The Original Sin of Global WarmingPosted: February 27, 2014
This might seem strange because Sagan was an early promoter of the theory that man-made emissions of carbon dioxide are going to fry the globe. But it’s not so strange when you consider the larger message that made Sagan famous.
As with many people my age, Sagan’s 1980 series “Cosmos,” which aired on public television when I was eleven years old, was my introduction to science, and it changed my life. “Cosmos” shared the latest developments in the sciences of evolution, astronomy, and astrophysics, but its real heart was Sagan’s overview of the history of science and the distinctive ethos behind the scientific method. Sagan returned again and again to one central theme: that the first rule of science is to follow the evidence wherever it leads, regardless of one’s wishes or preconceptions. He spoke eloquently about the Ancient Greek Pythagoreans and their attempt to suppress the facts about “irrational numbers” that didn’t fit their theory. And he spoke admiringly about the 17th-century astronomer Johannes Kepler, who started out pursuing a theory in which the planets move in circular orbits reflecting the ratios of the perfect Pythagorean solids—and ended up being driven by the evidence to reject this theory and discover completely new laws of planetary motion.
I didn’t end up becoming a scientist, but I absorbed Sagan’s basic lesson and have tried my best to adhere to it in my own field: follow the evidence wherever it leads.
But this can be a difficult rule to follow. It is easy to spot the unexamined assumptions of others, but harder to root out your own prejudices. A few years ago, while watching “Cosmos” again for the first time in 25 years, I was reminded that Sagan did not always practice what he preached, and his error sheds light on the global warming theory’s original sin against science. It is a sin that has only gotten worse and which explains the scandalous state of today’s debate over global warming.
In the third episode of “Cosmos,” Sagan presents our nearest planetary neighbors, Venus and Mars, as cautionary tales of what happens when a potentially Earth-like planet goes wrong and become inhospitable to life. In his telling, Venus is a warning about how a runaway greenhouse effect can turn a planet’s surface into an acidic furnace, while Mars is a cautionary tale about how an inadequate greenhouse affect can leave a planet cold, dry, and barren. He proceeds to apply these lessons to Earth, predicting two possible doomsday scenarios: one in which deforestation causes the Earth to cool, and one in which fossil fuels cause it to warm. (You can hear some of the audio here, but without Sagan’s original visuals.)
Human activities brighten our landscape and our atmosphere. Might this ultimately make an ice age here? At the same time we are releasing vast quantities of carbon dioxide, increasing the greenhouse effect…. It may not take much to destabilize the Earth’s climate, to convert this heaven, our only home in the Cosmos, into a kind of hell.
This is a bit of a cultural time capsule, preserving the precise moment at which scientific alarmists were switching from warning about a new ice age, in the 1970s, to warning about runaway warming.
Much of the planetary science behind these claims, by the way, turned out to be speculative and premature. In the 1990s, detailed satellite maps of Venus revealed the remains of enormous volcanoes and vast rivers of lava, implying that the planet had been entirely resurfaced by a volcanic apocalypse as recently as 100 million years ago—which strikes me as a much more reasonable explanation for why Venus has a surface temperature of 900 degrees and an atmosphere full of sulfuric acid. As for Mars, its much smaller size and lack of a planetary magnetic field, which allows its atmosphere to be stripped off by the solar wind, are adequate explanations for its cold, thin air and the absence of surface water. So Venusian SUVs and overenthusiastic Martian loggers are probably off the hook.
To his credit, Sagan admits that the science on this subject is still in its early stages—but then he makes a disastrous error.
And yet we ravage the Earth at an accelerated pace, as if it belonged to this one generation, as if it were ours to do with as we please…. Our generation must choose. Which do we value more: short-term profits or the long-term habitability of our planetary home?…
The study of the global climate, the sun’s influence, the comparison of the Earth with other worlds, these are subjects in their earliest stages of development. They are funded poorly and grudgingly, and meanwhile we continue to load the Earth’s atmosphere with materials about whose long-term influence we are almost entirely ignorant.
Can you see the error? Sagan enters this topic with a clear animus against the profit motive and a pre-established belief that industrial civilization is “ravaging the earth.” These are the obvious cultural biases of a late-20th-century modern liberal…
- Who Was Carl Sagan? (davidreneke.com)
- Carl Sagan’s Two Warnings For Humanity In His Very Last Interview – You Might Want To Hear This (thinkaboutitdocs.com)
- Carl Sagan Unfiltered (parisachenbach.wordpress.com)
- The Green Socialists of Mars (sultanknish.blogspot.com)
- Neil deGrasse Tyson is optimistic about Earth’s future (and his new TV series) (mnn.com)
- Charles of the day: Charles Sagan (touchmyculture.com)
- Carl Sagan: Two Warnings For Humanity in His Last Interview (humansarefree.com)