Lindzen, R.S. 2010. Global warming: The origin and nature of the alleged scientific consensus. Problems of Sustainable Development 5: 13-28.
What was done
The author -- who is the Alfred P. Sloan Professor of Meteorology in the Department of Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology in Cambridge, Massachusetts (USA), and who has long been critical of climate-alarmist claims of impending catastrophic CO2-induced global warming -- discusses (1) the ability of state-of-the-art global climate models to accurately simulate earth's climatic future and (2) the appropriateness of employing those simulations as justification for unprecedented actions to totally reformulate the energy base of the industrialized world in an attempt to drastically reduce anthropogenic CO2 emissions, which Bill Gates has said should be reduced to zero by the year 2050 in his 12 February 2010 Palm Springs TEDActive presentation (http://www.ted.com/talks/bill_gates.html).
What was learned
In statements summing up his evaluation of the pertinent science, Lindzen writes that (1) "the physics of unresolved phenomena such as clouds and other turbulent elements is not understood to the extent needed for incorporation into models," so that (2) models are presently merely "experimental tools whose relation to the real world is questionable," that (3) "current models depend heavily on undemonstrated positive feedback factors to predict high levels of warming," that (4) "there is compelling evidence for all the known feedback factors to actually be negative," that (5) "even supercomputers are inadequate to allow long-term integrations of the relevant equations at adequate spatial resolutions," that (6) "current models all predict that warmer climates will be accompanied by increasing humidity at all levels" but that "such behavior is an artifact of the models since they have neither the physics nor the numerical accuracy to deal with water vapor," and that (7) "the models' predictions for the past century incorrectly describe the pattern of warming and greatly overestimate its magnitude." In this regard, Lindzen further states that a doubling of the air's present CO2 content might lead to a warming of only "0.5 to 1.2 degrees centigrade," which is in harmony with the earlier analyses of Idso (1998), who employed a total of eight separate and independent "natural experiments" to demonstrate that in the real world, "a 300 to 600 ppm doubling of the atmosphere's CO2 concentration" -- which is somewhat less than the doubling of the air's current CO2 concentration referred to by Lindzen -- "could raise the planet's mean surface air temperature by only about 0.4°C."
What it means
Lindzen concludes that "with poor and uncertain models in wide use, predictions of ominous situations are virtually inevitable -- regardless of reality," and, therefore, he says that "it goes almost without saying that the dangers and costs of those economic and social consequences [of doing what the world's climate alarmists want everyone to do] may be far greater than the original environmental danger."
Idso, S.B. 1998. CO2-induced global warming: a skeptic's view of potential climate change. Climate Research 10: 69-82.