As the adage goes, college students stay for years and faculty for life, but the university stays forever. At least, that’s what Yale is hoping to accomplish with one of the most ambitious sustainability initiatives in University history: its greenhouse gas reduction strategy.

Launched in 2005, the GHG plan commits the University to reducing its carbon dioxide emissions by 10 percent below 1990 levels by 2020, or 43 percent below 2005 levels. The Office of Sustainability announced in August of this year that the University has already cut emissions by 19 percent from 2005 levels­, putting Yale on track to meeting 2020 goals.

Meanwhile, the campus has grown by over 7 percent in the three years since the initiative was announced and will continue to grow, a fact officials point out with pride.

“That’s been tough since [lowering emissions and increasing campus size] are seemingly divergent paths,” senior energy engineer Tom Downing said last year.

Officials said they are positive that at current rates, Yale will meet its reduction goal on time or even early. The University has been reducing emissions from 1990 levels by an average of two percent per year, said Keri Enright-Kato, the project manager at the Office of Sustainability.

“Oh, we’ll meet 2020, sure, we feel very confident,” Downing told the News. “And we have … a framework of a plan on how we’re going to get there.”

That plan depends mainly on lowering energy use and boosting efficiency in buildings on Central Campus, the medical campus and the recently acquired West Campus.

Although the GHG strategy does not encompass emissions from Yale’s fleet of vehicles or from student and employee transportation, buildings are the dominant source of emissions on campus, said Arnulf Grubler, a professor of energy and technology at the School of Forestry & Environmental Studies, who helped compile an inventory of Yale’s emissions in 2005.

“Everything is determined by … the heat energy of the buildings and the power plants that serve the buildings,” Grubler said, adding that the average Yale building consumes “astronomically high” amounts of energy. According to the inventory report, which was based on data from 2002, energy used in Yale buildings — described as “energy dinosaurs” — is up to 18 times that of comparable educational buildings in Europe and twice that of Stanford’s buildings.

Downing said that in addition to renovating existing buildings, University engineers are researching sustainable designs for Yale’s many new construction projects, including the new residential colleges and West Campus. Yale’s campus, which is currently 13.5 million square feet, is projected to expand by 15 percent by 2020.

“Even though those buildings are new and certainly contributing, we’re looking to minimize their impact,” Downing said. “We are looking at campus and as we grow it, certainly to grow it in an energy-efficient manner.”

Enright-Kato added that Yale’s new buildings are constructed according to standards known as LEED — Leadership in Energy and Environmental Design — with six buildings in the design stage that meet LEED standards. When it opens this winter, one of Yale’s signature successes in sustainable construction will be Kroon Hall on Science Hill, which is expected to receive a platinum LEED certification for its solar panels, geothermal energy system and rainwater harvesting system. The new building will use nearly two-thirds less energy than other academic buildings here.

Downing mentioned that replacing inefficient systems and equipment may lessen the emissions of existing buildings, especially for labs, which are traditionally the most energy-consuming areas of campus. In addition, he said, engineers are concentrating on recovering and reusing lost heat.

One way to do that, Grubler suggested, is to insulate Yale’s buildings so less heat is needed in the first place, allowing the two campus power plants to burn less fuel. But Grubler added that he had not yet seen a concentrated effort to renovate Yale’s old facilities for greater sustainability, leading him to question how the University would continue to cut emissions.

The inventory used to measure GHG reduction progress, he said, is “very simplistic.”

“It takes the dominant part,” he said. “That’s good, but it’s not complete … you ask the question, well, you’re on track, so why are you on track?”

While officials are pleased with Yale’s progress, they are far from complacent about the GHG strategy, especially because new technology may eventually enable the University to save more energy on the building side, Downing said.

“Based on the information we have, we have a plan, but you know there’s always uncertainty,” he said.