A recent study has shown that Malaspina Glacier, Alaska’s largest Piedmont glacier, is more at risk from seawater intrusion than previously thought.
The glacier lies below sea level, and channels undercut its bulk, allowing the ocean to enter it should the coastal barrier erode. Malaspina’s loss could lead to significant sea-level rise. Rising global temperatures are causing the permafrost zone in front of the glacier to waste away. Historical satellite imagery has shown water bodies in front of the glacier expanding over time, forming a lagoon system and eroding its coastal barrier.
To estimate Malaspina’s future, the researchers used the Arizona Radio Echo Sounder (ARES), mounted in an airplane as part of Operation IceBridge. While the airplane crisscrossed the glacier, the ice-penetrating radar “x-rayed” it, resulting in a “3D body scan” of the glacier and underlying bedrock.
They conclude that Malaspina alone could raise the global sea level by 1.4 millimeters, or just under 1/16 of an inch, and contribute 560 cubic kilometers, or 134 cubic miles, of ice to the ocean.