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  • Global dimming and global warming « RealClimate
    ch people wild 2006GL028031 pdf As I don t get why Stanhill references that but still sees a problem it seems likely I need to consider deeper than my half hour lunchbreak allows Wild et al above is of interest in terms of diurnal range changes as a finger print of CO2 driven warming 13 Surly says 15 Nov 2007 at 8 37 AM Climate Audit won best science blog What is this world coming to 14 Charles Muller says 15 Nov 2007 at 9 13 AM A general comment I used to think it s global brightening GB 1990 2002 rathe than global dimming of the previous decades that poses a challenge to climate models detection attribution for the recent significatve warming 1977 2006 This brings at least three questions did Earth really experience a 12 or 15 yrs of increasing insolation on surface that is is GB a reality or an artifact of poor climatologies if so what was the amount of energy imbalance for the period and could this have influenced the temperature records specifically the temperature trends of the 1990s and early 2000s finally do AR4 climate models reproduce the trend the graph above is not clear for the most recent period 15 Lynn Vincentnathan says 15 Nov 2007 at 9 34 AM I m not sure what you all are saying I don t have time to delve Is it this someone pointed out that due to the aerosol effect there has been some global dimming this contradicts the global warming theory Which we all know is fasle since the climate scientists have been taking this aeosol effect into account and actually only when they do take it into account does the actual data make sense And no mention of how global dimming may be masking a truly alarming global warming once the aerosol effect goes away which it would at least due to the fact that the aeosols only last a short time in the atmosphere while CO2 lasts a long long time And that the actual sensitivity of warming to GHGs might be perhaps higher than figured due to this aerosol effect Is that it or am I missing something The reason I ask is that there are some people who are at a much lower stage of scientific savvy on this entire issue of GW who might like to understand this site 16 Hank Roberts says 15 Nov 2007 at 10 02 AM Surly you re mistaken Where did you get your belief Why do you trust your source Do you know how to look this up for yourself 17 Hank Roberts says 15 Nov 2007 at 11 20 AM http www thaindian com newsportal health india getting five percent less sunlight now than in 1980 due to industrial pollution 1005239 html November 15th 2007 Padma Kumari and her colleagues at the Indian Institute of Tropical Meteorology in Pune reckon that the country is getting about five per cent less sunlight than it did 20 years ago The researchers studied data from the India Meteorological Department and measured differences in solar radiation at 12 stations across the country between 1981 and 2004 http weblogawards proboards85 com index cgi board 2007pollchanges 18 Hank Roberts says 15 Nov 2007 at 11 38 AM http www tellinya com read 2007 11 09 science blogs 2007 anatomy of a break in 19 henry says 15 Nov 2007 at 1 59 PM Comment by Steve Reynolds As Timothy says that chart does convey a lot of info Any reason for it stopping in 2000 Second try Also can you think of any reason why the same averaging periods are not used for both Could these charts be updated showing current temps and rad with a 30 year averaging period ending in 2000 Response The averaging period for the dimming is so that it is lined up with the satellite obs and for the SAT it was for graphical convenience In each case the different trends are apparent in the early part of the record The models only go up to 2000 with observed forcings and that is why they are truncated then The satellite data have not yet been processed AFAIK for the 2000 period gavin 20 marko says 15 Nov 2007 at 4 03 PM There was a Nova episode PBS regarding the Global Dimming People were clued in when they looked at the pan evaporation rates and saw it did not jive with temperature record Good episode and it was what brought me here to this site to learn more of the underlying science So thanks Y all Though I am curious too where would we be without the global dimming which has essentially masked global warming from what I understand 21 CobblyWorlds says 15 Nov 2007 at 4 47 PM 12 CORRECTION My ref to Wild et al I quoted the wrong paper What I link to may still be useful in the context of this issue but it is not cited by Stanhill In Stanhill s paper is he really right to implicitly equate the TOA defined radiative forcing change with a change in surface insolation 2 4 vs 20 watts m2 Or is my understanding flawed 14 Charles Muller Read the paper I refer to in 12 section 3 re temperature impacts Increased insolation is suggested to have caused the reduction in diurnal trend to desist more surface insolation raised daytime warming rates I for one am happy to see people including Gavin discuss their papers here as an amateur it s hard to keep a view of how much significance to research without comment to guide that And as a penniless amateur I rely upon what researchers put in their publications pages More guests please Figen Mekik s involvement in her thread was very useful 22 Surly says 15 Nov 2007 at 6 00 PM Hank if you re referring to me in 16 I did google the topic and apparently Bad Astronomy and Climate Audit tied for first place although it looks as if there was a bit of skullduggery at play in the vote 23 Chris C says 15 Nov 2007 at 6 17 PM good stuff I seen the two other responses in EOS Silliness 24 Richard Ordway says 15 Nov 2007 at 7 21 PM Yes that method seems successful for the Climate Audit blog if I am allow to mention it that just won the best science blog Weblog award They are voted on by the public and not scientific entities and you may place a vote every 24 hours One report I read stated that most Americans don t even know the defintion for area and think that creationism is more likely than evolution so if it sounds real duh it must be real http 2007 weblogawards org news voting rules php 25 Jim Galasyn says 15 Nov 2007 at 8 59 PM Somewhat OT but I m very interested to hear thoughts Climate change worse than predicted A REPORT by Australian scientists has warned that the world is warming faster than predicted by the United Nations top climate change body The report prepared by Dr Graeme Pearman former head of the CSIRO s atmospheric research unit found temperatures and greenhouse pollution were rising faster than forecast by the Intergovernmental Panel on Climate Change IPCC The report prepared for the Climate Institute noted that the IPCC s recent Fourth Assessment Report used material published up to mid 2006 but many important new observations had been published since These suggest that the IPCC assessment is underestimating the risks of adverse impacts due to increased warming during this century and that impacts previously considered to be at the upper end of likelihood are now more probable the report reads Greenhouse emissions are rising faster than the worst case IPCC scenarios 26 Jim Galasyn says 15 Nov 2007 at 9 06 PM Climate Audit tied with Bad Astronomy both with exactly 20 000 votes Not sure what the deal was there Best Science Blog By Kevin Aylward on November 1 2007 2 09 PM We are announcing a tie between Bad Astronomy Blog and Climate Audit so there will be two winners in this category Both blogs agree with this decision We thank them both for helping resolve the issues that affected this poll as voting closed Thursday 27 chip says 16 Nov 2007 at 12 04 AM A quick comment on the Australian story posted earlier I know skepticism is usually derided on this blog but it s stories like this that make me think a little skepticism is warranted The newspaper treats the Climate Institute as an independent scientific body but if you look at the Institute s website you find this reason for its founding The impetus for this was simple a belief that the extreme urgency of the situation requires decisive commitment and action from government and industry on a grand scale So it s an advocacy group There s nothing wrong with that of course but I wouldn t call it objective science either That the media goes along with the charade is more than enough reason to be skeptical For what it s worth I think the planet has been warming and that people are partly responsible But almost everything other than these two points is very complex the extent of the warming and our influence the ramifications economic and societal costs and benefits etc So the crowing about consensus and the sneering at denialists comes across as simplistic and rather juvenile 28 Steve Reynolds says 16 Nov 2007 at 12 49 AM Climate Audit tied with Bad Astronomy both with exactly 20 000 votes Not sure what the deal was there Clear explanation here Some of you have been understandably a little puzzled and seeking to interpret the matter Here s a bit of the background http www climateaudit org p 2347 29 Timothy Chase says 16 Nov 2007 at 2 43 AM Jim Galasyn 25 wrote Somewhat OT but I m very interested to hear thoughts Climate change worse than predicted Well there is the difference between the destructive effects of the warming which are looking like they will be worse than what the IPCC expected judging from the rate of loss on Artic sea ice acceleration of Greenland the West Antarctic Peninsula the weakening of the carbon sinks the extreme weather which we are already seeing etc the rise in greenhouse gases which is worse than what the IPCC projected and the rise in temperatures themselves Different timescales The effects of accelerating CO2 emissions We aren t seeing them yet nor should we be The effects of carbon dioxide are cummulative and seven years aren t much time to accumulate those effects Remember what we do now won t change things much at all for the next thirty or forty years We will just be paying for our past sins at least as far as CO2 is concerned But by the end of the century what we do from here on out will be the difference between temperatures rising by 7 F and 15 F in some parts 30 John Mashey says 16 Nov 2007 at 3 28 AM re 10 Nick And a really great way to do it is to check Tufte s website for his course schedule and sign up you get all 4 books as part of the package which is about 50 of the total cost leaving only the price of about 4 tanks of gasoline Very well worth it All the books are good for insight but the newer ones are truly beautiful 31 Alexander Ac says 16 Nov 2007 at 4 04 AM What about evaporation then There are claims that potential evaporation actually decreased within the last decades Increased diffuse radiation decreases evaporative demand more than do increased air temps More here http www science org au natcoms pan evap pdf 32 Paul Gosling says 16 Nov 2007 at 6 00 AM Gavin Re your response to my comment 11 I had a look at the global dimming posts most of the data are from the Northern Hemisphere and all are taken on land a reduction of about 4 in three decades Since the late 1980s a recovery seems to be occurring but the studies demonstrating this are not yet published Which suggests that the data are regional at best and with the recovery reported show no overall trend in the observational record So I come back to my original point that there is no overall trend in the observational data and the argument relies heavily on models which are a poor match for observational data 33 cce says 16 Nov 2007 at 10 28 AM Not sure if anyone has done any regional studies comparing local emissions to dimming but global sulfur dioxide emissions peaked in the late 80s and have since fallen to about 1970 levels Response Only true for US definitely and Europe possibly Definitely not true for China and India and therefore unlikely to be true for the globe gavin 34 Jim Galasyn says 16 Nov 2007 at 11 02 AM Thanks to Steve for explanation on the vote Fun with online polls never stops 35 Francis Massen says 16 Nov 2007 at 1 15 PM I fully agre with Paul Gosling 11 and 32 that the observational data in the given plot do not show any dimming but on the contrary rather a brightening if you omit the Pinatubo caused negative spike I really would like to see observational data confirming the hypothesized dimming for both NH and SH My own solar measurements done in Luxembourg show an increase in solar energy and in sunshine duration since 1998 sure this is a local trend so I do not claim global valididy See here 36 dhogaza says 16 Nov 2007 at 1 53 PM So the crowing about consensus and the sneering at denialists comes across as simplistic and rather juvenile Except for the fact that the scientific consensus in no way depends on advocacy groups making your statement a bit of a strawman 37 Adam says 16 Nov 2007 at 2 07 PM I m going to ask an off topic question here mostly to settle a debate with some denialists At this point the earth s current tilt is about 23 5 degrees does this angle put more radiation in the NH Could this contribute at all to NH warming Thanks for any input 38 David B Benson says 16 Nov 2007 at 2 43 PM Adam 37 Orbital forcing by not only precession but the strictly orbital parameters as well is well understood According to orbital forcing theory the climate should have been slowly cooling for the last several thousand years and continue to do so for the next 20 000 years 39 stuart says 16 Nov 2007 at 3 19 PM Adam have you considered that the earth rotates around the Sun The tilt of the earth means that the NH gets more radiation in half the orbit and the SH gets more radiation in the other half We call the result seasons Response Be nice It s conceivable that Adam is really talking about the precession which does make a difference to NH summers However we are currently at almost the least favorable position for NH summer warmth it was much more favorable 9000 years ago gavin 40 Adam says 16 Nov 2007 at 3 26 PM Thanks David Is there a link were I can learn more 41 Barton Paul Levenson says 16 Nov 2007 at 3 48 PM Adam posts I m going to ask an off topic question here mostly to settle a debate with some denialists At this point the earth s current tilt is about 23 5 degrees does this angle put more radiation in the NH Could this contribute at all to NH warming Thanks for any input Only for half the year The other half it contributes to SH warming The Earth s rotational axis is fixed with respect to the stars not the sun 42 David B Benson says 16 Nov 2007 at 4 37 PM Adam 40 Here is one place to get started http www aip org history climate cycles htm 43 David B Benson says 16 Nov 2007 at 5 12 PM Adam 40 Some analysis of orbital forcing http tamino wordpress com 2007 02 16 by request 44 Richard Ordway says 16 Nov 2007 at 7 13 PM Adam posts I m going to ask an off topic question here mostly to settle a debate with some denialists At this point the earth s current tilt is about 23 5 degrees does this angle put more radiation in the NH Could this contribute at all to NH warming Thanks for any input The basic idea as far as I understand it others feel free to jump in is that the obliquity tilt is about 1 2 way now between its two extremes and is decreasing the warming effect on the NH The current tilt is 23 5 and it is decreasing by about 0 00013 per year Obliquity controls the seasonal variations As the axial tilt decreases the differences between seasons decrease In general these combined three long term Milankovitch forcings are heading us into an ice age in perhaps another 15 000 years or so as we have been doing for the last 6000 years until we humans started changing this cycle about 1750 by burning fossil fuels and adding greenhouse gases and making the Earth s average surface temps warmer and the stratosphere and mesosphere colder our new human caused geologic age is sometimes named the Anthropocene I understand that all three Milankovitch cycles are presently about in the middles of their forcings This has helped create a strangely calm last 10 000 years Holocene The last time

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  • Aerosols, Chemistry and Climate « RealClimate
    Cerf seems to think that Gore was instrumental in creating the internet and he was actually there Where were you 13 Richard Wesley says 13 Jul 2008 at 4 38 PM Sorry my cite was removed for some reason 14 Al Crawford says 13 Jul 2008 at 5 21 PM In an interesting bit of information the AP is reporting that a Rutgers University yellow submarine named Scarlet Knight is collecting raw data on the temperature and salinity of the seawater A comment on Al Gore In the late 1980 s and early 1990 s Al Gore was promoting the internet heavily This was a time when I was using the predecessor of the internet At that time I thought he was a person of vision and influence concerning the potential of the internet It was unfortunate that he misspoke about inventing the internet But he did see its potential before many others His vision about the internet then and his vision about the climate now are to be commended 15 Hank Roberts says 13 Jul 2008 at 6 33 PM Al Crawford writes ignoring all the help checking the story It was unfortunate that he misspoke about inventing You misspeak since that s not what the man said Check your sources If you believe what you write is true where are you getting it why do you consider your source reliable on this Who s your authority 16 Chuck Booth says 13 Jul 2008 at 9 11 PM Re Al Gore and the invention of the Internet Perhaps we can put this to rest once and for all and get back on topic In March 1999 Gore told CNN s Wolf Blitzer that he took the initiative in creating the Internet According to Stephen Wolff of Cisco Systems who oversaw the National Science Foundation s NSFnet the Internet s immediate precursor in 1986 then senator Gore pushed through legislation requiring a White House study on whether telephone companies could create a national network It s what the Internet is now said Wolff Ref Science Vol 283 March 1999 page 1975 17 Al Crawford says 13 Jul 2008 at 9 42 PM If you believe what you write is true where are you getting it why do you consider your source reliable on this Who s your authority My source is my memory I remember when he said it and it gained wide coverage in the press and on TV So I do consider my source reliable Now he did not really mean to say he invented the internet but rather that he played a part in its development which he did from a political standpoint And he quickly put out corrections But what he actually said certainly came out that he was claiming the invention of the internet He misspoke If you can find a source that contradicts my memory then so be it But that is what I remember 18 Timothy Chase says 13 Jul 2008 at 10 28 PM Al Crawford wrote in 17 But what he actually said certainly came out that he was claiming the invention of the internet He misspoke If you can find a source that contradicts my memory then so be it But that is what I remember Here is a recording with sound effects added by someone who clearly doesn t like Gore where Gore says I took the initiative in creating the internet You can listen to it yourself During my service in the United States congress I took the initiative in creating the internet http www youtube com watch v LpxtKcLSFWw Here is the context that it is ripped from But it will emerge from my dialogue with the American people I ve traveled to every part of this country during the last six years During my service in the United States Congress I took the initiative in creating the Internet I took the initiative in moving forward a whole range of initiatives that have proven to be important to our country s economic growth and environmental protection improvements in our educational system Al Gore invented the Internet resources by Seth Finkelstein http www sethf com gore He is clearly claiming credit not for inventing the internet but for leading the legislative action necessary to make it a reality The word invent first appeared in a mailing list message headline by a reporter for a Republican press release There is a link to the message in the analysis by Seth Finkelstein which I linked to above Incidentally I didn t have to rely upon memory which is a good thing as my memory isn t that great Instead I just looked it up on the internet First at YouTube using Gore internet as the search terms to get the recording then in Google using the words in the recording to get the context Took maybe thirty seconds total 19 Rod B says 13 Jul 2008 at 11 03 PM I too was involved with what became the internet in the mid 80s and truth in lending I am not an Al Gore supporter or admirer He did state that he invented the internet As I recall it was an inadvertent overstatement and a misspeak No Hank I m not going to round up all the peer reviewed papers on it I think in the run up to the 2000 campaign However as Senator if memory serves Gore he was tremendously influential with the White House s Office of Telecommunication Policy OTP and NSF and Congress to get funding and support for transforming the internet from the then network a very small restricted to a few Universities National Labs and the like and to be used only for academic research and funded mostly by NSF into the precursor of what it is today with ubiquitous and widespread including commercial com access and use Invent it No Damn important to its growing up Yes Is this deja vu 20 Al Crawford says 14 Jul 2008 at 12 11 AM There is a full moon out tonight no I do not have a reference and it is cloudy where I am at so I can t really see but I know there is a full moon out tonight Why do I know because of all of the silly stuff in this thread since I made my comment about Al Gore 14 I made a post about a cute yellow sub that is zipping along in the Atlantic using only the power of the currents And it is collecting a bunch of raw data about the ocean Then as a side note I made what I thought was a complement to Al But I didn t give a reference And all hades broke loose And I am completely confused about how all of this is related to the climate I think I will go to bed and sleep on it Maybe when I wake in the morning all the werewolves will be gone P S Check out We Can Solve It and join Al s effort at saving the world And you might also like to go to http www climatecrisis net also in honor of Al 21 Jim Peden says 14 Jul 2008 at 12 38 AM Al Gore s exact words were I took the initiative in creating the internet I ll leave it to the semantics experts to decide whether creating and inventing are the same thing Actually ARPANET had been in operation before Gore joined the Senate so the internet as we know it today was more of a release for public and corporate consumption of an entity which had previously been the exclusive domain of a few universities and their government funding agencies Actually Big Business pushed harder for public participation than private individuals who generally didn t have a clue I don t like Al Gore for many reasons but if he took a leadership role in prying it away from the Ivory Tower crowd and their funding sources then I m forced to tip my hat to him as a man with an exceptionally accurate long range vision for it s possibilities 22 John Mashey says 14 Jul 2008 at 12 50 AM Rod B Al Crawford You want to believe something that simply DID NOT happen Gore chose his words rather carefully and the Finkelstein reference in 18 is useful in understanding the real sequence I got a copy of the Vint Cerf Bob Kahn letter when it came out One of Dave Farber s friends forwarded it to me It was accurate then and that hasn t changed 23 Jim Eaton says 14 Jul 2008 at 1 00 AM For those of you who trust Snopes com to sniff out urban legends you can check out http www snopes com quotes internet asp Snopes agrees with Richard Hank Chuck and Timothy that invent is pure fiction 24 dhogaza says 14 Jul 2008 at 2 06 AM He did state that he invented the internet No one has EVER come up with a source that shows he actually said that The quote s well known and is as has been given above he claimed credit for taking the INITIATIVE in creating it through funding As I recall it was an inadvertent overstatement and a misspeak No Hank I m not going to round up all the peer reviewed papers on it Because of course he never actually said it You want to BELIEVE he said it nothing more 25 Timo Hämeranta says 14 Jul 2008 at 2 21 AM Well always please consider what we don t know e g Fuzzi S M O Andreae B J Huebert M Kulmala T C Bond M Boy S J Doherty A Guenther M Kanakidou K Kawamura V M Kerminen U Lohmann L M Russell and U Pöschl 2006 Critical assessment of the current state of scientific knowledge terminology and research needs concerning the role of organic aerosols in the atmosphere climate and global change Atmospheric Chemistry and Physics Vol 6 pp 2017 2038 June 9 2006 online http www atmos chem phys net 6 2017 2006 acp 6 2017 2006 pdf In spite of impressive advances in recent years our present understanding of organic aerosol OA composition physical and chemical properties sources and transformation characteristics is still rather limited and their environmental effects remain highly uncertain 26 Martin Vermeer says 14 Jul 2008 at 6 32 AM misspeak is a misnomer no Gore s error was to provide a single easy soundbite ready to be ripped out of context As everybody knows the proper thing to do is place parts of the sound bite far apart on the audio track as he did in the NPR interview recently so the swiftboaters have to get competent in audio editing 27 Martin Vermeer says 14 Jul 2008 at 8 51 AM Al Gore s exact words were During my service in the United States Congress I took the initiative in creating the Internet Factually true correct English and not even ambiguous Take the Red Pill folks Figure this one out for yourselves and reality will never be the same again 28 Lawrence Brown says 14 Jul 2008 at 9 12 AM Re 7 One doesn t have to remain ignorant Read one or more of the books recommended listed in the post All Paper Salutes To The Environment or a book of your choosing that explains the science behind global warming Don t shoot the messenger Al Gore is a well informed non scientist not the one who uncovered this phenomena Attend lectures and conferences where available One doesn t have to remain ignorant except by their own choosing 29 Boris says 14 Jul 2008 at 9 57 AM Newsbusters is not just a denialist site they actively promote the idea that AGW is a fraud Results 1 10 of about 5 730 from newsbusters org for global warming fraud 0 36 seconds Simply put they are conspiracy theorists of the most irrational stripe 30 Hank Roberts says 14 Jul 2008 at 10 20 AM Rod don t trust your memory about things you wish were true If you can t grok this you can t do or read science Yes perhaps there s a huge conspiracy out there altering all the records people on all spokes of the political wheel do have this suspicion about what they think they remember seeing that they deeply believe but have never been able to document But go with the odds If you can t find it you probably were fooled the first time and have been fooling yourself ever since recalling that Republican press release cited above Read Doonesbury instead you ll get a clearer picture of how the world works 31 Rod B says 14 Jul 2008 at 10 49 AM All of you took the initiative proponents edited that s enough No more comments from anyone on this please moderator 32 David B Benson says 14 Jul 2008 at 11 47 AM Please Al Gore and the internet however thrilling to some yawn has nothing to do with climatology Drop it ok 33 Bart Verheggen says 14 Jul 2008 at 12 23 PM To get back to the subject If part of the recent European warming past 25 years or so is due to the decrease in aerosol loading then the rate of warming may decrease when the aerosol loading starts to stabilize That was the bottom line of an interesting presentation at the EGU this year not published yet It s bound to raise a lot of questions and the results are prone to be abused but the analysis seems sound if somewhat speculative and with large error bars 34 Ryan Sullivan says 14 Jul 2008 at 1 43 PM I think in your attempt to clarify the issues you have confused things a bit by over simplifying Your statement that aerosols are not smog is not correct Aerosols are an important component of photochemical smog forming through similar reactions involving hydroxyl radicals nitric oxides ozone VOCs and sunlight that also produce the gaseous component of smog These secondary aerosols have important impacts on visibility health and regional climate Also stating that aerosols are dominated by sulphate emissions from coal burning power plants is overly simplistic and inaccurate Yes coal power plants are major sources of primary combustion aerosols i e soot coal fly ash and also sulphur dioxide which can produce secondary sulphate aerosols But sulphate aerosols are not the major aerosol component by particle mass or number The lagest sources of aerosol mass are from sea salt and mineral dust By number it is typically a mix of sulphate nitrate ammonium and a wide spectrum of carbonaceous elemental and organic carbon compounds Most tropospheric aerosols are internal mixtures of these components as opposed to pure single component aerosols which is how climate models frequently inaccurately represent them This mis representation and can have significant ramifications for estimating the direct and indirect effects of aerosols on climate Sorry to be nit picky but I was surprised to see such inaccurate and simplistic statements made on this blog which typically goes to great lengths to be both detailed and accurate These misconceptions regarding aerosols are commonly stated not just in the media but also in the atmospheric sciences community and are very troubling Response Always happy to have nitpicks to be clear I was talking about anthropogenic aerosols for which sulphates are the biggest contribution The EPA report was focused on ozone and that was the contrast I was highlighting gavin 35 Francis Massen says 14 Jul 2008 at 3 05 PM European mean ground ozone levels are declining not rising as could be expected from a possible warming trend See here for my measurements in a semi urban region Diekirch Luxembourg and here for the US 8 hour air quality BTW I am not sure if the ozone health issue is not overstated I spoke to several medicals also lung experts who never had a patient unwell of too high ozone levels Usually the discomfort was a result of excessive heat and bad air where O3 is only one of many factors 36 Rod B says 14 Jul 2008 at 3 32 PM Hank I was half way with you philosophically at least until you wrapped your arms around Doonesbury P 37 Hank Roberts says 14 Jul 2008 at 5 42 PM Rod Doonesbury Sunday 600 600 000 Beware the press look to the original source in the science journals 38 Ryan Sullivan says 14 Jul 2008 at 6 41 PM Thanks for your reply Gavin I understand what you wanted to contrast with Sulphate is not typically the dominant anthropogenic aerosol component however though many climate models treat it as such The carbonaceous aerosol component typically dominants PM1 aerosol mass see for example Zhang Q et al Ubiquity and dominance of oxygenated species in organic aerosols in anthropogenically influenced Northern Hemisphere midlatitudes Geophysical Research Letters 34 13 doi 10 1029 2007GL029979 2007 This is a nice summary of many measurements of PM1 aerosol chemical composition Though note that the instrument used cannot measure non volatile aerosol components that don t evaporate 600 C or so Thus they cannot measure soot mineral dust or some refractory organic carbon compounds 39 Rod B says 14 Jul 2008 at 9 36 PM Hank Yeah but is it peer reviewed 40 Jim Eaton says 15 Jul 2008 at 3 29 AM Rod B Says Hank Yeah but is it peer reviewed Doonesbury is peer reviewed by the millions of readers who follow the strip Can millions of readers possibly be wrong 41 pete best says 15 Jul 2008 at 5 59 AM Re 10 a very sobering account given by Dr James Hansen there one which is undoubtably true and yet very people know it to be so Ask any

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  • The Arctic Climate Impact Assessment « RealClimate
    Campaign for a Hydrogen Economy will be allowed to quote you without too much hassle when we reiterate the obligation which this generation has to switch from fossil fuels in their entirety to the only feasible alternative renewable electricity and renewably generated hydrogen 9 Ferdinand Engelbeen says 16 Dec 2004 at 11 32 AM The Greenland photos are at http home scarlet be ping5859 greenland html without the In addition to my comment at 9 The warming between 1905 1945 was global as good as the warming in the second period 1975 1998 Between 1945 and 1975 there was a global cooling trend That can be seen on the GISS graphs at http www giss nasa gov data update gistemp graphs But the regional climate of Greenland and of most of the Arctic remained longer cooler compared to the global trend in the second warming period I have looked at all data of circumpolar stations Some 30 had a peak in the 1930 1940s followed by a cooling until 1975 and a warming thereafter exceeding the warming of the 30 40s That were mainly stations in Alaska and Eastern Siberia The remaining polar stations had similar trends but a longer cooler period until around 1990 but don t surpass the 1930 1940s in recent temperatures This is at odds with climate models which predict higher increases in temperature at higher latitudes than near the equator if GHGs are the main cause of the increase in temperature Response On this and your previous comment I can only again point to the analysis of the warming pattern published in Johannessen et al Tellus 2004 Their Figure 1a clearly shows the difference between the 1930s and the recent warming and concludes recent warming is likely to be anthropogenic If you disagree with the findings in this peer reviewed paper I propose you contact its authors If you think their analysis is flawed in any way submit a comment to the journal as is the custom in such cases stefan 10 Ferdinand Engelbeen says 16 Dec 2004 at 10 20 AM In addition to message 4 I have the impression that current Greenland climate is not very different of that in the 1930 1940s See the temperature trends of all Greenland stations from the GISS database at http home scarlet be ping5859 greenland temp html As far as can be seen in the long trends the temperatures today are about as high as in the period 1930 1940 Thus local warming now is not worse than in that period And the main increase in temperature was before 1930 when the human made extra GHG level was much lower than today Thus mainly natural Btw Greenland even in the south has little or no agriculture see http home scarlet be ping5859 greenland html They have some sheep and reindeer farming but most income is from fishing shrimps and halibut some halve of the GDP is from subsidies by Denmark When we were there they were investigating the growth rate of different wood species to see if that could work 11 Ferdinand Engelbeen says 16 Dec 2004 at 7 30 PM The difference between Johannessen and my comment is that I have only looked at land temperature trends while Johannessen e a mainly looked at sea surface temperatures and ice cover But nevertheless their graphs are interesting I suppose that you are a little confused with the height of the temperatures The 1930 1940 s globally were colder than today but the polar temperatures were near equal land a little lower sea a little higher today But as the graph 1a shows even the lower latitudes were higher in temperature in that period thus the temperature increase was globally On land this is even more pronounced see the temperature trends of the contiguous USA at http www giss nasa gov data update gistemp graphs Moreover the other graphs of modelled GHGs influence 1b and GHGs aerosols 1c clearly show that the models don t reproduce reality for GHGs alone the latest decades are much too warm and the 1930 1940 periode too cold For GHGs aerosols the low to mid latitudes in recent decades are too cold and the 1930 1940 period is even cooling further If a model isn t able to reproduce reality i e not validated it is inapropriate to make any conclusions from the results And the researchers clearly underplayed the solar cycles in these matters As recently retired process automation engineer but interested outsider in climate research I don t think my remarks will pass any peer review appropriate or not I have some experience with modelling be it for chemical processes I know how difficult it is to tune a model even if all physico chemical parameters are or should be known Therefore I am a little skeptic about climate models where a lot of physics and feedbacks are not even known to any accuracy 12 Pierre Lutgen says 18 Dec 2004 at 2 55 PM I am in possesssion of several reports which show that UV radiation in the Northern and in the Southern atmosphere is decreasing and even if it had moderately increased in the Arctic this would be much less the radiation for inhabitants in the Alps or at the Aequator I can share these data with those who want to receive them There are also reports which claim that the icecap at the Antarctic and in Greenland are increasing This would be logical as a consequence of more evaporation of the oceans and consequently more precipitations in these cold areas 13 Eli Rabett says 25 Dec 2004 at 6 33 PM F Engelbeen s claim that he only looked at land temperature trends while Johannessen e a mainly looked at sea surface temperatures and ice cover is a Tech Central Station like Johanneseen et al s surface temperature data set was taken from a unique century long SAT dataset focused on the high latitudes of the

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  • The Arctic Climate Impact Assessment II « RealClimate
    Baliunas explained The first point was addressed in a previous post and the second statement probably refers to the mid Holocene and so the previous comment on Michaels is relevant The degree of natural variability is of course key in attributing climate change to anthropogenic changes and all estimates of this based on proxy records in the past and modelling studies point to the recent warming as being outside the range of natural variability Change is indeed a constant but it is the magnitude and rate of change in the current situation that is unusual And finally a new definition of the word refute McCain s claims about a robin population explosion in the Arctic were refuted as well Marlo Lewis a senior fellow at the Competitive Enterprise Institute CEI said Even if it s true that robins are making their first appearance in Arctic areas what it means it that the robin s habitat is expanding I always thought environmentalists liked birds To me this is good news Lewis added Apparently refute now means to agree in every respect Comments pop up 1 One Response to The Arctic Climate Impact Assessment II 1 Ziel says 15 Dec 2004 at 1 57 AM Do you think that McCain s comment about robins in the Arctic being a sure sign of global warming is worthy of refutation on this site 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 of the Gulf Stream System doiknow What is the best description of the greenhouse effect James Powell Unforced Variations Feb 2016 Jim Galasyn What is the best description of the greenhouse effect Jack Barrett 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

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  • The Arctic Climate Impact Assessment III « RealClimate
    polar vortex appear to be quite model dependent and so predictions of this aspect of polar change are highly uncertain Changes to date in the Antarctic though do appear to require some amount of change in the polar vortex to explain in particular the large amount of springtime cooling in the polar vortex there Shindell 2003 Thus while the dynamic feedback finds some support in the data and in models it is not well quantified However none of the above mentioned studies show any signficant improvements in the next few decades and thus all actually support the measured ACIA statement This can t therefore be claimed as evidence for unjustified hype References Arctic Climate Impact Assessment ACIA Overview Report 2004 Impacts of a Warming Arctic Arctic Climate Impact Assessment Cambridge University Press Austin J D Shindell S R Beagley C Br hl M Dameris E Manzini T Nagashima P Newman S Pawson G Pitari E Rozanov C Schnadt and T G Shepherd 2003 Uncertainties and assessments of chemistry climate models of the stratosphere Atmospheric Chemistry and Physics 3 1 27 Nagashima et al 2002 Future development of the ozone layer calculated by a general circulation model with fully interactive chemistry Geophysical Research Letters 29 10 1029 2001GL014026 Shindell D D Rind and P Lonergan 1998 Increased polar stratospheric ozone losses and delayed eventual recovery owing to increasing greenhouse gas concentration Nature 392 589 592 Shindell D 2003 Perspective Whither Arctic climate Science 299 215 216 Comments Off on The Arctic Climate Impact Assessment III Comments are closed 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 of the Gulf Stream System doiknow What is the best description of the greenhouse effect James Powell Unforced Variations Feb 2016 Jim Galasyn What is the best description of the greenhouse effect Jack Barrett 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

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  • Will spring 2005 be a bad one for Arctic ozone? « RealClimate
    has some great publications that address scientific questions environmental effects and the impact of the Montreal Protocol http www unep org ozone Public Information 4D PublicInfo FAQ asp 8 Pat Neuman Hydrologist says 15 Mar 2005 at 5 51 AM In Earth s past what was the ozone layer like during the globally high temperature episodes 55 mya 100 mya 220 mya Major extictions took place during these episodes The extinctions near the late Paleocene Eocene Thermal Maximum PETM 55 mya were mainly marine species It seems likely that depletion of the ozone layer near the PETM led to a loss of plankton and resulting collapse of marine ecosystems Evidence exists of ultra violet radiation in late Permian extictions 230 250 mya I haven t read anything on what may have contributed to the extinctions during the Cenomanian Turonian 94 100 mya It seems likely that ozone depletion contributed to the major extinctions that took place during these warm global periods Major extictions also occurred at the end of the Cretaceous 65 mya believed to be related to an asteroid crash into the sea off the Yucatan Peninsula Is it possible that the ozone layer was depleted from water vapor that entered the stratosphere from the big splash Response The problem with hypotheising ozone changes in the past is that ozone leaves no unique geochemical trace and thus you have to rely on models completely to fill in the gaps However ozone reponses to climate changes are quite sensitive to the initial base state how much stratospheric water vapour was there how much methane volcanic aerosols etc since it forms as a delicate balance between UV related production and chemical loss which is highly non linear I would be very hesitant in attributing mass extinctions to ozone losses In the PETM case we did some calculations showing around 20 max depletion for various CH4 release scenarios I m sure someone will do a better calculation at some point but this first cut doesn t seem high enough to justify your claim Global warming of around 4 to 5 degrees is a more likely cause gavin 9 Pat Neuman Hydrologist says 15 Mar 2005 at 10 36 PM I wrote It seems likely that depletion of the ozone layer near the PETM led to a loss of plankton and resulting collapse of marine ecosystems gavin replied I would be very hesitant in attributing mass extinctions to ozone losses My comment It seems unlikely to me that a 4 to 5 degree warming of the atmosphere would have caused the PETM marine extinctions I think the food supply plankton for marine ecosystems was cut off near the PETM What happened to the PETM marine vegetation and why How important is the ozone layer in protecting vegetation on water and land Vegetation is at the bottom of the food chain If vegetation dies 10 William says 18 Mar 2005 at 4 23 PM This may be of interest Ozone values over the UK are currently quite low This afternoon I measured 230 DU over BAS in agreement with the forecast Values are normally around 350 DU at this time of year Values are probably at their lowest today but will remain significantly below average over the weekend Which i got from Jonathon Shanklin in Cambridge 11 Francis MASSEN says 22 Mar 2005 at 6 08 PM Answer to 10 Ozone values are VERY variable even if there is a mean sinusoidal pattern over Europes latitudes see http www meteo be english pages OzonEN html or http meteo lcd lu dobson05 html the variations from that mean trend are exceptional great as such a local measurement of low values is never a hint to a lowering trend and the opposite is true also Btw I am still waiting for Gavins Arctic ozone loss happening read my comment 5 and again watch http www temis nl protocols o3field data forecast today np gif for a very healthy O3 layer 12 Ferdinand Engelbeen says 22 Mar 2005 at 6 18 PM Data from the Swedish Odin satellite indicate that no arctic ozone hole will appear this winter despite fears to that effect See for the full article http www spacedaily com news ozone 05d html 13 Markus Rex says 24 Mar 2005 at 6 48 AM Comment on 5 and 11 The Arctic ozone layer is very variable mainly for dynamical reasons This makes it difficult to separate chemical ozone loss from natural changes induced by transport Sophisticated approaches are needed to reliably quantify anthropogenic chemical loss of ozone from observations A number of approaches have been developed over the past couple of decades and these are well documented in the literature But it is also well known that just looking at fields of total ozone does not tell us much about chemical loss total ozone is a measure of the thickness of the ozone layer The link given in the comment of Francis Massen points to a total ozone map The comment suggests that by looking at this map everyone can convince himself that no chemical ozone loss took place so far But total ozone maps are not able to support any statement about chemical ozone loss in the Arctic Due to transport processes total ozone over the Arctic and northern mid latitudes increases each winter Depending on the meteorological conditions during the winter chemical loss chews away part of this increase The transport processes are also very variable from winter to winter and the amount of ozone pumped into the Arctic is also correlated with temperature this is not a causal relationship the correlation exists because variability in temperatures and in ozone transport are both driven by the same atmospheric processes From just looking at total ozone how can we seperate natural variability in transport from anthropogenic chemical loss Just one example how problematic the interpretation of total ozone maps is Look at ftp toms gsfc nasa gov pub eptoms images npole Y2005 IM

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  • 2005 Record Arctic Ozone Loss « RealClimate
    Roberts says 9 May 2005 at 8 37 PM Disclaimer I have no competence at all in this area professionally I search and sometimes ask questions to elicit answers that haven t been typed yet On this one I can t even guess which datasets were used I do find a few that are old but interesting http strat www met fu berlin de products cdrom html section4 html section4 2 QUOTE 4 2 SPARC Stratospheric Temperature Trend Assessment STTA Ramaswamy et al 2001 Under the auspices of the World Climate Research Program WCRP the sub program SPARC Stratospheric Processes and Their Role in Climate initiated the STTA Group The charter was 1 to bring together all available data sets of stratospheric temperatures and 2 to analyse the trends in a consistent manner The results of this work are published in Ramaswamy et al 2001 The report deals carefully with all the problems arising from the various very diverse data sets and their trends END QUOTE And this one does graph trend lines for polar stratospheric temperature that on average over recent years would correlate to the trend line for area for PSCs in the article being discussed http strat www met fu berlin de products cdrom html section2 3 html section2 3 1 QUOTE 2 3 1 Temperature Trends at the North Pole since 1956 The time series of the 30 hPa annual mean temperatures  C at the North Pole is shown in Fig 19 It is based on the data given in Table 4 If a linear trend is calculated for the whole series the trend is 0 50 K decade with a probability of 99 But again as discussed above the interannual variability is large even in the annual mean and it is difficult to decide if this calculation is the correct answer to the question about temperature trend in the stratosphere END QUOTE Again disclaimer I definitely don t know what I m talking about I m just pointing and grunting 6 Hank Roberts says 9 May 2005 at 8 47 PM Skip that last one this seems more on point well keep the disclaimers I still don t know anything From http strat www met fu berlin de products cdrom html section2 1 html fig13 Figure http strat www met fu berlin de products cdrom fig fig13 gif Caption Figure 13 Number of days with temperatures lower than Tnat white or Tice red at a 50 hPa and b 30 hPa Integral for each season of the area in of the Northern Hemisphere which had temperatures low enough for the formation of PSCs c at 50 hPa and d at 30 hPa Fig 2 in Pawson and Naujokat 1999 updated 7 Hank Roberts says 10 May 2005 at 6 06 PM Markus s thumbnail isn t yet linked to a full size image looks to me like the bottom two I found at http strat www met fu berlin de products cdrom fig fig13

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  • Retreating Glacier Fronts on the Antarctic Peninsula over the Past Half-Century « RealClimate
    studies concerning the rest of Antarctica and I see his point Personally I would ve included or required wording as such in the background info and possibly the conclusions to put the results of the study in the proper context 7 Stephen Berg says 26 Apr 2005 at 9 51 PM Authors Cook and Dr Vaughan were on the CBC s Quirks and Quarks radio show this past Saturday Here is an excerpt of their segment http www cbc ca quirks media 2004 2005 mp3 qq 2005 04 23c mp3 A description of the show can be found here http www cbc ca quirks archives 04 05 apr23 html 8 Steve Bloom says 27 Apr 2005 at 4 18 AM Re 5 To understand this issue you need to read the prior RC article the second linked reference at the end of this article and all of its linked references There is no substitute for a little homework and in any case it s unfair to the RC authors to ask them to simply repeat or restate information that s already been provided Re 6 I don t believe Michaels is taken seriously in the scientific community His favorable reference to State of Fear is a dead giveaway as is his broad brush scathing dismissal of the scientific consensus on human caused climate disruption In any case why should the Science article s references be limited to just the purported cooling in the main part of Antarctica What about all the melting ice everywhere else on the planet 9 John Booth says 27 Apr 2005 at 3 14 PM Very interesting piece I look forward to reading it in Science A couple of questions immediately came to mind that perhaps someone can answer Is the determination of glacier recession based solely on interpolation of aerial and satelite images If so does the report detail how scaling viewing angle and sea level were accounted for 10 alex kahl says 28 Apr 2005 at 8 15 PM Has anyone else been following Elizabeth Kolbert s series in the New Yorker Although she is a political correspondent her work usually includes the interaction of science and politics She was the New Yorker reviewer of Crichton s book back in December Anyways I have found the first two parts of her series to be enjoyable even though I was highly skeptical at the outset as I am with any mainstream presentation of the climate change science The first two parts of her series seem to be the type of writing that we really need to bring the mounting evidence of anthropogenically induced climate change into the public arena without contention I am curious what other folks think about the series thus far The first part is available here at the New Yorker magazine s website As a grduate student studying the export flux of biogenic particles from the ocean s surface I have been pleasantly surprised with the breadth of scientific evidence she has brought together Plus she seems to have given the appropriate credit where it is due by citing Manabe among others for early climate modelling and Broecker for his conceptualization of the conveyor belt as two of many examples 11 Brad Westervelt says 30 Apr 2005 at 7 17 PM In particular there was a period in the late 1980s and early 1990s when retreat slowed down along most of the coast and we don t see any cause for this in the temperature records so there may be some other factors at work perhaps ocean temperature Perhaps the elsewhere discussed global dimming phenomena airborne particulate from volcanoes unusual storms or other factors during said period reducing the cumulative light energy worldwide Response Global dimming is mostly associated with anthropogenic aerosols and in the southern hemisphere these are in pretty short supply gavin 12 stephan harrison says 2 May 2005 at 4 33 AM Response to Number 11 Could this slowing of glacier recession be related to changes in precipitation In Patagonia we noticed a short readvance within a general recession phase of the outlet glaciers around the early 1990s The glaciers were probably responding to a marked increase in precipitation in the region in the 1970s and 1980s and I think a similar situation has occurred in parts of New Zealand 13 Joseph O Sullivan says 2 May 2005 at 8 50 AM RE 5 Michaels on the TCS website is referring to an AP article The article is at http www enn com today html id 7581 RealClimate has mentioned Patrick Michaels on the Jan 20 post Peer Review A Necessary but not Sufficient Condition and TCS on the Feb 8 post Strange Bedfellows Bringing up Michaels employment with Cato is important Cato and TCS are political advocacy groups as are many of these think tanks They advance conservative and corporate political agendas That is why conservative foundations and industry fund them For examples see http www environmentaldefense org article cfm contentid 3804 CFID 21084385 CFTOKEN 29888831 and http www motherjones com news feature 2005 05 some like it hot html Being politically active for conservatives industry environmentalists or any other group is not a bad thing Any political advocacy group has an agenda and when evaluating their messages about climate change science it is important to examine how they advance this agenda Every political group uses spin to try to persuade the public but Cato and TCS are some of the groups that use what can be called extreme tactics in the climate change science debate Cato and TCS are hostile to environmental regulation Current environmental regulations were passed after environmental groups ran political campaigns that reflected the public s call for action addressing environmental problems Conservatives and industry were stung by these political defeats Noting the success of environmentalists conservatives and industry founded their own political advocacy groups like Cato and TCS to oppose environmental regulation Cato TCS and other groups are waging a public relations campaign

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