Across university campuses in California on Friday, students and faculty members marched, chanted and waved signs in support of the graduate students at the University of California, Santa Cruz who have been waging a months-long strike for a cost-of-living-adjustment amid soaring rents.

But despite that widespread support, many of those same UC Santa Cruz graduate students were readying themselves for the possibility of losing their teaching jobs and being forced to drop out of school.

Since December, 233 graduate student instructors and teaching assistants have refused to submit nearly 12,000 grades from the fall quarter. And as of this month, the strike as expanded to include all teaching and grading duties, with research assistants refusing to do additional work.

The students are striking for a $1,412-a-month cost-of-living-adjustment, something they say they desperately need amid the towering rents in Santa Cruz and the growing housing crisis in California.

Graduate students at UC Santa Cruz currently make $2,434 a month before taxes, but many students “end up spending 50% and oftentimes 60% to 70% of their wages on rent”, said Jane Komori, a third-year graduate student studying the history of consciousness. “This cost-of-living-adjustment is what we would require to no longer be rent-burdened. It’s nothing extravagant. The median rent for a one-bedroom in Santa Cruz is nearly $3,000. We’re not asking for that. We’re just asking enough of a wage increase so we can be out of our rent burden, address our other expenses, and teach and research as we’re meant to.”

Massive march meets the picket line and pours into the streets at UCSC as part of UC-wide action for COLA and to #defendthestrike and #spreadthestrike. @payusmoreucsc pic.twitter.com/gxiBO3K5Di — Will Parrish (@willparrishca) February 21, 2020

Classes and office hours have been canceled throughout the strike. The administration responded with two supplemental programs that will cost about $7m a year – one that will offer a yearly $2,500 need-based housing fellowship and another that offers doctoral students a five-year funding program.

The supplemental programs would not be nearly enough for graduate students to get by in Santa Cruz, Komori said. Two weeks ago, the students escalated their strike, and one week ago, the University of California president, Janet Napolitano, announced that the strike “will have consequences, up to and including the termination of existing employment at the University”.

Lori Kletzer, the executive vice-chancellor of UC Santa Cruz, set a deadline for 11:59pm Friday for all graduate students to turn in their grades. “We are giving these students one final opportunity to fulfill their teaching responsibilities and show that they can fulfill future responsibilities,” she wrote. “Those who do not submit full grade information by February 21 will not receive spring quarter appointments or will be dismissed from their spring quarter appointments.”

For many students, that will mean having to drop out of their programs, Komori said. For international students like Komori, who is from Canada, that can put visas at risk. “It’s a big scary decision for a lot of people, but there’s been a lot of really positive conversations,” she said. “One thing is that our administration hasn’t guaranteed that we won’t face some kind of discipline or retaliation even if we do turn in the grades. We haven’t closed the poll but a good number, potentially a majority of people, still plan on withholding grades and will continue to hold them past the deadline.”

Some graduate students have pledged not to take the teaching assistantships of anyone who has been fired, a move that will have an impact on the next quarter. Komori adds that a mass firing could “significantly affect” the number of courses the school could offer in the next academic quarter.

The graduate students are represented by United Auto Workers Local 2865, which negotiated a contract in 2018 that got them a 3% wage increase and included a no-strike clause – meaning this current strike, known as a “wildcat strike”, has been taken without the union’s approval. More than 80% of the members on campus voted against the contract initially.

The administration has cited this as a reason for not negotiating with the graduate students. “To accede to the demands of a group of employees engaged in an unauthorized wildcat strike would undercut the very foundation of an agreement negotiated in good faith by the UAW and ratified by thousands of members across the system,” Napolitano said.

The administration agrees the “housing crisis is complex, systemic, and at the same time, deeply personal for many”, Kletzer wrote.

“Where we differ, however, is in the approach to solve this problem.”

Meanwhile, the movement is growing. Talk of “spread the strike” has begun at UC Davis, UC Irvine, UC San Diego, UC Riverside and UC Merced, Komori said. On Wednesday, the Democratic presidential hopeful Senator Bernie Sanders tweeted his support.

UCSC grad students are fighting to have their labor rights acknowledged. I strongly urge the president of the UC system to stop threatening them, especially immigrant students, for organizing. I stand with @payusmoreucschttps://t.co/x03yyR70ZT — Bernie Sanders (@BernieSanders) February 20, 2020

“It’s incredibly empowering for people who are getting fired on our own campus to know that there will be major disruption throughout the university system and a ton of pressure on the office of the president when those campuses go on strike with us,” Komori said. “I think if all the campuses stand together on this, they won’t have a choice but to address it.”

• This article was amended on 24 February 2020. The university is called the University of California, Santa Cruz; not the University of Santa Cruz as stated in an earlier version. It was also changed to reflect that some, not all, students have pledged not to take the teaching assistantships of anyone who is fired.