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Comments 36651 to 36700:

36651. Tom Curtis at 09:45 AM on 12 May 2014
       Global warming theory isn't falsifiable
       

       Dikran Marsupial @64, here is the latest model/observation comparison from Real Climate for September SIE:

        

       Looking closely we see one or possibly two values below two StDevs of the multi model mean.  We see a further six (seven counting 2013 more than one but less than two StDev from the multi model mean.  Given 34 observations (35 including 2013), that yields a p-value well above 0.05 even though the p-value for one (possibly two) observations by itself is less than 0.05.  If the observations were randomly clustered, therefore, the models would not yet have been falsified.  That is because, as you well know, the probabiliy of a particular event occuring increases with the number of trials.

       Of course, the events are not randomly clustered.  They show a distinct trend, and an analysis of trends may show that with regard to trends the observations have a p value less than 0.05 relative to distribution of the models.  Unfortunately, I don't know that as I have not seen that analysis.  If it is, by convention the sea ice modules for C-MIP3 might be considered falsified.  Of course, as you know, the standard that data with a p value less than 0.05 falsifies a model is a fairly arbitrary convention.

       My point, however, is that the potential falsification of the sea ice models does not equate to a falsification of O-A General Circulation Models of which they are components.  For the GCMs, the sea ice modules are just one component.  Because the models have statistical output, a p value less than 0.05 for one module does not mean a p value less than 0.05 for the total output of the GCM - and it is only the latter that would falsify the GCM (even under the standard convention).  That is because even if the models were entirely correct, over a number of predicted observations, some would be expected to have p values less than 0.05 just by chance.

       As an aside, at Real Climate, Gavin wrote:

       "Sea ice changes this year were again very dramatic, with the Arctic September minimum destroying the previous records in all the data products. Updating the Stroeve et al. (2007)(pdf) analysis (courtesy of Marika Holland) using the NSIDC data we can see that the Arctic continues to melt faster than any of the AR4/CMIP3 models predicted. This is no longer so true for the CMIP5 models, but those comparisons will need to wait for another day (Stroeve et al, 2012)."

       (My emphasis)

       Consulting Fig 9.24 in AR5 WG1 Ch9, we see that the models are not falsified with regard to Sept sea ice extent (which is not the same as saying they perform well).  Apparently, however, they now have a problem with Arctic winter sea ice extent.

36652. jetfuel at 09:38 AM on 12 May 2014
       It's cooling
       

       Dikran, I looked at the NH min sea ice trend you predict. It looks like a good fit, but 2013 (not incl) bounced back to the very upper limit of grey shaded area (@5.1M) and 2014 will have to be less than 5.1M min for the 95% CI to continue to match. Your graph ends with 2012. The 2012-2013 recovery reasonably matches the largest of any shown, that of 1997-8. Looks like 2032 is the min=0 prediction without 2013 data included. I presume this chart will be redone if Sept 2014 min exceeds 5.1M?

36653. Tom Curtis at 08:58 AM on 12 May 2014
       It's cooling
       

       DM @234, the graph you show shows almost no trend for sea ice extent maximum.  It also shows sea ice extent maximums substantially less than the March average sea ice extents from the NSIDC:

       

       As the link to the image you use mentions Goddard, how sure are you of its reliability?

       In any event, here is the EEA arctic SIE analysis for Nov 2012 (there most recent), which has the advantage of showing the trend lines:

       

       As can be seen, the trend for both March and September are both negative, but the absolute value of the September trend is more than twice that of March.  It follows, as you point out, that the sea ice extent recovery increases, on average every year.

       It is very clever of jetfuel to turn evidence of decreasing sea ice extent at all times of year into proof that the Arctic is cooling /sarc

36654. Dikran Marsupial at 03:55 AM on 12 May 2014
       It's cooling
       

       jetfuel wrote "All from nsidc: In Sept 2012: 3.425M sq km ice area. In Mar 2013 peak day: 15.10M sq km. 15.1-3.425=11.675M sq km increase. I will eventually learn how that compares since 1981. "

       perhaps you should perform this analysis before making claims about how unusual the increase is.  Now had you been paying attention to the replies to your comments, you would know that the answer has already been pointed out to you more than once.  Here is the important graph:

       

       The increase isn't that dramatic compared to previous years, and is due to the fact that winter maximum is declining a bit more slowly than the summer minimum (for fairly obvious reasons).  However the trends in both are downwards.  Look at the trends, not the noise.

36655. jetfuel at 03:47 AM on 12 May 2014
       It's cooling
       

       Geographic area: Central Indiana, Yes, sorry, I did have the last two winters switched for ice area growth. The second to last season was the one with over 11M of increase.

       All from nsidc: In Sept 2012: 3.425M sq km ice area. In Mar 2013 peak day: 15.10M sq km. 15.1-3.425=11.675M sq km increase. I will eventually learn how that compares since 1981. Then after that huge increase, the following winter saw only 15.229-5.1=10.129M sq km. Sorry I had the two years confused with each other. Still, one would think that both years are normal or above normal ice increase (10.129 and 11.675 million sq km). For instance, Sept 23, 1997 to March 1998 increase was only 9.328M sq km of increase, and that was one of the the coldest recent winters, peaking at 15.955M sq km of ice area.

       Warmest Arctic air in a while causes nearly the most ever (10.1M), if not most ever (possibly the previous year with 11.675M), sq km of ice to form during the same time puzzles me as to why the warm air didn't stunt ice growth comparatively.

       Records, records, and more records: from mlive.com: clarifies my earlier estimates:

       "Lake Superior is still over 60 percent covered in ice as of yesterday Saturday April 26, 2014. The satellite pictures shown above were the latest I could find that had clear skies and good vision of the ice. These high resolution satellite images come from April 23 and April 24, 2014.

       On Wednesday April 23, 2014 Lake Superior had 68 percent ice cover. According to the Great Lakes Environmental Research Laboratory, the previous highest amount of ice on that date was in 1979 when there was 38 percent ice cover.

       So the ice on Lake Superior is currently almost twice as much as recorded for this late date in the ice season. The records go back to 1973.

       On Wednesday, Lake Michigan still had 15 percent ice cover. The highest amount in the records on that date was five percent in 1979. This means Lake Michigan has three times the previous highest ice amount on April 23.

       Lake Huron was still reporting 25 percent ice, with the previous late season high at 11 percent in 1996."

       I learned that while area never eclipsed the 1979 mark, the lasting of ice was the highest on record. This tells me that possibly the volume of ice was surely a record since accurate records of area started in 1973. Some said 2014 was going to be the summer of zero Arctic ice. It may turn out to be the summer of June Lake Superior ice. In other news media statements, I'm led to believe that I live in the only part of Earth that is cooling over last 30 months. US Midwest.

       Moderator Response:

       [JH] Posting a potpurri of factoids is akin to sloganeering which is prohibitied by the SkS Comments Policy. Future posts of this nature will be summarily deleted.

       Since you have repeatedly posted poturris of factoids, you are also engaging in excessive repititon which is also prhobitied by the SkS Comments Policy.

       You are now skating on very this ice indeed. 

36656. Dikran Marsupial at 01:05 AM on 12 May 2014
       Global warming theory isn't falsifiable
       

       Tom, there is a distinction between the models being falsified (which they are by the sea ice extent, where the observations are far enough from the models to be falsified at a sufficently low alpha for us to be confident that they do get sea ice extent wrong) and the theory underpinning the models.  mbarret was talking about the falsification of the models.  It isn't a big deal that the models are falsified as GEP Box's famous quote tells us that all models are wrong (but some are useful).  If we gather enough data all models can be shown to be wrong, however that doesn't mean the underlying theory is wrong, just that some particular refinement or detail is missing from the model.

       However, my point remains, even without the models, the scenario I mentioned would falsify the theory within a reasonable timeframe, so mbarret is still wrong!

36657. michael sweet at 23:33 PM on 11 May 2014
       Global warming theory isn't falsifiable
       

       mbarrett:

       Your claim that Climate Science is falsifiable only after we are dead is false on its face.  In 1896 Arrhenius predicted that the climate sensitivity was 4.5C/doubling of CO2.  That number (calculated with a pencil) is still within the IPCC accepted range (although it is at the high end of the accepted range).  His calculation has been validated by observations since then.  Skeptics ignore the history of climate science when they say the science is not falsifiable.

       Likewise, in 1989 James Hansen and denier Richard Lindzen testified before congress.  Hansen asserted that the warming signal could be observed while Lindzen testified that it was not warming.  The observations currently are "unequivical" that Hansen was correct and Lindzen's position has been falsified.   Lindzen has proposed many skeptical theories over the past 40 years.  All have been decisively falsified.  He will be remembered as an abject failure and a hinderance to determination of the facts about Climate Science.

       Numerous other examples exist where Climate Science has correctly predicted changes in advance.  The recent National Academy of Science and American Association for the Advancement of Science Reports contain myriad examples of effects predicted decades to centuries ago that are now measured.  Skeptical claims that changes will be small have been decisively falsified.  

       The question before us now, that scientists are currently debating, is will the changes be catastrophic or just really bad?  How long will you live?  If the drought currently occuring in Texas and Caifornia turns out to be the first major (USA) agricultural hit from AGW we will know if 5-10 years.  I expect to live about 30 years.  That is enough to see big changes from BAU.

       Your claim of "It seems to me a climate science model is not sufficiently falsifiable for many years." is only true if you ignore all the evicence that has already been collected.  Of course if your standard is that anything learned before today doesn't count, it will be longer before AGW is proven again.

36658. Kevin C at 18:22 PM on 11 May 2014
       We can't count on plants to slow down global warming
       

       Among the many interesting sociological studies to be on the online response to climate change stories, I think there may be an interesting investigation to be done into the types of stories which don't attract comments. This is a data stream which is missed by more typical studies. (As an extra bonus, the ethics approval would be very simple).

36659. Tom Curtis at 10:58 AM on 11 May 2014
       Global warming theory isn't falsifiable
       

       mbarrett @59:

       "I don't think its pointless. In fact, the lack of expertise of, well, everyone who is not an expert, is entirely the point, (remember the objective of this website)."

       You should learn, and remember Werner Heisenberg's definition of an expert:

       "An expert is someone who knows some of the worst mistakes that can be made in his subject, and how to avoid them."

       There are two corrollaries:

       1)  Mistakes made by experts tend to be interesting, in the sense that you have to learn something new (expand the emperical content of the theory) to refute them; and (more relevant to this discussion)

       2)  Non-experts do not know all the basic mistakes in a theory, and will tend to repeat them.

       Arrogant non-experts repeat them ad nauseum.

       You can see the efforts of (often arrogant) non-experts trying to "falsify" climate science by repeating basic mistakes, often mistakes refuted decades, and in some cases centuries ago, in most of the comment threads on SkS.  An informative introduction to the arrogance of non-experts can be found by reading the comments in the 2nd Law of Thermodynamics thread.

       In any event, there is a clear disparity between experts and non-experts.  The criticisms of non-experts will almost inevitably be uninteresting - mere repetitions of mistakes that have been refuted beforehand.  Because they are not experts, they do not know any better.  In order to effectively criticize the theory you have to be able to distinguish between the interesting criticisms (those which are not mere repetitions of past mistakes), and the uninteresting repetition of basic mistakes - and to do that you need to be familiar enough with the literature to know of those past occurences of the basic mistakes and the papers that responded to those past mistakes, and refuted them.

       In contrast, when responding to basic mistakes, you do not need to know what was wrong with all basic mistakes, but only that to which you are responding.  Likewise, to understand the basic concepts of the theory, you do not need to be expert.  You should, however, recognize that understanding the basic concepts (which takes a few hours study) does not provide the platform for criticizing the theory that comes from many years of intensive study as found in experts.

       As an anology, I understand the basic principles of carburetion.  That does not mean I am able to effectively criticize the design of any modern carburettor or fuel injection system.  I would be a fool to think my limited knowledge gave me that ability.  But that in know way means I am unable to show the errors by bigger fools who think carburettors would be improved by placing an impermiable membrain across the barrel, or by removing the jets.  Sadly, most inexpert criticisms of climate science show little more sophistication or cogency than those the analogy (I again refer you to the 2nd law of thermodynamics thread if you don't believe me).

       For some strange reason, most people are willing to respect expert knowledge in nearly all topics.  But they seem to think that expert knowledge ceases to exist if the topic is relevant to public policy.  They seem to think that just because the refutation of their particular objection was not included in a basic presentation of climate science (or just as often, included but simply not understood by them), that therefore the refutation does not exist and that they have refuted with a few moments of uninformed thought the work of thousands of experts.  They are deluding themselves, and you do them no favour by pretending otherwise.

       This does not mean that they should not attempt to refute climate science.  In fact I encourage them to do so.  But to do so they must put in the effort to become genuinely expert.

       Moderator Response:

       [JH] How about transforming this very informative comment into a SkS article?

36660. Tom Curtis at 10:08 AM on 11 May 2014
       Global warming theory isn't falsifiable
       

       Dikran Marsupial @60, the models have not been falsified by Arctic Sea Ice extent.  A climate model predicts a very large number of variables.  For any given variable, it may show values with a p value of 0.01 (for instance), but with 20 or more variables predicted, the probability of any one variable showing a p value that low is quite high.  With 20 variables it is 0.1821, which is well above the conventional 0.05 falsification standard.  Climate models, of course, have far more than 20 variables.

       Having said that, if we consider the sea ice modules of climate models in isolation, arguably they have been falsified.  Arguably because, according to Popper, whether or not a theory has been falsified is always a matter of convention.  (Indeed, given the Duhem-Quine thesis, that falsifications are matters of convention follows by necessity.)   As such they may need to be replaced with better modules, and the climate modelling community and particularly the sea ice extent community are very busy trying to assess to what extent the discrepancy is a statistical fluke, and to what extent their theory needs modification.

       Here, it is necessary to bear in mind Lakatos statement that all research programs "... grow in a permanent ocean of anomalies", that "All theories, in this sense, are born refuted and die refuted".  As a result of this, in his opinion, the important feature of science is not falsifiability, but the determination to eliminate anomalies only by growing the emperical content of the theory - something which is very evident in climate scientists and notably absent from their critics (who tend to ignore anomalies in their own, very stunted theories).

       For what it is worth, Lakatos was a student of Popper's, and considered by Popper to better understand Popper's theory of falsification than any person other then himself - until that is, Lakatos showed signs of independent thought.

36661. Tom Curtis at 09:33 AM on 11 May 2014
       It's cooling
       

       jetfuel @228, it is not part of the polar vortex theory that the large southern excursions of the polar jet stream that brings unusual cold for the 21st century will always occur over Illinois.  On the contrary, it is a chaotic process, and can at any longitude.  Thus, in 2011 it occured over Europe, and weakly over the US eastern seaboard:

       

       In 2012 over the extreme eastern region of Siberia:

       

        

       In 2013, over the Siberia, Mongolia, China and Japan:

       

       And as already seen, in 2014 it occured over the majority of the contiguous US.

       Further, the theory is not that similar events have not occured in the past.  Rather, it is that the warmer Arctic ocean makes such events far more likely.

       If you are going to criticize a theory, you need to actually read the theory in the scientific papers, and make sure you understand it.  If not, you will inevitably end up criticizing a straw man.  You can start with Honda et al (2009), which discusses the connection specifically with connection to Eurasia, and Liu et al (2012) , which extends the theory to include the US.

36662. Composer99 at 06:02 AM on 11 May 2014
       It's cooling
       

       Also, this year's sea ice maximum extent was the fifth lowest in the satellite record. What is more, the seven lowest maximum extents have all occured in the last seven years.

       And, now that I've noticed it:

       then as winters and summers have gotten colder where I live over the last 30 months,

       First, citation please. Second, what of it? A small region on the Earth is very likely to see much more variability in its temperature trends in 30 months than it will in, say, 30 years (which is the usual standard for establishing temperature trends in climate).

36663. Composer99 at 05:57 AM on 11 May 2014
       It's cooling
       

       jetfuel, frankly speaking your sense of personal incredulity about what is going on is not a sufficient substitute for analysis based on the available evidence. Especially not when you are backing that up with sea ice numbers that appear to be coming out of thin air.

       I should like to reiterate Tom Curtis' point that winters that are exceptional in the 1990s through the present were once a commonplace, and as such by over-stating their importance you are falling for the shifting baselines fallacy.

       I must make a special note about:

       used to explain why we were having a normal 1900's winter,

       Well, yes. Because in the 2010's a "normal 1900's winter" is exceptional and requires an explanation.

36664. MA Rodger at 05:45 AM on 11 May 2014
       It's cooling
       

       jetfuel @228.

       You say "....it formed over 11 million sq km of new ice between Sept 2013 and March 2014." I do not recognise that figure. Using NSIDC monthly data, Arctic SIE rose 9.45M sq km. Daily SIE data from JAXA increases this slightly to 9.64M. Daily SIA yields a yet larger number - 9.92M - but none of these nmbers are "over 11 million sq km" and none of them are "a new record."

       I am therefore entirely perplexed as to what it is you think you are about with these numbers you present here. Explain yourself - if you can.

36665. jetfuel at 02:49 AM on 11 May 2014
       It's cooling
       

       2011-2012 winter was hardly a winter. 2012-2013 was normal for winter. 2013-2014 was setting all kinds of records in Indiana. We just broke a record for fewest 70 degree days by late April that stood for 99 years.

       Warm air always blows up into the Arctic. whether it stayed there or not this past winter, it formed over 11 million sq km of new ice between Sept 2013 and March 2014, and while that was happening, the Arctic is so unusually warm, that it splits up it's cold air mass and smaller pockets drift down over Canada, Indiana, etc. So this year the bad news is: it's negative 25 instead of negative 35 at the North Pole while a new record is set for newly formed seasonal ice area increase throughout the Arctic?

       "One thing that is pretty clear is that the cause-and-effect chain for any changes won't have just two links in it" This is exactly why the Polar Vortex narrative that followed 2 days of media silence on Jan 24th this year, used to explain why we were having a normal 1900's winter, and so universally pushed on me by the media, has me agreeing with this quote and all this PV narrative. If the north pole fell apart in January, then as winters and summers have gotten colder where I live over the last 30 months, it seems that just the opposite is happening. Something about warmest Arctic air causes nearly most ever, if not most ever, ice to form during the same time doesn't sound right. And now I'm told that the PV breakup is common pattern? This was the most uncommon winter since 1993-4 here. What recent year exhibited this same PV disruption?
       

       Moderator Response:

       [JH] Please specify the geographic that is covered in your characterization of recent winters. Is it North America? The entire Northern hemisphere?  

       You also state: This was the most uncommon winter since 1993-4 here. Where is "here"?

36666. Dikran Marsupial at 02:44 AM on 11 May 2014
       Global warming theory isn't falsifiable
       

       mbarret models are not necessarily inductive, I could make a mathematical model of a double pendulum (a chaotic system) based on physical laws, or a statistical model of the body mass of dinosaurs.  There is a spectrum of model types and GCMs are closer to the double pendulum model than statistical ones.

       The length of time required to falsify a climate model is also no where near as long as you suggest.  A statistically significant cooling over a period of 30 years, during which CO2 had continued to rise and there was no change in otherf forcings which could explain the cooling would consitute a falsification of the models.  Such a test has already been performed and the models were not falsified, but they could have been, which is what makes the theory scientific form a Popperian perspective.

       "Or to put it another way, falsification is impossible if one is hindered from falsifying."

       This is nonsense on stilts.  Climatologists are in no way unusual in their view of falsificationism, and modellers are perfectly happy to talk about the failings of their models. 

       Besides, the models have been falsified, they predict that Arctic sea ice loss will be slower than that we have observed, so much so that it lies outside the spread of the models.   The skeptics don't seem to want to talk about that though ;o)

36667. mbarrett at 22:37 PM on 10 May 2014
       Global warming theory isn't falsifiable
       

       I don't think its pointless. In fact, the lack of expertise of, well, everyone who is not an expert, is entirely the point, (remember the objective of this website). There are two ways falsifiability is valid in climate change science. One is the implicit falsifiability of a given theory or research paper, (obviously the rightful point of this page), the other is the value the scientific community attaches to falsifiability as a tool of the non expert to critique their scientific standards. Or to put it another way, falsification is impossible if one is hindered from falsifying. Popper's political opinions, it seems to me, explain the value he attached to falsifiability. If I may make one criticism of your comments, it's that perhaps don't make it clear that you understand a perfectly excellent scientific theory, such as AGW, is not necessarily a showroom example of falsifiability.

36668. Tom Curtis at 21:14 PM on 10 May 2014
       Global warming theory isn't falsifiable
       

       mbarrett @57, I'm so sorry.  I had forgotten that Popper's falsificationsim demanded falsification within a certain time limit.  So good to learn that theories that the Sun will eventually become a red giant are unscientific because we will not be around to falsify them /sarc

       (As an aside, the climate models have not been falsified yet, and may not be falsified when we are long dead - but could have been falsified on their first production.  Your conflation of "has not been falsified" with "is falsifiable" is noted, however.  I draw your attention once more to the pointlessness of having a right to examine whether or not climate science is falsified, coupled with a complete lack of ability to deal with the issues involved. 

36669. mbarrett at 20:32 PM on 10 May 2014
       Global warming theory isn't falsifiable
       

       Thank you for the interesting reply Tom. I am especially taken by your strong reaction to my comment about models:

       The most bizzare claim you make is that the reliance on models is problematic with regard to falsification.

       I had always assumed that proponents of falsifiability were specifically thinking of the drawbacks of "induction heavy" methods, such as models, especially when, as in the case of climate science, they will only be proven correct when we're all dead. It seems to me a climate science model is not sufficiently falsifiable for many years. I'd be interested to know what other posters think. 

       Moderator Response:

       [JH] Plese note that the all-vounterr SkS author team is constructing a time travel machine a la H.G. Wells.

36670. MA Rodger at 19:21 PM on 10 May 2014
       It's cooling
       

       jetfuel @225.

       You appear to be asking a rhetorical question - "This didn't have anything at all to do with this last very cold winter?" What is still a mystery to me is which winter you are trying to refer to. 'This last winter' was not 'very cold' for an Arctic winter. Indeed, it was rather warm. (See this graphic of Arctic Ocean Lower Troposhpere Temperatures - usually 2 clicks to 'download your attachment'.) Nor was the previous winter (2012/13) particularly cold. What was cold was the Arctic summer & autumn of 2013.

       Given such circumstance, the use of your rhetorical question appears to be misplaced. Indeed, you point out yourself that extra ice volume is due in part to the "retention of thick, multiyear ice", a situation more associated with low levels of melting than with high levels of freezing which sort of fits with the Arctic temperatures over recent seasons.

       So is your use of the term "winter" correct and if so which winter are you attempting to refer to?

36671. Tom Curtis at 19:08 PM on 10 May 2014
       It's cooling
       

       jetfuel @223 writes:

       "I'm looking for an anomoly where it is much warmer in the Arctic in the winter so as to cause a once in decades event"

       Let's ignore the fact that the cold North American winter was not a once in decades event, but an almost commonplace winter as little has half a century ago; and has only become exceptional by comparison to recent warmth.

       Rather, let's focus instead on the unusual situation where jetfuel claims to be looking for anomalous warmth, but does not bother looking at surface temperatures to find that anomalous warmth:

       

       (Gisstemp polar authographic projection of 2014 winter temperature anomaly.)

       We'll also not ignore the fact that the theory jetfuel is criticizing is that reduced sea ice extent in late autumn creates greater warmth in the Arctic, destabilizing the jet stream resulting in unusually cold early winters.  Therefore references to March sea ice extents, sea ice volume and (most especially) Antarctica are all red herrings.  What he should be looking at is the November sea ice extent which was the sixth lowest on record.  That was only 6.8% below the 1981-2010 average, but that period (1981-2010) shows continuous decline so that it was much more than that below the 20th century average.

36672. jetfuel at 17:12 PM on 10 May 2014
       It's cooling
       

       From nsidc: Preliminary measurements from CryoSat show that the volume of Arctic sea ice in autumn 2013 was about 50% higher than in the autumn of 2012. In October 2013, CryoSat measured approximately 9,000 cubic kilometers (approximately 2,200 cubic miles) of sea ice compared to 6,000 cubic kilometers (approximately 1,400 cubic miles) in October 2012. About 90% of the increase in volume between the two years is due to the retention of thick, multiyear ice around Northern Greenland and the Canadian Archipelago.

       This didn't have anything at all to do with this last very cold winter?

36673. Rob Painting at 16:54 PM on 10 May 2014
       Earth's five mass extinction events
       

       Varika - note too that the sustained high levels of atmospheric CO₂, due to this volanic outgassing over geological time scales, would have greatly increased the chemical weathering of rocks at Earth's surface mainly because of the intensified water cycle - more rain washing dissolved inorganic carbon (carbonate & bicarbonate ions in particular) back to the ocean.

       Over time this overcompensated for the loss of carbonate ions, and the oceans were actually more conducive to shell formation than they are today, despite the lower than present pH (acidification). This why the Cretaceous (meaning chalk) Period was so favourable to marine calcification.

       This doesn't occur with geologically-abrupt increases in atmospheric CO₂, pH and carbonate mineral saturation state decline in tandem making seawater corrosive because the rate of weathering is far too slow to provide bicarbonate and carbonate ions back to the ocean. The weathering feedback which counteracts corrosive oceans can take over a hundred thousand years to respond sufficiently.

       Hope this helps clear up this apparent paradox. SkS will have a rebuttal on this topic soon.

36674. Glenn Tamblyn at 16:41 PM on 10 May 2014
       It's cooling
       

       jetfuel.

       It is probably too simplistic to try and relate the splitting of the polar vortex to just ice extent. There were major influxes of warm air into the Arctic along 2 corridors - the east pacific and US West coast, and east of Greenland over Svalbard. These incursions of warm air split the vortex and in effect partly pushed it out of the Arctic. Given the time of year this occurred at I think it was more likely directly caused by weather patterns further south. However that doesn't rule in or out other relationships between the polar regions and lower latitudes. For example changes in NH snow cover, changes to the Polar Jet Stream, warming of ocean currents affecting Sea Surface Temperatures etc. Things are changing up there, global warming is a very big part of that, but the exact dynamics and trajectory of everything that will happen isn't clear. One thing that is pretty clear is that the cause-and-effect chain for any changes won't have just two links in it.

36675. jetfuel at 16:22 PM on 10 May 2014
       It's cooling
       

       JH, from your response to my 10% number. I'm trying to find support for the polar vortex line I've been told. Does the scientific expert concensus say 2% or more under March 2013 mean total ice area easily triggered this winter's polar vortex disintegration? I'm looking for an anomoly where it is much warmer in the Arctic in the winter so as to cause a once in decades event. I'm not seeing such an anomoly is total late March 2014 sea ice. Not seeing it in Antarctic sea ice coverage over last 2 years. Not seeing it in 2014 ice volume at the Arctic (up 800 cubic miles). What I do see is a dramatic improvement from 2012 to 2013 Sept Arctic sea ice area, revovering 49% of the gap to 1981-2010 mean sea ice coverage (nsidc). From the 3.45M sq km of sea ice on Sept 13, 2012 to 5.1M sq km on same day of 2013 is a 49% recovery of the 3.37M sq km gap from the 3.45 of 2012 to the 1981-2010 mean of 6.82 M sq km. Why just focus on the .8M sq km or so gap in max ice area (~2-3%) in March and ignore the 11+M sq km seasonal 2013 increase? In questioning my use of 'recovery'? 11+M is a whole lot more new added ice for it to be coinciding with the Polar Vortex falling apart. On the contrary, with 11+M sq km of new ice added, it makes sense to me that this winter was like it was. It was ranked 53rd coldest in Indiana in the last 100 years. Pretty average for the last 100 years. 2nd consecutive winter wher it is colder than the previous one. If the '14-'15 winter makes another similar jump, we might break the 1979 Great Lakes frozen area % record that we came within 1% of this past winter.

36676. Tom Curtis at 16:18 PM on 10 May 2014
       Global warming theory isn't falsifiable
       

       mbarrett @55, it is hard to disagree that the "...public may rightfully use scientific tools such as falsifiability to analyse the legitimacy of climate science arguments...".  You appear, however, to not know what is meant by that - and demonstrate it immediately by continuing your claim, specifying that that right extends to analyzing "...to the legitimacy of climate science arguments that are presented in summarised, or superficial form".

       Certainly the public has a right to check the accuracy and adequacy of summary presentations of science, but that is not a process of falsification.  Checking the accuracy of reports of science involves comparisons of the report to the original science, ie, the scientific papers and review articles on which the reports are based.  Further, while the public has the right to do that, only those of the public sufficiently scientifically literate to read and comprehend the original papers are able to do it.  Asserting the public's right to do something without asserting also the public's responsibility to make sure they are sufficiently able to do it is mere demagoguery.

       As noted, not only does the public have the right to fact check popular articles, they have the right to check the scientific adequacy of the original science - but again the responsibility to be sufficiently informed applies.  Based on hard experience, scientists consider it necessary to get the equivalent of a Bachelor of Science with Honours, and be well on the way to completing a PhD to reach that level of qualification.  While we need not expect the public to go to that extent, we should at least expect them to be approaching that level of expertise before they comment.  The sad fact, however, is that most comments by so-called "skeptics" here and across the net come from people who do not even understand the theory they purport to falsify.  Sadly, this cartoon fairly represents the current state of public debate on global warming:

       

       Finally, as we are talking about falsification, before publicly commenting on whether or not a theory is falsified, people should at least understand what is meant by "falsification".  At a minimum they should know the difference between universal and existential statements (with the former being falsifiable but not verifiable, and the later being verifiable and not falsifiable); between methodological and naive falsification; and also understand the Duhem-Quinne thesis, and its relevance to falsification.  Lacking that understanding, attempts at falsification reduce to crass cherry picking of straw man theories.

       Your list of problematic features suggests you do not have that level of understanding.  As the topic here (even with the absent OP) is falsification, and given your introduction, it appears that you consider "problematic" features as being those that indicate the underlying theory to be either falsified, or unfalsifiable - where the latter indicates it has no empirical content.  Yet you list features (purported ad hominen attacks, "perceived" reluctance to share data and methods, supposed reliance on models, etc, which have no bearing on whether or not a theory is falsifiable.  I get the distinct impression that you have merely used the topic here to introduce vague claims without justification in a topic where defence of those claims will be "off topic", so that you will not have to defend them.

       The most bizzare claim you make is that the reliance on models is problematic with regard to falsification.  In fact, a theory is just a set of propositions closed under implication.  A model is a set of propositions closed under implication with particular initial and boundary conditions.  A model, therefore, takes a theory and shows the empirical implications of that theory under certain empirical conditions.  Models, are, therefore, the means of generating falsifiable content from a theory.  With the understanding that mathematically (and logically), a model is a set of equations plus initial and boundary values, models need not be computer models.  Further, no theory that is not presented as a model (ie, the equations plus conditions) has falsifiable content.

       If you truly understood science and falsification, you would, as I, not find the use of models in climate science as problematic.  Rather, you would find the almost complete lack of models from skeptics concerning.  It means that in scientific terms, they have no theory.  Just some words to act a rallying cries. (There are, of course, a few exceptions to this generalization.)

36677. Glenn Tamblyn at 15:57 PM on 10 May 2014
       Earth's five mass extinction events
       

       Varika

       I second what Rob has said. The reference is to changes in tectonic CO2 emissions and a doubling during the Cretaceous of that tectonic rate. Human emissions are much larger than either rate - the US Geological Survey's estimate is that human CO2 emissions are 130 times total volcanic sources. Where elevated tectonic emissions can matter is when they go on for millenia and longer. Even the eruption of a super volcano such as Toba or Yellowstone is thought to only put the equivalent of 1/2 of human emissions into the air, and only for the duration of the eruption.

       This is the record of CO2 in the atmosphere from the Mauna Loa observatory:

       

       We might just barely see a wiggle on the annual mean line (black) around the time of the 1992 eruption ofMt Pinatubo if we squint hard and wish a lot. No sign of wiggles around the times of the eruptions of Mt El Chichon in 1982 and Mt Agung in 1964. Those were the big 3 eruptions during the period of the record. Far bigger than volcanic emissions but essentially an annual cycle is the absorption then release again of CO2 by deciduous plants (the wiggles in the red line). We can actully see the forests of the Northern Hemisphere going through their seasonal cycle.

36678. mbarrett at 14:22 PM on 10 May 2014
       Global warming theory isn't falsifiable
       

       The public may rightfully use scientific tools such as falsifiability to analyse the legitimacy of climate science arguments that are presented in summarised, or superficial form, (websites such as this one, Wikipedia, media articles, government policy statements etc). This communication needs to be beyond reproach. I don’t feel that this required level of "trust" is presently met regarding falsifiability. Using a benchmark of unfalsifiable pseudoscience such as the statement "Ghost are real and only people who believe in ghosts can see them", I find the following problematic:

       - Whenever temperature records are adjusted or otherwise shown to be previously flawed, the data has logically been proven to be unreliable. However, as long the new data supports the hypothesis, the original failure/limitation of the scientific method is ignored.

       - The definitive scientific meaning of the statement “The anthropogenic global warming signal has definitely emerged” is "flexible" in terms of its communication to the public in relation to natural variability.

       - A reliance on a multitude of complex and easily adjustable models.

       - Contradictory statements about the significance of short term/decadal temperature trends and the reasons for them. (Eg. Late 20th century temperature record versus 21st century temperature record).

       - Noteworthy examples of a perceived reluctance by climate scientists to publicly share all data and methods.

       - Climate scientists who are subject to ad hominem attacks from colleagues only after they dissent from the consensus, not before.

36679. Daniel Bailey at 12:37 PM on 10 May 2014
       Earth's five mass extinction events
       

       The science is settled:  It's Not Volcanoes.

36680. Occamsrzzr at 11:54 AM on 10 May 2014
       IPCC overestimate temperature rise
       

       I don't know why this is not in the top ten.  I hear this all the time.

36681. grindupBaker at 09:55 AM on 10 May 2014
       Answers to the top ten global warming 'skeptic' arguments
       

       Skeptical101 #14 My interpretation and synopsis of the considerable technical detail and references provided by Tom Curtis #15 & One Planet #16, #17 is that your "...not use it as an argument to support AGW" is correct if used over periods in which short term natural variability influences the trend strongly (<30 years was mentioned sometimes) and, in particular, the models are not able to predict the ENSO conditions at all well. However, over the somewhat longer term of several decades or more it'll all average out and leave the trend. I recall some article about South Pacific Easterly winds strengthening the last "couple decades or so" (?) and pushing more heat down into the South Pacific than might have been expected. I find that graph that's often on SKS per Tom #15(2) to be quite illuminating and I keep trying not to mention that it makes me wonder whether El Nino years are pulling away from La Nina & neutral since ~1991 with El Nino at 0.23 Celsius / decade because I know the data since then is too sparse and varied and definitely <30 years. If I'm right in 30 years hold a seance and tell me about it.

36682. Rob Honeycutt at 05:02 AM on 10 May 2014
       Earth's five mass extinction events
       

       Varika...  The comment you're responding to here is discussing the difference between tectonic and volcanic emissions in the Cretaceous to tectonic and volcanic emissions now, excluding human emissions.

       Man-made emissions of CO2 are about 100X that of natural sources. 

       http://hvo.wr.usgs.gov/volcanowatch/archive/2007/07_02_15.html

36683. Varika at 04:57 AM on 10 May 2014
       Earth's five mass extinction events
       

       Sorry, I'm used to forums where I don't have bold/italics options.  I will use those in the future here.

36684. Varika at 04:20 AM on 10 May 2014
       Earth's five mass extinction events
       

       "Eruptive tectonic activity (volcanoes; igneous province eruptions etc.) were active during much of the Cretaceous at a level that resulted in raised greenhouse gas warming and an increase in the carbon cycle at a rate around double that of present."
       
       Alright, I'm confused.  If the Cretaceous had carbon cycle increases at a rate double of the present, that means that volcanoes were putting out twice what's being put out today at any given time, right?  So if that's true, how can we cause a faster acidification of the oceans when we are putting out less carbon per year than those volcanoes?

       Moderator Response:

       [RH] Please note that we would prefer people not use all caps for emphasis, as it tends to read like shouting. Please use the bold or italics tools at the top of the comment box to add emphasis. Also, make sure you read the commenting guidelines.

       All caps changed to bold.

36685. Dikran Marsupial at 03:31 AM on 10 May 2014
       There is no consensus
       

       bakertrg wrote "so 97% of scientists are taking the position that THE cause of global warming is anthropogenic but none of them are publicly stating that humans are the cause of climate change? Maybe I'm missing something but that seems to contradict itself."

       do yourself a favour and go and read the paper and the comment thread to see what has been discussed already.  Most papers on climate change are independent of whether the cause of the change is anthropogenic or natural.  To give you an example, I have worked on statistical downscaling, which attempts to estimate the effects of large scale atmospheric circulation (which GCMs model fairly well) on local (e.g. station-level) scale (which GCMs fundamentally can't do beause the grid boxes they use are too large).  A paper on statistical downscaling doesn't need to make any statement at all on what causes climate change because that is not what the paper is about and academic papers tend not to make assertions that are not directly justified by the analysis given in the paper.  There are many other topic in climate change that are not concerned with attribution, which is why relatively few explicitly take a stance.

       Now this will be obvious to anybody that understands the culture of scientific publication.  Scientists do have better things to do with their time than answer questions raised on climate skeptic blogs, and as a result, you will only generally be assured of a climate change paper taking a stance on the cause of the change if the subject of the paper is an attribution study.

       "Despite what it may appear to be my goal is to find answers. "

       Then perhaps next time someone answers your questions, you shouldn't accuse them of being disingenuous and copping out.  This is especially true if you are going to convert

       "97% of the papers that take a position on the question do take the position that it is mostly anthropogenic."

       and

       "If you want a study of scientists that are publicly stating that humans are the primary cause of climate change, then you won't find one, because scientists have better things to do"

        into

       "97% of scientists are taking the position that THE cause of global warming is anthropogenic"

       EMPHASIS yours.

36686. MA Rodger at 03:20 AM on 10 May 2014
       It's cooling
       

       jetfuel's numbers for ASIV make no sense whatever unless it is about the state of the Arctic back in early November 2013 & the numbers are not meant to be exact.

       @218 jetfuel states "This is a lot, but this past winter added 800 cubic miles (3200 GTonnes) to the Arctic ice mass, to reach a peak of 2200 cubic miles of sea ice." Since the summer 2013 minimum, PIOMAS has never shown numbers higher than 2,620 cu km (ie GTonnes) above the previous year. That was back at the beginning of November 2013, more Autumn than Winter. That difference has been shrinking since then & since the beginnng of March 2014, ASIV has been lower than the 2013 equivalent. This '2200 cubic miles' figure is ~9,000 cu km. That was the value of ASIV back at the beginning of November 2013.

       As for the relevance of these numbers - pass.

36687. Dikran Marsupial at 02:42 AM on 10 May 2014
       It's cooling
       

       jetfuel, I demonstrated that the "recovery" was actually just a continuation of the downward trend in March maximum sea ice extent, and that an increase in the winter gain is what is expected simply because March sea ice extent is declining a bit more slowly than the September minimum extent.

       There is nothing special about the recovery in the last three years.  If you disregard the evidence and cherry pick in this manner, don't be surprised if your assertions are viewed with skepticism.

36688. John Hartz at 02:40 AM on 10 May 2014
       It's cooling
       

       jetfuel:

       Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

       Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.

36689. Composer99 at 02:15 AM on 10 May 2014
       It's cooling
       

       jetfuel:

       Do you think that Arctic maximum extent is the only factor determining the behaviour of the polar vortex? Yes or no?

       If yes, can you justify this position?

       As far as your comment on the ice volume goes, PIOMAS anomaly data show ice volume has dropped by approximately 10,000 km³ since 1979. An 800 km³ increase in one year (and there are plenty of upward jolts in the data even as it follows the downwards trend) is much too short a time period to start speaking of a "recovery".

       I have reproduced the graph below:

       

36690. jetfuel at 01:47 AM on 10 May 2014
       It's cooling
       

       nsidc data shows late March peaks of 15.22 million sq km for 2012, 15.1 million for 2013 and 14.9 million for 2014. The 1981 to 2010 avg is 15.4. The avg of 2012-2014 March peaks is 2.13% below the 1981-2010 avg peak of 15.4 million. 2.13% less ice area is the reason the Polar Vortex fell apart? The other 14.9 million sq km of ice couldn't save the vortex? Then, why hasn't this Vortex disintegration happened nearly every other year? Area with at least 15% ice is a rough indicator. the tremendous increase in ice volume in 2013 and 2014 also needs consideration. 2014 saw an 800 cubic mile seasonal increase in sea ice volume. That's the source of the 'recovery' I spoke of. For me to believe the 'polar vortexfell apart' line, I'd expect 10% less ice volume compared to last year, not 1.3% less ice area (14.9M vs 15.1M sq km) and a volume increase.

       Moderator Response:

       [JH] What is the basis of your "10% less ice voume" metric? Is it merely your personal opinion, or is it based on sound scientific research?

       In case you have not noticed, personal opnions about science carry very little weight with the users of this website.  

36691. Tom Curtis at 00:03 AM on 10 May 2014
       There is no consensus
       

       franklefkin @598, thankyou.

       I should have checked more closely before responding to the latest denier cherry pick on temperatures.  As it stands, my claim that bakertrg's claim re 21st century trends being "trivially false" needs to be withdrawn.  It is merely obviously false.

       Obviously false because, firstly, with five established temperature records, claiming a negative trend with two of them show a positive trend is begging the question as to which record is superior.  We can, off course, look for a tie breaker among the records.  Noticing, however, that the only surface record with truly global coverage, and the satelite record with the greatest covered area both show positive trends shows the negative trends of the others to be due to information they exclude rather than a property of global temperatures.  Further, the fact that newer records (HadCRUT4-hybrid, BEST) also show positive trends corroborates GISS and UAH as showing the better record, as do indirect measures of temperature such as Sea Level rise, and receding glaciers.

       Alternatively, we may decide to treat all records alike, and simply take an average - except that the average of the 5 established records gives a positive trend - and including the newer records (HadCRUT4-hybrid; and BEST) makes that postive  rend even stronger.

       Finally, we need only notice that pushing the start date of the trend back one year (two years for RSS), or the end date back to Dec 2010 to make the trends positgive to see that the negative trend even in those records with the trend depends essentially on a chery picked period.

       Regardless of all this, it appears that bakertrg has dropped that claim, so this is now beside the point.

36692. chriskoz at 20:11 PM on 9 May 2014
       2014 SkS Weekly News Roundup #19A
       

       Thanks for the encouragement Rob,

       Sure I can find time to compose something over this weekend. I dunno how to submit, I guess I contact John once I have something...

       Moderator Response:

       (Rob P) - Sounds like a plan. Whenever you're ready.

36693. Dikran Marsupial at 19:33 PM on 9 May 2014
       Sea level rise predictions are exaggerated
       

       jetfuel wrote: "Looking at Post #5's Graph above, the 2006 peak is about 2mm below the 2011 valley. I would draw a new best fit curve starting in 2006 that shows an 8 mm rise in 6 years, or 1.33 mm/yr."

       The human eye is only too good at finding patterns in noisy data, even when they don't actually exist.  That is why statisticians have invented methods for this problem, variously known as "breakpoint analysis", "broken stick regression", "segmented regression" etc.  What these methods do is determine whether the improvement in the fit of the model justifies the additional model complexity introduced by adding a breakpoint, which introduces at least two additional parameters to the model.

       If you don't follow standard statistical practice in this way and just pick the breakpoints by eye, you will generally end up overfitting the data and drawing meaningless conclusions based on the noise.  It is the sort of thing that is a recipe for confirmation bias.  So while you might do that, a scientist probably would know better.

36694. Glenn Tamblyn at 18:42 PM on 9 May 2014
       Sea level rise predictions are exaggerated
       

       Stephen, a significant part of the dip in 2011/12 ended up in Australia. Lake Eyre and several other lakes in Central Australia filled for the first time in years - flamingo heaven. Then slowly evaporated away over the next 2 years.

36695. Doug Bostrom at 15:39 PM on 9 May 2014
       As Population Surges, Harsh Climate Of Southwest Will Only Get Harsher
       

       If you're interested in water issues affecting the SW US you'll want to follow John Fleck's Inkstain.

       Fleck's a journalist in New Mexico, where water can't be taken for granted, is the subject of barely civil interjurisdictional struggles for partitioning and is generally sufficiently fraught to require a beat reporter.

36696. Stephen Baines at 15:27 PM on 9 May 2014
       Sea level rise predictions are exaggerated
       

       Thanks TC for the updated graph.  Yes I was referring to the trend line you would get from the graph in the OP.  It's not surprising that with more data you get reversion to the mean trend line.

       The recent large fluctuations around that mean trend are pretty interesting though.  I remember the decline was attributed to La Nina transporting water to temporary storage on land, but I haven't read anything really recent on that.  Even the large La Nina in 98-99 didn't have as big an effect.  I should look it up.

36697. Tom Curtis at 15:03 PM on 9 May 2014
       Sea level rise predictions are exaggerated
       

       jetfuel @39, Stephen Baines @40, here is the most recent update of sea level increase from the University of Colorado:

       

       As you can see, the trend from 1993 is still 3.2 mm per annum.  Clearly jetfuel's prediction of a trend of approximately 1.33 mm per annum is inaccurate.  I suspect Stephen Baines prediction of an increased trend since 2006 is also inaccurate, but that is not so obvious.  (It is more likely to have been accurate to early 2013 as in the OP.)

       Looking at the great lake data, Lake Ontario rose 0.11 meters between April 2013 and April 2014 inclusive, but fell 0.05 meters from May 2013 to April 2014, the actual one year "rise".  Even the former is no where near record breaking, being near one eigth the 0.86 meter rise from Dec 2012 to July 2013, although that does have a large seasonal component.  There have been larger seasonal and annual increases in the past. (For data, follow Stephen Baines' link.) 

36698. Stephen Baines at 10:24 AM on 9 May 2014
       Sea level rise predictions are exaggerated
       

       Jetfuel...your approach would almost certainly seriously underestimate the sealevels for 2012 and 2013 presented in the updated graph in the OP, since starting in 2006 looks like it would give you a steeper slope than the 3.2 mm /year overall average.  Which is why we don't draw regressions on small subsets of the data, especially cherrypicked ones.  Why would you take the trouble to go through the comments and ignore the updated graph anyway?  

       With regard to lake levels, there has been little net change in level of the Great Lakes over the time frame of the sealevel observations.  That includes this year.  You must be thinking about seasonal changes, but those are irrelevant to sea level change since they are ephemeral.  Also this year does not seem unusual when you look at the data.

       BTW moderators, the link to the updated version of the fisgure in comment 5 appears to be broken.

       Moderator Response:

       [DB] Fixed.

36699. John Hartz at 08:22 AM on 9 May 2014
       There is no consensus
       

       bakertg: 

       Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

       Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.

36700. jetfuel at 08:12 AM on 9 May 2014
       Sea level rise predictions are exaggerated
       

       Looking at Post #5's Graph above, the 2006 peak is about 2mm below the 2011 valley. I would draw a new best fit curve starting in 2006 that shows an 8 mm rise in 6 years, or 1.33 mm/yr. With all that I've read lately about the cold 2012-13 and 2013-14 northern winters, I'd venture to say 2013 and 2014 would follow the 1.33 mm/yr line. Hardly the makings of flooding Florida, where I lived for 17 years in a house that is 14 feet above sea level. There's only so much water in the Olagalla aquifer, and when it is 70% empty in 2060, the rate of draw from it falls off a cliff. Then there's the huge increase in Great Lakes water levels this year. An unbelievable record increase in Lake Ontario and 14 inches added to Superior. Just Superior's gain offsets 7/33 of all land based melt from Antarctica. (cubic miles fraction for 1 year)

       Moderator Response:

       [JH] Please explain exactly how you did your "curve fitting" and provide the sources for the data that you have included in your post. Until you comply with this request, your future posts will be deleted.

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