Stephen Schneider - Early Work

Early Work

Schneider grew up in Long Island, New York. He studied engineering at Columbia University, receiving his bachelor's degree in mechanical engineering in 1966. In 1971, he earned a Ph.D. in mechanical engineering and plasma physics. Schneider studied the role of greenhouse gases and suspended particulate material on climate as a postdoctoral fellow at NASA's Goddard Institute for Space Studies.

In 1971, Schneider was second author on a Science paper with S. I. Rasool titled "Atmospheric Carbon Dioxide and Aerosols: Effects of Large Increases on Global Climate" (Science 173, 138–141). This paper used a 1-d radiative transfer model to examine the competing effects of cooling from aerosols and warming from CO₂. The paper concluded:

However, it is projected that man's potential to pollute will increase 6 to 8-fold in the next 50 years. If this increased rate of injection... should raise the present background opacity by a factor of 4, our calculations suggest a decrease in global temperature by as much as 3.5 °C. Such a large decrease in the average temperature of Earth, sustained over a period of few years, is believed to be sufficient to trigger an ice age. However, by that time, nuclear power may have largely replaced fossil fuels as a means of energy production.

Carbon dioxide was predicted to have only a minor role. However, the model was very simple and the calculation of the CO₂ effect was lower than other estimates by a factor of about three, as noted in a footnote to the paper.

The story made headlines in the New York Times. Shortly afterwards, Schneider became aware that he had overestimated the cooling effect of aerosols, and underestimated the warming effect of CO₂ by a factor of about three. He had mistakenly assumed that measurements of air particles he had taken near the source of pollution applied worldwide. He also found that much of the effect was due to natural aerosols which would not be affected by human activities, so the cooling effect of changes in industrial pollution would be much less than he had calculated. Having found that recalculation showed that global warming was the more likely outcome, he published a retraction of his earlier findings in 1974.

In 1976 Schneider wrote The Genesis Strategy: Climate and Global Survival in which he said:

One form of such pollution that affects the entire atmosphere is the release of carbon dioxide (CO₂) gas.... Human activities have already raised the CO₂ content in the atmosphere by 10 percent and are estimated to raise it some 25 percent by the year 2000. In later chapters, I will show how this increase could lead to a 1° Celsius (1.8° Fahrenheit) average warming of the earth's surface... Another form of atmospheric pollution results from... atmospheric aerosols... there is some evidence that atmospheric aerosols may have already affected the climate. A consensus among scientists today would hold that a global increase in atmospheric aerosols would probably result in a cooling of the climate; however, a smaller but growing fraction of the current evidence suggests that it may have a warming effect.

And in another section (What Does It All Mean?", p. 90):

I have cited many examples of recent climatic variability and repeated the warnings of several well-known climatologists that a cooling effect has set in – perhaps one akin to the Little Ice Age - and that climatic variability, which is the bane of reliable food production, can be expected to increase along with the cooling.

In 1977 Schneider criticized a popular science book (The Weather Conspiracy: The Coming of the New Ice Age), which predicted an imminent Ice Age. He wrote in Nature:

...it insists on maintaining the shock effect of the dramatic...rather than the reality of the discipline: we just don't know enough to choose definitely at this stage whether we are in for warming or cooling— or when.