49 former NASA astronauts and scientists sent a letter to NASA, requesting that they stick to using empirical data to evaluate the effects of carbon dioxide, and to back off the claims of catastrophic climate change. The text of the letter is pasted below:

Dear Charlie,

We, the undersigned, respectfully request that NASA and the Goddard Institute for Space Studies (GISS) refrain from including unproven remarks in public releases and websites. We believe the claims by NASA and GISS, that man-made carbon dioxide is having a catastrophic impact on global climate change are not substantiated, especially when considering thousands of years of empirical data. With hundreds of well-known climate scientists and tens of thousands of other scientists publicly declaring their disbelief in the catastrophic forecasts, coming particularly from the GISS leadership, it is clear that the science is NOT settled.

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.

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. We request that NASA refrain from including unproven and unsupported remarks in its future releases and websites on this subject. At risk is damage to the exemplary reputation of NASA, NASA’s current or former scientists and employees, and even the reputation of science itself.

For additional information regarding the science behind our concern, we recommend that you contact Harrison Schmitt or Walter Cunningham, or others they can recommend to you.

Thank you for considering this request.

There are an impressive 49 signatories including well-known astronauts such as Walter Cunningham and Charles Duke. Check out the rest of the signatories here. While they don’t mention him by name, the letter signatories most likely take significant issue with the public actions of James Hansen, a well known global warming activist, who recently made the news for his insightful comparison of climate change to slavery.
Indeed, it isn’t at all hard to see the moral similarities between the burning of fossil fuels (which has made the lives of everyone in the world much better off throughout history) with the brutal practice of enslaving individuals, denying their right to life and liberty.