Rapid Viscoelastic Deformation Slows Marine Ice Sheet Instability at Pine Island Glacier

• Main Authors: Kachuck, SB, Martin, DF, Bassis, JN, Price, SF
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2020
• Subjects: marine ice sheet instability; solid Earth feedback; glacial isostatic adjustment; mantle rheology; West Antarctica; Pine Island Glacier; Meteorology & Atmospheric Sciences; Amundsen Sea; Misi; Antarc*; Antarctica; Ice Sheet; Pine Island
• Online Access: https://escholarship.org/uc/item/5mv7v85d

The ice sheets of the Amundsen Sea Embayment (ASE) are vulnerable to the marine ice sheet instability (MISI), which could cause irreversible collapse and raise sea levels by over a meter. The uncertain timing and scale of this collapse depend on the complex interaction between ice, ocean, and bedrock dynamics. The mantle beneath the ASE is likely less viscous (∼1018 Pa s) than the Earth's average mantle (∼1021 Pa s). Here we show that an effective equilibrium between Pine Island Glacier's retreat and the response of a weak viscoelastic mantle can reduce ice mass lost by almost 30% over 150 years. Other components of solid Earth response—purely elastic deformations and geoid perturbations—provide less stability than the viscoelastic response alone. Uncertainties in mantle rheology, topography, and basal melt affect how much stability we expect, if any. Our study indicates the importance of considering viscoelastic uplift during the rapid retreat associated with MISI.