Al Gore is endorsing Barack Obama and promising to help the Democrat achieve what eluded him — the presidency.

In a letter to be e-mailed to Obama supporters, the former vice president and Nobel Prize winner wrote, "From now through Election Day, I intend to do whatever I can to make sure he is elected president of the United States."

In 2000, Gore won the popular vote but lost the disputed 2000 election to George W. Bush, who captured Florida and its electoral votes after a divided Supreme Court ended the recount. Since then, Gore has made combatting global warming his signature issue, and has been recognized worldwide for his effort — from an Academy Award for a documentary for his effort to the Nobel prize.

"Over the past 18 months, Barack Obama has united a movement. He knows change does not come from 1600 Pennsylvania Avenue or Capitol Hill. It begins when people stand up and take action," Gore wrote. "With the help of millions of supporters like you, Barack Obama will bring the change we so desperately need in order to solve our country's most pressing problems."

The former vice president also asked for donations to help fund Obama's effort — the first time he's asked members of his Web site AlGore.com to contribute to a political campaign.

Gore is one of the most popular figures in the Democratic Party, but he kept a low profile in the primary campaign. He's planning to appear with Obama at a rally in Detroit Monday night.