A key signatory of a petition calling for government to sue companies that question climate change has pulled the letter from his institute's website amid revelations his family reaped $500,000 in salary and benefits last year from the government-funded organization. 

The controversy started after George Mason University climatologist Jagadish Shukla and 19 other scientists signed a letter on Sept. 1 urging lawsuits against companies like Exxon for, the petitioners claim, intentionally misleading about climate change. They say the federal government could sue using “RICO” laws originally designed to prosecute the mob, and Sen. Sheldon Whitehouse, D-R.I., has also backed the idea.

But global warming skeptics accused Shukla of channeling millions of dollars in government science grants into his own salary through a non-profit – while government agencies tell FoxNews.com that they stand by their grants.

Last year, tax records show that Shukla received a $333,000 salary and benefits from an organization he created called the "The Institute of Global Environment and Society" – a group that gets 90 percent of its revenue from government grants. His wife also received $166,000 in compensation from the group over the same period.

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A link to the letter on the Institute of Global Environment and Society website has been replaced with the following statement: “The letter that was inadvertently posted on this web site has been removed. It was decided more than two years ago that the Institute of Global Environment and Society (IGES) would be dissolved when the projects then undertaken by IGES would be completed. All research projects by IGES were completed in July 2015, and the IGES web site is in the process of being decommissioned.”

The organization has been operating since 1991, and total payments from the group to the Shuklas since 2001 (the most recent year records are available) amount to $5.6 million, according to an analysis of old returns by the Free Beacon.

In addition to the government grants, Virginia state records show that Shukla gets an annual salary of $250,000 from the public George Mason University. 

Shukla did not respond to requests for comment from FoxNews.com. A George Mason University spokesman declined to comment, referring all questions on the issue to Shukla.

The extensive taxpayer-funding for the climate advocate was first uncovered by University of Colorado environmental science professor Roger Pielke, Jr.                                        

“It sure looks like the taxpayer and the public university are being taken advantage of for financial gain… this is not how publicly funded science should be done,” Pielke told FoxNews.com.

Shukla’s group’s millions in grant money came largely from three government agencies: The National Oceanic and Atmospheric Administration (NOAA), the National Science Foundation (NSF), and NASA.

NSF maintains an online database that indicates it has given $29 million in grants in which Shukla is listed as the principal investigator and an additional $12 million through Shukla’s organization.

 One NSF grant to Shukla totaled some $7 million between 2004 and 2009 to “work towards an understanding of the predictability of Earth's current climate fluctuations on seasonal to decadal time scales using state-of-the-art, comprehensive models.”                                         

Asked about Shukla’s salary by FoxNews.com, spokesmen from all three government agencies did not get into specifics of the grants to him but said that their institutions have high standards for awarding grants.

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“EVERY proposal goes through the agency’s merit- review process, meaning each proposal is reviewed in a fair, competitive and in-depth manner,” NSF spokesman Peter West told FoxNews.com by email, also noting that NSF considers some 55,000 grant proposals a year and provides funding for some 11,000. The NSF told FoxNews.com that reviewers are aware of applicants' names when reviews are conducted.

The spokesman added: “Proposals are evaluated by a minimum of three independent reviewers consisting of scientists, engineers and educators who work neither for NSF nor for the institution that employs the proposing researchers. NSF selects reviewers from a national pool of experts in the appropriate fields to review the subject matter in any given proposal.”

Spokesmen from NOAA and NASA said that they do not have any currently active grants with Shukla's group. However, NASA noted that it does give grants to another organization called the “Center for Ocean-Land-Atmosphere Studies.” That group was created by Shukla’s group and is closely connected; it is run by another George Mason University professor named James Kinter, who also receives a $180,000 salary from Shukla’s group according the group’s 2014 tax return.

Both the NOAA and NASA said that costs are considered in reviewing grants.

“Proposals for NASA grants require a statement of the labor costs associated with the proposed activity. [Peer] reviewers assess the reasonableness of these labor costs,” NASA spokesman Stephen Cole told FoxNews.com.  

Skeptics say that Shukla’s financial operations illustrate that government-funded scientists have plenty of incentive to exaggerate the danger of climate change in order to secure more research funding.

“There is actually a good occasion for talking about the morality and even legal culpability but that group is the government-funded scientists… they do things such as conceal or refuse to publish data that we taxpayers pay for and when they in general conspire to misrepresent information to the public as was documented in the climate gate fiasco,” Alex Epstein of the Center for Industrial Progress told FoxNews.com. He also noted that mainstream climate models have consistently over predicted warming in recent years.

Lawyers who specialize in free speech issues say that it would be dangerous for government to prosecute anyone based on their climate change advocacy.

“This is certainly a threat to First Amendment liberties, both the freedom of speech and press,” Jonathan Adler, a law professor at Case Western Reserve University, told FoxNews.com.

“It's an effort to criminalize dissent on a contentious public policy issue -- and I say that as someone who believes that climate change is a serious problem that warrants serious policy responses, albeit not the same ones pushed by most environmental groups,” he added.

The idea for the lawsuit comes from successful litigation against tobacco companies, which were found to have knowingly lied about the safety of their products.

But major players in the tobacco lawsuits say this case is not clear-cut.

“There’s nothing illegal about being anti-science,” Doug Blanke, who once helped release 35 million pages of tobacco industry documents, and the founder of the Public Health Law Center, told FoxNews.com.

“Denying the consensus of the world’s climate scientists, like insisting the world is flat, is not against the law, in itself… The law only comes into play when a company knows the truth, and admits the truth behind closed doors, but then lies publicly about what it knows, in order to mislead the public and policymakers.  Is that the case with climate change? That will depend on what a company knew and when it knew it,” Blanke told FoxNews.com.

The author, Maxim Lott, can be reached on twitter at @maximlott