Obama, a first-term Democrat, also said he doubts Congress will pass immigration legislation this year, but he added that if the Senate can clear a bill "it lays the groundwork" for 2007.
Obama was guest speaker at The Associated Press' annual luncheon, held on the opening day of the Newspaper Association of America's convention.
He accused President Bush of a "stubborn refusal" to attack the causes of climate change, and said tougher fuel standards, stricter curbs on oil imports and more investment in cleaner energy are essential to avert global catastrophe.
"Saying that America is addicted to oil without following a real plan for energy independence is like admitting alcoholism and then skipping out on the 12-step program," said Obama in a reference to one of the principal themes of Bush's State of the Union address.
Republicans promptly returned the criticism.
"Rather than attack the administration, Sen. Obama would be better served to read the energy bill President Bush signed into law, particularly the portions that focus on energy-efficient vehicles, renewable energy sources and less reliance on foreign sources of fuel," said Tracey Schmitt of the Republican National Committee.
In addition to criticizing Republicans, Obama chided members of his own party.
He said Democrats "all too often are defending a social safety net that was constructed in the 1930s and '40s. My argument to Democrats has been that we need to cling to the core values that make us Democrats, the belief in universal health care, the belief in universal education, and then we should be agnostic in terms of how to achieve those values."
Obama, who was virtually unknown outside Illinois before he won a Senate primary in 2004, has quickly become a widely sought-after speaker for Democratic fundraising events. He is the only African-American in the Senate, and the party leadership frequently gives him a prominent role at events in Washington.
Asked about issues for 2008, he said the nation needs a "serious comprehensive approach" to energy independence. He said the technology exists to produce a car that can get 500 miles to a gallon of gasoline.
Obama prodded Democrats on education. "I do not believe that being against No Child Left Behind is an education policy," he said. "We should take a look at pay for performance," an idea not generally popular with teacher unions.
"I'm a big union guy and I have a sister who is a public school teacher. I think it is absolutely for us to engage teachers saying ... We are willing to pay you more, but we have a right to expect a better outcome."
In calling for greater federal spending on basic science and research, he said President Bush and congressional Republicans "are so committed to more tax cuts on top of what have been delivered that we are willing to cut into what is sort of the lifeblood of our economy."
The answer about issues for 2008 prompted a follow-up question: Would he confirm an interest in being on the ticket?
"Health care is important, too," he said to laughter.
Obama said the government should provide tax breaks and loan guarantees to show the way toward greater use of environmentally friendlier energy sources.
He cited several pieces of legislation he has introduced in Congress, including one to help defray the auto industry's costs of investment in more fuel-efficient cars. It calls for the federal government to pick up a portion of the costs automakers pay for retiree health care, so long as companies use some of the savings to retool their factories.
Obama said the Big Three automakers spent $6.7 billion on retiree health care costs in 2004.
"It's a win-win proposal for the industry — their retirees will be taken care of, they'll save money on health care, and they'll be free to invest in the kind of fuel-efficient cars that are the key to their competitive future," he said of the legislation. "As gas prices keep rising, the Middle East grows every more unstable and the ice caps continue to melt, we face a now-or-never, once-in-a-generation opportunity to set this country on a different course."
He said the country should reduce oil imports by more than 7.5 million barrels a day by 2025, a cutback two-thirds greater than the administration's target of 4.5 million.
He also said fuel economy standards should rise 3 percent a year over the next 15 years, beginning in 2008.
The use of ethanol in fuel should be encouraged, he said, supporting tax breaks for companies to install the necessary tanks on their cars and for consumers who use E85, a blended fuel.
"Unless we free ourselves from a dependence on these fossil fuels and chart a new course on energy in this country, we are condemning future generations to potential catastrophe," he said.