Nearly 50 former NASA scientists, astronauts and technologists are chastising NASA for its position on man-made climate change.

In a March 28 letter addressed to NASA Administrator Charles Bolden, the group of 49 former employees ask NASA and the Goddard Institute for Space Studies to “refrain from including unproven remarks in public releases and websites” because “it is clear that the science is NOT settled.”

“As former NASA employees, we feel that NASA’s advocacy of an extreme position, prior to a thorough study of the possible overwhelming impact of natural climate drivers is inappropriate,” the letter reads.

The group said that the statements that “man-made carbon dioxide is having a catastrophic impact on global climate change are not substantiated.”

“The unbridled advocacy of CO2 being the major cause of climate change is unbecoming of NASA’s history of making an objective assessment of all available scientific data prior to making decisions or public statements,” the letter reads.

NASA spokesman Steve Cole told The Daily Caller that they have not received the letter yet. “We are now aware of the correspondence but have not yet had an opportunity to review the contents,” he said.

The group, according to a news release, includes seven Apollo astronauts and two former directors of NASA’s Johnson Space Center in Houston. The letter surfaced Tuesday on the blog Watts Up With That?

“Our concerns are about the reputation for NASA,” former Apollo 7 astronaut Walter Cunningham told TheDC in an interview.

Cunningham noted that he has been friends with NASA Administrator Charles Bolden, who he calls “Charlie.”

“I’ve known him a long time,” he said. “He is a very fine guy.”

But then he added, “Not many of us are really all that pleased with what’s been happening to NASA.”

Cunningham explained that the co-signers came together through the NASA Alumni League’s Johnson Space Center Chapter in Houston.

Leighton Steward, a geologist who is chairman of Plants Need CO2, told TheDC that he helped “catalyze” the effort to draft the letter after being invited a year ago to speak with a group of retired NASA scientists in Texas about climate change.

“I said, ‘Hey you guys are high-profile, well-thought-of guys. If you’re this concerned about what NASA is saying, you ought to let them know about it.'”

Steward said the group is just a loose coalition of former NASA employees who agree on the topic and said they aren’t being funded by anybody.

“They don’t have a penny,” Steward said with a laugh.

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