Seasonal and Regional Manifestation of Arctic Sea Ice Loss

Ingrid H Onarheim,Tor Eldevik,Julienne C Stroeve,Lars H Smedsrud

doi:10.1175/jcli-d-17-0427.1

Ingrid H Onarheim, Tor Eldevik + Show 2 more

Open Access

https://doi.org/10.1175/jcli-d-17-0427.1

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Abstract

The Arctic Ocean is currently on a fast track toward seasonally ice-free conditions. Although most attention has been on the accelerating summer sea ice decline, large changes are also occurring in winter. This study assesses past, present, and possible future change in regional Northern Hemisphere sea ice extent throughout the year by examining sea ice concentration based on observations back to 1950, including the satellite record since 1979. At present, summer sea ice variability and change dominate in the perennial ice-covered Beaufort, Chukchi, East Siberian, Laptev, and Kara Seas, with the East Siberian Sea explaining the largest fraction of September ice loss (22%). Winter variability and change occur in the seasonally ice-covered seas farther south: the Barents Sea, Sea of Okhotsk, Greenland Sea, and Baffin Bay, with the Barents Sea carrying the largest fraction of loss in March (27%). The distinct regions of summer and winter sea ice variability and loss have generally been consistent since 1950, but appear at present to be in transformation as a result of the rapid ice loss in all seasons. As regions become seasonally ice free, future ice loss will be dominated by winter. The Kara Sea appears as the first currently perennial ice-covered sea to become ice free in September. Remaining on currently observed trends, the Arctic shelf seas are estimated to become seasonally ice free in the 2020s, and the seasonally ice-covered seas farther south to become ice free year-round from the 2050s.

Highlights

The rapid decline of Arctic sea ice is one of the clearest indicators of ongoing climate change (Serreze and Barry 2011)
To evaluate whether the summer and winter contrasts in the satellite era, presented here, are consistent in a longer time frame, we examine the gridded synthesis based on historical observations from 1950 to date provided by Walsh et al (2015)
If the Northern Hemisphere sea ice loss persists, the Arctic Ocean will become seasonally ice free, and further reduction of sea ice extent will have to be increasingly concerned with wintertime change

Summary

15 JUNE 2018

University College London, London, United Kingdom, and National Snow and Ice Data Center, Boulder, Colorado (Manuscript received 24 June 2017, in final form 14 March 2018)

Introduction

Data and methods

Seasonal asymmetry in summer and winter modes

Future perspectives

Findings

Summary and conclusions