A Low Order Theory of Arctic Sea Ice Stability

TL;DR

This paper presents a low-order model analyzing Arctic sea ice stability, highlighting how heat conduction and ice-albedo feedback influence response times and climate state transitions under increasing greenhouse gases.

Contribution

It introduces a simplified coupled sea ice and climate model that captures key physics governing stability and response times as climate warms.

Findings

Stability is primarily controlled by longwave radiation and heat conduction.

Ice-albedo feedback becomes destabilizing as ice cover diminishes.

Response times extend from about 2 to 5 years as the system approaches seasonal ice states.

Abstract

We analyze the stability of a low-order coupled sea ice and climate model and extract the essential physics governing the time scales of response as a function of greenhouse gas forcing. Under present climate conditions the stability is controlled by longwave radiation driven heat conduction. However, as greenhouse gas forcing increases and the ice cover decays, the destabilizing influence of ice-albedo feedback acts on equal footing with longwave stabilization. Both are seasonally out of phase and as the system warms towards a seasonal ice state these effects, which underlie the bifurcations between climate states, combine exhibiting a "slowing down" to extend the intrinsic relaxation time scale from ~ 2 yr to 5 yr.