CHARLOTTESVILLE - Virginia's state climatologist, whose doubts about global warming and utility-industry funding made him a lightning rod on climate change issues, quietly left his position over the summer.

Patrick J. Michaels, who had held the position since 1980, will remain as a part-time research professor on leave at the University of Virginia, Joseph C. Zieman, chairman of the school's Department of Environmental Sciences, told The Daily Progress of Charlottesville.

Michaels has been a leading skeptic of global-warming theories. While he believes global warming is real and influenced by humans, he contends it primarily is caused by natural forces.

That view caused Gov. Timothy M. Kaine's office to ask Michaels last year to refrain from using his title when conducting non-state business because of fears his views would be perceived as an official state position.

The governor's office said Michaels, who was appointed by former Gov. John N. Dalton, was not a gubernatorial appointee, contending his office had become U.Va.' s domain in 2000.

Michaels, 57, called his resignation a sad result of the fact that his state climatologist funding had become politicized, compromising his academic freedom.

"It's very simple," he said. "I don't think anybody was able to come to a satisfactory agreement about academic freedom."

George F. Allen, a friend of Michaels, twice intervened on matters involving funding for Michaels' office, once as governor and again as a U.S. senator.

In 1994, Allen restored a cut of more than $100,000 to Michaels' office that had been proposed by former Gov. L. Douglas Wilder. Eight years later, as a senator, Allen rescued Michaels' office from other proposed cuts that Michaels said would have wiped out his entire funding.

Democrats, top scientists and environmental advocates also have maintained that Michaels' reliance on large utility company contributions for private research was a conflict of interest.

Last summer, The Associated Press reported that a Colorado utility raised at least $150,000 in donations and pledges to help Michaels analyze global-warming research by other scientists.

In July, Michaels withdrew as an expert witness for the auto industry in a high-profile case in Vermont federal court rather than disclose his funding sources. He said he was hired by the Automobile Manufacturers Association, and that his donors had information they wanted to remain confidential.

"Global warming science is a controversial area, and those who do not believe that anthropogenic greenhouse gas emissions will inevitably result in extreme climatologic outcomes are often subject to public attack," Michaels stated in an affidavit to the court.

The state climatologist's office provides information and conducts research on the impact of weather and climate on economic and ecological systems.

U.Va. spokesman Fariss Samarrai said Jerry Stenger, who has worked in the climatology office for more than two decades, took over Michaels' duties, just not his title as state climatologist.

Michaels said he will continue to work at the libertarian-conservative Cato Institute in Washington, where he works while on leave from U.Va.

"I feel I can speak more freely," he said.