WASHINGTON  Former Vice President Al Gore said on Thursday that Americans must abandon electricity generated by fossil fuels within a decade and rely on the sun, the winds and other environmentally friendly sources of power, or risk losing their national security as well as their creature comforts.

“The survival of the United States of America as we know it is at risk,” Mr. Gore said in a speech to an energy conference here. “The future of human civilization is at stake.”

Mr. Gore called for the kind of concerted national effort that enabled Americans to walk on the moon 39 years ago this month, just eight years after President John F. Kennedy famously embraced that goal. He said the goal of producing all of the nation’s electricity from “renewable energy and truly clean, carbon-free sources” within 10 years is not some farfetched vision, although he said it would require fundamental changes in political thinking and personal expectations.

“This goal is achievable, affordable and transformative,” Mr. Gore said in his remarks at the conference. “It represents a challenge to all Americans, in every walk of life  to our political leaders, entrepreneurs, innovators, engineers, and to every citizen.”