Greenpeace accused a retired Penn State professor of being an “academic-for-hire” for the fossil fuel industry, but the researcher insists he was working as an independent consultant. The massive environmental organization released emails as part of what it’s calling a “sting” operation, which put two professors — the other works at Princeton — in the limelight this week.

Greenpeace UK approached former Penn State Sociology professor Frank Clemente, under the guise of an Indonesian coal mining firm, “to counter damaging research linking coal to premature deaths (in particular the World Health Organization’s figure that 3.7 million people die per year from fossil fuel pollution).” Greenpeace explained they selected these two academics because “have previously been linked to fossil fuel companies or climate sceptic organizations.” Clemente has argued against coal divestment among universities, a declaration that puts him at odds with Penn State’s energy plans.

Clemente, who retired from teaching sociology in 2010 and is now professor emeritus, agreed to write a report and said that ten-page paper would cost $15,000. Clemente told his “sponsors” that “there is no requirement to declare source funding in the US.”

Clemente also explained, “I am a full member of the graduate faculty here at Penn State so quoting me as Professor Emeritus at the University poses no difficulty whatsoever.”  This, in Greenpeace’s view, gave the impression that oil and coal companies can hire university scholars for climate skeptic research. To Clemente’s credit, his opinion on the science itself remained unchanged through the entire email exchange.

In an interview with the Australian Broadcasting Corporation, Clemente defended his role. “I write as an independent scholar fully apart from my non-salary role as Professor Emeritus. This is academic freedom.”

“I was not on the Penn State payroll during the publication of either of the two documents that were mentioned in the Greenpeace blog. Thus, the University is not responsible for my work in any way … I make my living as an independent consultant and generally charge an hourly rate.”

Penn State spokeswoman Lisa Powers backed up Clemente’s claims about his ties to the university. “Dr. Clemente has long since retired from the university (he is no longer on our payroll) and the university doesn’t have disclosure rules for retirees. When Dr Clemente expresses his views on issues publicly, they are his own and do not reflect the views of the university.”

Frank Clemente became a faculty member at Penn State in the 1970s. One of the students’ most beloved professors, in 2010, Onward State covered his last lecture, which drew a standing room-only crowd to 100 Thomas.

Clemente’s defense of coal probably put him at odds with another Penn State professor, Michael Mann, who has been one of the world’s leading climatologists on anthropogenic global warming.