U.S. investigators have cleared climate scientist Michael Mann of wrongdoing in a 2009 fracas over stolen emails from a British university.

The National Science Foundation found no "evidence of research misconduct" on Mann's part. Climate change skeptics had pointed to the release of the emails as evidence that researchers attempted to hide doubts about man-made global warming.

"It was a pretty definitive finding" that the charges "swirling around for over a year" were baseless, Mann said of the Aug. 15 report of the U.S. investigation. "I was very pleased."

Mann, a former professor at the University of Virginia and now a researcher at Pennsylvania State University, has been at the center of many attacks by climate change skeptics. Messages to and from him were found in the stolen emails from the University of East Anglia's climate research department. An email from another scientist speaking of Mann's work described a "trick" used in smoothing out year-to-year anomalies in climate change data.

A February report from the National Oceanic and Atmospheric Administration also found no evidence of misconduct.

A spokesperson for U.S. Sen. James Inhofe (R-Okla.), who has maintained that the theory of global warming is a hoax, suggested that the latest finding does not exonerate scientists.

"To say that the scientists have been vindicated is oversimplifying the situation," spokesman Matt Dempsey said. "What was revealed as part of the Climategate scandal was deeply troubling and certainly a setback for climate science" (Jim Efstathiou Jr., Bloomberg, Aug. 22). -- AP