In a new report, the American Association of University Professors is warning of a “systemic threat to higher education.”

That’s two in three weeks: last month AAUP warned that current use of Title IX in sexual harassment investigations is trampling academic free speech and due process rights.

Now, according to the group’s just-released “Annual Report on the Economic Status of the Profession,” tenured professors are on track to becoming an endangered species. Over the last 40 years, the proportion of faculty at American colleges and universities holding full-time tenured jobs has dropped 26 percent. And, the group says, things are about to get worse: the share of faculty members in line for tenure is down by a whopping 50 percent.

This won’t come as news to anyone who’s ventured onto a university campus in the last few decades, but, like so many other jobs in America, college teaching has been sliced, diced, and degraded—much of it parceled out at lowest cost to the academic equivalent of migrant workers.

These contingent faculty (who number in the thousands in Chicago) travel from one school to another piecing together a patchwork of part-time assignments to eke out a living. It’s not uncommon for them to wind up teaching more courses in a semester than their counterparts with full-time faculty jobs-for much less money and no benefits.

The average pay for a part-time university faculty member is $16,718. Meanwhile, tuition (and student debt) has skyrocketed. Tuition and fees are up about 28 percent in the last eight years alone. And the average salary for a university president has risen to $485,935.

The AAUP has been watching this problem develop since the 1970s. This year, for the first time, part-time faculty and graduate teaching assistants are included in its annual survey of the financial health of the profession. And their proliferation has become the report’s theme. “The increased reliance on faculty members in part-time positions has destabilized the faculty by creating an exploitative two-tiered system,” with negative effects on research and academic freedom, the report says.

How big is the problem? As of last count (2014), just 21 percent of faculty in higher education were full-time and tenured; 40 percent were part-time and contingent.

Part-timers and graduate students together now account for more than half the U.S. teaching force. And less than one-third of the average institutional budget is spent on instruction.

AAUP says higher education is at a crossroads: it can continue down this sorry path, or it can “take bold steps to rebuild the tenure system that made American colleges and universities the best in the world.” The way to do that, and to retain a “global advantage,” the professors say, is to convert part-time jobs to full-time jobs, and contingent faculty to tenured. AAUP estimates the average cost to convert one part-time faculty member to full-time would be $85,389 annually. At that rate, the group says, the cost of converting all part-time faculty to tenure track assistant professors “would represent 16.93 percent of U.S. higher education expenditures.” Annually.

Too much? Then, how about conversion to full-time instructors with benefits? That, the report says, would add 9.13 percent of total expenditures to the higher-ed budget.

Or how about starting by just converting half? If Ohio State University, for example, converted half of its 1,100 part-time faculty members to assistant professors, the cost would amount to only 1.26 percent of its total mammoth $4.9 billion budget.