BOULDER, COLO. — STUDENTS from all over the United States rallied for Earth at the University of Colorado over the weekend.The second annual Student Environmental Action Coalition (SEAC) conference called "Common Ground" drew some 2,500 students and other activists. Speakers included Noel Brown, North American director of the United Nations Environment Programme, and David Brower of Earth Island Institute. SEAC has grown from four members to 30,000 in two years. Its leaders expect that number to double by the end of this school year. Involving 1,500 campuses, it is estimated by some to be the largest and fastest growing student movement in the US. The SEAC network has begun to touch base with counterparts in at least 30 other nations. The phenomenal growth of SEAC may signal a return to '60s-like youthful social concern. Leaders say SEAC has filled a niche for growing student activism, providing a network and structure for what its members call "positive social change" and upsetting the cynicism and apathy of the past decade. "The need was there before we had the idea" to start SEAC, says national council coordinator for SEAC, Miya Yoshitani. "We didn't choose the issues, the issues chose us, and we acted on that need. There were student organizations on many campuses ... but they acted in isolation." The emphasis at SEAC is on education, says media coordinator Eric Kessler, echoing Mr. Brown's opening-night keynote address. Over 200 workshops covered two broad categories of discussion: global environmental and social justice. The workshops were designed to spell out the problems as they exist around the world from nuclear waste to pesticides to racism and labor resistance to environmental protection. Grass-roots workshops focused on activism - such things as starting and sustaining environmental groups on campus, "eco-feminism," how to get a community involved in recycling, and how to deal with the corporate world. SEAC has also produced a handbook for environmental responsibility called "The Student Environmental Action Guide: 25 Simple Things We Can Do." The book outlines what students can do in their immediate surroundings to recycle, preserve, conserve, and restore the environment. Brown addressed the need to consider issues of social justice as environmental issues. Poor nations depending on cash crops are hard-pressed to exploit their natural resources. People lose jobs when businesses shut down, and human hardship cannot be ignored even for the benefit of the earth, he said. Human economics is part of the environment, Brown added, and must be of major concern to environmentalists. Ms. Yoshitani dislikes terms like "leftist," since politics of the past is really not what SEAC is about, she maintains. Environmentalism crosses party lines and political philosophy, she says, and SEAC ideals are emphatically democratic. "For too long the environmental movement was seen as a white middle-class, middle-aged movement," says Yoshitani. "We want a broad-based movement, a grass-roots movement. We have a very strong involvement by people of color." SEAC expects to work with the UN and send a delegation to the UN's conference on the environment in Brazil next June. The press has consistently pointed to the '60s-like consciousness-raising, the left-of-center politics and rhetoric, and the counter-culture accouterments of the SEAC activists. But SEAC leaders maintain that their movement is not a repeat of the '60s. There is a kinder, and more serious air, a more inclusive attitude than the '60s ever produced, they say. Last year's first SEAC conference and rally was held at University of Illinois at Champaign-Urbana and hosted 8,000 students.