Antarctic ice stream thickening under Pliocene warmth

• Ice streams regulate most ice mass loss in Antarctica. Determining their response to Pliocene warmth could provide insights into their future behaviour, but is hindered by poor representation of subglacial topography in ice-sheet models. We address this limitation using a high-resolution regional model for Dronning Maud Land (East Antarctica). We show that the region’s largest ice stream, Jutulstraumen, thickens by 700 m under warm late-Pliocene conditions despite ice-shelf collapse and a retrograde bed slope, while nearby ice streams thin. While it is known that unstable retreat on a retrograde slope can be slowed under certain conditions, this finding illustrates that an ice stream can thicken and gain mass. We attribute thickening to high lateral stresses at its flux gate, which constrict ice drainage. Similar stress balances occur today in 27% of East Antarctica, and understanding how lateral stresses regulate ice-stream discharge is necessary for accurately assessing Antarctica’s sea-level rise contribution.

Subject headings

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Naturgeografi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Physical Geography (hsv//eng)

Keyword

Geography, Physical Geography

geografi med naturgeografisk inriktning

Publication and Content Type

vet (subject category)

ovr (subject category)