A polar research vessel has broken free from Arctic pack ice and returned home to Europe, after spending more than 500 days drifting across the High Arctic.

The schooner Tara, which was supported by the European Union, drifted almost 4,000 kilometres across the Arctic Ocean as scientists on board fed climate change data to 48 European laboratories.

The ship returned to its home port Saturday in Lorient, France. Its voyage began in September 2006, when an icebreaker helped position the Tara north of Siberia. Then, the crew waited for the pack ice to freeze around the ship.

"When you're in the Arctic, the High Arctic, you have an incredible sense … of freedom," expedition leader Grant Redvers of New Zealand told CBC News in an interview.

"It's just a huge expanse of frozen ocean, so for me it was more a sense of freedom than being trapped or confined."

Redvers said the Tara drifted faster than expected, likely because the ice was thinner and more mobile due to climate change. At one point, it was just 160 kilometres from the North Pole — the northernmost position ever reached by a schooner, he said.

"We positioned ourselves in the beginning of winter, and we waited for the ice to freeze around Tara. And then we were basically transported across the North Pole, from a position just north of the New Siberian Islands to the Fram Strait between Greenland and Svalbard," he said.

"So we drifted with the ice pack. It was a fantastic expedition. We spent two winters and one summer in the Arctic, almost a year and a half."

The Tara expedition was France's major contribution to International Polar Year research efforts, with funding from the European Union, its member states and even the French fashion designer Agnès B.

The data gathered during the voyage is currently being analyzed, with the goal of better forecasting climate in the changing Arctic environment, Redvers said.

"We were undertaking a number of different experiments throughout the duration of our expedition, from a depth of three and a half thousand metres in the ocean to a height of 2,000 metres in the atmosphere," he said.

"So we were basically characterizing climate warming in the Arctic region."