It may be because Antarctic sea ice is much less sensitive to the effects of climate change than that of the Arctic, which in stark contrast has experienced a dramatic decline during the 20th century.
‘The levels of the continent's sea ice in the early 1900s are in fact similar to the present, at between 5.3 and 7.4 million square km.’
Since satellite observations began, Antarctic sea ice has increased slightly over the past 30 years, said lead author Jonathan Day from the University of Reading. "Scientists have been grappling to understand this trend in the context of global warming, but these new findings suggest it may not be anything new," Day added.
The study revealed that the levels of the continent's sea ice in the early 1900s were in fact similar to the present, at between 5.3 and 7.4 million square km. However, Weddell Sea did have a significantly larger ice cover, the study said.
In the study, the team examined the ice observations recorded in the ships' logbooks of explorers such as the British Captain Robert Scott and Ernest Shackleton and the German Erich von Drygalski to compare where the Antarctic ice edge was during the Heroic Age of Antarctic Exploration (1897-1917) and where satellites show it is today.
"The missions of Scott and Shackleton are remembered in history as heroic failures, yet the data collected by these and other explorers could profoundly change the way we view the ebb and flow of Antarctic sea ice," Day said. The study was published in the journal The Cryosphere.