Editing Richard Lindzen (section)

===Climate sensitivity===
Lindzen hypothesized that the Earth may act like an [[Iris hypothesis|infrared iris]]. A [[sea surface temperature]] increase in the tropics would result in reduced [[cirrus cloud]]s and thus more [[infrared radiation]] leakage from Earth's atmosphere.{{Sfn | Lindzen | Chou | Hou | 2001}} Additionally, rising temperatures would cause more extensive drying due to increased areas of [[subsidence (atmosphere)|atmospheric subsidence]]. This hypothesis suggests a negative feedback which would counter the effects of {{CO2}} warming by lowering the [[climate sensitivity]]. Satellite data from [[Clouds and the Earth's Radiant Energy System|CERES]] has led researchers investigating Lindzen's theory to conclude that the Iris effect would instead warm the atmosphere.<ref>{{cite journal | first1=Bing | last1=Lin | title = The iris hypothesis: a negative or positive cloud feedback? | journal=Journal of Climate | year=2002 | volume=15 | issue=1 | pages=3–7 | bibcode=2002JCli...15....3L | doi = 10.1175/1520-0442(2002)015<0003:TIHANO>2.0.CO;2|display-authors=etal| doi-access=free }}</ref><ref name="NASA satellite instrument warms up global cooling theory">{{cite press release | url = http://www.nasa.gov/centers/langley/news/releases/2002/02-005.html | title=NASA satellite instrument warms up global cooling theory | first1 =Chris | last1 = Rink | first2 = Julia | last2 = Cole | publisher=[[NASA]] | date=January 16, 2002}}</ref> Lindzen disputed this, claiming that the negative feedback from high-level clouds was still larger than the weak positive feedback estimated by Lin et al.<ref>{{cite journal | first1=Ming-Dah | last1=Chou | first2=Richard S. | last2=Lindzen | first3 = Arthur Y.  | last3=Hou | title=Comments on "The Iris Hypothesis: A Negative or Positive Cloud Feedback?" | journal=Journal of Climate | year=2002 | volume=15 | issue= 18 | pages= 2713–15 | bibcode= 2002JCli...15.2713C | doi = 10.1175/1520-0442(2002)015<2713:COTIHA>2.0.CO;2| citeseerx=10.1.1.232.8350 }}</ref>

Lindzen has expressed his concern over the validity of [[climate model|computer models]] used to predict future climate change. Lindzen said that predicted warming may be overestimated because of their handling of the climate system's [[water vapor feedback]]. The feedback due to water vapor is a major factor in determining how much warming would be expected to occur with increased atmospheric concentrations of [[carbon dioxide]], and all existing computer models assume positive feedback — that is, that as the climate warms, the amount of water vapour held in the atmosphere will increase, leading to further warming. By contrast, Lindzen believes that temperature increases will actually cause more extensive drying due to increased areas of [[subsidence (atmosphere)|atmospheric subsidence]] as a result of the Iris effect, nullifying future warming.<ref name = stevenswnyt>{{cite news | last =Stevens | first = William K. | date=June 18, 1996 | title=Scientist at work: Richard S. Lindzen; A Skeptic Asks, Is It Getting Hotter, Or Is It Just the Computer Model? | url= https://www.nytimes.com/1996/06/18/science/scientist-work-richard-s-lindzen-skeptic-asks-it-getting-hotter-it-just-computer.html?pagewanted=1 | work =The New York Times | access-date=May 22, 2010}}</ref> This claim was criticized by [[climatologist]] [[Gavin Schmidt]], Director of [[NASA]]'s [[Goddard Institute for Space Studies]], who notes the more generally-accepted understanding of the effects of the Iris effect and cites empirical cases where large and relatively rapid changes in the climate such as [[El Niño]] events, the [[Ultra-Plinian]] [[1991 eruption of Mount Pinatubo|eruption of Mount Pinatubo in 1991]], and recent trends in global temperature and water vapor levels show that, as predicted in the generally-accepted view, water vapor increases as the temperature increases, and decreases as temperatures decrease.<ref name=GSchmidtContraLindzen>{{cite web | last = Schmidt | first = Gavin | date= February 14, 2006 | title=Richard Lindzen's HoL testimony | url=http://www.realclimate.org/index.php/archives/2006/02/richard-lindzens-hol-testimony/ | publisher=Real Climate}}</ref>

Contrary to the [[IPCC Third Assessment Report|IPCC's assessment]] in 2001, Lindzen said that climate models are inadequate. Despite accepted errors in their models, e.g., treatment of clouds, modelers still thought their climate predictions were valid.<ref name= guterlfnewsweek>{{cite magazine | last =Guterl | first = Fred | date=July 23, 2001 | title=The Truth About Global Warming | url=http://www.newsweek.com/id/78772/page/1 | magazine=Newsweek | access-date=2009-07-26}}</ref> Lindzen has stated that due to the non-linear effects of carbon dioxide in the atmosphere, CO<sub>2</sub> levels are now around 30% higher than pre-industrial levels but temperatures have responded by about 75% {{convert|0.6|C-change|2|abbr=on}} of the expected value for a doubling of CO<sub>2</sub>. The IPCC (2007) estimates that the expected rise in temperature due to a doubling of CO<sub>2</sub> to be about {{convert|3|C-change|abbr=on}}, ± 1.5°. Lindzen has given estimates of the Earth's climate sensitivity to be 0.5&nbsp;°C based on ERBE data.<ref name=erbe>{{cite journal | first1=Richard S. | last1=Lindzen | title=On the determination of climate feedbacks from ERBE data | journal=Geophysical Research Letters | year=2009 | volume=36 | issue=16 | pages=L16705 | bibcode=2009GeoRL..3616705L | doi=10.1029/2009GL039628 | display-authors=etal | doi-access=free }}</ref> These estimates were criticized by [[Kevin E. Trenberth]] and others,<ref>{{cite web |title=Working out climate sensitivity from satellite measurements |url=http://www.skepticalscience.com/Lindzen-Choi-2009-low-climate-sensitivity.htm |author=dana1981 |date=July 6, 2012 |work=Skeptical Science |access-date=December 20, 2022}}</ref> and Lindzen accepted that his paper included "some stupid mistakes". When interviewed, he said "It was just embarrassing", and added that "The technical details of satellite measurements are really sort of grotesque." Lindzen and Choi revised their paper and submitted it to ''[[Proceedings of the National Academy of Sciences of the United States of America|PNAS]]''.<ref name="www.nytimes 120501">{{cite news  | last = Gillis | first = Justin | title = Clouds' Effect on Climate Change Is Last Bastion for Dissenters  | url = https://www.nytimes.com/2012/05/01/science/earth/clouds-effect-on-climate-change-is-last-bastion-for-dissenters.html?pagewanted=3&_r=3& | newspaper =  New York Times | date = May 1, 2012 | access-date = January 24, 2014 }}</ref> The four reviewers of the paper, two of whom had been selected by Lindzen, strongly criticized the paper and PNAS rejected it for publication.<ref>{{Cite web | last = Schekman | first = Randy | author-link = Randy Schekman | title = Title: On the observational determination of climate sensitivity and its implications Ms. No.: 2010-15738 | url = http://www.masterresource.org/wp-content/uploads/2011/06/Attach3.pdf | publisher = PNAS Office | date = January 19, 2011 | access-date = January 24, 2014 | url-status = dead | archive-url = https://web.archive.org/web/20120619054256/http://www.masterresource.org/wp-content/uploads/2011/06/Attach3.pdf | archive-date = June 19, 2012 | df = mdy-all }}</ref> Lindzen and Choi then succeeded in getting a little known Korean journal to publish it as a 2011 paper.<ref name="www.nytimes 120501" /><ref>{{Cite journal | first1 = Richard S. | last1=Lindzen | first2=Yong-Sang  | last2=Choi | title=On the observational determination of climate sensitivity and its implications | journal=Asia-Pacific Journal of the Atmospheric Sciences | year=2011 | volume=47 | issue=4 |pages=377–390 | bibcode = 2011APJAS..47..377L | doi= 10.1007/s13143-011-0023-x| citeseerx=10.1.1.167.11 | s2cid=9278311 }}</ref> [[Andrew Dessler]] published a paper which found errors in Lindzen and Choi 2011, and concluded that the observations it had presented "are not in fundamental disagreement with mainstream climate models, nor do they provide evidence that clouds are causing climate change. Suggestions that significant revisions to mainstream climate science are required are therefore not supported."<ref>{{Cite journal | doi = 10.1029/2011GL049236| title = Cloud variations and the Earth's energy budget| year = 2011| last1 = Dessler | first1 = A. E.| journal = Geophysical Research Letters| volume = 38| issue = 19| pages = n/a|bibcode = 2011GeoRL..3819701D | citeseerx = 10.1.1.362.5742| s2cid = 17463106}}</ref>