Students at three major American universities are digging in for a series of prolonged sit-ins and risking suspension and arrest to demand that their schools divest from fossil fuels.

NYU’s protest, which launched Monday, saw students with NYU Divest occupying the administrative elevator and lobby of the school’s Bobst Library to demand the Board of Trustees holds a vote on divestment at its next meeting and allows the group to give them a presentation.

Protests began at Columbia University and the University of Massachusetts-Amherst last week as students demanded their administrations dump “support of global climate disaster, exploitation, and human suffering.”

All three occupations continued on Tuesday as students spent the night in administrative buildings, even as Columbia officials threatened to suspend the seven remaining protesters occupying Low Library.

“I am sitting in because I see climate justice as a human rights issue,” Nikita Perumal, an organizer with Columbia Divest for Climate Justice (CDCJ), told Salon. “It is immoral that Columbia actively profits from an industry that threatens the well-being of vulnerable communities around the world.”

Other organizers said they would not leave until Columbia’s president Lee Bollinger agrees to recommend to the Board of Trustees that the school divest its $9.2 billion endowment from the top 200 publicly-traded fossil fuel companies.

“Suspension threats are the administration’s way of bullying us out of Low Library,” CDCJ organizer Lucas Zeppetello, who is participating in the sit-in, said Monday. “They seek to drain our morale and demoralize the group. This strategy has failed largely due to the support we have received from on campus groups dedicated to peaceful protest.”

In fact, more than 60 professors, staff, and other faculty members from Columbia and Barnard (the woman’s liberal arts college affiliated with Columbia) published a letter of support for the students on Monday, calling on Bollinger to “directly and immediately” engage with the protesters.