cc: Kevin Trenberth , Phil Jones , j.renwick@niwa.co.nz, b.mullan@niwa.co.nz date: Thu, 23 Jul 2009 20:04:37 -0400 from: Michael Mann subject: Re: ENSO blamed over warming - paper in JGR to: Jim Salinger first email: ________ hi Seth, you always seem to catch me at airports. only got a few minutes. took a cursory look at the paper, and it has all the worry signs of extremely bad science and scholarship. JGR is a legitimate journal, but some extremely bad papers have slipped through the cracks in recent years, and this is another one of them. first of all, the authors use two deeply flawed datasets that understate the warming trends: the Christy and Spencer MSU data and uncorrected radiosonde temperature estimates. There were a series of three key papers published in Science a few years ago, by Mears et al, Santer et al, and Sherwood et al. see Gavin's excellent RealClimate article on this: [1]http://www.realclimate.org/index.php/archives/2005/08/et-tu-lt/ these papers collectively showed that both datasets were deeply flawed and understate actual tropospheric temperature trends. I find it absolutely remarkable that this paper could get through a serious review w/out referencing any 3 of these critical papers--papers whose findings render that conclusions of the current article completely invalid! The Christy and Spencer MSU satellite-derived tropospheric temperature estimates contained two errors--a sign error and an algebraic error--that had the net effect of artificially removing the warming trend. Christy and Spencer continue to produce revised versions of the MSU dataset, but they always seem to show less warming than every other independent assessment, and their estimates are largely disregarded by serious assessments such as that done by the NAS and the IPCC. So these guys have taken biased estimates of tropospheric temperatures that have artificially too little warming trend, and then shown, quite unremarkably, that El Nino dominates much of what is left (the interannual variability). the paper has absolutely no implications that I can see at all for the role of natural variability on the observed warming trend of recent decades. other far more careful analyses (a paper by David Thompson of CSU, Phil Jones, and others published in Nature more than year ago) used proper, widely-accepted surface temperature data to estimate the influence of natural factors (El Nino and volcanos) on the surface temperature record. their analysis was so careful and clever that it detected a post-world war II error in sea surface temperature measurements (that yields artificial cooling during the mid 1940s) that had never before been discovered in the global surface temperature record. needless to say, they removed that error too. and the correct record, removing influences of ENSO, volcanoes, and even this newly detected error, reveal that a robust warming of global mean surface temperature over the past century of a little less than 1C which has nothing to do w/ volcanic influences or ENSO influences. the dominant source of the overall warming, as concluded in every legitimate major scientific assessment, is anthropogenic influences (human greenhouse gas concentrations w/ some offsetting cooling due to sulphate aerosols). this later paper provides absolutely nothing to cast that in doubt. it uses a flawed set of surface temperature measurements for which the trend has been artificially suppressed, to show that whats left over (interannual variability) is due to natural influences. duh! its a joke! and the aptly named Mark "Morano" has fallen for it! m On Jul 23, 2009, at 7:57 PM, Jim Salinger wrote: Precisely. Mike Mann: You better rush something up on RealClimate. Jim, Brett, myself and maybe others will have to deal with the local fallout this will cause...oh dear...... Bye the way June was the warmest month on record for the oceans according tro NOAA Jim Quoting Kevin Trenberth <[2]trenbert@ucar.edu>: Exactly They use 2 datasets that are deficient in the first place and then they use derivatives: differentiation is a high pass filter, and so they show what we have long known that ENSO accounts for a lot of high frequency variability. It should not have been published Kevin kia orana from Rarotonga How the h... did this get accepted!! Jim Dominion today {24/7/09] Nature blamed over warming - describing recently published paper in JGR by Chris de Freitas, Bob Carter and J McLean, and including comment by J Salinger "little new" McLean J. D., C. R. de Freitas, R. M. Carter (2009), Influence of the Southern Oscillation on tropospheric temperature, J. Geophys. Res., 114, D14104, doi:10.1029/2008JD011637. paper at [3]http://www.agu.org/pubs/crossref/2009/2008JD011637.shtml -- Associate Professor Jim Salinger School of Geography and Environmental Science University of Auckland Private Bag 92 019 Auckland, New Zealand Tel: + 64 9 373 7599 ext 88473 ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. ___________________ Kevin Trenberth Climate Analysis Section, NCAR PO Box 3000 Boulder CO 80307 ph 303 497 1318 [4]http://www.cgd.ucar.edu/cas/trenbert.html ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. -- Michael E. Mann Professor Director, Earth System Science Center (ESSC) Department of Meteorology Phone: (814) 863-4075 503 Walker Building FAX: (814) 865-3663 The Pennsylvania State University email: [5]mann@psu.edu University Park, PA 16802-5013 website: [6]http://www.meteo.psu.edu/~mann/Mann/index.html "Dire Predictions" book site: [7]http://www.essc.psu.edu/essc_web/news/DirePredictions/index.html