Professor Richard K. Olson's voice swelled with pride as he reached the final stop -- the bathroom -- on a tour of Berea College's newest student housing.

"The throne!" he declared, displaying a massive, cream-colored composting toilet.

With its state-of-the-art wastewater treatment system, recycled wood cabinets and low-energy fluorescent lighting, Berea's $10 million "Ecological Village" represents the cutting edge of environmental architecture. And while this small southern Appalachian college still consumes plenty of natural resources, it has spent several years trying to preserve its surroundings by conserving energy and shifting to recycling.

While Berea has gone further than most, it is hardly alone. After decades of inertia, American colleges and universities have begun to recognize that they have lagged behind the corporate world in tackling energy conservation and efficiency, greenhouse gas emissions and trash generation, and many are taking new steps to minimize their environmental "footprint."

From the College of the Atlantic's zero-waste graduation this month in Maine to Ball State University's biodiesel-powered shuttle fleet in Indiana, schools are moving in ways large and small to cut energy use and carbon dioxide emissions.

They are driven by everything from the rising cost of natural gas to student activism, and the consequences can be significant for local air pollution as well as energy markets: Yale University emits as much as 2.3 million tons of carbon dioxide each year, more than 32 countries, but that's a 13 percent drop from its 1990 levels. Harvard University, meanwhile, now ranks as the country's second-largest university buyer of renewable energy.

"Those of us who study the environment but don't incorporate what we know into how we operate as an institution, we are failing in our educational task," said Berea College President Larry D. Shinn, who has made environmental sustainability central to his school's mission. "Most of us humans, especially Americans, don't understand what a precarious situation we're in relative to human-nature interactions."

It is difficult to gauge how green academia has become, because no one keeps overall statistics on this aspect of the 4,100 U.S. schools' operations. But across the country, college administrators are vying to outdo each other in environmental consciousness, sharing their strategies and boasting about their accomplishments. They are hiring "sustainability coordinators," negotiating new purchasing contracts and building more energy-efficient laboratories and dormitory rooms.

"It's almost like an episode of 'Can You Top This?' " said Princeton University dining services director Stuart Orefice, whose cafeterias serve cereal grown without pesticides and ship students' unused food to local pig farms. "It's a good-natured competition, if you will."

"Every college and university should be doing this," said Walter Simpson, university energy officer at the State University of New York at Buffalo. "There's no excuse for sitting on your hands and not engaging in energy conservation."

Tufts University committed six years ago to meet or beat the emission reductions outlined in the Kyoto Protocol, an international climate change treaty that the Bush administration disavowed in 2001. In 2003, Tufts President Lawrence S. Bacow went even further by pledging to cut its emissions by 10 percent below the 1990 level by the year 2020.

Tufts now trades its carbon emissions on the Chicago Climate Exchange, where participants can "trade" allowances of greenhouse-gas emissions. Because some polluters produce more emissions than are legally allowed, they can go to the exchange and, in effect, buy from other participants who fell short of their cap on emissions.

"We're greener than Harvard, without a doubt," boasted Sarah Creighton, project manager for Tufts' Climate Initiative.

Tiny Berea plans to reduce its energy consumption 45 percent by 2015 by retrofitting its buildings and shifting from an old coal-fired plant to a gas-fired one half the size. It has embarked on a massive renovation project that will eliminate the need to heat or cool its administrative offices at least three months of the year.

The 1,500-student college's most radical project is Ecovillage, a complex of 32 townhouses, a day-care center, community house and teaching facility where single mothers, married couples and a few other students live. The sunny apartments feature energy-storing concrete floors, recycled carpeting and low-flush toilets. Residents hold workshops on green cleaning products.

Many of the students who live there have become environmental proselytizers, telling friends back home that conserving energy does not mean forgoing showers.

"I'm not afraid of the concept now," said Carrie Watson, 23, a senior from Cincinnati who lives in the Ecovillage with her son, Tzuriel, 2. "That's so liberating."

In interviews, a number of university administrators said they felt an obligation to educate their students about the environment, because graduates will become consumers and policymakers.

"We have a profound responsibility to lead society, and one that is very long-lived, that's not determined by the marketplace, that's regardless of what the political leaning of the administration is," said Leith Sharp, director of Harvard's Green Campus Initiative.

Administrators offer several explanations why academic institutions have often acted more slowly than their corporate counterparts. Schools sometimes lack the money to invest in new technology, and some worry about how donors will perceive these expenditures. Berea officials, Olson said, were concerned whether Ecovillage housing would "look too weird" when it was being built.

"I don't think America's colleges and universities are leading the way," said David Krueger, who teaches business and environmental ethics at Baldwin-Wallace College in Berea, Ohio. "American businesses have been [faster to adopt] environment management systems."

But now many colleges and universities are rushing to catch up, and their influence is spreading. Princeton now demands 100 percent postconsumer recycled paper as well as sustainably caught fish from its suppliers, and says it does not pay significantly more for them.

Less wealthy, smaller schools can sometimes pivot more quickly. College of the Atlantic -- where all 280 students major in human ecology -- used utensils, bowls and cups made from compostable starch-based materials for its June 4 graduation. Once graduates and their families finished eating, students and staff threw these items -- along with all the leftover food -- into a campus solar composter built from recycled material.

As a 150-year-old institution that espouses social justice -- it was the first interracial, coeducational college in the South and charges no tuition in exchange for 10 hours a week of campus work -- Berea's officials and students see environmental sustainability as critical to its survival.

Universities do have one advantage over corporations, said Princeton vice president for facilities Michael McKay, because they can afford to think long-term.

"We expect to be here for another 500 years at least," McKay said, "and we'll live with our mistakes as well as our successes."

Staff researcher Karl Evanzz contributed to this report.

At Berea College in Kentucky, Tamara Williams and Carrie Watson work in a garden in exchange for student housing in the Ecovillage on campus.