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Early explorer logbooks reveal Antarctic sea ice has barely changed in 100 years

Submitted by: Odio @ 08:46 AM | Friday, November 25, 2016 | (url: http://www.scienc...)

Logbooks from the likes of Captain Robert Scott and Sir Ernest Shackleton - key figures in the 'Heroic Age' of Antarctic exploration - have revealed that sea ice levels in Antarctica have barely changed over the past century, despite global temperatures hitting record highs year after year.

That finding might seem counterintuitive, especially given that sea ice in the Arctic has never been so depleted. But it might actually help us explain one of the biggest mysteries surrounding climate change: how Antarctica appears to be thriving - and sometimes even expanding - despite all odds.

"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," says lead researcher Jonathan Day from the University of Reading in the UK.

Day and his team examined observations of sea ice recorded in the official logbooks from 11 voyages that took place between 1897 and 1917, including three missions led by Captain Scott, two by Shackleton, and sea-ice records from French, German, and Belgian explorers.

These logbooks include observations of many environmental and meteorological phenomena, recorded several times a day throughout each mission by the explorers and their crew.

Many of the logbooks had been recently digitised as part of the International Comprehensive Ocean-Atmosphere Data Set initiative, but others were digitised especially for this study, and the information within was collated into a dataset of 191 observations of sea ice positions spanning two decades.

These observations were then compared to satellite data from 1989 to 2014, and other than the sea ice edge in the Weddell Sea declining by about 14 percent over the past century, the team found that ice conditions during the golden age of exploration were surprisingly similar to those in Antarctica today.