Norway this month became an unlikely leader in a growing social movement: persuading investors to sell their stock in fossil fuel companies.

In Norway’s case, its $890 billion pension fund — the largest sovereign wealth fund in the world — will begin divesting itself of its stakes in coal companies. The move, approved by Parliament on June 5, offered a powerful endorsement of a tactic its backers say has the potential to reduce carbon consumption and in that way limit harmful greenhouse gas emissions.

The fossil fuel divestment movement, begun on the campus of Swarthmore College in Pennsylvania in 2011, has gathered force in only four years. AXA, the French insurance group, said it would sell $560 million in coal investments. The Rockefeller family said its enormous philanthropic arm would sell fossil fuel investments, starting with coal. And the endowments of several universities, including Stanford and Syracuse, have purged coal company stocks.

“There’s been a tipping point in the last six months,” Ben Caldecott who researches energy and climate change as director of the Stranded Assets Programme at Oxford University, said in an interview. Coal prices are being hammered. The Dow Jones coal index is down 86 percent since 2011. In a recent securities filing, Peabody Energy, one of the country’s biggest coal producers, recently listed the divestment campaign as a risk factor that threatened its share price.