Now that his Cabinet is in place, U.S. President-elect Barack Obama has chosen his top four advisers on science and technology. The choices show that Mr. Obama plans to be more aggressive than the Bush administration in its approach toward global warming.

Mr. Obama has chosen Harvard University physicist John Holdren, a leading expert on climate change, as his main science adviser, the director of the White House Office of Science and Technology Policy. "A physicist renowned for his work on climate and energy, he has received numerous honors and awards for his contributions, and has been one of the most passionate and persistent voices of our time about the growing threat of climate change. I look forward to his wise counsel in the years ahead," he said.

Joining Holdren on the president's Council of Advisers on Science and Technology will be Nobel Prize-winning scientist Harold Varmus, a former director of the National Institutes of Health, and Massachusetts Institute of Technology professor Eric Lander, who specializes in human genome research.

The president-elect has picked marine biologist Jane Lubchenco to lead the National Oceanic and Atmospheric Administration, or NOAA, which does much of the government's research on global warming. "As an internationally-known environmental scientist, an ecologist and former president of the American Association for the Advancement of Science, Jane has advised the president and Congress on scientific matters, and I am confident she will provide passionate and dedicated leadership at NOAA," he said.

Mr. Obama's science team will deal with global warming after the Bush administration opposed mandatory cuts of greenhouse gas pollution.

Last year, former Surgeon General Richard Carmona testified to Congress that top administration officials often dismissed global warming as a "liberal cause" and tried to play down public health reports because of political considerations.

The Bush administration also tightly restricted government funding for stem-cell research because of concerns about the use of human embryos.

"Promoting science is not just about providing resources. It is about protecting free and open inquiry. It is about ensuring that facts and evidence are never twisted or obscured by politics or ideology," said Mr. Obama.

In his weekly radio address Saturday, Mr. Obama said he hopes to restore America's place as the world leader in science and technology. "I am confident that if we recommit ourselves to discovery, if we support science education and create the next generation of scientists and engineers right here in America, if we have the vision to believe and invest in things unseen, then we can lead the world into a new future of peace and prosperity," he said.

Mr. Obama made his final Cabinet appointments on Friday. He chose Congresswoman Hilda Solis as labor secretary and Republican Congressman Ray LaHood to lead the transportation department.