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Eric the Red at 22:47 PM on 16 June 2011There's no room for a climate of denial
Utahn, You present a good point. (I just happened to glance back at this thread to see if there was any recent activity). Let us say that a medical advance did not overturn a medical belief, but simply reduced its significance. Now the "consensus," which may have been rather loose, is not exactly overturned, but minimized. Now, back to climate. How much does CO2 drive climate? 100%, 75%, 50%, less? If a loose consensus thought it was about 75%, and scientific research determined it was only 50%, does that really overturn the original belief? I would agree that a true consensus does not get overturned often, but one of the biggest medical changes would be the discover of bacteria-causing ulcers revamping ulcer treatment. -
John Russell at 22:41 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Thanks, Dikran.Moderator Response: [Dikran Marsupial] No problem, lets see if it has any success! -
Eric the Red at 22:33 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
Sphaerica, I would agree with your statement that it would be frightening if a grand solar minimum resulted in a large temperature decrease masking a less large temperature increase from CO2. Temperatures were particularly depressed in the U.S. and Europe during the Maunder. http://earthobservatory.nasa.gov/IOTD/view.php?id=7122 If a grand minumium occurred, and it was insignificant, then the role of the sun would be largely removed as a climate driver. The following paper does a nice job of comparing solar activity to different temperature reconstructions (Mann and Moberg). From a purely scientific viewpoint, another grand minimum would present an excellent opportunity for solar-related climate research. http://www.acrim.com/Reference%20Files/Scafetta%20&%20West_Phenomenological%20reconstructions%20..since%201600.pdf -
Ken Lambert at 22:29 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
Albatross #6 Temperature should be roughly proportional to energy added to the system - which is the time integral of TSI. You should show curve of the integral of TSI wrt time in comparison with temperature. If TSI of 1365.5 is your baseline then the TSI-time integral will be roughly linear upward - roughly matching your temperature curve. -
Eric (skeptic) at 22:11 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
Mod, thanks. I just noticed that the paper says the same. The paper also acknowledges that TSI is perhaps an oversimplification. They seem to think that solar spectrum changes manifest more as short term factors in solar cycles (which then balances out) than as an effect that would be prominent in a deep minimum. They don't mention solar magnetic except as a proxy for TSI. My view is spectral effects are a complete unknown and magnetic effects are only barely understood. Neither translates to a forcing of any consequence in a simple GCM. People like Lockwood (e.g. http://www.eiscat.rl.ac.uk/Members/mike/publications/pdfs/2010/267_Woollings_2010GL044601.pdf) show the effect as weather pattern changes like blocking, not forcing changes. Certainly the blocking in the recent past has shown to lead to localized Arctic warming and associated warming feedbacks. But there may be more dramatic weather pattern effects with a deeper minimum that may cause cooling or, more likely, change the sensitivity to CO2 doubling. If nature decides to run that experiment, it will interact in interesting ways (for weather forecasters) with CO2 warming and associated moisture. -
barry1487 at 22:06 PM on 16 June 2011Our effect on the earth is real: how we’re geo-engineering the planet
It's sometimes said we are conducting an experiment with the Earth's atmosphere. That it is unplanned only emphasises the folly. Similarly qualifying our 'geoengineering' of the atmosphere works the same for me. -
snapple at 21:25 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Denialist "cherrypicking" from this BBC editorial really opened my eyes. Even I know what statistically significant means, but most people don't. You did not mention in your article what Pravda and the 9-11 Truther publication "Rock Creek Free Press" said about Dr. Jones. They made the same claims as the media you mention. Pravda even cited FOX News as their source. Pravda was actually slightly more accurate than the Daily Mail or the Fox News article they cited because they mentioned "statistically significant," but they didn't explain that term. The Pravda article was titled "Phil Jones Backs Out Of Global Warming Fuss" (2-16-10), but Pravda actually did report: The scientist behind the so-called "climate-gate" e-mail scandal now admits there has been no statistically significant global warming since 1995. http://legendofpineridge.blogspot.com/2010/02/daily-mail-and-fox-news-tell-b ig-lie.html These papers left out important information that Phil Jones told the BBC and that the BBC did report: BBC: How confident are you that warming has taken place and that humans are mainly responsible? Phil Jones: I'm 100% confident that the climate has warmed. As to the second question, I would go along with IPCC Chapter 9 - there's evidence that most of the warming since the 1950s is due to human activity. -
CBDunkerson at 21:20 PM on 16 June 2011Websites for Watching the Arctic Sea Ice Melt
PIOMAS (see link in #33 above) has released an update through the end of May based on a revised model and a new baseline (1979 - 2010 average). The new model is showing a less severe declining trend, but the minimum is still ~4000 km^3 ice last September. That would seem to imply that some of the older values have been reduced such that the overall trend is lower while still arriving at the same end result. There are also some new materials like a graph showing the baseline values compared to 2007 and the current year. There are new links to validation information and the values used for the anomaly graphs, but the links on the PSC page currently have some '-2' extensions which I had to manually remove to find the intended pages. Also, there is apparently going to be an announcement about Cryosat-2 data next week. Sounds like they are going to start releasing results.Response:[DB] Thanks for pointing that out. I was going to post this last night but my PC died:
The new graphics more clearly depict the 2-sigma bounds.
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John Russell at 20:55 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Dikran: please do me a favour: come over to 'Carbon Brief' and make the definitive expert comment on this thread. Preferably one that is understandable to the sort of person Bern describes.Moderator Response: [Dikran Marsupial] Done (I have made a long and detailed post, I'll happily discuss it further if it was over the top ;o) -
John Brookes at 20:55 PM on 16 June 2011Our effect on the earth is real: how we’re geo-engineering the planet
Thanks Mike for a thoroughly illuminating article. Its nice to know that some geologists can see what is happening. -
Dikran Marsupial at 20:44 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Bern, quite. Perhaps Prof. Jones problem is that he does understand it! ;o) -
Bern at 19:44 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Dikran: I share your pain, but not quite as acutely. After all, I actually took (and passed!) a stats class as part of my engineering degree, and I only have a vague understanding of confidence & statistical significance. Mind you, some of that might be due to it being close to 20 years since I needed to apply it... :-P But if someone who did stats at university level (even if only basic stats) has trouble with statistical significance, what chance those people who struggled with algebra in high school, and have not gone beyond basic financial arithmetic since? -
Glenn Tamblyn at 17:58 PM on 16 June 2011Our effect on the earth is real: how we’re geo-engineering the planet
Bart In a limited semantic sense you are right. However, actions such as large scale mining are intentional in their more limited scope. And I'm not sure the term Geo can be used only for planetary scale. What would be the right term to use for an intervention that isn't intentional? Perhaps simply GeoIntervention? But certainly the sense that our interventions are planetary in scale is an important one before we get into questions of intentionality. -
Dikran Marsupial at 17:39 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Journalist at BBC wrote: "If a trend meets the 95% threshold, it basically means that the odds of it being down to chance are less than one in 20." AAAAAAARRRRRGGGGHHHHH!!!!!!!! ;o) -
Dikran Marsupial at 17:27 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Charlie A - if you want to see a real error, then try Dick Lindzens comment "Look at the attached. There has been no warming since 1997 and no statistically significant warming since 1995. Why bother with the arguments about an El Nino anomaly in 1998? (Incidentally, the red fuzz represents the error ‘bars’.)", when the 1998 El Nino is a major cause of the trend from 1995 being relatively small!!! Essentially what Lindzen is doing here is cherry picking and getting in a pre-emptive strike on the argument demonstrating that he has been picking cherries at the same time! [self censored to keep in line with the comments policy ;o)]. -
bartverheggen at 17:23 PM on 16 June 2011Our effect on the earth is real: how we’re geo-engineering the planet
The term "geo-engineering" does not apply here, as it refers to both Geo: planetary scale Engineering: Intentional intervention/"making". I.e. an unintentional side effect of our actions is not engineering. Discussion is not helped by having multiple different meanings out there for one term. -
Dikran Marsupial at 17:17 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Charlie A (various posts). Yes, fine, the data are autocorrellated and an OLS trend is an optimistic calculation. However the basic assumptions of a hypothesis test are invalidated if you deliberately tune the start point to get the result you want (effectively it means you are performing a multiple hypothesis test, so the false-positive and false-negative error rates will be affecte dby that). The effects of not taking into account the autocorrellation is a minor issue compared to that. That means that just accounting for the autocorrellation would not be technically correct either. Secondly, it isn't a big deal anyway, simply because the expected magnitude of an anthropogenically induced trend is so small that you would not expect to reliably detect it over so small a window, as windows of that short duration tend to be dominated by sources of short term variabilty due to things like ENSO. See the paper by Easterling and Wehner which shows that GCM simulations show occasional periods of little or no warming, even during long term forced global warming of a decade or two, for precisely this reason. In other words the effective power of the test is very low. Lastly, a test of statistical significance provides evidence for making some claim based on the value of a single statistic alone. That is, if that one statistic were the only evidence you had that the climate was warming, you could only claim the planet was warming if there were a statistically significant trend. But the trend from 1995-2010 is not the only evidence we have, so Jones is perfectly justified in having 100% belief that the world is warming. Basically anyone who is making a big song and dance about the trend not being significant is defficient in their statistics for not understanding the multiple-hypothesis testing issue involved in the cherry picking of the start point to suit one particular argument, and defficient in their understanding of climate physics for not understanding why you wouldn't expect the trend to be statistically signficant with high probability even if there is a secular trend of the expected magnitude. -
Glenn Tamblyn at 16:57 PM on 16 June 2011The greenhouse effect is real: here's why
Just to add another wrinkle to the 12C/13C discussion. Not all plants preferentially absorb 12C. It depends on the photosynthesis mechanism they use. The simpler C3 photosynthesis pathway does produce reduced 13C. This appears to be an evolutionarily older mechanism. However the more efficient C4 pathway doesn't discriminate. C4 is believed to have developed relatively recently as an evolutionary adaptation to declining CO2 levels. The main plant species where this is a factor are the grains. Some of them are C3 and others C4. Most other types of plant families are C3. So an extra wrinkle in analyzing 12C/13C data is modern agriculture. We have substituted significant parts of the general biosphere with grain monocultures. So we have probably messed with the 12C/13C ratio for modern plant life compared to what it would be at the present time without the impact of human agriculture. Does this help us further in identifying a 12C/13C signature in atmospheric CO2? Possibly since fossil CO2 should be more 13C depleted than modern biogenic CO2. Can this be seen above the noise level? Dunno. -
Albatross at 16:14 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Charlie, "The question is whether Phil Jones's statement true" Sigh, trying very hard to reframe the argument and shift the goal posts are you not? Again, read my post above carefully. And also read the main post, the question that is being asked is this: "Why choose 1995 as the starting point in this question? " Also, have you asked yourself what type of statistical analysis and data Lindzen used to arrive at his conclusion that there had been no stat sig warming? Don't see you questioning his stats analysis, never mind the content of his email to Watts. He was showing Watts how to cherry pick and distort. Are you OK with that? I find your insinuations that Jones behave nefariously in this whole fiasco manufactured by Lindzen to be beyond the pale. -
Albatross at 16:06 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Charlie, Re GISTEMP, read my post again (and my other posts on this thread), and carefully. -
dhogaza at 15:47 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
"The flaw in the Fuelner paper is that he is concentrating on TSI, rather than the other items that the sun provides that affect climate." The only problem is that the various unicorn hypotheses have no known physics behind them. "From Earth Shine, it is known that the albedo of earth has increased as of late. Global cloud cover has increased by approx 4%, and the jet streams have moved markedly south in the NH for this time of year." Yes, La Niña, [-snip-] happens. Gosh. "Dr. Svelsgaard will be having a paper published in the near future that shows the variation in TSI to be extremely small in the past 1,000 years." Which is totally congruent with the mainstream POV that a solar minimum will have a small effect compared to CO2 forcing. "So, now that we know that TSI is relatively constant, it is very apparant that the other forces from the sun require careful scrutiny and study." Or maybe the engineers who build CO2 lasers know what they're doing (not surprising, since they work, after all). "Early results from CERN are showing that Dr. Svensmar" Early results from CERN showed chamber surface pollution of results, and nothing from CERN has shouted "climate science is a fraud!". The CERN researchers are still struggling to show any result that might be relevant, even in a minimal way. Meaning it's a bit to early to stare at our CO2 lasers going ... "need to throw you away, you don't really work!!!!" -
Charlie A at 15:44 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
#139 Albatross "Note too that they ignore the fact that the warming does meet the 95% confidence level in the GISTEMP data" Phil Jones's statement was about HadCRUT time series, not GISS. The question is not even whether the climate is warming. The question is whether Phil Jones's statement true. There are many, many statements that Phil Jones could have made that would be true. He chose to make a statement not supported by the facts ..... at least if one does a proper statistical analysis. -
Charlie A at 15:41 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
@138 Tom Curtis. Without getting too heavily into the math, the effect of autocorrelation in the time series is to reduce the effective degrees of freedom, thereby increasing the size of the uncertainty band compared to the standard deviation of the samples. This also happens when one applies low pass filtering to a time series. The is not due to measurement error, but due to the long term persistence evident in virtually every climatological time series. -
Miriam O'Brien (Sou) at 15:12 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
I didn't think the Maunder Minimum lasted 100 years, I thought it was only for around 70 years. How much is known from earlier centuries about solar minima? Now if we got an increase in volcanic activity at the same time that could be very bad for future generations. The initial emissions would presumably mask warming further and the extra CO2 would add to later warming, plus people might be inclined to delay the shift from fossil fuels. End up with a big shock at some stage. BTW - kudos to you, John, for getting this up so quickly. There is a lot of rubbish being posted around the traps and your article explains things very clearly. -
Albatross at 14:21 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
Kudos to John Cook for promptly addressing this issue so promptly! -
BaerbelW at 14:20 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
Adding to what Sphaerica posted, if a potential solar minimum is used as an excuse to keep on emitting CO2, we'll get bigger and bigger problems with ocean acidification - global warming's evil twin. -
Albatross at 14:09 PM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Curious thing, when Jones answered the loaded question and noted that the warming was not stat. significant at the 95% level, 'skeptics' then did not question his stats, or the particular data set that he used, in fact they accepted/endorsed the result without question and hyped the story. But now that he has determined that the warming in the HadCRUT3 (variance adjusted data) does meet the 95% criterion, they suddenly do take issue. Note too that they ignore the fact that the warming does meet the 95% confidence level in the GISTEMP data, not to mention all the other signs that the planet is warming:
[Source]
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Bob Lacatena at 13:55 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
I find a solar minimum to be very frightening, if the end result is to delay scaling back CO2 emissions (by further masking the effects of CO2), and if that solar minimum lasts for less than one thousand years (which means we'll emit way more than we should have and otherwise would have, but ultimately the level of warming will be the same, once the sun wakes up and the CO2 is still there, patiently waiting). -
Bob Lacatena at 13:50 PM on 16 June 2011It's the sun
834, Tor B, Apologies. Believe it or not, I read your post several times trying to figure out the intent. I even did a google search looking for your past comments, to see what sort of things you've posted previously. My bad. I think I've been getting way too feisty lately. Too much nonsense devoid of substance flying around here of late. It's just frustrating. Sorry again. -- Bob -
Tom Curtis at 13:48 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
Further to my @7, Hegerl et al also show an approximately 0.25 W/m^2 increase in solar forcing in the current "Grand Maximum". This is consistent with the change in insolation shown in the graph Albatross presents. Therefore the total difference in forcing between a Grand Maximum and a Grand Minimum is just 0.5 W/m^2 or 0.4 degrees C at equilibrium, and closer to 0.25 degrees as a transient increase. To put that into perspective, that is half of the total increase in radiative forcing from anthropogenic GHG emissions between 1979 and 2009. So, in rough terms, a decline from a Grand Solar Maximum to a Grand Solar Minimum would merely delay temperature increases due AGW by around 15 years, assuming the rate of increase in GHG emissions remains constant. -
Tom Curtis at 13:26 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
Alex C @4, you are correct about the volcanic forcing. You may want to check out Hegerl et al 2006 for more details. They show a total solar forcing for the Maunder Minimum of around -0.25 W/m^2, corresponding to a 0.2 degree C decline in temperatures after feedbacks, and with a larger volcanic forcing. -
Albatross at 13:21 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
The forcing in CO2 by 2020 is easily going to swamp any relatively small changes in the TSI, that was obviously not the case during the LIA when CO2 was near 280 ppm and volcanism was also unusually high. And people keep desperately hanging onto yet another extremely tenuous solar-related affects such as GCR (more about them here). The GCR argument is also a red herring. Heck the 'skeptic' tactic seems to be to throw as much stuff out there and hope that something might just stick. I don't understand why the skeptics are so excited about this, this finding is nothing new really, solar scientists expected that this solar cycle would be relatively quiet and that the downward trend ay continue, and now the "skeptics" are feigning surprise and excitement, because this after allis the silver bullet that will mean we can continue with BAU...umm, no. Also, by proclaiming an impending ice age as several 'skeptic' outlets have done, they are really painting themselves into a corner and setting themselves up for a fail, because the long-term warming will almost certainly continue, and their ridiculous claims of impending global cooling or an ice age will look incredibly stupid come 2020. Also, in 2010 global temperature records tied for the record highs despite the prolonged solar minimum and a developing record strength La Nina....again, solar is only a bit player compared to GHG forcing. Note also that the TSI and global SAT have been diverging the last 50 years or so.
[Source: SkS]
As for EarthShine data, SkS has also discussed that here. I would like a peer-reviewed reference to support the claim that global cloud cover has increased by 4%.
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Alex C at 13:13 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
Eric the Red, to not leave my statement so vague, Robock 1979 and the more recent Crowley 2000 concluded that increased volcanism had an impact as well. -
Tor B at 12:55 PM on 16 June 2011It's the sun
Sphaerica (829) appears to miss the intent of my posting "someone with knowledge will have to pick his [Stockwell's] writing apart". Albatross (830) reflects my view: I read a "new" "it's the Sun" and thought folks here could banish it properly. Tom Curtis (832) has done what I am not able to do. Thanks! -
Alex C at 12:52 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
Eric the Red: wasn't there also a period of extended volcanic activity concomitant with the Maunder Minimum? I cannot remember that detail, but for some reason I think I've heard that somewhere. Anyways, John is referencing the conclusions of Feulner 2010, so it's not like this is his own out-of-thin-air guess. Also, the link to Feulner 2010 needs a subscription to AGU, which I'm assuming a lot of us don't have. This link works (don't know how to hyperlink here): http://www.pik-potsdam.de/~stefan/Publications/Journals/feulner_rahmstorf_2010.pdfResponse:[DB] Hot-linked URL (hyperlinking tips here).
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Chris McGrath at 12:48 PM on 16 June 2011Speaking science to climate policy
Does anyone know the source of Risbey's reference to "a total global carbon emission allocation of between about 800 and 1000Gt carbon" and that "we have already emitted about 550Gt, leaving perhaps another 250–450Gt". Meinshausen et al (2009) “Greenhouse-gas emission targets for limiting global warming to 2°C” Nature 458:1158-1162 stated that, "Limiting cumulative CO2 emissions over 2000–50 to 1,000 Gt CO2 yields a 25% probability of warming exceeding 2 6C—and a limit of 1,440 Gt CO2 yields a 50% probability—given a representative estimate of the distribution of climate system properties." Meinshausen et al's figures are in CO2 while Risbey appears to be using carbon-only figures (Nb. We can convert from carbon to CO2 by multiplying by 44/12). Meinshausen et al are also talking about emissions between 2000-2050 while Risbey does not define the time interval so it appears he may be speaking about emissions since the beginning of the Industrial revolution. Can anyone clarify these figures? -
Eric the Red at 12:46 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
Curious why John thinks that the solar minimum (if it were to occur) would have such a slight effect on temperatures, when NASA (and others) have shown a much higher temperature decrease during the Maunder minimum.Response:[DB] Where was the anthopogenic CO2 spike comparable to that of the modern era during the Maunder Minimum?
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Bob Lacatena at 12:41 PM on 16 June 2011Clouds provide negative feedback
171, RW1, Look. Your comments contain nothing of substance other than to deride Dessler without foundation. He did a study and found that the net change in cloud feedback was positive, which supports the contention of many, many current climate scientists. Make a point and support it, or stop commenting. If you have a valid mechanism by which this may not be so, submit it and support it. If you have data that refutes Dessler's claim, submit it and support it. If all you have to say is "Negative could feedback! Negative cloud feedback! Dessler must be wrong!" then you're wasting everyone's time.Response:[DB] Agreed. No one wishes to waste their time by dialoguing with RW1 due to his unwillingness to learn and to properly support a position.
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Camburn at 12:41 PM on 16 June 2011How would a Solar Grand Minimum affect global warming?
The flaw in the Fuelner paper is that he is concentrating on TSI, rather than the other items that the sun provides that affect climate. From Earth Shine, it is known that the albedo of earth has increased as of late. Global cloud cover has increased by approx 4%, and the jet streams have moved markedly south in the NH for this time of year. Dr. Svelsgaard will be having a paper published in the near future that shows the variation in TSI to be extremely small in the past 1,000 years. So, now that we know that TSI is relatively constant, it is very apparant that the other forces from the sun require careful scrutiny and study. Early results from CERN are showing that Dr. Svensmark is correct about gamma rays and clouds. Earth shine would seem to confirm this. -
RW1 at 12:38 PM on 16 June 2011Clouds provide negative feedback
Sphaerica (RE: 170) "Believing that you can out-think them when you can't even get a decent grasp on Trenberth's energy budget diagram..." Find the appropriate thread and I'll be happy to discuss/debate Trenberth's energy budget with you or anyone. Every time I've tried, my posts seem to end up getting deleted for being off topic. Moderators, is there a thread where we can discuss this? If not, can you start one? -
RW1 at 12:29 PM on 16 June 2011Clouds provide negative feedback
Sphaerica (RE: 170), "The mechanisms have been explained to you several times. Clouds are not a uniform, one dimensional entity for which more clouds = more of the same. A large number of factors come in to play." I've never claimed clouds are uniform or a one dimensional entity. "Your simplistic view that net cloud impact on temperatures is normally mildly negative, and therefore any increase in clouds due to warming must be comparably more negative, is inadequate." A -20 W/m^2 net effect is not "mildy negative" - it is very strongly negative (or strongly cooling). In the absence of specifically identified and corroborated physical mechanisms to the contrary, this is an extraordinary claim requiring extraordinary proof. Ultimately, Dessler doesn't have it. -
Bob Lacatena at 11:34 AM on 16 June 2011It's the sun
832, Tom Curtis, You win the Comments-Rebuttal-Of-The-Month Award!!! [Darn. I wish I'd worked that one through. Very nice job, and a lesson for anyone who has fallen for any such similar denial nonsense. Just playing with numbers is a parlor game, not science. Casual readers should note that the basic problem with Stockwell's analysis was the creation of an arbitrary mathematical mechanism -- the accumulation of solar input -- without any corresponding physical mechanism to justify the assumption. He picked it just because it fit the data, and didn't take the thought process any further. As Tom demonstrated, the missing physical mechanism that justifies the mathematical trick to demonstrate the incline does exist, but sadly, for Stockwell, it's called the Greenhouse Gas Effect.] -
jonicol at 11:29 AM on 16 June 2011Examining Dr. John Christy's Global Warming Skepticism
KR You may already have seen this article at http://chartsgraphs.wordpress.com/2011/02/01/atmospheric-temperature-structure-2-stratospheric-cooling/ with some RSS charts showing the cooling you are talking about. -
Bob Lacatena at 11:20 AM on 16 June 2011Clouds provide negative feedback
168, RW1, No single paper needs to cover everything, all at once, to completely define something. He doesn't "admit" (and yes, I noticed your cleverly pejorative word choice) that he doesn't cover mechanisms, he simply "tells" you as much. You shouldn't have needed to bother him and ask such an obvious thing, which you would certainly have clearly known if you comprehended the paper. That said, I don't care how many times you've read the paper, you don't seem to be able to comprehend it or, rather, you don't seem to be able to separate what you believe (without adequate logic or evidence) from what current science says. The mechanisms have been explained to you several times. Clouds are not a uniform, one dimensional entity for which more clouds = more of the same. A large number of factors come in to play.- Are there more clouds at night, where their albedo is irrelevant?
- Are there more clouds at the poles or northern hemisphere in winter, where they merely shield reflective snow and ice, and so the difference in albedo is nil, while their radiative warming effects are increased?
- Are the clouds that form high altitude clouds of ice, that are pretty much transparent to visible light, but still have a strong GHG effect?
- Do the excess clouds form over or under existing cloud layers, again having little net effect on albedo, but definitely adding their radiative effects?
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jonicol at 11:05 AM on 16 June 2011Examining Dr. John Christy's Global Warming Skepticism
Thanks KR. That is a good clear article and explains the absorption processes logically. I will be following other material on matters alluded to there including David Archer's paper. I have also read your other suggestions you gave me in 52 KR which were also interesting and helpful. Cheers. -
RW1 at 10:55 AM on 16 June 2011Clouds provide negative feedback
KR (RE: 166), "Keep in mind that while specific humidity (total amount of H2O) in the atmosphere may be rising with temperature, relative humidity (relative to the total amount air can hold at any temperature) may remain steady or even decrease. So - steady or decreasing clouds with rising temperatures, neutral or positive feedback to warming." This really doesn't make sense. The fundamental problem is that clouds are controlling the water vapor concentration in a highly dynamic manner. The evaporated water vapor condenses in the atmosphere to form clouds, and then the formed clouds precipitate out the water from the atmosphere. As the clouds form and remain in the atmosphere, they reflect more solar energy away because the clouds are more reflective than the surface beneath them. This is why the net measured effect of clouds is to cool rather than to warm. Dessler's analysis is essentially claiming that all of the sudden the incremental effect of clouds on the next little bit of warming will be the warm rather than cool. -
Eric (skeptic) at 10:44 AM on 16 June 2011How would a Solar Grand Minimum affect global warming?
Interesting paper (on french web site). I was wondering what the downward blip was and it is apparently one or more volcanoes which can coincide with solar minima (reference was made to this paper http://www.mpimet.mpg.de/fileadmin/staff/claussenmartin/publications/bauer_al_1000_grl_03.pdf)Response: The downward blips over the 21st Century are volcanic eruptions randomly distributed (matching similar eruptions in the 20th Century). This was necessary to avoid artificial drift of the model from an unnatural lack of volcanic forcing. -
RW1 at 10:31 AM on 16 June 2011Clouds provide negative feedback
Sphaerica (RE: 167), "Your overly simplistic model of the system completely fails. It doesn't properly consider how clouds form, it doesn't understand that clouds do not need to decrease to provide a positive feedback, it doesn't account for the many varieties, locations (in space, meaning 3 dimensions, and time) of clouds, it fails on many, many other levels. At the same time, your interpretation of Dessler 2010 is flawed. You should probably read the paper several more times before commenting on it again." I have read the paper multiple times. I even emailed Dessler for clarification on a few things. He admits outright that his analysis doesn't analyze any mechanisms, just data. That the net effect of clouds is to cool by 20 W/m^2 would have to be explained. Just claiming the derivative to changes in surface temperature is positive, as Dessler does, even though the net entire effect is to cool is not good enough. -
Tom Curtis at 10:08 AM on 16 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Charlie A @135, I am very far from expert on statistics, so I would appreciate somebody who is expert either confirming, or correcting the following (Hint: Dikran). However, it appears to me that your statement about that:"The time series shows autocorrelation (i.e. residuals are not white), so the uncertainty bands should be expanded. But he does not do so."
is incorrect. Specifically, the time series does show autocorrelation, but the error bars show measurement error, which would be white noise. Consequently, the effect of auto-correlation in the series would be to reduce the expected error rather than increase it in that nearby terms would provide some (very limited) information about the probable values of their neighbours. -
Tom Curtis at 09:48 AM on 16 June 2011It's the sun
Tor B @826, Stockwell provides very little information to provide a counter analysis. The majority of the information comes from this diagram:
As you can see, he plots temperature against the cumulative solar forcing. The only way that can be appropriate is if there has been no increase in Outgoing Longwave Radiation to dissipate the increased incoming solar energy, thus allowing it to accumulate. As a rise in temperature will result in a rise in OLR all else being equal, he leaves entirely unexplained why OLR has not increased over the period, and why it did increase in previous centuries, thus allowing the solar forcing to dissipate and temperatures to not rise as they have in the twentieth century. What Stockwell needs, therefore, is a mechanism that provides a near linear reduction in OLR over time. (Care to guess where this is going?)
Oddly, and obviously, there is a known mechanism which has been increasingly been reducing the OLR over the course of this century. It is the increase in the Greenhouse Effect due to increased anthropogenic emissions of Greenhouse Gasses. Indeed, the increased forcing (reduction in OLR for a given surface temperature) has risen approximately linearly over the last half of the twentieth century:
Further, it turns out that using a linear increase in anthropogenic forcings plus solar forcings, plus volcanic forcings plus the MEI (an index of the El Nino Southern Oscillation), an even better correlation with temperatures can be found than that found by Stockwell:
So it turns out that the evidence Stockwell has uncovered is in fact evidence of an increasing anthropogenic forcing - he is just not good enough an analyst to realise it.
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