Carol Browner, chief climate and energy adviser to President Obama, announced last night that she plans to leave her position soon.
Browner, a 55-year-old lawyer who served as U.S. EPA administrator during the Clinton administration, did not say immediately what she plans to do after she leaves the White House.
She was one of Obama's "czars," a group of high-level advisers not confirmed by the Senate and who drew the ire of some Republicans at the beginning of his presidency.
During her time at the White House, Browner was a leader on a number of energy and environmental issues, including the aftermath and cleanup of last year's massive Gulf of Mexico oil spill.
Her primary role, however, was to help guide the administration's response to climate change. She leaves office with that mission still unfinished, as the administration shifts from pursuing new emissions reduction laws to defending its existing authority to curb emissions from a critical new Republican House majority.
Browner helped to broker a 2009 deal between automakers, states and other stakeholders that led to the first nationwide regulation of greenhouse gas emission from cars and trucks. She was involved in negotiations on Capitol Hill that resulted in the House, then controlled by Democrats, passing a comprehensive climate change bill, an effort that later died in the Senate.
Her departure from the White House is something of a surprise. While it was widely assumed that she was going to reduce her energy and environment portfolio, Browner was expected to stay on in another role, perhaps as a deputy chief of staff.
But the fact that she had not been vetted by the Senate for her current position continued to rankle Republicans, who had threatened to call her in to testify in this new Congress, particularly about her work on the climate bill.
Scott Segal, an energy lobbyist with Bracewell & Giuliani, said in a statement that Browner's departure may represent a policy shift within the Obama administration.
"Carol Browner was a passionate contributor to a strong White House commitment to environmental policy," he said. "Her departure may be part of a legitimate effort to pay careful attention to addressing some of the real regulatory obstacles in the way of job creation in the United States."
Segal noted that EPA plans to propose and finalize greenhouse gas emissions standards in the coming years for the power and refining sectors, which he said could be harmful to economic growth.
"Infusing the White House with some new and fresh viewpoints makes sense," he added.