Editor’s note: This is the fourth in an occasional series of stories on the measures that individual Schools at Harvard are using to reduce greenhouse gas emissions.

Harvard’s School of Engineering and Applied Sciences (SEAS) is a rigorous world of applied mathematics, materials science, bioengineering, and other demanding disciplines.

But it is also a world in which nearly every common space includes green laminate signs or motion-control sensors to turn off lighting. The collective message: Be green.

Turn off the lights, wear a sweater, shut the sash on your fume hood. It’s not rocket science. Or, as they say at SEAS: It’s not quantum physics.

But simple steps like these — along with exacting building standards and other technical measures — have helped SEAS to reduce its greenhouse gas (GHG) emissions 11 percent from fiscal 2006 to fiscal 2009. That kind of progress also owes a lot to University-wide measures to save energy, said Edward P. Jackson, SEAS director of physical resources.

That number puts the School on track to meet the University’s ambitious GHG emissions goal of a 30 percent reduction by 2016, inclusive of growth, with 2006 as the baseline year.

SEAS tightened the University-wide standard for temperature set points by adjusting heating and cooling systems to start later and finish earlier. “We did it, and waited for complaints,” said SEAS manager of facilities Donald Claflin. “And there weren’t many.”

Saving energy is everybody’s business, from big energy systems to students who pause to shut off the lights. “It’s a lot of little pieces,” he said. “Everybody’s involved. Everybody’s a player.”

On the technical side, SEAS has installed efficient lighting in its five buildings, and on the two floors it leases at 60 Oxford St. It has also implemented an automated energy management system in the Maxwell Dworkin building, and examined its operating system through the lens of energy savings. By this fall, SEAS will have motion-detection sensors on lights in all of its operation.

“It’s many small steps,” said Fawwaz Habbal, SEAS executive dean. “Little drops of water on a stone will eventually make a mark.”

This kind of effort — assess, innovate, invent — is perfect for engineers, he added. “You give us a problem and we solve it.”

SEAS students, faculty, and staff also are exploring other pathways to sustainability. Some are personal-scale pathways. Custodian Joanne Carson sets aside coffee grounds in a composting bowl in the kitchen at Pierce Hall. People take them home for their gardens, she said.

Other pathways are on a bigger scale. For one, in fiscal 2009, SEAS recovered 60 percent of its recyclable waste, piling up 73 tons for the blue bin.

All SEAS buildings are covered by a green cleaning program that minimizes chemical use. And four LEED projects are under way at SEAS; one more is complete. (LEED stands for Leadership in Energy and Environmental Design, a professional U.S. rating system for sustainable building.)

The SEAS Computing and Information Technology office has already been converted from 2,000 square feet of lounge space to three energy-efficient offices in Maxwell Dworkin.

At SEAS Northwest Labs B1, a LEED project now under construction will bring together researchers in medicine, engineering, biology, and applied sciences.

Renovations are ongoing at the SEAS Vlassak Lab and the Weitz Lab, both in the Gordon McKay Laboratory of Applied Science on Oxford Street. LEED-standard renovations are also taking place in two engineering science laboratories at 58 Oxford St.

“Labs are really challenging,” said Habbal. At SEAS, they are energy-intensive hives of complicated gear, from computers, fume hoods, and imaging systems to quantum-cascade lasers.

In addition, SEAS researchers there are looking into new sources of energy, African water resources, efficient computing, carbon sequestration, and the chemistry of climate change.

Sustainability, said SEAS administrative director Jennifer Casasanto, “is part of our dialogue.”

Sustainability is also about encouraging ideas. That means student involvement.

SEAS is part of an arts-science collaboration that helps students and faculty turn their ideas — many of them about green technology — into practical reality. The Laboratory at Harvard, located in the Northwest Science Building, is run by SEAS faculty member David Edwards, Gordon McKay Professor of the Practice of Biomedical Engineering, along with SEAS staff member Hugo Van Vuuren.

A couple of ideas have already reached reality. One is the sOccket, a portable energy-making device shaped like a soccer ball. Kick, dribble, or throw it around, and the sOccket — rigged with inductive coil technology — stores energy. Prototypes have been tested in South Africa and Kenya.

Also, SEAS student Henry Xie ’11 developed the Harvard Reuse List, an online supply swap for students and staff.

Traditional classroom work touches on sustainability, as well. The oldest such class — and “a capstone experience for students,” said Habbal — is Engineering Science (ES) 96.

Students take on real-world issues at Harvard, then produce book-length recommendations for action. Past examples include energy use at Pierce Hall, the Blackstone complex, and Harvard athletic facilities and Houses.

SEAS classes in applied mathematics, environmental engineering, and climate studies deal with sustainability too.

It’s an issue that requires cooperation, awareness, collective action, and intensive study. “The bottom line,” said Habbal, “is mindset.”

Living the lessons we have learned