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  • June « 2012 « RealClimate
    2012 Filed under Climate Science Open thread group 1 June 2012 This month s open thread Comments pop up 408 Site Google Custom Search Recent Comments What is the best description of the greenhouse effect Jim Eager What is the best description of the greenhouse effect Patrick Eriksson What is the best description of the greenhouse effect Kevin McKinney Anti scientists Carbomontanus What is the best description of the greenhouse effect Spencer Marvel et al 2015 Part III Response to Nic Lewis SteveS What is the best description of the greenhouse effect Chris Colose Blizzard Jonas and the slowdown of the Gulf Stream System doiknow What is the best description of the greenhouse effect James Powell Unforced Variations Feb 2016 Jim Galasyn With Inline Responses Marvel et al 2015 Part III Response to Nic Lewis SteveS Marvel et al 2015 Part III Response to Nic Lewis steve s Marvel et al 2015 Part III Response to Nic Lewis Andrew Kerber Blizzard Jonas and the slowdown of the Gulf Stream System Hank Roberts Blizzard Jonas and the slowdown of the Gulf Stream System doiknow Marvel et al 2015 Part III Response to Nic Lewis MartinM Anti scientists Don McKenzie Marvel et al 2015 Part III Response to Nic Lewis Matt Skaggs Anti scientists mikeworst New On line Classes and Models Marcus Pages Acronym index Data Sources Categories Climate Science Aerosols Arctic and Antarctic Carbon cycle Climate impacts Climate modelling El Nino Geoengineering Greenhouse gases Hurricanes Instrumental Record IPCC Oceans Paleoclimate Sun earth connections Communicating Climate Reporting on climate skeptics Extras Attic Comment Policy Contributor Bio s FAQ Glossary In the News Reviews Supplemental data Tutorials hydrological cycle Open thread RC Forum Scientific practice statistics The Bore Hole Books Contributors Highlights Dummies Guide to the latest Hockey Stick controversy El Nino Global

    Original URL path: http://www.realclimate.org/index.php/archives/2012/06/ (2016-02-13)
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  • May « 2012 « RealClimate
    Content changes in recent decades had an incorrect scaling for the GISS model data My error was in assuming that the model output which were in units W yr m2 were scaled for the ocean area only when in fact they were scaled for the entire global surface area see fig 2 in Hansen et al 2005 Therefore in converting to units of 10 22 Joules for the absolute ocean heat content change I had used a factor of 1 1 0 7 x 5 1 x 365 x 3600 x 24 x 10 8 instead of the correct value of 1 61 5 1 x 365 x 3600 x 24 x 10 8 This problem came to light while we were redoing this analysis for the CMIP5 models and from conversations with dana1981 at skepticalscience com These graphs appeared in Dec 2009 May 2010 Jan 2011 and Feb 2012 In each case I have replaced the graph with a corrected version while leaving a link to the incorrect version Links to the figures will return the corrected image and this is noted on the image itself Where possible I used the data that were current at the time of the original post Fortunately this only affects the figures used in these blog postings and not in any publications Apologies for any confusion This figure shows the comparison using the most up to date observational products NODC PMEL The basic picture is unchanged model simulations were able to capture the historical variance in OHC as best we know it now there remains significant structural uncertainty in those estimates There are clear dips related volcanic eruptions Agung El Chichon Pinatubo and an sharp increase in the 1990s Note that in GISS EH same AGCM but with a different ocean model OHC increases at a slightly slower rate than seen with GISS ER above Looking at the last decade it is clear that the observed rate of change of upper ocean heat content is a little slower than previously and below linear extrapolations of the pre 2003 model output and it remains unclear to what extent that is related to a reduction in net radiative forcing growth due to the solar cycle or perhaps larger than expected aerosol forcing growth or internal variability model errors or data processing arguments have been made for all four singly and together Analyses of the CMIP5 models will provide some insight here since the historical simulations have been extended to 2012 including the last solar minimum and have updated aerosol emissions Watch this space References J Hansen Earth s Energy Imbalance Confirmation and Implications Science vol 308 pp 1431 1435 2005 http dx doi org 10 1126 science 1110252 Comments pop up 33 Another fingerprint Filed under Climate modelling Climate Science hydrological cycle Oceans rasmus 20 May 2012 When my kids were younger they asked me why the ocean was blue I would answer that the ocean mirrors the blue sky However I would not think

    Original URL path: http://www.realclimate.org/index.php/archives/2012/05/ (2016-02-13)
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  • April « 2012 « RealClimate
    in 20th century tropical Atlantic SST changes a finding recently reaffirmed by a study published in Nature in showing how changes in radiative forcing from volcanoes can affect ENSO in examining the role of solar variations in explaining the pattern of the Medieval Climate Anomaly and Little Ice Age the relationship between the climate changes of past centuries and phenomena such as Atlantic tropical cyclones and global sea level and even a bit of work in atmospheric chemistry an analysis of beryllium 7 measurements Mike s earliest work as a physicist involved studying the behavior of liquids and solids and trying to understand phenomena such as the structural ordering of high temperature superconductors In the earth sciences he has published on topics as varied as the recovery from the KT boundary mass extinction event and the factors driving long term changes in the volume of the Great Salt Lake He has studied and published on the impacts of historical and projected climate change on everything from the behavior of the Asian Summer Monsoon to Atlantic Hurricanes to rainfall patterns in the U S And for those interested in the hard nosed statistics by which a scientist s productivity gets measured a quick check on the ISI web site will tell you that he has an H Index of 40 that means that 40 of his papers have been cited at least 40 times more than twenty of his papers have over 100 citations each and two have over 700 Those are high numbers by any comparison But back to the hockey stick Mike has weathered some rather intense scrutiny and criticism over the years mostly over the details of a paper nearly 15 years old Yet the basic conclusions of the hockey stick remain and indeed have been strengthened by subsequent work Most will be aware for example that the conclusion that the past few decades are likely the warmest of the past millennium i e the conclusion of the best known of Mike s papers in Nature and Geophysical Research Letters has never been seriously challenged But well beyond the simple fact of having been right Mike s work was seminal like Oeschger s in playing a pivotal role in launching an entirely new field of study Although some earlier work along similar lines had been done by other paleoclimate researchers Ed Cook Phil Jones Keith Briffa Ray Bradley Malcolm Hughes and Henry Diaz being just a few examples before Mike no one had seriously attempted to use all the available paleoclimate data together to try to reconstruct the global patterns of climate back in time before the start of direct instrumental observations of climate or to estimate the underlying statistical uncertainties in reconstructing past temperature changes Since Mike s pioneering work starting in 1995 hundreds of papers have adopted the basic approach he pioneered and numerous PHD projects have been launched to try to improve upon it Methods have improved of course and no doubt will improve further

    Original URL path: http://www.realclimate.org/index.php/archives/2012/04/ (2016-02-13)
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  • March « 2012 « RealClimate
    the last 17 years Plot all the months of these 17 years to get plenty of data points A good idea is to show a streched plot with longer time axis More Comments pop up 119 Updating the CRU and HadCRUT temperature data Filed under Climate Science Instrumental Record gavin 20 March 2012 The latest incarnation of the CRUTEM land surface temperatures and the HadCRUT global temperatures are out this week This is the 4th version of these products which have undergone a number of significant changes over that time and so this is a good opportunity to discuss how and why data products evolve and what that means in the bigger scheme of things More Comments pop up 83 Sherwood Rowland CFCs ozone depletion and the public role of scientists Filed under Climate Science Greenhouse gases group 13 March 2012 Many of you will have read the obituaries of the Nobel Prize winning chemist Sherwood Rowland Nature BBC who sadly died over the weekend DotEarth has a good collection of links to papers videos and tributes More Comments pop up 47 Older Entries Site Google Custom Search Recent Comments What is the best description of the greenhouse effect Jim Eager What is the best description of the greenhouse effect Patrick Eriksson What is the best description of the greenhouse effect Kevin McKinney Anti scientists Carbomontanus What is the best description of the greenhouse effect Spencer Marvel et al 2015 Part III Response to Nic Lewis SteveS What is the best description of the greenhouse effect Chris Colose Blizzard Jonas and the slowdown of the Gulf Stream System doiknow What is the best description of the greenhouse effect James Powell Unforced Variations Feb 2016 Jim Galasyn With Inline Responses Marvel et al 2015 Part III Response to Nic Lewis SteveS Marvel et al 2015 Part III Response to Nic Lewis steve s Marvel et al 2015 Part III Response to Nic Lewis Andrew Kerber Blizzard Jonas and the slowdown of the Gulf Stream System Hank Roberts Blizzard Jonas and the slowdown of the Gulf Stream System doiknow Marvel et al 2015 Part III Response to Nic Lewis MartinM Anti scientists Don McKenzie Marvel et al 2015 Part III Response to Nic Lewis Matt Skaggs Anti scientists mikeworst New On line Classes and Models Marcus Pages Acronym index Data Sources Categories Climate Science Aerosols Arctic and Antarctic Carbon cycle Climate impacts Climate modelling El Nino Geoengineering Greenhouse gases Hurricanes Instrumental Record IPCC Oceans Paleoclimate Sun earth connections Communicating Climate Reporting on climate skeptics Extras Attic Comment Policy Contributor Bio s FAQ Glossary In the News Reviews Supplemental data Tutorials hydrological cycle Open thread RC Forum Scientific practice statistics The Bore Hole Books Contributors Highlights Dummies Guide to the latest Hockey Stick controversy El Nino Global Warming and Anomalous U S Winter Warmth Hurricanes and Global Warming Myth vs Fact Regarding the Hockey Stick On attribution On mismatches between models and observations On Sensitivity Part I Tropical Glacier Retreat Water Vapour feedback

    Original URL path: http://www.realclimate.org/index.php/archives/2012/03/ (2016-02-13)
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  • February « 2012 « RealClimate
    artifact of biological growth effects which lead to a substantial underestimation of the largest volcanic cooling events in trees growing near treeline We speculate that this underestimation may also have led to overly low estimates of climate sensitivity in some past studies attempting to constrain climate model sensitivity parameters with proxy reconstructed temperature changes Tree rings are used as proxies for climate because trees create unique rings each year that often reflect the weather conditions that influenced the growing season that year For reconstructing past temperatures dendroclimatologists typically seek trees growing at the boreal or alpine treeline since temperature is most likely to be the limiting climate variable in that environment But this choice may also prove problematic under certain conditions Because the trees at these locations are so close to the threshold for growth if the temperature drops just a couple of degrees during the growing season there will be little or no growth and therefore a loss of sensitivity to any further cooling In extreme cases there may be no growth ring at all And if no ring was formed in a given year that creates a further complication introducing an error in the chronology established by counting rings back in time More Comments pop up 56 So What s A Teacher to Do Filed under Climate Science group 4 February 2012 Guest Commentary by Eugenie Scott National Center for Science Education Imagine you re a middle school science teacher and you get to the section of the course where you re to talk about climate change You mention the C words and two students walk out of the class Or you mention global warming and a hand shoots up Mrs Brown My dad says global warming is a hoax Or you come to school one morning and the principal wants to see you because a parent of one of your students has accused you of political bias because you taught what scientists agree about that the Earth is getting warmer and human actions have had an important role in this warming Or you pick up the newspaper and see that your state legislature is considering a bill that declares that accepted sciences like global warming and evolution of course are controversial issues that require alternatives to be taught More Comments pop up 217 Older Entries Site Google Custom Search Recent Comments What is the best description of the greenhouse effect Jim Eager What is the best description of the greenhouse effect Patrick Eriksson What is the best description of the greenhouse effect Kevin McKinney Anti scientists Carbomontanus What is the best description of the greenhouse effect Spencer Marvel et al 2015 Part III Response to Nic Lewis SteveS What is the best description of the greenhouse effect Chris Colose Blizzard Jonas and the slowdown of the Gulf Stream System doiknow What is the best description of the greenhouse effect James Powell Unforced Variations Feb 2016 Jim Galasyn With Inline Responses Marvel et al 2015 Part III Response

    Original URL path: http://www.realclimate.org/index.php/archives/2012/02/ (2016-02-13)
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  • January « 2012 « RealClimate
    Australia explaining some of the key drivers of our climate and how some are changing A TV series that ran on Norwegian TV NRK last year included a simple and fun cartoon that demonstrates some important concepts relative to weather and climate In the animation the man s path can be considered as analogous to a directional climatic change while the path traced by his dog s whimsical movements represent weather fluctuations as constrained by the man s path the leash and the dog s moment by moment decisions of what seems important to investigate in his small world What might the leash length represent The man s momentary pause The dog s exact route relative to concepts of random variation The messages in this animation are similar to the recent results of Grant Foster and Stefan Rahmstorf in ERL see post here We d also like to praise the TV series Siffer hosted by an enthusiastic statistician explaining how most things in our world relate to mathematics The series covers a range of subjects for instance gambling theory the Tragedy of the Commons anecdotes about mathematical riddles medical statistics and construction design it even answers why champagne from a large bottle tastes better than that from a smaller one There is also an episode devoted to weather forecasting and climate Success in understanding our universe often depends on how the story about it is told and a big part of that often involves how mental images are presented Mathematics and statistics can describe nature in great detail and elegance but they are often difficult and inaccessible to the average person Conversely the man and dog animation is intuitive and easy to comprehend Similarly Hans Rosling s Fun with Stats provides some very nice demonstrations of how to convey meaning via the creative display of numbers Comments pop up 68 Open Climate 101 Online Filed under Climate Science david 16 January 2012 Almost 3000 non science major undergraduates at the University of Chicago have taken PHSC13400 Global Warming Understanding the Forecast since Ray Pierrehumbert and I David Archer first developed it back in 1995 Since the publication of the textbook for the class in 2005 and a much cleaned up 2nd edition now shipping enrollment has gone through the roof it s all I ve been able to teach the last few years trying to keep up with demand I hear it is the largest class on campus with 4 500 students a year out of an annual class of only around 1400 Now the content of this class is being served to the internet world at large Open Climate 101 More Comments pop up 99 An online model of methane in the atmosphere Filed under Climate Science david 11 January 2012 I ve put together an easy to play with online model of methane in the atmosphere I m going to use it for teaching along with the rest of the Understanding the Forecast webmodels but it was designed

    Original URL path: http://www.realclimate.org/index.php/archives/2012/01/ (2016-02-13)
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  • December « 2011 « RealClimate
    slowdown in energy desire to ask questions and attendance But there were still a lot of good talks to be seen Perhaps most relevant here were a few sessions talking about initial results from the CMIP5 models and the data with which they are being assessed Overall most comparisons to the CMIP3 models showed that despite substantial improvements in resolution completeness and scope the CMIP5 models do not show any dramatic differences at the broad scale diagnostics global means etc This is not particularly surprising since it is expected that the importance of the new simulations will be seen in the differences between model types i e including carbon cycles atmospheric chemistry etc or in new kinds of diagnostics from say the initialized decadal predictions that weren t available before Looking back at the whole meeting 20 000 scientists dozens of simultaneous sessions it is perhaps worth noting the reasons why such meetings are so important Obviously no one can see everything that is relevant to their research or talk to everyone they might want to but there is a lot that can be seen and absorbed much more efficiently than would be possible at home The social aspect of conferences is also important beer is an essential lubricant for geophysicists it seems More important than the sessions are often the chance encounters on the escalators or corridors Many people get to meet in person who only ever emailed and this includes other bloggers as well as scientists We met Eli Rabett John Cook Skeptical Science Zeke Hausfather Kate ClimateSight Steve Easterbrook and many others who are only known by their screen names and comments Many of the scientists whose work has been discussed here recently were also present Andreas Schmittner Robert Rohde of BEST Jim Hansen Ben Santer Roy Spencer along with many many first timers whose work will become more prominent The palpable sense of excitement at the directions the science is taking is very much driven by the bright ideas and new approaches being generated by the younger scientists including undergraduates and graduate students And it is the serendipitous encounters with these new voices that are the most unanticipated and unplanned benefits of these meetings This doesn t happen with Skype unfortunately We know that we didn t see everything we wanted to so if any other attendees are reading this we encourage them to point out in the comments any particular highpoints they came across especially if the talks were part of those broadcast or if the poster is available on line Comments pop up 75 Older Entries Site Google Custom Search Recent Comments What is the best description of the greenhouse effect Patrick Eriksson What is the best description of the greenhouse effect Kevin McKinney Anti scientists Carbomontanus What is the best description of the greenhouse effect Spencer Marvel et al 2015 Part III Response to Nic Lewis SteveS What is the best description of the greenhouse effect Chris Colose Blizzard Jonas and the slowdown

    Original URL path: http://www.realclimate.org/index.php/archives/2011/12/ (2016-02-13)
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  • November « 2011 « RealClimate
    by Bernt Øksendal where it is sourced to a sign outside the mathematics reading room at Tromsø University The actual source appears to be a 1951 report on an education workshop by Earl C Kelley a professor at Wayne University sleuthing by QI Comments pop up 55 Times Atlas map of Greenland to be corrected Filed under Arctic and Antarctic Climate Science Communicating Climate In the News Reporting on climate eric 8 November 2011 We were pleased to hear from the University of Arizona s Jeff Kargel that the Times Atlas folks are now updating their atlas of Greenland As we reported earlier the first edition was completely in error and led to some rather bizarre claims about the amount of ice loss in Greenland Kargel reports that HarperCollins publisher of the Times Atlas has now fully retracted their error and has produced a new map of Greenland that will be made available as a large format 2 side map insert for the Atlas and will also be available free online Meanwhile Kargel and colleagues have produced their own updated small scale map and have written a paper that includes both their new map and a description of the incident that led up to it Kargel was instrumental in pushing the cryosphere community to send a strong message to the publishers that they needed to correct their mistake A pre print of the paper currently under review and under public discussion on Cryolist is available here Figure 1 in Kargel et al 2011 generated by a collaboration of the Geological Survey of Denmark and Greenland GEUS and the Programme for Monitoring of the Greenland Ice Sheet PROMICE with the Polar Geospatial Center Department of Geology and Geophysics University of Minnesota Contact Michele Citterio GEUS for questions about the glacier outlines or Paul Morin UMinn for questions about the MODIS base image mosaic HarperCollins is to be commended for listening to the scientific community and producing a corrected map Unfortunately and despite recent events demonstrating that popular allegations against climate scientists are all wrong HarperCollins still says on their web site that it s all the scientists fault for not being clear The one thing that is very apparent is that there is no clarity in the scientific and cartographic community on this issue they write Hmm Our own view is that anyone flying over Greenland en route to Europe from North America would instantly have recognized a problem with the Times Atlas assuming they knew their location of course As Kargel and colleagues write in their paper Distinguishing manifest ignorable nonsense from falsehoods that might take root in the public mind is difficult but the magnitude of and apparent authority behind this particular mistake seemed to warrant a rapid and firm response The eventually constructive reaction of HarperCollins which not only withdrew its mistaken claim but also produced a new map to be included in the Times Atlas as an insert shows the value of such a response No less

    Original URL path: http://www.realclimate.org/index.php/archives/2011/11/ (2016-02-13)
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