Late in 1966, in the United States Weather Bureau computer lab, a Japanese immigrant named Syukuro Manabe would be the first to quantify the relationship between carbon dioxide and the temperature of Earth’s atmosphere.
The notion that the Earth’s atmosphere retained heat from sunlight had been understood since the early nineteenth century. Water vapor being the primary driver, traps heat energy at low altitudes and warms the planet’s surface by about sixty degrees Fahrenheit. If the Earth had no atmosphere, its surface temperature would average zero degrees Fahrenheit. The question was whether other atmospheric gasses contributed to this greenhouse effect. Carbon dioxide was believed to have an effect, but it made up just three parts per ten thousand of Earth’s atmosphere by volume. Researchers wondered whether its impact could be detectable.
Manabe simulated the effects of atmospheric change from equations in basic thermodynamics. His simulation included a plot of points representing the sensitivity of Earth’s temperature to carbon dioxide at different altitudes. His printer didn’t have the capability to fit a curve to the data, so, for the final step, he had to draw it in himself.
His results revealed that boosting carbon dioxide from three parts per ten thousand to six could cause Earth’s average surface temperature to rise by more than four degrees Fahrenheit. Secondly, Manabes simulation predicted that carbon dioxide would trap heat energy in the lower atmosphere. The Earth’s surface and it’s oceans would get hotter, while the upper atmosphere would cool.
https://www.newyorker.com/news/persons-of-interest/the-man-who-predicted-climate-change