Titre du document / Document title

Abrupt mid-twentieth-century decline in Antarctic sea-ice extent from whaling records

Auteur(s) / Author(s)

DE LA MARE W. K. ⁽¹⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Australian Antarctic Division, Department of the Environment, Sport and Territories, Channel Highway, Kingston, Tasmania 7050, AUSTRALIE

Résumé / Abstract

A decline in Antarctic sea-ice extent is a commonly predicted effect of a warming climate. Direct global estimates of the Antarctic sea-ice cover from satellite observations, only possible since the 1970s, have shown no clear trends. Comparisons' between satellite observations and ice-edge charts obtained from early ship records suggest that sea-ice extent in the 1970s was less than during the 1930s, an indication supported by limited regional observations. But these observations have been regarded as inconclusive, owing to the limited spatial and temporal scope of the early records. A significant data source has, however, been overlooked. The southern limit of whaling was constrained by sea ice, and since 1931 whaling records have been collected for every whale caught, giving a circumpolar coverage from spring to autumn until 1987. Here, an analysis of these catch records indicates that, averaged over October to April, the Antarctic summer sea-ice edge has moved southwards by 2.8° of latitude between the mid 1950s and early 1970s. This suggests a decline in the area covered by sea ice of some 25%. This abrupt change poses a challenge to model simulations of recent climate change, and could imply changes in Antarctic deep-water formation and in biological productivity, both important processes affecting atmospheric CO₂ concentrations.

Revue / Journal Title

Nature    ISSN  0028-0836   CODEN NATUAS 

Source / Source

1997, vol. 389, n^o6646, pp. 57-60 (16 ref.)

Langue / Language

Anglais

Editeur / Publisher

Nature Publishing Group, London, ROYAUME-UNI  (1869) (Revue)

Mots-clés anglais / English Keywords

Sea ice

;

Climate modification

;

Southern Ocean

;

Mots-clés français / French Keywords

Glace marine

;

Modification climat

;

Mers Antarctiques

;

Mots-clés espagnols / Spanish Keywords

Hielo marino

;

Modificación clima

;

Mares antárticos

;

Localisation / Location

INIST-CNRS, Cote INIST : 142, 35400006898077.0130