At the time of publication, over 30 students were still occupying Massachusetts Hall, which houses administrative offices, including that of President Drew Faust.

Jasmine Opie, member of Divest Harvard, told Common Dreams over the phone that the direct action is "open-ended" and students are prepared to stay the night. The mood at the protest is "excited and enthusiastic," said Opie, despite the administration's refusal, so far, to engage in meaningful and transparent discussions with demonstrators.

The protest is timed to coincide with Global Divestment Day on Friday and Saturday, which will see more than 400 actions and protests sweep the world, from France to Australia to South Africa. The growing international push to divest has already won significant victories, including the agreement of over a dozen U.S. universities, the World Council of Churches, and the British Medical Association to withdraw their funds from oil, gas, and coal companies.

Harvard students say they hope their campaign can make a meaningful contribution to these international efforts.

"By investing in fossil fuel companies, Harvard jeopardizes the future of its students and the world," Sima Atri, a third-year student at Harvard Law School, said in a press statement. "Our action today is not just about climate change, but about larger issues of injustice. We refuse to stay silent as Harvard profits from business practices that are causing disproportionate harms on already marginalized communities."

The sit-in stems from nearly three years of active organizing at the Boston-area campus to demand that Harvard immediately halt new fossil fuel investment, withdraw its current holdings of $79.5 million in the top 200 publicly traded fossil fuel companies, and within the next five years, reinvest this money in "socially responsible funds."

The campaign has already garnered broad support from undergraduates, alumni, and faculty. Over 230 faculty members have signed onto an open letter to the President and fellows urging the institution to divest. "We know that fossil fuel use must decrease," the letter states. "To achieve this goal, not only must research and education be pursued with vigor, pressure must also be exerted."

In November 2014, Harvard students sued the corporation to compel it to divest, alleging that the "Corporation’s funding of global warming harms its students and future generations."

Last May, students blockaded the office of President Faust demanding a real debate on divestment.

While campaigners have been repeatedly rebuffed by administrators, they vow to continue their efforts.

"After three years of conversations that led nowhere, merely requesting further discussion is both insufficient and disrespectful to the communities who bear the direct consequences of the fossil fuel industry’s actions," Divest Harvard declared in an article released Thursday. "Harvard’s actions must reflect the urgency of the global need for action."

Updates and reports on the sit-in are being posted to Twitter: