June 30 (Bloomberg) -- A small middle school with plants sprouting on its roof and a research complex at Harvard University with sunlight-harvesting glass-bubble lounges would seem to have little in common. Yet both show how quickly the green revolution in building design is moving -- unleashing architectural inventiveness not seen in 100 years.

Climate change has lent urgency to building-industry efforts that have simmered quietly for years. This fall, when students return to Sidwell Friends, a private K-12 school in Washington, D.C., they'll check rooftop succulents that are now three seasons old.

The plants are a teaching tool, though they also harvest rainwater and add insulation. They are among a wide array of devices that reduce energy and otherwise soften the school's effect on the environment.

Sidwell was a pioneering effort all of two years ago. Building green is moving so quickly that it's now seen as mainstream.

Harvard wants to be the Sidwell of the university set. It's building a new $1.2 billion, four-building science complex in Boston where swooping bridges and bubble-shaped winter gardens will emerge from sober, four-story limestone rectangles. This is style that, in green terms, ``does everything,'' said the architect, Stefan Behnisch of Behnisch Architekten in Stuttgart, Germany.

Sidwell Expansion

Both Sidwell and the Harvard complex are called platinum buildings in green parlance. That refers to the top rating in the U.S. Green Building Council's voluntary Leadership in Energy and Environmental Design program, or LEED. Sidwell was the first school to secure a platinum rating, a very demanding standard.

Philadelphia architecture firm Kieran Timberlake added wings to a small brick building at Sidwell to make a casual, open U. It faced one part with a handsome fretwork of angled vertical boards to deflect unwanted summer sun.

Sidwell's kids happily act as docents. On a tour, one child volunteered that the chimes I heard tinkling in the science-wing hallway signaled that the solar chimney was working. This device eliminates air-conditioning by using the buoyant effect of sun- warmed air to draw ventilating breezes into the classroom.

Horizontal shelves in the hallway bounce daylight inward, which makes the school a pleasant place -- and light fixtures are rarely needed.

Bleachers were recycled as window sills. An enhanced- efficiency heating and cooling system saves energy.

Upfront Costs

According to Rachel Gutter, the schools sector manager at the Green Buildings Council, public systems in five states and the District of Columbia have committed to various levels of LEED certification.

``Sidwell Friends raised the bar,'' she said.

Michael Saxenian, assistant head of Sidwell and its chief financial officer, said there was a long debate about how green to go, with the school's leadership worrying that the upfront costs might be seen as frivolous. With energy prices soaring, Sidwell's commitment now seems prudent.

Architects are also learning how to build-in low-energy tactics for less, according to architect Stephen Kieran. He said optimizing the building's orientation to the sun can be complex to analyze but cost nothing extra to build.

Student Activism

Pushed by student and academic activism, universities compete to out-green each other. Harvard's science complex became a showcase because it will inaugurate the university's new 200- acre Allston campus when it is completed in 2011. When the campus is built out 30 years from now, Allston will add 10 million square feet across the Charles River from the Cambridge campus.

Behnisch's low-rise buildings, which will house stem-cell research and other science programs, shift horizontally like a stack of limestone-and-glass dominos. Calibrated to changes in the sun's angle, the overlaps protect labs and offices from unwanted heat and glare while letting in ambient light. The plant-filled gardens draw sunlight, controlled by reflective louvers, into collaboration-enhancing lounges and cafes.

Behnisch stretches hallways into tapering tubular bridges that link the buildings like stretched musculature. These are among the spaces that will be minimally heated and cooled, saving more energy.

Who says green buildings must look like windmill-decorated bunkers?

Saving Energy

The laboratories in the 1-million-square-foot science complex are especially difficult candidates for green design because so much research is undertaken in controlled environments that demand enormous amounts of energy-intensive heating and cooling. Behnisch, working with Payette, a local lab-design expert, discovered they could drastically reduce the space dedicated to the most exacting lab functions. That choice alone will cut energy use some 70 percent.

Green-building advocates don't yet know how to design buildings that are truly carbon-neutral. (That means using no fossil fuels or electricity generated off-site.) Yet now they know they can get close -- which could not be claimed persuasively when Sidwell Friends opened such a short time ago.

With a little school and a gigantic university pushing this trend, green building's massive potential may trickle down fast.

(James S. Russell is Bloomberg's U.S. architecture critic. The opinions expressed are his own.)

To contact the writer of this story: James S. Russell in New York at jamesrussell@earthlink.net.

Last Updated: June 30, 2008 08:35 EDT