so engineers know where to look closely" ^[10]. I think that order of work is right. Screen from the air, then drill where the survey shows a contrast.

The thing this doesn't tell you is how often the screen is right. The article does not report how often a drone anomaly matched what a borehole later found. A conductivity map also shows ground that has already changed. A foundation fails on two other quantities: how far the ground settles and how much load it can bear. Those are the quantities the group is trying to project forward ^[12]. The team lists digital twins among its techniques ^[4].

Forecasting has a scale problem of its own. The group's 2026 study covers the whole Arctic Coastal Plain ^[13], and the author wrote: "A regional permafrost map alone cannot tell a builder how a particular foundation or road will survive as temperatures rise" ^[3]. The study puts about 80% of buildings on the plain at risk of damage from sinking land by the 2090s ^[15]. Only a site survey tells an owner whether a given building is in that share. The figures assume greenhouse gas emissions stay high ^[14].

The rise comes late and fast. The overall at-risk share stays below 10% around midcentury, then climbs rapidly between the 2060s and 2080s ^[14]. Infrastructure can stay in service for 20, 50 or more years ^[11]. A foundation poured in 2026 with a 50-year life would still be carrying load in 2076, partway through that climb ^[1].

The statewide cost estimate covers less than the projection does. A 2025 study put thaw damage at $37 billion to $51 billion for buildings and roads alone ^[1], with $14 billion between the low and high ends ^[2]. Pipelines are outside that range. The Coastal Plain study puts them most at risk of any category, about 90% by the 2090s ^[15], in a region that includes Prudhoe Bay and much of Alaska's oil industry operations ^[13].