When Jerome C. Ringo joined the board of the National Wildlife Federation in 1995, he was the only African-American at the meetings.
Mr. Ringo, now president of the Apollo Alliance, a coalition of environmental, labor and business groups, says that even today, he is often the only environmentalist in the room who is not white.
"We're not where we were, but we're not where we want to be," Mr. Ringo said of the environmental movement's efforts to diversify.
National environmental organizations have traditionally drawn their membership from the white and affluent, and have faced criticism for focusing more on protecting resources than protecting people.
But with a black president committed to environmental issues in the White House and a need to achieve broader public support for initiatives like federal legislation to address global warming, many environmentalists say they feel pressure to diversify the movement further, both in membership and at higher levels of leadership.
"Our groups are not as diverse as we'd like, but every one of the major groups has diversity as a top priority," said Frances Beinecke, president of the Natural Resources Defense Council. "There's great commitment to making the environmental movement representative of what the country is."
The effort to broaden support comes as the groups find themselves competing with industries that oppose environmental measures, sometimes claiming that they will result in higher energy bills or the loss of jobs.
"The organization has to be able to credibly build trust with communities of color who are going to be targeted by the opponents of change," said Sanjay Ranchod, a member of the Sierra Club board who is leading efforts to attract more minorities.
The need for racial diversity has been a persistent issue in the environmental movement: In 1990, leaders of civil rights and minority groups wrote an open letter that accused the 10 biggest environmental organizations of "racist" hiring practices.
Richard Moore, one of the letter's signers, said the public indictment was set off by several cases in which the groups had pushed for protection of lands at the expense of minority rural communities.
Over the years, organizations like the Natural Resources Defense Council have formed partnerships with smaller environmental groups that emerged in the 1980s and '90s to represent the interests of low-income and minority constituencies.
But more substantial change, Mr. Moore said, has been slow to come.
"If you're going to be impacted by an issue, you bring the impacted people to the table," said Mr. Moore, who is now executive director of the Southwest Network for Environmental and Economic Justice, a coalition of 60 groups.
Cara Pike, the author of a 2007 study commissioned by the environmental law group Earthjustice, said the research found that the "greenest Americans," many of them members of environmental groups, were overwhelmingly white, over 45 and college-educated. "The focus of green groups has been to target the greenest Americans," Ms. Pike said, "and as a result, we've left other people out of the equation."
National polls show high environmental concern among minorities. A post-election poll for the National Wildlife Federation in November, for example, found increasing support among blacks and Latinos for candidates keen on addressing global warming. And surveys by the Public Policy Institute of California have found that minorities are sometimes even more concerned than white respondents about environmental issues like air pollution.
But until recently, social concerns did not appear to be "on the radar" of many large environmental organizations, said Julian Agyeman, chairman of the department of urban and environmental policy and planning at Tufts University and author of the 2005 book "Sustainable Communities and the Challenge of Environmental Justice."
Even organizations like the Sierra Club, which has incorporated social justice work since the 1990s, concede that their diversity efforts have failed to gain traction. The organization's executive director, Carl Pope, points at "cultural barriers" that in effect shut the door to nonwhites regardless of good intentions.
"If you go to a Sierra Club meeting, the people are mostly white, largely over 40, almost all college-educated, whose style is to argue with each other," Mr. Pope said. "That may not be a welcoming environment."
Those who join such groups sometimes do not stay long. Marcelo Bonta, 35, who worked for four environmental groups before becoming a diversity consultant in Portland, Ore., five years ago, said he found "a need to conform," down to the way to dress.
"It's the tyranny of fleece," Mr. Bonta said. "I always felt I had to dress down."
Some larger environmental groups are taking steps to make up for the past.
Roger Rivera, president of the National Hispanic Environmental Council, an advocacy group in Washington that promotes environmental careers among Latino students, said that for more than a year he had been attending meetings of the Green Group, a loose association of about three dozen environmental organizations, as "an observer."
Mr. Rivera, who served on President Obama's transition team for the Interior Department, said the Green Group formally invited his organization to join in January - soon after the election of the first black president, he pointed out.
Larry Schweiger, who is chairman of the association and president of the National Wildlife Federation, said the invitation to groups like Mr. Rivera's was "part of an overall effort to get more engagement in the climate issue."
Lisa P. Jackson, whom Mr. Obama appointed as administrator of the Environmental Protection Agency, emphasized inclusion at a recent conference of environmental justice groups in New York City. Ms. Jackson told the audience that she hoped to bring more diversity to the agency - its staff of about 1,700 is 69 percent non-Hispanic white - "so we look like the people we serve."
(In addition to Ms. Jackson, who is black, Mr. Obama's environment team includes an Asian, Steven Chu, as energy secretary; a Latino, Ken Salazar, as interior secretary; and Carol M. Browner, who is white, as the coordinator of energy and climate policy.)
Van Jones, whose national organization, Green for All, was also invited to join the Green Group, said that while environmental justice groups were focused on "equal protection from bad stuff," groups like his wanted "equal access to good stuff" and to use green jobs to lift urban youths and others out of poverty.
"The more the green movement transforms into a movement for economic opportunity," Mr. Jones said, "the more it will look like America."