The effort was led by the environmental group Greenpeace, which bought shares of the oil company to gain voting rights.
The group claims that tar-sand extraction will affect an area the size of Florida, including millions of acres of boreal forest, and will release more than 10 times the greenhouse gases caused by conventional oil drilling.
Although the science behind the environmentalists' claims is contested by the oil industry and some analysts, the central role of oil revenue in the Norwegian economy is much clearer.
Norway invests oil revenues in its government pension fund, also known as the Petroleum Fund, making it one of the largest such funds in the world, with assets worth $14 billion last year.
But the tar-sands investment has provoked environmentalists, who have decried the government's unwillingness to consider what they believe is the particularly severe environmental cost of wrenching oil from sand. The government is a majority shareholder in StatoilHydro, with two-thirds of the stock.
The shareholder motion to disinvest was supported by several Swedish pension funds. It sent other investors in the oil-sands project, including Denmark's Danske Bank, scrambling to consult ethical investment advisers.
"This puts the government in a very strange position now," says Martin Norman, a campaign manager for Greenpeace Nordic.
"On the one hand, they're working very hard to get global commitment to climate-change targets at the Copenhagen climate negotiations this fall. But on the other hand, they have nothing to say about their company's activity in the tar sands."
Not in Norway's backyard?
Like its Nordic neighbors, Norway has long been a proponent of high environmental-protection standards. The country also shares an open electricity market with Sweden, Denmark, and Finland, 50 percent of which is renewable energy, mainly hydroelectric power.
StatoilHydro counters criticism of its tar-sands investment by pointing to its growing portfolio of wind and wave energy projects and its strong environmental record for oil drilling in the North Sea.
"The world needs more energy and less CO2 emissions," says Ola Morten Aanested, a spokesman for StatoilHydro in Norway. "Our operations in the North Sea are extremely CO2-efficient compared to other oil producers around the world, and that's something we can take with us to Canada."
Professor Øystein Noreng, an oil industry expert at the Norwegian School of Management, and an outspoken critic of the environmental movement, says the tar-sands campaign is misdirected.
"Opponents of the tar-sands extraction should focus on the Alberta government and the Canadian federal government, not on investors. Canada is a democratic country with a rule of law, and the oil companies are not doing anything illegal there," Professor Noreng says.
"In any case, if Statoil pulls out, it would be a purely symbolic success for the green lobby," he continues. "There are plenty of other companies from China and elsewhere waiting to take over, so it would have zero effect on the environment. In fact, it could be worse, given that Norway has one of the best records for environmental protection."
Norwegian climate-change activists argue that there is a growing gulf between the country's desire to be seen as environmentally friendly and the power of its oil industry.
"We've not got to the stage yet of debating Norway's oil production in terms of climate change," says Ingeborg Gjærum, leader of Nature and Youth, which is allied to the global organization, Friends of the Earth.
"According to government targets, we will be carbon neutral by 2030, but at the same time, our oil company is intent on exploiting tar sands and pushing for oil drilling in the Arctic."
Nature and Youth won a case at Norway's consumer-complaints tribunal last year when the group challenged an advertising campaign presenting the oil company as a champion of the environment.
Retirement or environment?
Despite the efforts of environmental groups to push climate-change issues up the political agenda, the Canadian tar sands are unlikely to play an important role in Norway's national elections this fall, says Steinar Holden, professor of Economics at Oslo University.
"Norway has a strong economy, mainly because of our oil revenues and budget surplus. Oil production is not seen as a cause of climate change. People see consumption as more of a problem," he explains.
"Only environmental activists are concerned about the tar sands," he says. "People would be more concerned if the stocks invested in the Petroleum Fund did not fulfill environmental standards."
The fund is invested in stocks and securities that meet ethical guidelines.
Greenpeace is also counting on ethical consideration in the next stage of its tar-sands campaign. More than half of all Swedish investment funds – including several StatoilHydro shareholders – have environmental sustainability conditions that may prevent them investing in the oil company. Almost one-fifth of US and European funds have similar rules.
"The truth about tar-sands extraction is out now," says Greenpeace campaigner Martin Norman. "I can't see how any funds can stay invested in tar sands now."