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Arctic sea ice melt - natural or man-made?

Posted on 9 June 2008 by John Cook

Arctic sea ice has declined steadily since the 1970s. However, the 2007 summer saw a dramatic drop in sea ice extent, smashing the previous record minimum set in 2005 by 20%. This has been widely cited as proof of global warming. However, a popular mantra by climatologists is not to read too much into short term fluctuations - climate change is more concerned with long term trends. So how much of Arctic melt is due to natural variability and how much was a result of global warming?

The long term trend in Arctic sea ice

Global warming affects Arctic sea ice in various ways. Warming air temperatures have been observed over the past 3 decades by drifting buoys and radiometer satellites (Rigor 2000, Comiso 2003). Downward longwave radiation has increased, as expected when air temperature, water vapor and cloudiness increases (Francis 2006). More ocean heat is being transported into Arctic waters (Shimada 2006).

As sea ice melts, positive feedbacks enhance the rate of sea ice loss. Positive ice-albedo feedback has become a dominant factor since the mid-to-late 1990s (Perovich 2007). Older perennial ice is thicker and more likely to survive the summer melt season. It reflects more sunlight and transmits less solar radiation to the ocean. Satellite measurements have found over the past 3 decades, the amount of perennial sea ice has been steadily declining (Nghiem 2007). Consequently, the mean thickness of ice over the Arctic Ocean has thinned from 2.6 meters in March 1987 to 2.0 meters in 2007 (Stroeve 2008).

 

Global warming has a clearly observed, long term effect on Arctic sea ice. In fact, although climate models predict that Arctic sea ice will decline in response to greenhouse gas increases, the current pace of retreat at the end of the melt season is exceeding the models’ forecasts by around a factor of 3 (Stroeve 2007).

 


Figure 1: September Arctic Sea Ice Extent (thin, light blue) with long term trend (thick, dark blue). Sea ice extent is defined as the surface area enclosed by the sea ice edge (where sea ice concentration falls below 15%).

What caused the dramatic ice loss in 2007?

The sudden drop in sea ice extent in 2007 exceeded most expectations. The summer sea ice extent was 40% below 1980's levels and 20% below the previous record minimum set in 2005. The major factor in the 2007 melt was anomalous weather conditions.

An anticyclonic pattern formed in early June 2007 over the central Arctic Ocean, persisting for 3 months (Gascard 2008). This was coupled with low pressures over central and western Siberia. Persistent southerly winds between the high and low pressure centers gave rise to warmer air temperatures north of Siberia that promoted melt. The wind also transported ice away from the Siberian coast.

In addition, skies under the anticyclone were predominantly clear. The reduced cloudiness meant more than usual sunlight reached the sea ice, fostering strong sea ice melt (Kay 2008).

Both the wind patterns and reduced cloudliness were anomalies but not unprecedented. Similar patterns occurred in 1987 and 1977. However, past occurances didn't have the same dramatic effect as in 2007. The reason for the severe ice loss in 2007 was because the ice pack had suffered two decades of thinning and area reduction, making the sea ice more vulnerable to current weather conditions (Nghiem 2007).

Conclusion

Recent discussion about ocean cycles have focused on how internal variability can slow down global warming. The 2007 Arctic melt is a sobering example of the impact when internal variability enhances the long term global warming trend.

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Comments 201 to 250 out of 529:

  1. koyaanisqatsi PS AGW alarmists talk about the end of life, the other talk about the end of civilization. The damage will be done if we pay too much attention to either. Skeptical examination of both arguments should lead to a realization close to the truth so I suggest keeping an open mind.
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  2. As an example of alarmism and what scientists really think, take a look at this article at Scientific Blogging.
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  3. Quietman, Thanks for the link. That's a useful web site. All the article does is urge caution and suggest the most extreme predictions of global sea level rise are unlikely. Emphasis on "unlikely". The authors wisely avoid the use of the word "impossible", but then they are scientists. The fact is we don't really know quite what to expect with any certainty...but you and I already understand that. Where you can get into real trouble is reading and believing nonsense at right and left wing blogs. Usually they get things completely wrong, although I confess I hold right wing blogs most accountable for outright deception. Gore has been accused of being an alarmist, but so many of his claims have turned out to be about right. For years, even before it was mentioned in the press, I was concerned about our climate being in an roughly unstable or meta-stable climate equilibrium. Once the "tipping point", if there is one, is reached, it may not matter what we do to try to correct the problem. That is still a concern. As an example of unhealthy GW or AGW denial, try: http://www.climate-skeptic.com/
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  4. koyaanisqatsi I agree completely. My problem has been discerning who is right and left wing so I look for key words just like when I am involved in an argument with a creationist (but the key words are different of course). If a political party or name is used, the words "global warming" rather than "climate change" or "climate shift", or obvious falsehoods (the opposite of something that I know as fact, albeit I am limited there somewhat) and with creationists it's "scripture" and for I.D. it's "validate" or the third law of thermodynamics. But some sites that are claimed neutral are actually quite biased and sites that are called denier sites by alarmists sometimes are neutral or just anti-alarmist, so it's difficult to tell. So I read what they say and then decide if it's crap or not.
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  5. PS What do you think about the Friends of Science website?
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  6. I don't seem to have much problem identifying which are right wing and which are left wing sites. It's usually, not always, fairly obvious. If in doubt, I Google on the organization, the articles authors, etc. The truth is out there. I agree...best to read what they say and decide if it adds up to crap or crackerjacks. I'm not familiar with Friends of Science and their server is not responding right now. I mention Climate Skeptics because I realized I was reading mostly GW environmentalist materials and web sites. So I thought I'd engage the so-called Climate Skeptics in a healthy debate. What was I thinking? I was savagely attacked for simply asking why they applied a curve to UAH satellite and said I felt a straight line filtered out the noise better (as is done here, I think). A 5-th order least squares polynomial curve was used, although it took me a long time to get that information. It actually looks as though that curve was fudged a bit to make it appear as if global temperatures had dropped during the period just before the satellite data and at the end of the satellite data (2007, I believe). Very odd. I persevered a bit, but most replies to my ?s were of the "if you knew anything about science, you'd..." variety. So much for debate. There are honest GW/AGW skeptics or deniers out there...I am certain of that. Well-intentioned skepticism is essential to scientific debate. It keeps us all honest and forces us to think and rethink the science.
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  7. Quietman, I don't look for who's right wing or left wing , I look for who's lying and who's not. 100% of the time, it's the right wing and the deniers that lie. And you still haven't addressed the specific points I've made or the references I've provided. Another denier tactic. Please explain the difference between the graph on the petition project website and the graph on this website. And tell me which one you give credibility to. Should be simple, yes?
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  8. Koyaanisqatsi, curves are fudged with A LOT on so-called skeptic web sites. Example, icecap.org, ran by Joe D'Aleo. Check out how his "analysis" is analyzed by a real mathematician here: http://tamino.wordpress.com/2008/02/03/exclamation-points/ Of course, there is the always funny Anthony Watts. http://tamino.wordpress.com/2008/03/02/whats-up-with-that/ Look at the comments thread, it is enlighting as to how Watts handled the all thing. Last year I lost count of how many of those sites were attempting to convince readers that the opening of the Amundsen Northwest passage was not remarkable. They were not even arguing the significance of it, simply trying to misrepresent what was happening. WA's post above is typical of a common argument trying to suggest that the loss of Arctic sea ice (very significant since 05) is compensated by the increase of Antarctic sea ice (not statistically significant). The amount of pure and simple deception on so-called skeptic sites is MASSIVE. The other thing they like a lot is conspiracy BS and accusations of fraud against all scientists whose conclusions they dislike. A case in point was the outcry for J. Hansen to release GISSTEMP code, which was done but has led nowhere, as you could expect. Although I do not look much at environmentalist's sites on GW, I gather that there is a lot of exaggeration there on many aspects. One especially annoying one is the relation between hurricane activity and warming. So far, the only thing that can be reasonably asserted is that warmer SSTs do lead to faster intensification of storms. Everything else is debatable. Nevertheless, what I have seen from "skeptics," their double standard of scrutiny for liked vs. disliked hypotheses and the similarity of their methods to that of the tobacco industry led me to be very skeptical of the skeptics.
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  9. Thanks for the Palaeos link, Quietman, great site.
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  10. Philippe They also have a newer sister site, Palaeos.org which is a wiki site, but it lacks the humor of Palaeos.com and that's one of the attributes that I like.
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  11. koyaanisqatsi Re: "If in doubt, I Google on the organization, the articles authors, etc." I do that when in doubt as well. I agree Climate Skeptics is somewhat unreliable as they are too one sided. I do read at Climate Debate Daily becasue they catagorize the articles into pro and con columns and I can find both good and bad articles in both columns (much prefeable to all bad). PS Google "Real Climate" for authors and funding.
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  12. PS Another site, listed as neutral at the above linked site is Title of Link Opposing Views, that has a Yes and a No column and rates the accuracy.
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  13. Koyaanisqatsi (tough screen name, really), no reason to google when you can get the info from the horse's mouth: http://www.realclimate.org/index.php/archives/2005/02/a-disclaimer/langswitch_lang/in The featured link to Science unfortunately is not part of the free content, so you'd need subscription to see it. It's also worth looking at the credentials of the contributors. You can look these up too: http://www.nature.com/nature/journal/v442/n7098/full/442009a.html http://www.sciam.com/article.cfm?id=science--technology-web-a-2005-10-03&page=2 EMS provides only web hosting to the site. Real Climate states clearly it is by no means affiliated to EMS. None of the contributors receives any kind of financial compensation from EMS or any other source. They are all working scientists employed by a variety of agencies and universities and run the site on their spare time. Here is EMS' site: http://www.sciencecommunicationnetwork.org/
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  14. Try not to lose it Phillipe. We saw predictions given with great certainty that 2008 was going to set all time records for arctic sea ice loss. Never mind "all time" is only 30 years. It didn't happen and only some last minute current effects got it close. this year was 13% higher sea ice cover at minimum than last. I doubt it has any significance, just like last year didn't. If you are unaware that the antarctic remains cold and that sea ice around the antarctic is at near record levels you'd best broaden your filters. Ice shelfs are supposed to break off, it might matter if it happened far more than usual (if we knew what was usual) or if it had no other explanation like volcanism upstream, but since that is not the case in the antarctic... Meanwhile despite polar bear populations also being at unprecedented highs, the World Wildlife Fund runs a series of scare adds about vanishing polar bears.
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  15. You can doubt or believe whatever about significance, that has no bearing on facts. It is a fact that, if not for the landmass of Greenland, you could circumnavigate the pole in open water above the Arctic circle as we write this. You need to cite a source for that 13% figure and say what it represents. I look at ice extent, monitored by NSIDC: http://www.nsidc.org/arcticseaicenews/ The 08 minimum has not happened yet, so citing your unsupported, unexplained 13% as if it was already recorded is misleading. It's kinda strange that you repeat that same number from several days ago, although the 08 extent has decreased in the meantime. You'd have to show me the maths demonstrating that this and last year's loss of Arctic sea ice are not statistically significant and that Antarctic sea ice is actually outside of range. Why don't we look at these graphs: http://www.nsidc.org/data/seaice_index/ I note that they're not exactly on the same scale because if they were, the Arctic one would end way outside of the graph. The Antarctic, however, shows no particular trend. Also you need to say which way you want to have it: the 07 Antarctic "record" is a satellite era record only, which does not seem to bother you when it's in the southern hemisphere. However, you emphasize the satellite observation time span about the Arctic, even though the 07 low is lower than any other observation ever, including non satellite. For those interested, more info on that here: http://tamino.wordpress.com/2007/10/08/sea-ice-north-and-south-then-and-now/ The links I gave above contain more detailed maths about the Arctic vs Antarctic subject: http://tamino.wordpress.com/2007/12/12/denial/ It is from last year but is just as applicable this year. If you find that time series analysis faulty, by all means explain why it is so.
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  16. Well I can't find it right now, here is a place to start though they are debating over weather the increase is 10% or 30% and it looks like it is coming in a little higher than the 10%. http://wattsupwiththat.wordpress.com/?s=Arctic+Sea+Ice+Extent
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  17. Anthony Watts as a reliable source? Please. Go for what they have there if you want, I have formed my opinion on Watts and his site and have not yet seen reason to change it. Watts' blog is by no mean a place to start on anything. Saying that there is an Arctic ice increase this year when last year's loss was staggering is profoundly misleading. It's like saying that you're getting plenty of food if you're eating an apple per day after a week of total fasting. EVEN IF it is 10% more than last year, that would make it a 17% departure from the 79-00 average and 2nd lowest on record. As I said earlier, that would include all records, not only satellite. If you have real data to dispute that, I'm all ears.
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  18. koyaanisqatsi, In #198, you said;- "So try http://folk.uio.no/tomvs/esef/esef0.htm to sort through what Prof. Segalstad did say and what he meant when he said it. Why should others have to do your literature search for you?" LOL! Nothing in the link you provided contradicts my original point, which was that Tom Segalstad is a well respected scientist, and one who has left the IPCC because he simply doesn't believe that their "science" is correct. If you think that I have misrepresented "what Prof. Segalstad did say and what he meant when he said it", please feel free to show me how. In the light of this, your throw-away line; "Why should others have to do your literature search for you?", is both childish and offensive.
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  19. Wow! Anthony Watts wasn't the source, just the reporter, and now he is unreliable? Never mind, objectivity has left the building. Being accurate and data driven now makes you "unreliable". Anyone who does not preach the "Gospel" of Al Gore must be crazed. As I said in the first place this year ice cover was more than last year. Which is clearly true despite the "consensus" predictions of a few months ago. We also know that last year had non GW reasons for being low, as John stated in the original post. Your assertion that the Antarctic shows no trend is very interesting. If the world is warming shouldn't the antarctic ice be shrinking? No trend? you have an interesting ability to call tiny trends definite if they support you and larger ones non existent when they don't. It is clearly colder in the Antarctic than 50 years ago. Further 2007 was a record high for Antarctic sea ice extent since satellite records began just as it was a record low in the North. Sorry, I forgot, nothing can possibly disprove or even argue against catastrophic global warming caused by CO2 it must remain forever unfalsifiable, Amen. Maybe we should discuss "all time" records that could not possibly be correlated, like pre and post satellite, and then we can lament the vanishing polar bear. Occams razor is slicing this issue to ribbons. As for circumnavigating the pole in open water I suggest you go ahead and try it, start today. It won't prove anything the constriction of the polar sea is the reason ice can survive summer up there. But, I think it would calm your fears very quickly.
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  20. You say Watts is data driven but you're not presenting any data. Watts is as biased as they come and also incompetent in time series analysis, the link I posted shows as much. To my knowledge, Watts is not a scientist but if you have a science publication of his to point to, I'll be glad to look it up. http://tamino.wordpress.com/2008/03/02/whats-up-with-that/ I don't know what predictions you're referring to, what I recall reading from people who actually study ice was that a loss such as that of 07 was unlikely to be equalled. However, there was great unpredictability due to the loss of multi-year ice. Blog opinions and the like are not what I'd be looking at for this, perhaps that's what you're alluding to. Why not give links to these "consensus predictions"? The ice cover is larger than last year indeed, not by much and significantly lower than 2005, so it is the second lowest on record; I said that if you had data to dispute that fact I was all ears, that still stands. You're not offering data, just rethoric. The Links I posted above show Arctic and Antarctic sea ice anomalies. Arctic is down, Antarctic is flat. There is no statistically significant change of Antarctic sea ice in the satellite era observations. Once again, if you have data to dispute that, present it. http://www.nsidc.org/data/seaice_index/ It shows very well which trend is "tiny", or non existent, and which one is "definite." As for pre satellite data, I understand why you don't want to go there, it shows a huge loss of Antarctic sea ice that would not help your case. Data here: http://hadobs.metoffice.com/hadisst/data/download.html The overlap period with satellite data shows excellent correlation, as shown here: http://tamino.wordpress.com/2007/10/08/sea-ice-north-and-south-then-and-now/ "If gw is happening, shouldn't the Antarctic warm?" Interesting question. Why don't you try to find out? The answer is not exactly simple and involves the Southern Annular Mode, among other things. You are getting a little sloppy in the rethoric. It does not help your case either to remind that last year's loss was due to an extraordinary combination of weather factors. This year, the combination did not repeat, yet the ice loss is very close, indeed closer to 07 than to 05, which is 3rd lowest on record and already well below 79-00 average. It obviously means that an extraordinary combination of weather factors was not necessary for a very large loss to happen again. Other sloppy rethoric points are: The calling on Al Gore, which I do not recall ever mentioning in this discussion, or on this site (or ever? not sure). Link to one of my posts to correct me if I'm wrong, although it does not have anything to do with the subject. I don't care about Gore. The calling on "catastrophic" whatever, which I do not recall mentioning either. You are essentially trying to make a strawman using stuff that I never even approached. Looking at my posts here will clearly indicate that I am not into catatastrophism. Some people are, not me. I do think that GW can have quite serious consequences; that's different from predicting doom. My fears? Be more specific. I am defending, with an abundance of data, the point of view that the last 2 years' loss of Arctic sea ice have been significant, statistically and otherwise. The fact that the Northwest and Northeast passages have open water at the same time is quite significant. Where did I state a "fear?" That idea of "constriction" of ice is interesting. Have any pointer to a scientific source explaining the concept?
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  21. John, Your article equates GW with AGW. Simply stating that 'global warming' is causing arctic sea ice to melt says nothing about the cause or nature of the warming. Based on all the evidence I have seen (including your article above) the jury is still out on whether the perceived arctic sea ice melt is natural or man-made... only time will tell.
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  22. Quietman et al, The climate change over the past few million years has zero, zilch, nada, nothing to do with any change between the '30s and today. They are completely different mechanisms. Every metric tells us that it is warmer now than in the '30s. You reject this conclusion, based on numerous independent observations, in favor someone's crackpot theory about plate tectonics. A few other various topics: 1) It is physically impossible for the Earth to behave like Venus. Temperatatures would have to be warm enough to boil the ocean for that to happen. 2) The 619 authors of AR4 WGI are listed here: http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_Annexes.pdf They are all scientists. The only time politicians are involved is in drafting the Summary for Policymakers, and even then they can't override the lead authors. As for scientific content, Chapter 9 alone (Understanding and Attributing Climate Change) has 10 pages of citations. 3) The IPCC accurately summarizes the state of the peer reviewed science, which is why the relevent scientific societies (who are responsible for actually producing the science) endorse the IPCC findings. 4) The record Antarctic Sea Ice Extent was recorded in 1973, the first year we have satellite data. http://polynya.gsfc.nasa.gov/seaice_datasets.html 5) These were the predictions for September Sea Ice Extent made back in May (in millions of square km) From http://www.arcus.org/search/seaiceoutlook/report_may.php 3.1 3.5 3.6 3.8 X 2 4.1 4.2 X 2 4.4 4.5 X 2 5.0 5.3 5.5 The average prediction was 4.3 million km and the median was 4.2. 2007 was about 4.3 million km. Current conditions are at about 4.7 million square km. The 1979 to 2000 average is about 7 million square km. 2008's melt will not match 2007, but it falls within the expected range. 6) An enhanced greenhouse effect implies a cooling stratosphere, a drop in outgoing longwave radiation, and nights that warm faster than days. Each one of these predictions has been measured.
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  23. WELL, I think this thread just melted a few more km of sea ice! The graph curve shows an increasing trend downwards. The question...is this natural or man-made is a bit spurious ( or are we not 'natural'?)...and the answer, despite all the heated exchanges and hyperbole, is we don't know. All we KNOW is what the graph shows and the rest is an attempt to explain what we see. It is not good enough to simply say it is AGW...it may be, but until it is realistically modelled and all other factors shown to be irrelevent, then I will remain unconvinced of the argument. In any event, melting sea ice = drop in ocean temp - more biomass (plankton like it cool) = more sequestration of CO2 and so we go round again. The system as a whole has numerous ways to address imbalances as it has (successfully)in the past.
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  24. Lee Grable: We all lie, every day of our lives. We lie by omission. We lie by commission. We lie in error, even though we believe we have the truth. We lie by quoting truth out of context. We lie by not telling the whole truth. We lie to others and to ourselves in order to make life bearable. We lie by selecting information that suits our purposes. We lie to avoid facing the truth.. We all lie, in many ways and for many reasons. Data has been omitted from various studies because 'it did not fit' (including AGW supporters), and there is currently a debate about this; Beck's 180 year analysis of chemical CO2 records. This site has 'lies' in it. In one thread is a statement that there are 300 stations worldwide measuring CO2 - which is not true, there are 298 datastreams but not all measure CO2 and some of those streams come from the same stations. Whilst the statement is untrue, it does not invalidate the argument that there is sufficient empirical evidence available to validate the argument, nor does it cause me to dismiss out of hand any other statements made by the person concerned.
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  25. Mizimi Yes the Arctic and Polar bears do heat things up.
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  26. Mizimi, your equation melting ice=colder ocean does not quite work out. Melting ice means no albedo and increased absorbtion of solar energy by the Arctic ocean, leading to higher ocean temp. Arctic biomass does not like it. If you're talking about the German teacher Beck who cooks graphs, it's worth pointing to the other side of his story: Beck is a buffoon who fakes data. http://www.realclimate.org/index.php/archives/2007/06/curve-manipulation-lesson-2/langswitch_lang/in http://www.realclimate.org/index.php/archives/2007/05/the-weirdest-millennium/ Whether or not you agree with RC's position their critique of Beck is exactly on point. Data is data (or in Beck's case, the lack thereof)
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  27. Phillipe Re: "Beck is a buffoon who fakes data." Other than Real Climate*, can you prove either of these claims? Beck being right or wrong means nothing to me or to my argument but I am curious about the attacks. *Sorry but thier alarmist reputation leaves much to be desired.
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  28. As I said, you can check the posts and see for yourself whether or not the critics are valid. Beck's CO2 curve is based on the assumption that there were humongous biospheric fluxes of CO2, which are simply not physically possible. Furthermore, the isotopic signature that would go with this is absent from the proxies. It explains CO2 rise as a feedback to temp increase but with inconsistent response depending when it's convenient for him or not. It also assigns peaks in CO2 in the curve to volcanic eruptions, while the Mauna Loa record shows no such variations associated with Pinatubo or El Chichon. There is too much litterature to link to on the subject, just about all current research on CO2 changes over time will contradict Beck. This piece of work was "published" by Energy and Environment, which does not really have a peer-review process but instead is subject to the whims of the editor, Sonja Boehmer Christensen. She has a history of sympathy for the Young Earth creationist ideas, among other things. On another occasion, Beck took an IPCC graph and doctored it so as to exaggerate past temperature changes by a factor of 3 (chenged the scale on the Y axis). He also takes care of stopping the graph at 1970, although the x axis continues to 2000, which allows him to suggest that the MWP was warmer than today. If today's temp were on that graph, they would be way higher than anything in the MWP. It would still be useless, since that reconstruction is old and totally outdated now. Beck's graph (graph only, no comments): http://www.realclimate.org/images/beck_modified_large.jpg Original IPCC curve is in the RC thread. Beck's article in German can be found here: http://www.readers-edition.de/2007/05/07/der-co2-betrug-der-groesste-skandal-der-wissenschaftsgeschichte-der-neuzeit In this one, rather interesting is the apparently cyclic evolution of temperature, which seems to be Beck's take on Dansgaard-Oeschger cycles. According to most research, these cycles do have a periodicity around 1500 years, but they are not present in proxies for the past 23000 years or so. http://en.wikipedia.org/wiki/Dansgaard-Oeschger_event (ref at bottom of page). Beck shows spikes at -400, then at 1200, so far so good (except for the lack of D-O cycles for 20 millenias). However, there is another one correponding to our recent temp increase. It should not be there before 2800, if the periodicity is conserved. If you look carefully at Beck's graph, you'll see a little break in the x axis, and then suddenly, the scale shifts. The curve, however continues its beautiful sinusoid movement unchanged to conveniently peak at present time. Simply hilarious. Enough about Beck, that's already a lot of time wasted on this.
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  29. Philippe Apparently Beck is not the only author that puts yhe medieval temperature maximum higher than today. "Environmental Effects of Increased Atmospheric Carbon Dioxide" by ARTHUR B. ROBINSON, NOAH E. ROBINSON, AND WILLIE SOON, Oregon Institute of Science and Medicine, 2251 Dick George Road, Cave Junc tion, Oregon 97523: "current Earth temperature is approximately 1 °C lower than that during the Medieval Climate Optimum 1,000 years ago" But the graphs that accompany the above paper do not look anything like Becks. This does not confirm (or deny) Becks paper but does show that the time period was warmer than today which confirms the many other articles I have read on the medieval warm period. I did look at RC but they appear to be alone in their belief.
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  30. The Oregon Institute of Science and Medecine? Willie Soon, of the Soon and Baliunas fraud? Are you trying to suggest that this is a science paper? How closely did you check this? You must apply the same standards of scutiny to these sources that you apply to RC, otherwise you're not skeptical, you're just biased. RC alone in their belief? Which one, the fact that there is no detectable D-A cycle in past 10000 years (at least)? What scientific references do you have to contradict that fact? Did you consider that real scientists don't even know of Beck's existence because he does not do science, does not publish anything and is totally irrelevant to any real science debate? Beck is not an author. It is not a belief but a fact that all the serious reconstructions (based on real data) put the present times warmer than the MWP. Why don't you check real science papers and see where their conclusions are going? You can leave out Mann if you think there has been too much controversy around it already. Tha fact that Beck makes up cycles that are nowhere to be found in data and then manages to skew his own made up graph in a way that wouldn't fool a high schooler does not bother you, yet you accuse the RC contributors of defending beliefs without substantiation? What the heck? On the other hand, you subscribe to Fairbridge hypothesis that he himself did not have enough confidence in to actually publish, but that's not acting on faith? Look, you can believe whatever you want. This blog is about saying exactly what the exisiting SCIENCE (published in peer-reviewed science publications) says on one subject, and there is really no doubt on that side. You can argue ad nauseam about why what you believe is not in the existing published science, I won't discuss that any more, it is in fact off topic in the context of this blog.
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  31. Ah, the OISM sand their oh-so-funny petition. Since you're all about seeing both sides of the story, you could of course check source watch: http://www.sourcewatch.org/wiki.phtml?title=Oregon_Institute_of_Science_and_Medicine It is interesting that the "Institute" lists deceased faculty members as well as live ones. Could they have a shortage of credible names? That would be ironic, considering how open they are to anybody and everybody for signing their pathetic "petition." As anamateur paleontologist, you might be interested to know that one of the educational resources listed by Robinson in his homeschooling site is this: http://www.chalcedon.edu/ I'm sure that you will find their take on evolution interesting.
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  32. Philippe The top link in 231 is a Wiki site and appears to be mostly political. Maybe right, maybe wrong (opinion). The second link did not work, but chalcedon? Sorry I don't buy into home schooling. Schooling should be in done in institutions. Home study is another subject. I don't know or for that matter care about these petitions or any consensus as you already know. I support the Fairbridge hypothesis because of the logic, but admit that "gravity" is a subject poorly understood, only because I have never found a good explanation for what it is, only admissions that it is not fully understood. And yes this is off topic and needs to be dropped.
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  33. Don't tell me to drop it when you're the one who brought it up. The Robinson/Soon pile of nonsense is not a science paper and OISM is a crackpotery nest. The facts cited and supported on Sourcewatch are facts, you can check them for yourself because they are referenced. Beck is the father of all crackpots and wiki, for instance, is a lot more informative and accurate about D-A cycles than Beck. Plus they have links to real papers, so once again, you can check for yourself.
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  34. Phillipe: "It matters to us because of the social implications of having irrational superstitious people designing school curricula and shaping policies." So if we dumped all the historical "school curricula" designed and taught by christians and muslims and hindus etc and all that followed from them.....just where would we be? Still sitting in our caves, probably. And by inference, every scientist who is a christian, muslim, etc etc is an irrational superstitious person who should be shut out of any process of determining how society should be shaped? And of course their work must be unacceptable since they are irrational and superstitious. How many scientists working on climate change have religious beliefs? When can we start the witch hunt? #226 On ice melt and sea temps et seq. Like all things to do with climate, no single subsystem works out in isolation. That is our biggest problem, we do not have enough knowledge to complete a model. I quoted a very small part of a cycle which is happening right now. Like all parts of the overall system it gets more and more complex and inter-ractive as you trace each component. More plankton=bigger predators right down the food-chain, locking up CO2. Plankton and other biota die, drift to the ocean floor and lock up CO2 for 1000's of years. More plankton= more sulphur dioxide = more clouds. Climate is as intricate as life, if not more so; every sub=system is dependent to a greater or smaller extent on all the others through feedback mechanisms and it is foolish to try and isolate parts of the whole and say "This is the answer". It is not a simple system and thus cannot be resolved in a simplistic manner.
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  35. Philippe Re: your comment 230: "You can argue ad nauseam about why what you believe is not in the existing published science, I won't discuss that any more, it is in fact off topic in the context of this blog." Re: my comment 232: "And yes this is off topic and needs to be dropped. " Re: your comment 233: "Don't tell me to drop it when you're the one who brought it up." I was in agreement was I not?
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  36. Philippe My point about Wiki is that I don't go there. As I said they (and you) may be right or wrong. All I said is that the medeval thermal maximum is disputed. The reference I used may be a poor one but it is not the only one. I have seen this many times in different places but the only place I see it as lower is at Real Climate. But the point is irrelevant. I have no argument.
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  37. Mizimi, people who deny the reality of evolution and want to have creationism taught as if it was science are irrational and superstitious. Allowing them to alter school curricula will be detrimental to education. I have not yet personally met a Christian scientist who believed that ID or creationism should be called a scientific alternative to Evolution. You seem to go on a tagent and essentially make a strawman, but I won't discuss it. What evidence do you have that sea ice melting will be beneficial to the cycles that you so vaguely and loosely describe? Studies? Links? If you are so intent on respecting the complexity of climate, how can you suscribe to the simplistic and fabricated nonsense that Beck spreads around? There is an enormous amount of real scientific litterature out there on every aspect of climate (even hypothetical ones) and on the all shebang as well. Your disdain for wiki is rather strange, Quietman. I recently noticed they have a lot of links to Palaeos.
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  38. Philippe Distain is a little strong. I use the wiki sites for a quick reference but I don't take them seriously and double check what I read. I see too much inconsistancy and errors in subjects that I am very familiar with. As I said before, Palaeos is two sitesL Palaeos.com and Palaeos.org, the dot-org site is a wiki and while better than wikipedia is still questionable and needs to be verified. Kind of like peer-reviewed papers (more than an article but less than established documents). The references posted at both, however, are reliable means of cross-checking. A wiki that slams people (or any site that does this) I simply don't go to. I come to this site with an open mind and to learn more about Climate Change. But as a skeptic I question both extremes and take neither as fact. It has helped my understanding quite a bit. I just don't care to argue with someone that has a closed mind as you have seen. I do not address anyone once I have seen the trend in their arguments. I have done some editing on Wikipedia but essentially spelling and grammar. When I disagree I go to the discussion page to point out the errors and let the original author do the edits (and there are many errors).
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  39. # 222 cce >> "The climate change over the past few million years has zero, zilch, nada, nothing to do with any change between the '30s and today. They are completely different mechanisms." What evidence do you have for that? cce>> "Every metric tells us that it is warmer now than in the '30s. You reject this conclusion, based on numerous independent observations, in favor someone's crackpot theory about plate tectonics." A large number of skeptics believe that the GW is happening. What they have trouble swallowing is that it is happening as a result of human activities. cce>> "(3) The IPCC accurately summarizes the state of the peer reviewed science, which is why the relevent scientific societies (who are responsible for actually producing the science) endorse the IPCC findings. Yes, they do at the moment. But recently, more and more scientists are changing their minds (as good scientists should) and rejecting AGW when the data and observations don't agree with the hypothesis. And AGW is just that at the moment, an hypothesis.
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  40. Phillipe: try these as starters:- ice core records siple curve pre ind co2 www.john-daly.com/zjiceco2.htm http://books.google.co.uk/... http://www.agu.org/pubs/crossref/2006/2005JC002994.shtml http://www.google.co.uk/search?hl=en&rlz=1G1GGLQ_ENUK279&q=arctic+phytoplankton+bloom&meta= Whilst it is off topic you might like to read these on treeline movement and CO2 response which show that the biosphere is responding with negative feedback. http://www.sciencedirect.com/... http://216.239.59.104/... co2 effect on trees growth rate sour oranges
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  41. I do not appreciate the condescending implication of "starters." I have some clues about all this. You bringing Beck in the discussion does not really indicate that you know better than I. However, I notice that you now are using better sources. So now we can talk. Jaworowski has his opinion and the link you give is just that, his opinion. He has consistently declined to bet against IPCC predictions, so I don't know how much confidence he has in his own opinion. Nevertheless, that piece is not peer-reviewed science. The book is quite interesting. It emphasizes the fact that the ICE-EDGE is the really important area for production, since open water becomes very quickly nutrient depleted. Production of phytoplankton is good but eutrophization hardly qualifies as a boom for marine life. It is really anyone's guess how that ecosystem will fare if the Arctic becomes totally open in the summer. However, the book seems to suggest that the longer the water is open and the larger the open area, the quicker it will be nutrient depleted. I noted another return on your search query page indicating a lack of success at netting krill, why is that? http://www.imr.no/arctic/cruise_diary/phytoplankton_bloom_on_spitzbergen_bank The AGU paper is about a computer model to simulate blooms and does not really go beyond that, at least as far as the abstract says. Am I to assume that you trust computer models for complex systems involving biological and physical components? The Siberian forest paleo data is interesting but what exactly is your point there? Does it really suggest a much different total latitudinal repartition ot just different boundaries? How exactly is it applicable today, when humans have so much influence on ecosystems? The bristlecone vertical growth paper says this: "Average density above tree line is greater than below tree line, though no statistical significance can be shown." If I had the classic, obnoxious skeptical attitude, I'd say that you really can't draw any conclusion from this because of the lack of statistical significance. I won't go as far, but say that it remains to be shown that this is more of an extension in vertical repartition than simply a upshift. As for your other links on growth rates (and your summary dismissal of the Rubisco activase problem on the other thread), it considers trees in isolation of ecosystems. There is no doubt that biomass can store carbon, everybody knows that. The problem is that we won't let it happen. Let me put it on other words: how likely is it that the enhanced growth rates, will compensate for the land use changes? How about more frequent wildfires? How about parasites and invasive species? You made the argument that complexity restricts our comprehension about climate, but complexity is even more of a restricing factor with forecastin the behavior of ecosystems. You have no problem betting on it, that's your take. The tree paper also says this: "However, the scientists who conducted the study said such high growth rates probably will not be sustained as the experiment continues. They emphasized that the results do not indicate that more lush plant growth would soak up much of the extra CO2 entering the atmosphere from fossil fuel burning."
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  42. Well I don't know I have seen a lot of things from astronomy papers to medieval records that strongly support a warmer middle ages. Cherry picked proxy studies showing otherwise do not convince. I have no idea about Soon or various others and I don't much like OISM. However for scientific method you might want to be careful. Robinson is best known as a whistle blower on scientific method. Linus Pauling made similar charges against him and rather famously lost the ensuing law suit along with the money for his Nobel prize.
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  43. WA I agree, botanic references in the historic records alone implicate a much warmer climate *in the locations where they were written) at that time. It proves that parts of the earth currently cold were warmer then but it does not prove it was a global phenomena. It was likely a situation more like today where we see climate shifts. I don't know what astronomy says but I am interested in knowing if it was truely a global phenomena (the current is not global as can be proven by looking at local climate histories that have remained stable).
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  44. A few cherry picked proxies? That's your description. For those who'd rather check for themselves, the latest reconstruction is here: http://www.pnas.org/content/early/2008/09/02/0805721105.full.pdf+html All data, methods, and computer code are also available online.
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  45. Philippe Thanks for the PNAS link, that is an interesting paper. But please note the last statement just above their conclusion.
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  46. Yes check for yourself... not just at that one spot. For tree ring proxies used in the famed hockey stick and elsewhere cherry picked might be too kind. Many of them may not even be good proxies for temperature at all. An average of selected doubtful proxies does not make for a reliable record. If you can find how they chose which proxies to use and which to exclude, and why, you will find interesting reading. We have digressed a long way. How about all of those predictions of the Arctic ice disappearing this summer? How well did they make out now that the minimum is past? Remember how the young ice from last winter was going to melt much easier and all that stuff?
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  47. I don'tknow what predictions you are referring to, you're still not linking anything. The real experts were actually quite close to the mark. After all that thread on ice, you still can't look up NSIDC. You'll find all you need to know there. BTW, the answer is, they don't really know. It shows indications that the minimum has happened but only time will tell for sure.
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  48. Philippe I have to agree there. Last year was quite unusual and without the freak weather and would likely not have melted as much as this year. It does remain to be seen.
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  49. One of the possible contributions to Actic warming was raised by leebert (posts # 29,34,37,42,47,49,58). This is so-called "black carbon" (part of the man-made aerosol load from burning "dirty fuels"), of which leebert referred to work by Ramanathan who has published extensively on this subject. The human-induced aerosol load from human emissions results in a combination of cooling and warming [black carbon on ice reduces albedo and promotes melting of ice; aerosols in the atmosphere screen the solar irradiation ("global dimming"] which counters greenhouse-gas-induced warming. In fact Ramanathan has shown that the overall effect of man-made aerosols is to counter the effects of global warming resulting from man-made enhancement of the Earth's greenhouse effect (see my posts # 33,39,41,45,48,53,66). Ramanathan has just published a detailed account of the committed effect of our greenhouse gas emissions, once the "cooling" effect of atmospheric aerosols is gradually overcome. It's not an encouraging scenario. It's pertinent that the very author that leebert has used to downplay the role of greenhouse gas emissions on global warming and Arctic sea ice attenuation, is actually one of the most vociferous scientists publishing on the extreme dangeroers of the committed warming that will result from our already-released greenhouse gas emissions. here's the abstract of the paper about to be published in the Proceedings of the National Academy of Sciences: On avoiding dangerous anthropogenic interference with the climate system: Formidable challenges ahead V. Ramanathan and Y. Feng Abstract "The observed increase in the concentration of greenhouse gases (GHGs) since the preindustrial era has most likely committed the world to a warming of 2.4°C (1.4°C to 4.3°C) above the preindustrial surface temperatures. The committed warming is inferred from the most recent Intergovernmental Panel on Climate Change (IPCC) estimates of the greenhouse forcing and climate sensitivity. The estimated warming of 2.4°C is the equilibrium warming above preindustrial temperatures that the world will observe even if GHG concentrations are held fixed at their 2005 concentration levels but without any other anthropogenic forcing such as the cooling effect of aerosols. The range of 1.4°C to 4.3°C in the committed warming overlaps and surpasses the currently perceived threshold range of 1°C to 3°C for dangerous anthropogenic interference with many of the climate-tipping elements such as the summer arctic sea ice, Himalayan–Tibetan glaciers, and the Greenland Ice Sheet. IPCC models suggest that ≈25% (0.6°C) of the committed warming has been realized as of now. About 90% or more of the rest of the committed warming of 1.6°C will unfold during the 21st century, determined by the rate of the unmasking of the aerosol cooling effect by air pollution abatement laws and by the rate of release of the GHGs-forcing stored in the oceans. The accompanying sea-level rise can continue for more than several centuries. Lastly, even the most aggressive CO2 mitigation steps as envisioned now can only limit further additions to the committed warming, but not reduce the already committed GHGs warming of 2.4°C."
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  50. I forgot to post the url for the Ramanathan article in press in PNAS (see post #249) It's: http://www.pnas.org/content/early/2008/09/16/0803838105.abstract
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