By diving into archives, scientists confirmed that floes are melting faster than ever before.

By Marlene Cimons, Nexus Media News

When retired Canadian meteorologist Michael Purves transcribes the handwritten notes from an ancient ship’s log, he finds himself transported back in time a century, imagining he is on board an old cutter, a fast-moving patrol boat, as it sails through the Bering Sea.

In August 1919, for example, the cutter Bear, one of the forerunners of today’s Coast Guard, was en route to remote villages north of Nome, in modern-day Alaska, carrying supplies and people when it ran into heavy ice. The crew had no choice but to stop and wait for the winds to shift.

“Stopped, dropped kedge [secondary anchor] to await an easterly shift of the wind, to clear sea of ice for further progress to the northward and eastward,” the Bear’s navigator wrote. “The continual S.W. and South winds have banked ice up along the Alaskan shore, and made an impenetrable barrier… On account of the leaky condition of the boiler, it is not deemed expedient to stand to the northward and westward for a clear passage, because of the liability of strong east winds moving the pack off shore, thereby imprisoning the vessel and making extrication impossible.”

U.S. Coast Guard

“They couldn’t make further progress north because the ice was too solid, and they were afraid of getting trapped in the ice,” Purves said. “The Bear used both sail and steam. With a leaky boiler, they would have to rely on sail, and it would be difficult to extricate themselves from the ice without having reliable steam power.”

The mission of cutters like the Bear was to protect lives and property at sea. That included combatting smuggling and the poaching of marine mammals. Boats like the Bear also brought medical supplies and care to native communities, including in the aftermath of the devastating Spanish Flu epidemic.

Those early navigators continue to serve the country up this day. Though they couldn’t have imagined it, their handwritten chronicles provide 21st Century scientists with important clues about the fate of sea ice under a warming climate.

Until recently, logs like these were not easily accessible, and could only be viewed at the National Archives. But digital imaging—and painstaking work by volunteers like Purves—have enabled scientists to learn about ocean conditions in the 1900s, specifically sea ice.

Before, computer models approximated ice loss based on data obtained from satellites images beginning in 1979 and from fixed instruments and submarine observations. The models could estimate what had the Arctic had looked like a century ago, but until now, they couldn’t confirm their calculations were correct.
Information gleaned from the old logs corroborates computer models generated by the University of Washington’s Pan-Arctic Ice Ocean and Modeling System, or PIOMAS, scientists said. The logs confirm what the models have estimated—that Arctic sea ice loss has been unprecedented.

“The current rate that Arctic sea ice is disappearing is the highest it’s been over the past century-plus,” said Kevin Wood, a researcher at the Joint Institute for the Study of the Atmosphere and Ocean, a partnership between the University of Washington and the National Oceanic and Atmospheric Administration. He said the logs illuminate this fact, and are especially valuable because they had not been used in earlier studies.