Recent Comments

Prev  889  890  891  892  893  894  895  896  897  898  899  900  901  902  903  904  Next

Comments 44801 to 44850:

44801. Tom Curtis at 06:14 AM on 6 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       stealth @34: "I think my bullsh*t sensor is pretty good."

       One component of an effective bullsh*t sensor that is often missing is an appropriate respect for expertise.  An expert has been succinctly defined as a person who knows all the  basic mistakes in their field, and how to avoid them.  Ergo the most basic feature of the non-expert is that they do not know how to avoid basic mistakes.  That can be simply because the relevant information available to them is limited compared to that possessed by the expert; or because of lack of knowledge of the literature in which the basic mistake they are making was first proposed, then refuted. 

       This is not to suggest that experts are always right.  However, if you are genuine about avoiding bullsh*t your first instinct when you come up with a significantly different answer to that of the experts is to ask yourself, "What am I missing?"  The arrogance of AGW "skepticism" as practised at WUWT etc is seen in the failure of this form of self skepticism.  

44802. Tom Curtis at 06:02 AM on 6 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Stealth @35, by a rough pixel count, there is an approximately 0.15 C increase in temperature due to anthropogenic factors shown in the chart from 1880-1950.  That is much smaller than post 1950 but not zero.  Others have provided an the data needed on natural forcings over that period.  It should be noted that part of the 1910-1940 temperature increase is due to a switch from strong La Nina conditions arount 1910 to strong El Nino conditions around 1940.  

       There remains, however, a small component of that increase which is not yet explained by either known forcings or ENSO variation.  This may be due to problems in the temperature record.  Global coverage of SST (in particular) fell significantly during WWI and WWII and immediately after due to reduced the effect of the wars on merchant shipping.  It may also be due to an underestimate of the forcing from Black Carbon (BC).  Finally, it may also be due to the Atlantic Multi-decadal Oscilation. 

       Post 1950, natural forcings are negative such that anthropogenic factors represent around 90% of all forcings from 1880-2010 (as shown above).  The uncertainty about that is sufficiently large, however, that it could be significantly lower than that.

44803. Alexandre at 06:00 AM on 6 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       I found a correlation between global temperatures and the quantity of headlines about the private life of celebrities. I think the obscure journal may be interested in it - but I'll see if I get a better offer from Energy & Environment.

       Science Daily, here I come!

44804. Matthew L at 05:49 AM on 6 June 2013
       Will Tropical Forests Remain Carbon Sinks?
       

       Interesting paper. It is sort of intuitive that an ecological system as intense as rainforest would already be close to saturation as a carbon sink.  What is interesting though is that recent research has shown that the CO2 fertilisation affect, and hence (presumably) the carbon sink potential of plant biomass, is most apparent in arid and semi-arid regions which are already showing rapid greening in response to elevated CO2.

       The major benefit in a dry climate of higher CO2 levels is that a plant can get the CO2 it needs from the air with fewer stomata in its leaves.  Fewer stomata means less water loss from the leaf and hence the plant can produce the same carbohydrates through photosynthesis with less water (or more carbohydrates with the same amount of water).

       Research has been published in Geophysical Research Letters that shows an increase of 11% in green foliage cover between 1980 and 2011, mainly in arid and semi-arid areas.  This means that as the rain forests decline as a carbon sink that the slack may be taken up as arid areas green and increase their role as a carbon sink.  Isn't nature wonderful!

       http://onlinelibrary.wiley.com/doi/10.1002/grl.50563/abstract

44805. KR at 05:27 AM on 6 June 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       Dr. Tung - I believe that what Dikran has shown with his synthetic data case is that inappropriately detrending (linearly in his synthetic experiment) cyclic forcings, forcings superimposed on nonlinear trending anthropogenic forcings, causes a clear mixing of the signals. And his synthetic data shows a corresponding reduction in attribution to any nonlinear components, errors in identifying known inputs.

       I would also agree with his last comment about correct component labeling. 

       By extension the same method of analysis (MLR), applied in your paper, is subject to the same issues - that a linear detrending of a cyclic signal (AMO) that is potentially a superimposition on a nonlinear trend (anthropogenic and other forcings, known to be nonlinear in sum) can and will lead to false conclusions about anthropogenic attribution.

       A simple linearly detrended AMO by definition suffers from an undetermined amount of multicollinearity with nonlinear forcings. Separate methods for identifying the shape of the underlying trends, upon which the AMO is superimposed, must be used to avoid this problem. 

44806. David Lewis at 04:59 AM on 6 June 2013
       It's CFCs
       

       GreenCooling:  Mario Molina et.al. noted in 2009 in Reducing abrupt climate change risk using the Montreal Protocol and other regulatory actions to complement cuts in CO2 emissions which was published in pnas that:

       "The Montreal Protocol is widely considered the most successful environmental treaty, phasing out almost 100 ozone-depleting chemicals by 97% and placing the ozone layer on the path to recovery by mid-century (18). It also is the most successful climate treaty to date..."

44807. Glenn Tamblyn at 04:20 AM on 6 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Stealth

        

       In addition to the other comments about 1910 to 1940's warmth, this is interesting from GISS. Warming by latitude vs time (available here):

       

       A significant part of the warming was just in the Arctic. Also the station coverage of the Earth was in flux during that period. Stations were being added to the Arctic at that time which previously had no useful coverage. The Antarctic only started getting decent coverage after the International Geophysical year in 1957. I have some doubts about how much credence we can give the 1910-1940's data if there was a regional warming just as station coverage was changing in that very region.

       Also there was a definite bias change in the measurement of Sea Surface Temperatures during the years of WWII due to a change in the mix of nationalities measuring SSTs (and thus measurement methods) during the war. This has been partly corrected through an adjustment to those records just recently but it is unclear how completely that has resolved the issue.

44808. David Lewis at 03:46 AM on 6 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       Harris Farman and Fahey actually used the word "hydrophobic".  Duh.  One reason CFCs and other ozone destroying substances make it up into the stratosphere is they do not mix with water molecules in the troposphere to be rained out.  Lu needs CFCs to appear on the surfaces of the ice particles that make up the polar stratospheric clouds found in Antarctica so the reaction he believes in can take place.  Ice isn't liquid or gaseous water, but the Farman paper states the claim "seems very unlikely". 

44809. Dikran Marsupial at 03:10 AM on 6 June 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       KK Tung, wrote "My procedure" found something, but it was not an AMO. The fact that you gave it the name AMOd does not make it an AMO."

       Similarly a variable in your MLR analysis is labelled as being AMO but that doesn't mean that it actually is the true AMO signal.  As I have pointed out linear detrending does not remove all of the anthropogenic contamination of the AMO signal, nor for that matter does it remove the contamination due to other natural forcings, such as solar and volcanoes.  It is this contamination by both natural and anthropogenic forcings that means that some of the warming due to anthropogenic forcing can be misattributed by your MLR analysis to the variable that you have labelled as AMO. 

44810. KK Tung at 02:46 AM on 6 June 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       In reply to post 129 by Dikran Marsupial:  I thought I was quite clear already, but it seems that I needed a lesson in communication, or I was trying to be too polite, which hinders communication in forums like this.  When I said:
       

       "How do you know the true value for the AMO is zero? Must it be that in your mind you identified the 70-year oscillation as the AMO?''

       
       I meant it as a rhetorical question.  The answer of course is that you did not put it in your example.  It was entirely in your head, and you did not tell your MLR what you meant by AMO. When you replied :"I know this by construction.". You seemed to miss the irony.

       
       I thought I had explained it:

       "But by construction your AMOd regressor does not contain any 70-year signal, nor does your observation. In fact there does not exist any 70-year signal anywhere in your example. So it trivially follows that you will not get any 70-year signal by multiple regression. It now becomes a word game on what you call your AMOd. You could just as well call it the "quadratic". Then you always get zero for the nonexistent 70-year AMO cycle in your MLR."

       Now in post 129, you continue to miss the point that I was trying to make, but now you think I was missing your point:
       "You clearly still do not understand the point of the thought experiment.  In the thought experiment there is no AMO influence on observed temperatures, but your MLR procedure DOES find one, even though it doesn't exist.  That is the problem."

       "My procedure" found something, but it was not an AMO.  The fact that you gave it the name AMOd does not make it an AMO. Please do your thought experiment again but this time give your AMOd the new name quadratic.
       

44811. tcflood at 02:42 AM on 6 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       David Lewis @6

       Just to cut down on the confusion factor, you probably mean that CFC's are "strongly hydrophobic."

44812. John Hartz at 01:55 AM on 6 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       Are the powers-to-be at the Univesity of Waterloo under the thumb of the Harper government?  

44813. dana1981 at 01:54 AM on 6 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       John H @9 - thanks for that link, yes, Gilkson does a nice job debunking this myth as well.  I notice he has an Escalator link in there :-)

44814. Bob Loblaw at 01:46 AM on 6 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       Oops. Make that "Alternatively, languish as a tenured assistant associate professor ..."

44815. Bob Loblaw at 01:44 AM on 6 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       The usual progression in Canadian universities is:

       - hired as an untenured assistant professor

       - get tenure, get promoted to associate professor. Sometimes a single step, sometimes two, depending on the university - but usually they happen at roughly the same time. In very rare cases, I have seen faculty get tenure, then sit at the assistant professor level for years.

       - continue to develop your fiefdom and accumulate enough papers/grad students/research grants to get promoted to full professor (i.e., "professor", with no assistant or associate prefix). (Alternatively, languish as a tenured assistant professor for the rest of your career.)

       On this basis, my guess is that Lu has tenure. Number of publications often counts more than quality...

44816. John Hartz at 01:30 AM on 6 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       Andrew Gilkson, Earth and Paleo-Climate Scientist at the Auatralian National University, has also writtten a devastating critique of Lu's paper.

       Gilkson's critique, Are CFCs responsible for global warming? was posted on The Convesation on June 5.

       Gilskson and Dana cover much of the same ground in their respective posts.  

44817. Rob Honeycutt at 01:22 AM on 6 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Stealth...  I may be repeating Kevin and KR, but I think you'll find there to be a general consensus in the research that early 20th century warming was only partly due to anthro-GHG forcing.  From ~1940 to 1970 you get a slight cooling due to anthro-aerosols, and then late 20th century is likely all due to anthro-GHG forcing.

       I have to say, it sounds like you're taking an appropriately skeptical approach to the issue.  It's greatly appreciated.  It's hard but we all have to try to check our biases at the door when looking into scientific issues.

44818. Kevin C at 01:05 AM on 6 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Stealth: Here's the Potsdam data which was an input to CMIP5 in excruciating detail. link

       Start with pages 4-7. Volcanic is on page 45. Solar is on page 46 (note the scales).

44819. KR at 00:34 AM on 6 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Stealth - In the early 20th century solar activity was relatively high (positive influence), and even more importantly there was a distinct paucity of volcanic action (less negative influence); notice the flat volcanic graph during that period. There's a SkS thread on this very topic - What caused early 20th Century warming - which is worth looking at.

44820. MA Rodger at 00:30 AM on 6 June 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years?
       

       So where is Amo? Perhaps we should look where he was last reported being seen.
       The first graph plots 5-year rolling average of AMO (after Enfield) over the last 130 years along side the three surface global temperature records, all averaged, de-trended and re-based for comparison.

       So is the wobble in the global temperature records actually AMO? Like 'Where's Waldo?' it isn't just any old kid with glasses in a colourful jumper & bobble hat that we are looking for.

       

       Now these different temperature records do provide differerent breakdowns of the global total. NASA GISS, for instance, provides temperature records for different latitudes of the globe.

       The graph below compares such data for different latitudes for the Southern Hemesphere against AMO. I see no sign of AMO there.

       

       An identical graph but the Northern Hemesphere does show a goodly wobble. So can we see Amo in the Northern Hemisphere?

       

       Perhaps. But here's a thing. The size of those wobbles increase as the Northern latitude increases and the size of the trend that has been subtracted to present the graph also increases with that same increasing latitude, as the fourth graph here illustrates.

       

       So here's a question. If this increase with latitude applies to both wobble and trend, would this not indicate a common source for both of these elements of the global temperature record? If not, what mechanism would provide the same trend for different causes, one AMO-caused the other a global-wide climate forcing. This is a tricky question because according to the proposal before us, AMO does not cause any trend.

        

44821. MA Rodger at 00:15 AM on 6 June 2013
       Another Piece of the Global Warming Puzzle - More Efficient Ocean Heat Uptake
       

       tcflood @23.

       
       I was much to hasty @21 with my analysis of recent OHC and fell foul of a bit of inadvertent cherry-picking.

       So we come to agreement. I calculate OHC as per Levitus at 0.5 W/m^2 yielding a global warming of some 0.6 W/m^2.

       The graph I mentioned also didn't appear. It cannot be displayed here but only be linked to from its present location (see down link here - it may take 2 clicks 'to download your attachment'.) due to the Google double click.

       So Trenberth's missing energy remains missing.

44822. StealthAircraftSoftwareModeler at 23:33 PM on 5 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       New question about the charts in this post:

       The contributing factors (all the ones in the various colors) seem to add up relative to the 1985 baseline for years between 1955 and 2010. If I add up ENSO, VOL, etc to the temperature on the top chart, they all add up. Before 1955 there is component data but it doesn’t produce any temperature movement. From 1910 to 1945 there was a large warming period of almost 1 deg C, but the component values do not reproduce that. The ANT chart also seems to be saying that all ANT effects have been from 1960 until today – is this censuses view on AGW? I thought the AGW claim is that the industrial age and CO2 increase has caused most of the warming. If ANT hasn’t affected temperature from 1910 to 1945, what caused the large temperature increase from 1910 to 1945?

44823. StealthAircraftSoftwareModeler at 23:23 PM on 5 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Manwichstick @27

       I agree that “incomplete” is a better word for models. My full saying about models is: “all models are wrong, but some are more useful than others.” My group does the best it can in our models, and there can be life and death decisions riding on them (that’s always humbling). All sorts of design trades have to be made, and real time is a major one – a great answer 5 minutes after you are dead is not better than a good answer in 5 seconds.

       scaddenp @29

       Your question about “evaluating truth” is a good one. I think “wallow” is a bit of a strong negative word, but I understand what you are saying. I read what “the others guys” have to say and examine the data they have. If it makes sense then I incorporate it into my world view. I guess since I don’t believe anyone, and I become convinced of things based on the data and the most creditable explanation of the data. I think my bullsh*t sensor is pretty good. But I also know I have been wrong many times in my life on many things, and have changed positions based on the results, so I feel that I am very open to the facts and what they say. I truly believe that reality has a persistent voice.

       So far, what I really like about this site is that everyone seems open and has provide excellent information, and a lot of it. I have to wait until the weekend to review and digest some of it. My day job isn’t paying me to research the climate. :-)

44824. Paul D at 21:50 PM on 5 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       scaddenp@28

       Thanks, that's interesting.
       
       Not a great deal of difference other than higher solar irradience would seem to make it hotter than the CO2 forcing and the Arctic and land masses would be much more hotter than would be the case if the forcing were just CO2 and/or others.

44825. chriskoz at 18:25 PM on 5 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       GFW,

       Lu's profile page at UW places him as an associate at the faculty of Physics & Astronomy, and he looks on the picture as a young person (certainly not "emeritus" type ala Singer), nothing about his tenure but I guess as an associate he doesn't have one yet.

       One thing is certain, he tries to apply his Astronomy skill to the field where he lacks basic knowledge and it's surprising that he's been able to do it (publish poor work) three times. I wonder, Mike Mann style, if he has certain other affiliations business or political or such, that make him so biased in this filed unknown to him.

44826. Glenn Tamblyn at 18:22 PM on 5 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       He describes himself as:

       Qing-Bin Lu, PhD

       Professor in Physics, Chemistry and Biology

       Canadian Institutes of Health Research (CIHR) New Investigator

       Department of Physics and Astronomy

       University of Waterloo

44827. David Lewis at 18:22 PM on 5 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       Climate Science Watch has a page up entitled Response by Qing-Bin Lu to “Qing-Bin Lu revives debunked claims about cosmic rays and CFCs”   On it, Lu says he is not aware of any experimental evidence of "the physical mechanism by which CO2 warms the planet".  His actual words were:  "I do not know who has done such experiments".

       Joe Farman, the first person to observe the Antarctic ozone hole, critiqued Lu's idea that cosmic rays cause it, in 2002 (with Harris and Fahey, in Comment on "Effects of cosmic rays on atmospheric chlorofluorocarbon dissociation and ozone depletion").  Lu's idea then was that CFCs were observed to be in lower concentration over Antarctica therefore cosmic rays must cause this, therefore cosmic rays, not UV photolysis, was the cause of the ozone hole.  It was as solid as that.  It had something to do with something Lu thought must be going on on the surfaces of the polar stratospheric clouds, i.e. ice particles that ozone scientists suddenly realized were there.  He had no measurements.  Farman said no one has ever measured anything like what Lu is talking about on the surfaces of ice particles in the stratosphere over Antartica, or in a laboratory, and Lu is not citing measurements now.  Farman said CFCs are "strongly hydrophilic" and therefore why should they suddenly be attracted to solid water particles?  Farman stated that the observed concentration of CFCs in the atmosphere over Antarctica was consistent with the idea that UV photolysis breaks up CFCs mainly in the tropical and subtropical stratosphere and with what is known about the movement of air from the troposphere to the stratosphere and within the stratosphere.  

       What amazed me was that the Dean of the Faculty of Science at Waterloo allowed the Waterloo News to publish his statement that he, Terry McMahon, has swallowed Lu's gibberish, hook, line, and sinker.  Waterloo has a good reputation in Canada, especially in computer science.  If its Dean of Science claims one of the scientists there has come up with a paper overturning 150 years of climate science, it is no wonder that some newspapers covered it.  The question is, who were the "peer" reviewers, and how has Lu palmed off his work all these years as something Waterloo would want to be associated with?  McMahon must believe Lu is something like Einstein, the discoverer of a new way to see....  No wonder the human race is doomed.  

44828. Dikran Marsupial at 17:56 PM on 5 June 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       KK Tung wrote "Of course when there is no AMO in your data you are not going to find an AMO using the method of multiple linear regression analysis (MLR)."

       You clearly still do not understand the point of the thought experiment.  In the thought experiment there is no AMO influence on observed temperatures, but your MLR procedure DOES find one, even though it doesn't exist.  That is the problem.

44829. GFW at 17:49 PM on 5 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       Is this guy an actual tenured prof? But not an aging "gone emeritus" type? It's supposed to be really hard to get a professorship at any halfway decent U these days, and Waterloo is more than halfway decent.
44830. Paul Pukite at 16:25 PM on 5 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       The other fitting step that QB  Lu from U of Waterloo applies is a crucial  9-year lag from halocarbon increase to temperature effect. Below is my attempt at reconstructing what Lu attempted to do via the 9-year lag. Note that he also uses R instead of R^2 to make the correlation look better.  As Dana said, the lag is not there in the OHC data.

       

44831. sylas at 14:55 PM on 5 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       The journal IJMP-B is a low impact journal, yes; but it serves well in its particular focus; which is mainly condensed matter physics, superconductivity and the like. The problem is most likely somewhere within the editorial board, allowing this otherwise respectable if low impact journal to be a soft touch for pseudoscientific climate denial. It is something the editorial board really needs to look at seriously.

        

       Declaring my own personal interest: I'm one of the six people who helped put together a response to the nonsensical Gerlich and Tscheuschner (2009) at IJMP-B, with Joshua Halpern as the main author of the rebuttal piece.

44832. JohnMashey at 14:26 PM on 5 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       1) The journal that published this also published Falsifiation Of The Atmospheric CO2 Greenhouse Effects within The Frame Of Physics, Gerlich, G. and R. D. Tscheuschner (2009).  Needless to say, it did not accomplish that goal, but one has to wondre about the journal.

        

       2) The most puzzling is why on Earth U Waterloo, generally a fine scholl in science and engineering, put out  big press release on this.  Professor ought to be free to publish what they can get accepted ... but I don't think a university is *required* to create a gushing press release for every paper. Sadly, this diminishes U W's reputation in my mind, anyway.

44833. jyyh at 14:06 PM on 5 June 2013
       Lu Blames Global Warming on CFCs (Curve Fitting Correlations)
       

       Thanks Dana for going by numbers dissecting this roadkill of a study.

44834. Tom Dayton at 11:41 AM on 5 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Stealth, to illustrate and augment the advice given you about modeling by other folks in this thread, I encourage you to read a brief history of modeling here at Skeptical Science, and for more the detailed history by Spencer Weart.  Note that even in the 1820s, Fourier was using a model.  Not a computerized model. Not a model as complex as the ones used today.  Each improvement in the science involved an improvement in the models, but only relatively recently did they get "complicated" in modern terms.  Even the earliest models were quite successful in predicting global temperature relative to other possible predictions such as "the Earth is frozen solid" and "the Earth is cooling drastically" and "the Earth is maintaining its temperature" and "the Earth will be as hot as the Sun in fifty years."  Complication is needed only to fine tune the predictions by the desired amount.

       You can try some simple models yourself by getting an introductory textbook such as David Archer's "Global Warming: Understanding the Forecast," or by taking notes while watching his free online lectures from his class at the University of Chicago.

       Tamino has illustrated a simple climate model you can run without a computer if you have a lot of time, or with a spreadsheet if you don't mind using a computer. He also has a followup that's only a bit more complicated.

       There are a bunch of other climate models that are simple enough for learning and teaching. One list has been compiled by Steve Easterbrook.

       You also might be interested in Steve Easterbrook's comments on verification and validation (V&V) of climate models.  Steve once did V&V for NASA.

44835. GreenCooling at 11:40 AM on 5 June 2013
       It's CFCs
       

       Apologies, the figure above with 3 graphs was adapted from Velders et.al. (2007, 2009), but it is actually figure 5-6 from the Scientific Assessment of Ozone Depletion: 2010, a collaboration of WMO, UNEP, NOAA, NASA & EC, see page 5.29 for associated explanation.

44836. Dave123 at 10:49 AM on 5 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Hi SASM-

       My understanding of the magnetic impulse hypothesis is that the energy dumped into the upper atmosphere by a coronal mass ejection is supposed to radiate/convect to the ground, and this is being ignored in conventional measurement of TSI.  That doesn't actually happen.

        

       NASA Coronal Mass Ejection

       As this article indicates, the green house gases in the thermosphere reradiate 95% of the energy back into space....sort of an energy shield out of science fiction.  (But it being cited by people who mince words as proof that AGW isn't real because in this case CO2 acts as coolant)

       The article also note that as big as this energy dump was, comparted to the earth's outbound IR buget the amount is very small, and wouldn't ever be notice by anyone on the surface of the earth.  Compare this qaulitatively with the feeling of the sun on your face or a cloudy night being warmier than a clear one.

       "footnote: (1) No one on Earth’s surface would have felt this impulse of heat. Mlynczak puts it into perspective: “Heat radiated by the solid body of the Earth is very large compared to the amount of heat being exchanged in the upper atmosphere. The daily average infrared radiation from the entire planet is 240 W/m2—enough to power NYC for 200,000 years.”

44837. Glenn Tamblyn at 10:33 AM on 5 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Stealth

       I come from a combined MechanicalEngineering/IT background. So lots of thermodynamics etc and software - although not modelling.

       An important point to consider when thinking in terms of models is the scale (in space, time, magnitude) of the different factors. To take an analogy:

       I install a new swimming pool in my backyard. To fill it I throw the garden hose in and turn it on. This may take daya to fill the pool. My family are impatient so they start using the pool before it is full.

       If I want to model what will happen to the water level I have different factors to consider-

       • volume and shape of the pool which might be complex but is static.
       • Flow rate through the hose
       • Volume of my families bodies and how much water they displace
       • How often and when they use the pool
       • how much they splash around and thus how many and what waves they make
       • Whether the dog occassionally leaps into the pool chasing a frisbee.

       Although there are multiple factors, they are not all equal. The Volume/Flowrate factors are the dominant factors and they are actually fairly simple to model. To a first order approximation that is all I need to model.

       When I factor in the displacement of my families bodies there are multiple questions to be resolved - how often and when do they use the pool, fully submerged or only partly, do they all use it at the same time etc. But the magnitude of the total effect they can have is small compared to the total volume of the pool.

       Then when I look at the impact of the waves they create it gets even more complex - all the factors previously plus what are they doing in the pool - just quietly floating, swimming laps, fighting, diving, splashing water out of the pool. Are they relaxed adults or hyperactive teenagers. How many high caffiene energy drinks have they had. Again much more complexity but now dealing with smaller scale phenomena; not really the average level of the pool anymore but the spatial distibution of its level in the form of waves.

       But our first order approximation is still pretty close to the right result.

       
       Climate modelling is similar. A range of basic processes that aren't as complex as people think, leading to a general result. Then additional details that add complexity and more detail to the result but don't significantly change the broad result.

       People often look at the complexity of weather and asume that this is  the starting point for Climate modelling when it isn't. Climate modelling actually comes at the problem from the opposity direction - start with the broadest mechanisms then seek to progressively refine the result through more detail and complexity. Interestingly the history of Climate Models has been that the results produced by the very earliest models haven't changed much as they have been refined to the very much larger models of today.

       The modellers have been trying to do two things by adding more features and detail.

       1. Try and determine whether any of these additional complexities have changed the broad conclusions of the simpler models. By and large they haven't.
       2. Try and determine in greater detail what the trajectory of the warming will be, what path it will follow to the final conclusion. This has had some success but not as well. Models of Arctic sea ice haven't captured the pace of melting very well, they aren't modelling changes in the Trade winds very well etc.

       The problem is that if we want to compare real world changes with the model predictions, in shorter time frames it is harder to discern the broader trends from beneath the 'noise' of the smaller details in the data, and the models don't do as well at modelling the smaller details.

       So some people fall into the fallacy of thinking that if the models can't capture the detail as well, that this in someway constitutes evidence that they can't model the basics. If I can't model the waves on my pool very well, then surely I aren't modelling the volume of the pool and the flow rate in the hose very well.

       Also it is very easy to look at the complexity of weather and asume that this is the starting point for the level of complexity in modelling climate. However climate is actually the average of the weather and the average of the weather patterns are actually simpler than the details - storm tracks tend to run here, rainfall bands are here, ocean currents follow these tracks etc.

       Then the underlying drivers for these patterns can be simpler still. Evaporation is strongest in the tropics so more upwelling of air happens there. Air cools and changes density at known rates with altitude, warming water by x degrees will change it's density by y. At it's simplest adding a certain amount of Greenhouse gas will restrict the flow of energy to space by X Watts/M² , the Earths surface needs to warm by Y degrees to restore the Earth's energy balance.

44838. scaddenp at 08:15 AM on 5 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Stealth - if you are going to wallow in likes of Watts or McIntyre, then I hope you will try to ensure that you opinions are formed on the basis of published science and not misrepresentation of science. When you are presented with conflicted information, what method are you going to use evaluate truth here?

44839. scaddenp at 08:11 AM on 5 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Paul D - sorry, the paper has a data page which produces plots for various forcings. You can do say a lat/lon map for 2xCO2 with 100 year response and then compare that to an equivalent Solar forcing.

44840. Manwichstick at 06:55 AM on 5 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       @SASM #23

       modeling is always wrong (meaning it is never fully correct under all cases) and that the real world is different than the lab world, which is different than the modeled world, at least for aircraft and radars. I strongly suspect the climate is even more complex than what I have dealt with, which makes me very skeptical that climate scientists have a full grasp on the complexities of the climate.

       I would like to chip in with a thought about climate modelling -big picture- which your comment reminded me of. A model by definition is "wrong", but lately I have been trying to use the word "incomplete" instead so that I don't create the impression that a model has no utility.  I would agree that our planet's climate system is more complex than smaller scale models pertaining to stealth aircraft design - however that doesn't mean that climate models have less predictive power than the models you have dealt with.

       I like to use the example of radioactive elements. The moment when an individual nucleus will blow is fundamentally unknowable. However, from this utter lack of causation knowledge comes a term "half-life" that is startilingly accurate in it predictions. Sometimes an infinite mess of choas when looked at in small chunks is freakishly predictable in the large scale. Like-wise, I think the earth's climate system is surprisingly reducable to a planet-wide, yearly average temperature, despite the appearence of innumerable interactions and parameters depending on how deep you go in the oceans, how high in the atmosphere, and with what 3-D pixel size resolution you care about. And I don't think we've seen a great increase in accuracy in our climate models since in the early eighties. Those simpler models spat out numbers with great "big picture" accuracy.

       From a distance, the earth is a tiny speck of wet rock , with a thin coating of gas, circling a heat source.  Dead simple to calculate its average temperature over long time scales... well, maybe having to guess a bit about aerosols...

       Now models zoom in more, calculate more, they add more coupling between the various "spheres" (litho, cryo, atmos, oceans) but even after decades when you get the same big picture answer for the earth's average temperature, you realize these "complex" models are merely arguing over who/what/where gets the energy that is sloshing around our planet. Does chopping the energy units into smaller and smaller peices and putting GPS-like tracking on them as they move around really make that much  difference? When you put a bubble around the earth and measure every thing that is going in and out - this is something much simplier to model than wing dynamics at different altitudes, or whatever cool classified things you were working on.

       Stealth, earlier you said, "I’m sure CO2 does absorbs some IR wavelengths; ".

       That is so important to focus on  -CO2 MUST warm the planet. If you still have any doubts, visit a lab with an infrared microscope and exhale on it. You will get the same absorption pattern you see from satellites looking down at the earth. So, with no way to argue against increasing CO2 causing warming, the interesting questions become: warming where, how fast, will it be dangerous, is there anything that will cool us down, etc.

       The questions we want climate models to answer now are much more specific: will the water level in this river go up or down in the next 30 years? What is the climate like on that exo-planet? Would you recommend I build my hut on this hectare of permafrost here?

        

       You mentioned some of the websites you go to for information. I've recently become sad about the futility of the Anthony Watts site. I think of the wasted hours people put in there under the partial guise of growing our scientific knowledge. If the purpose is public opinion and political medling, then it is less wasteful - but I have found it to be a very irrelevant space for scientific knowledge as it pertains to climate change. It feels like I'm watching a movie starring teenagers who get deeper and deeper into trouble because they refuse to take the advice of the police. 

44841. funglestrumpet at 06:52 AM on 5 June 2013
       Communicating climate change at the Maths of Planet Earth conference
       

       For an interesting insight into energy usage and what it could mean for climate change the website 'Our Finite World' run by Gail Tverberg, a highly regarded actuary, is well worth a visit. Her most recent post Oil Limits and Climate Change is, as you might guess, particularly relevant to sks followers.

       Her take on energy supply indicates that soon we will not be able to maintain BAU simply because oil is becoming ever more difficult - and thus ever more expensive - to extract, to the point where it will be simply unaffordable for many. Unfortunately, this also means that we will not be able to feed the population as it now stands, let alone in the near future when it hits nine/ten billion. Gruesome as the thought is, it does mean that energy use will decline significantly and with it CO2 production. I suppose we should be glad, but I find little of cheer in the implications of same.

44842. Paul D at 06:29 AM on 5 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       scaddenp@18

       I might be missing something, but I can't see a mention of varying insolation in that Hansen paper abstract.

44843. kiwipoet at 05:06 AM on 5 June 2013
       The 5 characteristics of global warming consensus denial
       

       Good comment, jdixon1980. I've always thought the funding argument absurd because all scientists are dependent on funding, all researchers need grants. What about those physicists/mathematicians of M Theory with their eleven dimensional multiverse? What could be crazier than that? They have to keep juggling those eleven dimensions just to keep their funding going! And don't get me started on black holes! Now there's a racket!

       John Hartz is right: stay clear and keep sane!

44844. KK Tung at 04:50 AM on 5 June 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       Clarification to my post 127: There are so many parts to the yes or no question that you posed that my single "No" answer may not fully answer the question:

       Forgetting for the moment whether the scenario in the thought experiment is plausible or not, do you agree that the thought experiment does show that there can be circumstances where the regression analysis can fail and missattribute warming due to anthropogenic emissions to the AMO?  Yes, or No. 

         The answer is "No" to the first part of the answer: "do you agree that the thought experiment does show".  The thought experiment is trivial and inappropriate as I explained later.  The answer is "yes" to the second part of the question "do you agree there are circumstances where the regression analysis can fail".

44845. KK Tung at 04:39 AM on 5 June 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       In reply to Dikran Marsupial's post 126: I am not sure if you understood what I was trying to say in my post 125.  Of course when there is no AMO in your data you are not going to find an AMO using the method of multiple linear regression analysis (MLR).  So the answer is No, not because of the fault of the method, but because you should not have used that method.

       On the anthropogenic trend, the way you applied the MLR is to break up the nonlinear anthropogenic trend into a linear part and a quadratic part, using the two regressors, which were called by me in post 125 as linear and quadratic. If you ask the questionh, does the regression coefficient of quadratic in the MLR include the true value of the quadratic term in your anthropogenic trend, the answer is yes.  And if you ask the question, does the regression coefficient of linear in the MLR include the true value of the linear part in your anthropogenic trend, the answer is also yes.  So the MLR gives you the right answers.  But what you were doing is to rename linear anthropogenic, and ask the question, does the regression coefficient of this newly named anthropogenic response include the true value of the anthropogenic response in the observation that you constructed, the answer is not necessarily, depending on how large your quadratic term is.

       Please don't get me wrong. I am not here to defend MLR as a fail-proof method.  It can fail, and we need to always on guard for that happening.  But in this case it "fails" only because you gave your regressors wrong names.

44846. Rob Honeycutt at 03:59 AM on 5 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Stealth @23...  I think you'll find people here to be very supportive of taking a genuinely skeptical approach to this issue.  It is a very complex science, but there are some very fundamental elements that drive the scientific understanding of climate.

       Primarily, the scientific understanding of climate change is not based on modeling or hockey stick graphs.  It's based on the fundamental physics of atmospheric greenhouse gases that has been known for 150 years.

       I think you'll find that climate modelers actually would agree with you when you state, "modeling is always wrong (meaning it is never fully correct under all cases)."  That's why climate modeling is about establishing boundary conditions rather than attempting to specifically model exactly what the climate is going to do.  That is why you'll always see climate scientists referring to "model ensembles" rather than any specific model.

44847. Doc Snow at 03:29 AM on 5 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       On the question of the Sun, and its impact on Earthly climate, it's worth noting that the question of Solar variability has been revolutionized by satellite observations.  Prior to the satellite era, variations in solar output were less than experimental error, and it was commonplace to use the term 'solar constant' to refer to a particular defined measure of solar energy:

       http://en.wikipedia.org/wiki/Solar_constant

       Since then, the term has fallen largely out of use.

       However, that doesn't mean that measurement of solar output was non-existent prior to satellites.  Indeed, the history goes back to the late 18th century at least:

       http://doc-snow.hubpages.com/hub/Fire-From-Heaven-Climate-Science-And-The-Element-Of-Life-Part-One-Fire-By-Day

       It's worth mentioning Claude Pouillet in this context; he was able to make a pretty decent estimate in the 1830s--better, in fact, than the formidable American astronomer Samuel Langley, some of whose data was so serviceable to Svante Arrhenius in calculating the first model of CO2-induced warming, back in 1896.  I've written about Poillet, and Langley and Arrhenius, too--for those who may be interested, those stories are at:

       http://doc-snow.hubpages.com/hub/The-Science-of-Global-Warming-in-the-age-of-Napoleon-III

       http://doc-snow.hubpages.com/hub/Global-Warming-Science-And-The-Dawn-Of-Flight

44848. tcflood at 02:02 AM on 5 June 2013
       Another Piece of the Global Warming Puzzle - More Efficient Ocean Heat Uptake
       

       MA Rodger,

       I just gleaned from the paper that they get the 0.6(+/-0.4) by assuming their OHC is complete and accurate and calculating back to what the outbout LWR must be. I have to say that it would be much wiser to just say we don't have a good number on the OLWR and carry on with our analysis of total global heat change and its relationship to average global near-surface air temperature. Perhaps the public needs to be trained to key on total heat changes rather than the AGNSAT (if possible). 

44849. tcflood at 01:47 AM on 5 June 2013
       Another Piece of the Global Warming Puzzle - More Efficient Ocean Heat Uptake
       

       MA Rodger,

       Thanks for taking your time to respond.

       I'm mainly interested in the error analysis and am apparently having trouble with the math. The numbers in the figure are the same as in the paper. Please check me ...

       SWR(in) - SW(out) - LW(out)  =  TOA imbalance

       = 340.2(+/-0.1) - 100.0(+/-2) - 239.7(+/-3.3)

       = 0.5(+/-3.9)

       I have been trying to come to grips with the old denialist chestnut that there was no "missing heat."  If the error in the imbalance is 8 x the value, perhaps the best answer is that the initial assertion was ill-advised becasue we can't say whether there was energy missing or not from our global heat accounting (including all the spheres - atmo, hydro, cryo, etc.).  This then leaves us unencumbered to deal with "15 year heating pauses" as the natural result of changing O-A heat transfer patterns without getting sidetracked by the red herring of the "missing heat" cavil.  

44850. StealthAircraftSoftwareModeler at 23:25 PM on 4 June 2013
       Imbers et al. Test Human-Caused Global Warming Detection
       

       Okay, there's a lot of information here that I would like to take a closer look, and it will take a little bit to go through it. This post and thread is exactly what I have been wondering about, which is specifically trying to address and measure how much warming is due to AGW. I’ve done a lot of general internet research over the last year or two and have been on this site, Real Climate, Anthony Watts’ site, Roy Spencer, Steve McIntyre among other sites trying to gather information and fuse it together into what I think it a coherent picture. I expect that mentioning some of these names on this site might be offensive, so I apologize in advance.

       My general philosophy is that I believe none of what I hear and only half of what I see. My background is dual BS in Physics and Computer Science with 30+ years in software development and modeling, most all of it related to stealth aircraft -- real time software systems operating in real world environments to support pilot decision making process. It requires modeling aircraft, weather, terrain, weapons, sensors, threats and so on. Lots of optimization algorithms to maximize opportunity and minimize risk. It has been a fun and cool job, and very interesting. If I have learned one thing, it is that modeling is always wrong (meaning it is never fully correct under all cases) and that the real world is different than the lab world, which is different than the modeled world, at least for aircraft and radars. I strongly suspect the climate is even more complex than what I have dealt with, which makes me very skeptical that climate scientists have a full grasp on the complexities of the climate. This is not a criticism of climate scientists, it is just hat things are hard and complex. After all, if it was easy, then everyone would agree and there wouldn’t be much debate.

       Give me a day or two to wallow in these links and I’ll post some more questions shortly. Thanks for the feedback.

Prev  889  890  891  892  893  894  895  896  897  898  899  900  901  902  903  904  Next