If You Wish To Make Up Facts From Scratch...
Did the late scientist Carl Sagan  once advocate for increased carbon dioxide emissions? That's what the Washington Examiner claims in a recent commentary  by Shannon Goessling, Executive Director  of the Southeastern Legal Foundation, which advocates  for "limited government" and "the free enterprise system":
In the 1970s and '80s, climatologists and astrophysicists were setting off alarms about pending global cooling and "the new ice age." Headlines in major weekly news magazines warned of a cooling catastrophe, with experts like famed astronomer Carl Sagan calling on industrialized countries to produce more carbon dioxide to offset the pending disaster.
The claim that scientists predicted an imminent "ice age" in the 1970s is a common myth  employed by conservative media outlets who invariably cite headlines in "news magazines" rather than scientific literature. A 2008 paper  in the Bulletin of the American Meteorological Society actually reviewed the climate research published in the 70s and concluded that "global cooling was never more than a minor aspect of the scientific climate change literature of the era, let alone the scientific consensus" and "emphasis on greenhouse warming dominated the scientific literature even then."
As for the allegation that Sagan called for higher CO2 emissions, William Poundstone, who wrote a Sagan biography , says "that claim is new to me." According to Poundstone, Sagan was concerned about greenhouse warming as early as the 60s:
That claim is new to me. While I can't prove a negative, I would be very skeptical of it unless they've got some period documentation. Sagan was at any rate one of the first to worry about global warming. He was a principal architect of the current understanding of Venus, showing that the carbon dioxide in its atmosphere caused it to be much hotter than astronomers of the time had imagined. In my Sagan biography I write (p. 45):
"One day in Berkeley, Carl told Ronald Blum (he had moved west, too) that he was worried about the carbon dioxide in the air. The burning of fuel was creating more carbon dioxide. This would increase the earth's greenhouse effect and warm the globe with disastrous consequences. At the time, that was an incredible if not crazy thing to say. It could not have been later than 1963."
This was based on an interview with Ronald Blum, a college friend.
Science historian Spencer Weart  also said he had never heard the claim that Sagan called for increased CO2 emissions:
No, I never heard that Carl Sagan, or indeed anyone in the 1970s, endorsed the idea of producing CO2 to forestall an ice age. It's true that the idea of using CO2 in this way was circulated already early in the 20th century, but anything along those lines would have been speculation about a distant future--few expected a real ice age would come except over the course of centuries or, more likely, millennia.
Not only does the Washington Examiner op-ed revise 1970s history, it also takes liberties with more recent news. The op-ed, titled "Ice age threat should freeze EPA global warming regs," says astrophysicists recently predicted that because of low sunspot activity, "we may be heading into the next ice age."
But the scientists who conducted that solar research had a different take : "We are NOT predicting a mini-ice age. We are predicting the behavior of the solar cycle. In my opinion, it is a huge leap from that to an abrupt global cooling, since the connections between solar activity and climate are still very poorly understood."