Former President Bill Clinton took the stage at the U.S. Green Building Council’s sixth annual Greenbuild conference in Chicago yesterday morning and, before a crowd of 6,000 people who gathered to hear his keynote address, described the green building movement the nation’s largest economic opportunity since the country mobilized for World War II. “It’s not going to be easy, but we have to move away from the carbon economy,” Clinton said, adding that he considers green building to be “perhaps the most important cause we can be involved in today.”

In a lightly political speech—we are facing an election year, after all, and his wife is running for president—Clinton talked about the failed model of the Kyoto Protocol, the need for greater international cooperation, and the efforts of his Clinton Climate Initiative to effect change throughout the world. “It’s critical that we negotiate a successor to Kyoto by 2009 or 2010,” Clinton said, “and we need a broader consensus on China and India.” He added that the logic many people use to criticize the cost of green building—that China and India are doing nothing and, therefore, gaining a competitive advantage—was flawed and akin to saying that the world should just have fun until we burn the planet down. “That ensures failure,” he observed.

Clinton made several references to his vice president, Al Gore, who, along with the United Nations’ Intergovernmental Panel on Climate Change, won the Nobel Peace Prize this year for raising public awareness about the environment. Noting that such efforts have succeeded in changing people’s attitudes, Clinton said that the time has come to “operationalize” the change. To that end, his foundation will use more than $5 billion in financial commitments to undertake a green retrofit program for buildings in 40 cities, beginning with a pilot project in Chicago. Clinton added, incredulously, that this sum represents a doubling of the worldwide investment in improving energy efficiency. “We don’t know what we can do because we just got started,” he observed. But the movement is picking up steam. Clinton recently met with officials from GE Real Estate, which has committed to greening its 385-million-square portfolio, representing a value of more than $70 billion.

Although he supports greening buildings, Clinton admitted that he was surprised when USGBC president and CEO Rick Fedrizzi presented him with a LEED Platinum plaque for his presidential library in Little Rock, which was designed by Polshek Partnership Architects to be a LEED-rated building and was recently re-certified under the LEED for Existing Buildings program. Later in his talk, Clinton invited school administrators and government leaders, including the governor of Kansas, Kathleen Sibelius, up to the stage to applaud their efforts at greening schools. Clinton said that he considered school design of utmost importance because the future of green design rests in the hands of children.