Stephen H. Schneider (born c. 1940?) is Professor of Environmental Biology and Global Change at Stanford University. 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

Honors

\n* 1992. Macarthur Fellow "Genius Award."\n* 2002. Elected to the National Academy of Sciences.\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 global warming theory, in which carbon dioxide emissions are held to increase the earth's temperature.

Public Relations

\nScheider has commented publicly about the frustrations and difficulties involved with assessing and communicating scientific ideas.\n

Neglecting the complexities

\nIn a Scientific American article Schneider writes:\n:I readily confess a lingering frustration: uncertainties so infuse the issue of climate change that it is still impossible to rule out either mild or catastrophic outcomes, let alone provide confident probabilities for all the claims and counterclaims made about environmental problems. Even the most credible international assessment body, the Intergovernmental Panel on Climate Change (IPCC), has refused to attempt subjective probabilistic estimates of future temperatures. This has forced politicians to make their own guesses about the likelihood of various degrees of global warming. [1]\n

Scary scenarios

\nSchneider once spoke of the difficulties scientists have communicated their work to the public:\n:"On the one hand, as scientists we are ethically bound to the scientific method, in effect promising to tell the truth, the whole truth, and nothing but - which means that we must include all the doubts, the caveats, the ifs, ands, and buts. On the other hand, we are not just scientists but human beings as well. And like most people we'd like to see the world a better place, which in this context translates into our working to reduce the risk of potentially disastrous climatic change. To do that we need to get some broadbased support, to capture the public's imagination. That, of course, entails getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have. This 'double ethical bind' we frequently find ourselves in cannot be solved by any formula. Each of us has to decide what the right balance is between being effective and being honest. I hope that means being both." (Quoted in Discover, pp. 45-48, Oct. 1989, see also American Physical Society, APS News August/September 1996). (source[1])\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: global warming\n

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