School districts around the country, forced to resort to drastic money-saving measures, are warning hundreds of thousands of teachers that their jobs may be eliminated in June.

The districts have no choice, they say, because their usual sources of revenue—state money and local property taxes—have been hit hard by the recession. In addition, federal stimulus money earmarked for education has been mostly used up this year.

As a result, the 2010-11 school term is shaping up as one of the most austere in the last half century. In addition to teacher layoffs, districts are planning to close schools, cut programs, enlarge classes and shorten the school day, week or year to save money.

“;We are doing things and considering options I never thought I'd have to consider,”; said Peter C. Gorman, superintendent of the Charlotte-Mecklenburg schools in North Carolina, who expects to cut 600 of the district's 9,400 teachers this year, after laying off 120 last year. “;This may be our new economic reality.”;

Districts in California have given pink slips to 22,000 teachers. Illinois authorities are predicting 17,000 job cuts in the public schools. And New York has warned nearly 15,000 teachers that their jobs could disappear in June.

Secretary of Education Arne Duncan estimated that state budget cuts imperiled 100,000 to 300,000 public school jobs. In an interview on Monday, he said the nation was flirting with “;education catastrophe,”; and urged Congress to approve additional stimulus funds to save school jobs.

“;We absolutely see this as an emergency,”; Duncan said.

Everywhere, school officials tend to overestimate the potential for layoffs at this time of year, to ensure that every employee they might have to dismiss receives the required notifications.

Whether the current estimates rise or fall will depend in part on labor negotiations under way in hundreds of districts, and on how taxpayers vote on school levy proposals in many states and towns. But those adjustments will affect the likely layoff numbers only at the margins.

Some of the deepest cuts are in Los Angeles, where Superintendent Ramon C. Cortines sent notices to 5,200 of the district's 80,000 employees last month, telling them that they were losing their jobs.

“;I've been superintendent in five major school districts, and had responsibility for cuts for years—but not this magnitude, not this devastating,”; Cortines said.

And there is no end in sight, he said. He cut his district's $12 billion budget this school year by $1 billion, has prepared $600 million in cuts for the term beginning in the fall and is looking ahead to a deficit for the following year of $263 million.

“;I don't see this being over in the year 2014-15,”; Cortines added.

In the economic stimulus bill passed in February 2009, Congress appropriated about $100 billion in emergency education financing. States spent much of that in the current fiscal year, saving more than 342,000 school jobs, about 5.5 percent of all the positions in the nation's 15,000 school systems, according to a study by the Center on Reinventing Public Education at the University of Washington.

States will spend about $36 billion of the stimulus money in the next fiscal year, leaving their budgets short by some $144 billion, according to the Center on Budget and Policy Priorities, a liberal-leaning research group.

About a quarter of all state spending goes to public schools, said Jon Shure, a state fiscal expert at the center, so without new aid, the continuing job losses will add to the nation's employment woes.

Warning of an educational emergency, Sen. Tom Harkin, D-Iowa, proposed a $23 billion school bailout bill last Wednesday that would essentially provide more education stimulus financing to stave off the looming wave of school layoffs.

“;This is not something we can fix in August,”; said Harkin, chairman of the Senate education committee. “;We have to fix it now.”;

Michael J. Petrilli, who served in the Education Department under President George W. Bush, predicted that the bill could attract significant support. But even if it is approved, Petrilli said, it would leave an underlying problem unresolved.

“;Is the federal government going to try to prop up states and districts forever?”; he said. “;If not, we're just kicking the can down the road. Eventually, districts need to learn to live with less.”;

Senior Democratic aides said that because Harkin's bill would add to the deficit, it was unlikely to pass.

A survey by the American Association of School Administrators found that 9 of 10 superintendents expected to lay off school workers for the fall, up from two of three superintendents last year. The survey also found that the percentage considering a four-day school week had jumped to 13 percent, from 2 percent a year ago.

One of those districts is Atwater-Cosmos-Grove City in Minnesota, which has asked the state to let it shorten the school week. The district's business manager, Dan Tait, called the measure “;another tool in the toolbox”; for reducing costs.

“;We're a district that's spread across 340 square miles, so we spend an inordinate amount of money on transportation for our 812 students,”; Tait said.

The current round of cuts is particularly wrenching, superintendents said, because their financing was already cut to the bone last year. For example, Barbara Thompson, superintendent of the Montgomery public schools in Alabama, said the state used to give her district $975 per student for supplies, technology and library costs.

“;They cut it to zero,”; Thompson said. “;So they can't cut it any more.”;

Not all school systems are in trouble. State mineral revenues, for instance, have largely spared Montana, North Dakota and Wyoming from serious belt-tightening.

But they are the exceptions. In early April, the Flagstaff, Ariz., school district's preliminary list of people who might not have jobs next year included almost a third of its 1,500 employees—every art, music and physical education teacher, every counselor and librarian, every teacher with three or fewer years in the district, and all temporary hires.

By the time reduction-in-force notices went out April 15, though, the number was trimmed to 223 teachers and 47 administrators. And if Arizona voters approve a 1-cent sales tax next month, the cuts will be much less drastic.

In the U-46 district in Elgin, Ill., Jose M. Torres, the superintendent, said he also had to contend with a budgeting roller coaster this spring. At this point, the only uncertainty is whether the district's 53 schools in Chicago's western suburbs will feel “;high pain or low pain,”; Torres said.

Seeking to cut at least $44 million from the district's $400 million budget, Torres has eliminated early childhood classes for 100 children, cut middle school football, increased high school class sizes from 24 to 30 students, drained swimming pools to save chlorine, and dismissed 1,000 employees, including 700 teachers.

“;This stuff really hurts,”; Torres said. And what is worse, he said, “;I think next year will be tougher than this year.”;

David M. Herszenhorn contributed reporting.