Sunday, November 8th 2009, 1:02 PM EST
There is a general impression, based on flawed analyses [Oreskes in Science 2004] that scientists support nearly unanimously the so-called scientific consensus on AGW. But more than 31,000 scientists and engineers disagree and have signed a petition that affirms their disbelief in AGW [for a listing of names see pp. 745-855, in Climate Change Reconsidered, available at www.NIPCCreport.org]
There is even widespread belief that major scientific societies, like the American Geophysical Union (AGU), have polled their membership before issuing formal Statements which essentially endorse the IPCC conclusion that the temperature rise of the past 50 years has been caused by human activity – and more specifically by the emission of greenhouse (GH) gases. Not so: This false impression seems to be due to a misleading survey result published in an AGU journal [P. Doran and M. Kendall-Zimmerman, Eos 90, 20 Jan 2009, pp 22-23].
We will discuss this survey here and the question of bias and confounding factors. The Eos authors report the response of 3146 earth scientists to two questions:
1. Has the climate warmed, cooled, or remained constant -- compared to pre-1800?
Regardless of what one may believe about the causes of climate change, the answer must be: 'Warming.' Pre-1800 refers to the Little Ice Age, which ended around 1800. [If the question were changed to 'compared to 1998,' then the answer would be 'Cooling.']
2. Do you think human activity is a significant factor in changing global mean temperature?
Here the answer will depend on what is meant by 'significant' -- and whether 'human activity' should include urbanization, land changes, agriculture, irrigation, deforestation, etc. Many might answer 'Yes' – even if they don't think that GH gases are a significant factor in climate change.
The authors report that their selection involved faculty in relevant academic departments and employees of government establishments. Presumably, they did not include retirees or those in the private sector. The authors claim that known dissenters were included. But my casual inquiries did not find anyone who participated.
Most of the responders described themselves as geochemists; only 5% claimed to be 'climate scientists.' (But where are the 'atmospheric scientists'?)
The widely quoted result of the survey is a 97.4% 'Yes' to question #2; it is based on a sample of only 77 responses from 'actively publishing climate scientists.' Disregarding the claimed accuracy, what can we deduce from this response? That these are likely individuals who derive large research grants and contracts from a federal budget that almost exclusively supports research designed to affirm AGW. [Of this same group, only 96.2% (rather than 100%) thought that the climate had warmed since 1800. It would be interesting to learn who these individuals are.]
By contrast, on question #2, less than half of 'economic geologists' (103 responses) said 'Yes' and slightly more than one-third of 'meteorologists' (36 responses) said 'No.'
The American Physical Society (APS) in 2007 published a position statement enthusiastically endorsing AGW, without reference to the views of its members. Recently, some 200 APS members and Fellows have petitioned the APS Council to change or withdraw the Statement, in view of scientific evidence that is counter to AGW. Perhaps there will develop a similar initiative within the AGU.