<div>In think Barton Paul Levenson's post in the following discussion regarding the first published response to Lindzen and Choi (2009) contains some excellent answers, backed by scientific research, to some of the common skeptical arguments regarding anthropogenic climate change. I pasted in his response, number 31, after the introduction comments below (or read here: <a href="http://www.realclimate.org/index.php/archives/2007/08/the-co2-problem-in-6-easy-steps/">http://www.realclimate.org/index.php/archives/2007/08/the-co2-problem-in-6-easy-steps/</a> ).</div>
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<div><a href="http://www.realclimate.org/index.php/archives/2010/01/first-published-response-to-lindzen-and-choi/#comment-153884">http://www.realclimate.org/index.php/archives/2010/01/first-published-response-to-lindzen-and-choi/#comment-153884</a></div>
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<h3 id="post-2671" class="storytitle">First published response to Lindzen and Choi</h3>
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<li><a title="View all posts in Climate modelling" href="http://www.realclimate.org/index.php/archives/category/climate-science/climate-modelling/" rel="category tag">Climate modelling</a></li></ul>— gavin @ 8 January 2010 </div>
<div class="entry">
<p>The first published response to <a href="http://www.agu.org/journals/gl/gl0916/2009GL039628/">Lindzen and Choi (2009)</a> (LC09) has just appeared “<a href="http://www.agu.org/journals/pip/gl/2009GL042314-pip.pdf">in press</a>” (subscription) at GRL. LC09 purported to determine climate sensitivity by examining the response of radiative fluxes at the Top-of-the-Atmosphere (TOA) to ocean temperature changes in the tropics. Their conclusion was that sensitivity was very small, in obvious contradiction to the models. </p>
<p>In their commentary, Trenberth, Fasullo, O’Dell and Wong examine some of the assumptions that were used in LC09’s analysis. In their <a href="http://www.realclimate.org/index.php/archives/2010/01/lindzen-and-choi-unraveled">guest commentary</a>, they go over some of the technical details, and conclude, somewhat forcefully, that the LC09 results were not robust and do not provide any insight into the magnitudes of climate feedbacks. </p>
<p>Coincidentally, there is a related paper (Chung, Yeomans and Soden) also <a href="http://www.agu.org.ezproxy.cul.columbia.edu/journals/pip/gl/2009GL041889-pip.pdf">in press</a> (sub. req.) at GRL which also compares the feedbacks in the models to the satellite radiative flux measurements and also comes to the conclusion that the models aren’t doing that badly. They conclude that</p>
<blockquote>
<p>In spite of well-known biases of tropospheric temperature and humidity in climate models, comparisons indicate that the intermodel range in the rate of clear-sky radiative damping are small despite large intermodel variability in the mean clear-sky OLR. Moreover, the model-simulated rates of radiative damping are consistent with those obtained from satellite observations and are indicative of a strong positive correlation between temperature and water vapor variations over a broad range of spatiotemporal scales. </p>
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<p>It will take a little time to assess the issues that have been raised (and these papers are unlikely to be the last word), but it is worth making a couple of points about the process. First off, LC09 was not a nonsense paper – that is, it didn’t have completely obvious flaws that should have been caught by peer review (unlike say, McLean et al, 2009 or Douglass et al, 2008). Even if it now turns out that the analysis was not robust, it was not that the analysis was not worth trying, and the work being done to re-examine these questions is a useful contributions to the literature – even if the conclusion is that this approach to the analysis is flawed.</p>
<p>More generally, this episode underlines the danger in reading too much into single papers. For papers that appear to go against the mainstream (in either direction), the likelihood is that the conclusions will not stand up for long, but sometimes it takes a while for this to be clear. Research at the cutting edge – where you are pushing the limits of the data or the theory – is like that. If the answers were obvious, we wouldn’t need to do research.</p>
<p><strong>Update:</strong> More commentary at <a href="http://dotearth.blogs.nytimes.com/2010/01/08/a-rebuttal-to-a-cool-climate-paper/">DotEarth</a> including a response from Lindzen.</p></div>
<div class="feedback"> <a title="Comment on First published response to Lindzen and Choi" onclick="wpopen(this.href); return false" href="http://www.realclimate.org/?comments_popup=2671">Comments (pop-up) (101)</a></div>
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<div class="commentnumber">31</div>
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<div class="comment-author vcard"><cite class="fn"><a class="url" href="http://bartonpaullevenson.com/" rel="external nofollow">Barton Paul Levenson</a></cite> <span class="says">says:</span> </div>
<div class="comment-meta commentmetadata"><a href="http://www.realclimate.org/index.php/archives/2010/01/first-published-response-to-lindzen-and-choi/comment-page-1/#comment-153810">9 January 2010 at 7:01 AM</a></div>
<p>Josh: 1. Demonstrate causation, not just correlation of CO2 levels relative to global temperature.</p>
<p>BPL: </p>
<p>Fourier, J.-B. J. 1824. “Memoire sur les Temperatures du Globe Terrestre et des Espaces Planetaires.” Annales de Chemie et de Physique 2d Ser. 27, 136-167.</p>
<p>Tyndall, J. 1859. “Note on the Transmission of Radiant Heat through Gaseous Bodies.” Proceed. Roy. Soc. London 10, 37-39.</p>
<p>Arrhenius, S.A. 1896. “On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground.” Phil. Mag. 41, 237-275.</p>
<p>Royer, D.L. 2006. “CO2-forced climate thresholds during the Phanerozoic” Geochim. Cosmochim. Acta 70, 5665-5675.</p>
<p>Came R.E., J.M. Eiler, J. Veizer, K. Azmy, U. Brand, and C.R. Weidman 2007. “Coupling of surface temperatures and atmospheric CO2 concentrations during the Palaeozoic era.” Nature 449, 198-201.</p>
<p>Doney, S.C. et al. 2007. “Carbon and climate system coupling on timescales from the Precambrian to the Anthropocene” Ann. Rev. Environ. Resources 32, 31-66.</p>
<p>Horton, D.E. et al. 2007. “Orbital and CO2 forcing of late Paleozoic continental ice sheets” Geophys. Res. Lett. L19708.</p>
<p>Fletcher, B.J. et al. 2008. “Atmospheric carbon dioxide linked with Mesozoic and early Cenozoic climate change” Nature Geoscience 1, 43-48.</p>
<p>W. M. Kurschner et al. 2008. “The impact of Miocene atmospheric carbon dioxide fluctuations on climate and the evolution of the terrestrial ecosystem”Proc. Natl. Acad. Sci. USA 105, 499-453.</p>
<p>Lean, J.L. and D.H. Rind 2008. “How natural and anthropogenic influences alter global and regional surface temperatures: 1889 to 2006.” Geophys. Res. Lett. 35, L18701.</p>
<p>Royer, D.L. 2008. “Linkages between CO2, climate, and evolution in deep time” Proc. Natl Acad. Sci. USA 105, 407-408.</p>
<p>Zachos, J.C. 2008. “An early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics” Nature 451, 279-283.</p>
<p>2. Use real-world emperical evidence, not flawed computer models.</p>
<p>See above. For carbon dioxide rising, see</p>
<p>Keeling, C.D. 1958. “The Concentration and Isotopic Abundances of Atmospheric Carbon Dioxide in Rural Areas.” Geochimica et Cosmochimica Acta, 13, 322-334.</p>
<p>Keeling, C.D. 1960. “The Concentration and Isotopic Abundances of Carbon Dioxide in the Atmosphere.” Tellus 12, 200-203.</p>
<p>For the new carbon dioxide being anthropogenic in origin, see</p>
<p>Suess, H.E. 1955. “Radiocarbon Concentration in Modern Wood.” Sci. 122, 415-417.</p>
<p>Revelle, R. and H.E. Suess 1957. “Carbon Dioxide Exchange between Atmosphere and Ocean and the Question of an Increase of Atmospheric CO2 During the Past Decades.” Tellus 9, 18-27.</p>
<p>3. Show emperical evidence for temperature rises following CO2 level increases, not before.</p>
<p>Google “PETM,” or check here, where a tight correlation is shown between temperature anomalies and CO2 level in the same year:</p>
<p><a href="http://bartonpaullevenson.com/Correlation.html" rel="nofollow">http://BartonPaulLevenson.com/Correlation.html</a></p>
<p>In a natural deglaciation, temperature rise does indeed precede carbon dioxide increase, because warmer water holds less CO2 and it bubbles out of the ocean. The additional CO2 then raises the temperature further in a feedback. But that is NOT what is happening now. We know the new CO2 is coming from fossil fuels and deforestation, not the ocean, through its radioisotope signature.</p>
<p>4. Demonstrate that CO2 is the sole major forcing in global temperature changes, not a minor player in a much larger game, involving clouds, solar flux and CRF.</p>
<p>This is a straw-man argument. Nobody competent ever said CO2 was “the sole major forcing in global temperature changes.” It happens to be the major (not the only) cause of the present global warming, but at other epochs other causes have been more important. See the Lean paper referenced above for an example of how they sort out change attribution.</p>
<p>5. Show that CO2 levels and greenhouse effect is not already saturated.</p>
<p>At the lowest levels of the atmosphere, it is mostly saturated–and it doesn’t matter. The atmosphere as a whole is *never* entirely saturated, and can’t be, and every level contributes to the surface temperature. Please read:</p>
<p><a href="http://bartonpaullevenson.com/Saturation.html" rel="nofollow">http://BartonPaulLevenson.com/Saturation.html</a></p>
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<p>Vision2020 Post: Ted Moffett</p></div></div>