MOSCOW — Russia is preparing to evacuate a drifting Arctic research station that was supposed to last until September because the ice it is built on is starting to break up.
The cracks are another indication of the rapid decline of the Arctic ice sheet — especially so because the encampment is on the Canadian side of the Arctic Sea, where the ice is oldest and most durable.
‘‘It’s a huge loss for us, and for science,’’ Vladimir Sokolov, director of the expedition, said in a phone interview from St. Petersburg, Russia. ‘‘For us, it is very important to get information about the climate system in the high-latitude Arctic.’’
A Russian icebreaker is expected to pick up the station’s researchers in about a week.
The station — the 40th in a string of North Pole drift stations that began in 1937 — went into operation last Oct. 1, later than usual because the leaders of the project had a difficult time finding a sufficiently robust floe to base the camp on.
According to the US National Oceanic and Atmospheric Administration, the extent of sea ice last September was the lowest on record, 18 percent lower than the previous minimum, in 2007.
Last year’s ice conditions, Sokolov said, forced the Russian researchers to look for a base floe closer to Canada than to their own country.
In years past, drift stations have remained in operation for 12 months or longer, with the exception of 2010, when an early breakup also caused a premature evacuation.
One station in the Soviet era, called North Pole-22, was launched Sept. 13, 1973 and stayed in service until April 8, 1982.
Because there is no land at the North Pole, the drift stations provide one of the most important means of studying sea-level conditions. The 16 researchers on North Pole-40 have been collecting data on low-altitude atmospheric conditions, ozone concentrations, ice thickness, sea temperature, and the ocean bottom.
For its first several months, the station drifted in a seemingly aimless fashion, about 85 degrees North latitude, according to the Arctic and Antarctic Research Institute, the sponsor of the study.
Then from Jan. 1 to May 1 it drifted almost directly due south, to about the 81st parallel, before starting to loop about again. All told, it drifted about 1,000 miles, though it has ended up just over 250 miles from where it began. The research station, like its predecessors, is at the mercy of the movement of the ice sheet.
NOAA’s ‘‘Arctic Report Card’’ notes in particular the decrease in older ice — that is, ice more than four years old. A long-lasting tongue of older ice that extended toward Russia virtually disappeared in 2012. Across the Arctic, older ice accounted for 26 percent of the ice cover in March 1988 and just 7 percent in March 2012.
Russian President Vladimir Putin made May 21 Polar Researchers Day, to honor the St. Petersburg institute. He also called on Russia’s United Shipbuilding Corporation to provide the icebreakers, drilling rigs, and extraction platforms that Russia needs for more efficient exploitation of Arctic resources.
Climate change has been linked by many scientists to the release of carbon into the atmosphere by the burning of fossil fuels, but Putin said the melting ice sheet gives Russia an opportunity, opening shipping lanes and access for drilling.
At a meeting of the Arctic Council in Sweden, Russia, the United States, and other nations recognized the potential threat posed by climate change to the Arctic environment, but did not pursue the issue.