WASHINGTON -- New York Mayor Michael Bloomberg on Thursday backed President Barack Obama over Republican Mitt Romney, saying the incumbent Democrat will bring leadership that is critically needed to fight climate change after the East Coast devastation wrought by Hurricane Sandy.

The endorsement from the politically independent and popular third-term mayor was a major boost for Obama, who is spending the campaign's final days trying to win over independent voters whose voices will be critical in determining who wins Tuesday's election.

Both candidates had eagerly sought the nod from Bloomberg, who didn't endorse a presidential candidate in 2008.

As New York continued to pick up the pieces after the superstorm devastated parts of the city this week, Bloomberg said Sandy had made the stakes of the election even clearer. He said the climate is changing and that Obama has taken major steps in the right direction.

"We need leadership from the White House, and over the past four years, President Barack Obama has taken major steps to reduce our carbon consumption," Bloomberg wrote in an online opinion piece, citing higher fuel-efficiency standards for vehicles and stricter controls on mercury emissions.

A billionaire businessman and former Republican, Bloomberg praised Romney as a good man who would bring valuable business experience to the White House. But he said Romney had reversed course on a number of important issues, including immigration, health care and abortion.

"If the 1994 or 2003 version of Mitt Romney were running for president, I may well have voted for him because, like so many other independents, I have found the past four years to be, in a word, disappointing," Bloomberg wrote.

Obama issued a statement welcoming the endorsement and pledging to continue to stand with New York in its time of need.

"While we may not agree on every issue, Mayor Bloomberg and I agree on the most important issues of our time -- that the key to a strong economy is investing in the skills and education of our people, that immigration reform is essential to an open and dynamic democracy, and that climate change is a threat to our children's future, and we owe it to them to do something about it," Obama said.

Bloomberg endorsed Republican President George W. Bush's re-election in 2004.