(born c. 1940?) is Professor of Environmental Biology and Global Change at
. His research includes modeling of the atmosphere, climate change, and "the relationship of biological systems to global climate change." He has helped draw public attention to the issue of climate change. \n
Changing views
In 1971 Schneider was second author on a Science paper with S I Rasool "Atmospheric Carbon Dioxide and Aerosols: Effects of Large Increases on Global Climate". This paper used a 1-d radiative climate 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 oC. 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.
CO2 was predicted to have only a minor role. However, the model was very simple and the calculation of the CO2 effect was incorrect by a factor of about 3 - a fact soon recognised.
In 1976 Schneider wrote "The Genesis Strategy" 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 1o Celsius (1.8o 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.
Two decades later, Schneider emerged as a leading advocate of the theory, in which carbon dioxide emissions are held to increase the earth's temperature.
)\nSome opponents have called Schneider a scaremonger, quoting only one sentence out of the long passage above: ". . . we have to offer up some scary scenarios, make simplified dramatic statements and little mention of any doubts one might have." Schneider says that sentence has been taken out of context. \nSee: