PROBLEM AND PROPOSAL

Because of global warming, the Arctic ice cap has been receding at about 8% in area per decade for the past thirty years.1 Loss of the ice cap was initially estimated by computer models to occur by 2100; however, now total loss in summer will be as soon as 2040 [2, 3]. Experts have predicted drastic reductions in arctic ecosystem populations which use the ice as a platform, including the possible extinction of polar bears [4, 5]. Drowned bears have already been observed as swimming distances to sound pack ice increase.6 With summer ice breakup coming seven to eight days earlier each decade, the end of ringed seal weaning season will start to be interrupted as soon as 2035 [7, 8] As has been documented already, pups born in the water rather than on ice will drown.9 Some native tribes along the Alaskan north shore also rely on seals for subsistence hunting.

Simplified trophic levels in the Chukchi/Beaufort Sea area.

Illustration by the author with images from a number of sources.

A NOAA scientist has stated that greenhouse gases already in the atmosphere will continue the warming trend for the next fifty years no matter how emissions are curtailed.10 If the arctic ecosystem is to be kept from substantial collapse in the next twenty to forty years, some interim measure is required until longer term solutions take effect. This paper proposes construction of pilot networks of platforms moored to the continental shelf of Alaska to form sea bridges/archipelagos for shelter, hunting and denning. (Fig. 1 and 2). Placed by ship, the platforms would use remotely operated vehicle (ROV) technology to submerge during the current complete winter freezes and surface during the iceless summers. If engineered with a design life of one-hundred years and then reproduced in other arctic regions, the global community would be given a reasonable amount of time to implement changes in energy production, and reverse global warming. The cost of the prototype project shown would be at least $300 million.11 12

Proposed network of floating platforms with simplified migration patterns of marine mammals

NETWORK LEVEL CONTEXT AND DESIGN

Most bears currently stay with the pack ice as it recedes and expands over the seasons. 13 So only a small number would be helped by bridges or linear archipelagos to land.14 However, bridges from the pack ice to the water over the shelf would be essential since eventually the ice edge will lie continually north of the shelf‘s food chain, and the seals - and in turn their predators - will begin to starve from lack of access. Finally, there will be no ice at all to stay with - approximately 2040. Without any sea bridges, those (excluding perhaps adult seals) that have stayed with the ice and not starved will finally drown. Array spacing at north and south extremes of any bridge would start at approximately a half mile in each direction to ensure bear cubs and foxes can manage the swim and are visually attracted out onto the water. Spacing would increase but never exceed ten miles to limit energy expenditure, hypothermia risk, ensure mutual sent detection (bears can smell a seal at twenty miles), and limit cost.15

Platform and Array Concepts

Due to current winter freezing (Nov-June), the platforms must be submersible to avoid dragging by drifting pack ice (Fig. 2). The platforms surface just beyond the fast ice in early summer where the water opens up first, and replace the lost ice as it recedes northward. As the winter freeze moves southward again in November, the platforms submerge to a depth of sixty feet in reverse order towards the coast.16 As a backup, if submersion fails, the sloped topsides redirect enclosing ice pressure downward so the platforms are pressed below any enclosing ice and not damaged. Landfast ice that occurs in less than 30 ft water depth is not suitable for platforms due to likely ice damage – keel gouging or full depth freezing. Gravel islands may be the best approach for creating platforms here. Platforms are interchangeable and configurations can be rearranged as conditions change.

Array Level Design

Polar bears use pack ice as a horizontal hunting blind to surprise seals at breathing holes or ice cracks. This strategy is essential to their survival as they are easily out maneuvered once in the water. Linked, octagonal platforms recreate blinds and the sheltered interior openings to the water recreate ice openings that seals and walruses prefer for basking in the sun with the assurance of a quick escape.

Platform Level Design

Each octagonal platform sits low in the water with sloped sides to be easily climbed onto.17 Marine grade 5083 aluminum is a proven maintenance free material for sea vessels, and marine grade rigid insulation infills the aluminum framing to provide buoyancy, structure for water pressure and thermal insulation. White top surfaces, gently sloped toward the sea are self-cleaning under rain or melting snow, and textured to provide traction for hauling out. 16