Gerald Herbert, Associated Press
Former Vice President Al Gore warned Thursday that drastic steps were needed to avoid a global economic and ecological cataclysm.

WASHINGTON — Former Vice President Al Gore on Thursday urged the United States to convert the nation's entire electricity grid to carbon-free energy within 10 years, warning that drastic steps were needed to avoid a global economic and ecological cataclysm.

"The survival of the United States of America as we know it is at risk," he said in a midday speech to a friendly crowd of mostly young supporters in Washington. "And even more — if more should be required — the future of human civilization is at stake."

Gore, who shared the Nobel Peace Prize in 2007 for his environmental advocacy, said in an interview that he hoped to raise the alarm so that the next president, whether Sen. Barack Obama or Sen. John McCain, can rally Congress and the nation to action. He disavowed any interest in returning to elective office.

His approach, which would require abandoning old-fashioned, coal-fired power plants, goes beyond what even the most audacious scientists and entrepreneurs have proposed, as a means, he said, of jolting the world out of old ways of thinking. Without great dreams, he said, great deeds are never achieved, citing the quest for the moon of the 1960s.

He said the United States and the rest of the world were facing unprecedented problems, including high energy prices, growing demand for electricity, dangerous changes in the climate driven largely by emissions of carbon dioxide and political instability in regions that produce much of the world's oil.

"We're borrowing money from China to buy oil form the Persian Gulf to burn it in ways that destroy the planet. Every bit of that has to change," Gore said.

His solution was to do away with all carbon-emitting forms of electricity production in the United States within 10 years, replacing them with alternatives like solar, wind and geothermal power, conservation and so-called clean-coal technology in which all carbon emissions from the burning of coal are captured and stored.

Gore admitted his plan would, at least initially, drive energy prices higher. But he proposed a payroll tax cut to offset higher prices for fuel and electricity.

He said he envisioned nuclear power retaining its current share of domestic electricity generation, about 20 percent. Coal, which produces about half of American electricity, would dwindle, while renewables, currently producing less than 3 percent of the nation's electricity, would rapidly grow.