Suddenly, “sustainability” seems to resonate with the sex appeal of “dot com” or “start-up,” appealing to droves of ambitious young innovators. Amelia Byers, operations director for Idealist.org, a Web site that lists paid and unpaid opportunities for nonprofit groups and social enterprise companies — some 5,000 of which are environmental organizations — said the number of jobs related to environmental work has roughly tripled in the last three years. “A lot of new graduates are coming out of a world where volunteerism and service has been something that has helped define their generation,” she said. “Finding a job with meaning is an important value to them.”

The rapid expansion of green jobs isn’t confined to the nonprofit sector. There is money to be made here as well. Ivan Kerbel, director of career development for the Yale School of Management, a graduate-level business program, noted that environmental issues like reducing waste and carbon footprints were increasingly important to corporations of all kinds, something business students are recognizing. Even ultra-ambitious M.B.A. candidates with C-suite aspirations are integrating issues like sustainability into their education, he said.

“The leading companies have taken it on in a way that means you don’t have to feel like you’re self-ghettoized into this functional niche,” he said.

Ms. Byers attributed the growth in part to a generational shift toward “values driven” professions. Unsurprisingly, such jobs are often quite hip.