Lincoln, a Republican, had spent eight years in the Illinois statehouse and a term in Congress when he was elected president, service almost identical to Obama's.

"The experience Lincoln's supporters valued most in that race was his powerful ability to inspire hope in the future at a time of impasse," Gore said.

"In 2008, once again, we find ourselves at the end of an era with a mandate from history to launch another new beginning. And once again, we have a candidate whose experience perfectly matches an extraordinary moment of transition," he said.

Gore said that the alternative, Republican presidential candidate John McCain, would be nothing more than a continuation of the Bush administration polices of the past eight years.

"Hey, I believe in recycling, but that's ridiculous," Gore told a massive audience of 70,000 on the closing night of the Democratic National Convention.

"With John McCain's support, President Bush and Vice President Cheney have led our nation into one calamity after another because of their indifference to fact, their readiness to sacrifice the long-term to the short-term, subordinate the general good to the benefit of the few and short-circuit the rule of law," Gore said.

Gore, a two-term vice president, was the Democratic nominee in 2000, losing that disputed election to President Bush. He has since focused his energy on fighting climate change, which he says threatens the planet. His work on the topic earned him a Nobel Peace Prize in 2007, and his documentary on the topic won him an Oscar.

He said Thursday that economic and international security hinge on solving the climate crisis. There are options available, he said. The only thing lacking is a president with the will to take it seriously.

"The carbon fuels industry - bil oil and coal - have a 50-year lease on the Republican Party and they are drilling it for everything it's worth," he said.

Gore said that Obama's character, vision and ability to unite people and inspire hope makes him the best choice for a country at a crossroads.

"There are times in the history of our nation when our very way of life depends upon awakening to the challenge of a present danger, shaking off complacency to rise, clear-eyed and alert, to the necessity of embracing change."