A younger, thinner Arctic ice cover: Increased potential for rapid, extensive sea‐ice loss

TLDR

Satellite‐derived estimates of sea‑ice age and thickness are combined to produce a proxy ice‑thickness record for 1982 to the present. The analysis reveals that the oldest and thickest multiyear ice has largely vanished, with 58 % now only 2–3 years old versus 35 % in the 1980s, and that the 2007 record minimum saw a 42 % decline in extent, driven by the loss of old ice and ice‑transport processes that amplify the albedo feedback.

Abstract

Satellite‐derived estimates of sea‐ice age and thickness are combined to produce a proxy ice thickness record for 1982 to the present. These data show that in addition to the well‐documented loss of perennial ice cover as a whole, the amount of oldest and thickest ice within the remaining multiyear ice pack has declined significantly. The oldest ice types have essentially disappeared, and 58% of the multiyear ice now consists of relatively young 2‐ and 3‐year‐old ice compared to 35% in the mid‐1980s. Ice coverage in summer 2007 reached a record minimum, with ice extent declining by 42% compared to conditions in the 1980s. The much‐reduced extent of the oldest and thickest ice, in combination with other factors such as ice transport that assist the ice‐albedo feedback by exposing more open water, help explain this large and abrupt ice loss.