WASHINGTON - Appealing for courageous action "before it's too late," President Obama launched a major second-term drive Tuesday to combat climate change and secure a safer planet, bypassing Congress as he sought to set a cornerstone of his legacy.

Abandoning his suit jacket under a sweltering sun at Georgetown University, Obama issued a warning about the environment: Temperatures are rising, sea level is climbing, Arctic ice is melting and the world is doing far too little to stop it. He said the price for inaction includes lost lives and homes and hundreds of billions of dollars.

"As a president, as a father and as an American, I'm here to say we need to act," Obama said. "I refuse to condemn your generation and future generations to a planet that's beyond fixing."

At the core of Obama's plan are new controls on new and existing power plants that emit carbon dioxide - heat-trapping gases blamed for global warming. The program also will boost renewable energy production on federal lands, increase efficiency standards and prepare communities to deal with higher temperatures. Obama called for the U.S. to be a global leader in the search for solutions.

But Obama's campaign will face extensive obstacles, including a complicated, lengthy process of implementation and the likelihood that the limits on power plants will be challenged in court. Likewise, the instantaneous political opposition that met his plan made clear the difficulty the president will face in seeking broad support.

"There will be legal challenges. No question about that," former EPA Administrator Christie Whitman said in an interview. "It's a program that's largely executive. He doesn't need Congress. What that does, of course, is make them (opponents) madder."

Declaring the scientific debate over climate change obsolete, Obama mocked those who deny that humans are contributing to the warming of the planet. "We don't have time for a meeting of the flat-Earth society," Obama said.

Climate plan at a glance

Some highlights of the plan:

Reduce pollution

• Issue a presidential memorandum to launch the first-ever federal regulations on carbon-dioxide emissions from existing power plants.

• Revise and reissue proposed limits on carbon dioxide emissions from new power plants.

• Expand permitting for renewable-energy projects like wind and solar on public lands, with a goal of powering more than 6 million homes by 2020.

• Develop a new set of fuel-economy standards for heavy-duty vehicles.

Prepare for climate change

• Create a National Drought Resilience Partnership to help communities, farmers and landowners prepare for droughts and wildfires.

• Promote climate change preparedness by creating a tool kit for local governments and businesses, and by partnering with hospitals.

• Update flood-risk reduction standards that all federally funded projects must meet.

Global efforts

• Work with China, India and other major polluting countries to reduce emissions.

• End U.S. public financing for new coal-fired power plants in other countries. Plants in the poorest countries using the most efficient technology available would be exempt.