Recent Variations of Sea Ice and Air Temperature in High Latitudes

TLDR

Feedbacks from sea‑ice and snow retreat amplify polar greenhouse warming projected by global climate models. The study examines gridded sea‑ice data alongside air temperature records to detect recent climate change in polar regions. Using a multi‑decadal gridded sea‑ice database covering the Arctic and Antarctic, the authors analyze fluctuations with seasonal‑to‑annual temporal scales and 30°–180° spatial scales, integrating these with temperature data. Arctic sea‑ice changes over recent decades match rising air temperatures, especially over northern land in winter and spring, while summer ice extent has declined with three new minima in 15 years; subarctic sea trends are weaker or negative, and no significant winter or Antarctic ice trends are observed, consistent with coupled atmosphere–ocean model experiments.

Abstract

Feedbacks resulting from the retreat of sea ice and snow contribute to the polar amplification of the greenhouse warming projected by global climate models. A gridded sea-ice database, for which the record length is now approaching four decades for the Arctic and two decades for the Antarctic, is summarized here. The sea-ice fluctuations derived from the dataset are characterized by 1) temporal scales of several seasons to several years and 2) spatial scales of 30°–180° of longitude. The ice data are examined in conjunction with air temperature data for evidence of recent climate change in the polar regions. The arctic sea-ice variations over the past several decades are compatible with the corresponding air temperatures, which show a distinct warming that is strongest over northern land areas during the winter and spring. The temperature trends over the subarctic seas are smaller and even negative in the southern Greenland region. Statistically significant decreases of the summer extent of arctic ice are apparent in the sea-ice data, and new summer minima have been achieved three times in the past 15 years. There is no significant trend of ice extent in the Arctic during winter or in the Antarctic during any season. The seasonal and geographical changes of sea-ice coverage are consistent with the more recent greenhouse experiments performed with coupled atmosphere–ocean models.