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A lie told often enough becomes the truth.
-- Vladimir Ilyich Lenin - See more at: http://thepeoplescube.com/lenin/lenin-s-own-20-monster-quotes-t185.html#sthash.aTrSI3tG.dpuf
A lie told often enough becomes the truth.
-- Vladimir Ilyich Lenin - See more at: http://thepeoplescube.com/lenin/lenin-s-own-20-monster-quotes-t185.html#sthash.aTrSI3tG.dpuf
A lie told often enough becomes the truth.
-- Vladimir Ilyich Lenin - See more at: http://thepeoplescube.com/lenin/lenin-s-own-20-monster-quotes-t185.html#sthash.aTrSI3tG.dpuf

Thursday, 10 May 2012

Reducing CO2 emissions - Not an effective control knob

Did Lacis et al try to turn the control knob up to 12 out of 10?
Tim Curtin’s just published paper (in The Scientific World Journal) uses econometrics to test various propositions underlying claims that observed global temperature change is mostly attributable to human-caused greenhouse gases, mainly carbon dioxide, and that although water vapour is recognized to be a dominant contributor to the overall greenhouse gas (GHG) effect, its effect is merely as a “feedback” from rising temperatures initially resulting only from GHGs and not at all from variations in the pre-existing natural evaporation that produces most atmospheric water vapour and rainfall.  The paper shows that global warming is not exclusively attributable to GHG like CO2, both because atmospheric water vapour existed before there were any significant increases in GHGs or global temperature and also because there is no evidence that such increases have produced measurably higher volumes of evaporation. Thus reducing emissions of CO2 is unlikely to be the effective climate “control knob” claimed by NASA’s Hansen, Schmidt, and Lacis (2010).

The links for the article are  http://www.tswj.com/2012/761473/ and the journal itself - http://www.tswj.com/contents/ 


Research Article
 ScientificWorldJOURNAL
Applying Econometrics to the Carbon Dioxide “Control Knob”
Timothy Curtin
Emeritus Faculty, Australian National University, Canberra, ACT 0200, Australia


Academic Editor: Donald H. Stedman
Copyright © 2012 Timothy Curtin. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This paper tests various propositions underlying claims that observed global temperature change is mostly attributable to anthropogenic noncondensing greenhouse gases, and that although water vapour is recognized to be a dominant contributor to the overall greenhouse gas (GHG) effect, that effect is merely a “feedback” from rising temperatures initially resulting only from “non-condensing” GHGs and not at all from variations in preexisting naturally caused atmospheric water vapour (i.e., [H2O]). However, this paper shows that “initial radiative forcing” is not exclusively attributable to forcings from noncondensing GHG, both because atmospheric water vapour existed before there were any significant increases in GHG concentrations or temperatures and also because there is no evidence that such increases have produced measurably higher [H2O]. The paper distinguishes between forcing and feedback impacts of water vapour and contends that it is the primary forcing agent, at much more than 50% of the total GHG gas effect.
That means that controlling atmospheric carbon dioxide is unlikely to be an effective “control knob” as claimed by Lacis et al. (2010).

Read More at Scientific World Journal...

1 comment:

  1. The following reference is also pertinent - and could be extremely important to the CO2 climate change debate.

    Paltridge, G., Arking, A. and Pook, M. 2009. Trends in middle- and upper-level tropospheric humidity from NCEP reanalysis data. Theoretical and Applied Climatology: 10.1007/s00704-009-0117-x. According to Paltridge et al. (2009), "water vapor feedback in climate models is large and positive," and "the various model representations and parameterizations of convection, turbulent transfer, and deposition of latent heat generally maintain a more-or-less constant relative humidity (i.e., an increasing specific humidity q) at all levels in the troposphere as the planet warms," and they say that this "increasing q amplifies the response of surface temperature to increasing CO2 by a factor or 2 or more." Consequently, knowledge of how q responds to atmospheric warming is of paramount importance to the task of correctly predicting how air temperatures respond to increasing CO2 concentrations. Against this backdrop, Paltridge et al. explored this important subject further by determining trends in relative and specific humidity at various levels in the atmosphere based on reanalysis data of the National Centers for Environmental Prediction (NCEP) for the period 1973-2007.

    The three researchers report that "the face-value 35-year trend in zonal-average annual-average specific humidity q is significantly negative at all altitudes above 850 hPa (roughly the top of the convective boundary layer) in the tropics and southern midlatitudes and at altitudes above 600 hPa in the northern midlatitudes." As a result, Paltridge et al. conclude that "negative trends in q as found in the NCEP data would imply that long-term water vapor feedback is negative - that it would reduce rather than amplify the response of the climate system to external forcing such as that from increasing atmospheric CO2." The ultimate outcome of this dilemma must therefore await a thorough study of the reliability of the pertinent NCEP data, in order to establish, in the words of the three scientists, "what (if any) aspects of the observed [humidity] trends survive detailed examination of the impact of past changes of radiosonde instrumentation and pro tocol within the various international networks" that collected the globe-spanning data that comprise the NCEP reanalysis archive.

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