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dana1981 at 01:16 AM on 17 June 2011How would a Solar Grand Minimum affect global warming?
Badger #20 - see Solar Hockey Stick -
Alex C at 01:07 AM on 17 June 2011How would a Solar Grand Minimum affect global warming?
thepoodlebites: Hm, well I uploaded the graph (Excel) in question to Flickr, it's here for viewing. -
Michele at 01:04 AM on 17 June 2011The Planetary Greenhouse Engine Revisited
Observing the Heart’s temperature profile, we note that in its atmosphere there are two broad sinks (the tropopause and the mesopause) that collect the upwelling&downwelling thermal energy flows, held by the existing temperature gradients, and radiate them to space. The lower atmosphere, near the surface, is affected by the surface, the troposphere and the tropopause. Simplifying, let’s assume that the atmosphere is restricted to the troposphere. We can say without any doubt that the tropopause emits only a part of the needed heat because its temperature (Tt) is lesser than the effective one (Te) whereas the surface (which has a temperature Ts higher than Te) encounters some difficulties/resistances to radiate to space and its emission takes place with an efficiency (ε) lesser than one. Off course, simplifying, the balance of the thermal fluxes requires that there must be εTs^4 + Tt^4 = Te^4. Also, observing the brightness temperature vs wavelengths, ”(e.g. here)” we read that the Earth’s thermal sinks of the atmosphere are due to CO2 as well as for Venus and Mars (the absence of another sink for the mesopause temperature lets us to claim that it is due also to the CO2 and that it is overlapped by the tropopause sink). We read too that Earth has some others GHGs and so, while several gases take part in reducing the efficiency (ε) of the surface emission, the sole CO2 determines Tt. We can claim that if the Earth’s atmosphere was totally without CO2, both Tt and Ts would be higher and the surface would be warmer. It’s astonishing, the “vituperated” CO2 plays the role of to limit the GH effect. Further. The behavior of the atmosphere has to be analyzed from a fluid-dynamic point of view taking into account that a particle of the atmospheric gas, once heated by the surface, leaves it and climbs adiabatically. Assuming that the changes over the time vanish for all the playing variables, we read: 1) The conservation of the momentum along the vertical direction states that, apart the viscosity, the vertical acceleration of the particle is generally (- g – (1/ρ)δP/δz) and for the adiabatic flow and for an ideal gas it is (- g - CpδT/δz). The acceleration is positive (the rising is accelerated, the falling is decelerated) if δT/δz is lesser than –g/Cp and vice versa. The rising/falling is uniform with δT/δz = -g/Cp. 2) The conservation of the energy (in absence of sources and sinks within the adiabatically rising particle) tells us that the total energy (CpT + u²/2 + gz + … ) is constant, that’s, CpT + gz = constant for the uniform flow, i.e. δT/δz = - g/Cp. In other words a particle that leaves the surface at the temperature T0 is able to reach the height z = Cp(T0 – T)/g and if it has to reach the tropopause to yield a part of the heat that is there emitted, it needs to start from the surface at least at the temperature Ts = Tt + gH/Cp (H is the thickness of the troposphere). Conversely, the surface has to be at least at Ts to be able to heat the particle. Thus, the surface temperature is determined by the thermodynamics and fluid dynamics, once the tropopause has been set up at the height where the pressure allows the largest emission (Earth’s and Venus’ tropopause have similar pressures and temperatures, but CO2 densities tremendously different, as well as for Earth’s mesopause and Mars’ tropopause. All this in agreement with the consolidated physics. I think all others argumentations would integrate it without repudiate it. -
KR at 01:03 AM on 17 June 2011How would a Solar Grand Minimum affect global warming?
Arkadiusz Semczyszak - It is well worth considering the relative scale of the forcings. TSI changes for a long term minimum will be on the order of about -0.25 to -0.5 W/m^2; this is equivalent in scale to about 15 years of GHG accumulation. Forcing changes due to greenhouse gas accumulation for a doubling of CO2 are 3.7 W/m^2. Considering our continuing emission of greenhouse gases, a prolonged minimum will only delay global warming by about 15-20 years. And we will have to deal with "...the duration of the forcing with potentially larger effects for longer lasting or repeated forcings.”, as you put it. -
Albatross at 01:00 AM on 17 June 2011Phil Jones - Warming Since 1995 is now Statistically Significant
Dikran, Many thanks for all your incredibly informative posts here. -
Alex C at 00:56 AM on 17 June 2011How would a Solar Grand Minimum affect global warming?
thepoodlebites: I just downloaded the annual data from your link and applied a linear fit to the data from the minimum which started cycle 21 to the minimum that ended cycle 23 - there is a very weak decrease in overall TSI during this interval (-0.001452 W/m^2/year). From eyeballing it, it does not seem like it is as much of a drop as shown in the PMOD data, but there is still a slight decrease. I'm going to go have a look-through how I can add in graphics here to give you the figure... -
John Hartz at 00:33 AM on 17 June 2011How would a Solar Grand Minimum affect global warming?
The latest findings about the causes of solor storms.... "Scientists Prove Existence of ‘Magnetic Ropes’ that Cause Solar Storms" ScienceBlog, June 15, 2011 -
John Hartz at 00:20 AM on 17 June 2011How would a Solar Grand Minimum affect global warming?
Where can I find a plot of TSI over a geological timeframe? -
thepoodlebites at 00:19 AM on 17 June 2011How would a Solar Grand Minimum affect global warming?
Why does Mr. Cook keep pushing the (Feulner & Rahmstorf 2010) paper as some sort of silver bullet, non-refutable proof that an extended period of unusually low solar activity would cause a decrease in global temperature of no more than 0.3 C? I have made several posts demonstrating the weak assumptions and speculative conclusions that this paper reports. And the links to the original paper are still not working, Feulner & Rahmstorf 2010. The paper assumes a minimal response to reduced solar irradiance (0.025 C), an enhanced response to CO2 doubling of 3.4 C (from A. Levermann, private communication, 2010). Plug these assumptions into the CLIMBER-3a model, and the model results support the assumptions. This result is a faulty form of reasoning that assumes the conclusions in the premises, i.e., circulus in probando. The conclusions here are speculative, not even close to being a silver bullet. The argument is still wide open, the effects of an extended period of unusually low solar activity on subsequent global temperatures. And Mr. Cook seems intent on continuing to push the PMOD solar data when the LASP data shows a better representation of TSI. The TIM instrument has measured a lower and more accurate TSI (1360.8) for solar min than PMOD and the LASP historical TSI reconstructions show no decrease in TSI levels over the last three solar cycles (21-23). But cycle 24 is indeed unusual and time will be the best laboratory to study the impacts on climate. -
KR at 00:12 AM on 17 June 2011How would a Solar Grand Minimum affect global warming?
Ken Lambert "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. " Minus, of course, the integral of TOA radiation to space. Otherwise the pure integral of TSI would result in a surface temperature cooking us millions (billions) of years ago. The increasing difference between TSI and temperature trends indicates that TOA radiation has decreased in relation to temperature, increasing energy accumulation/temperature, which would be the effect of GHG's. Your insistence on treating the climate as a single variable system (TSI), without considering other forcing changes, continues to lead you astray. -
Chris G at 00:00 AM on 17 June 2011The greenhouse effect is real: here's why
Daniel B (#34), That is a very interesting observation. Another round of thanks. Though, I'm not sure how to distinguish an introduction of positive feedbacks from an acceleration of FF use. Either would produce a greater number of months with increasing levels. The timing of the peaks or the shape of the curve might make do it, but that is likely a difficult signal to filter from the noise. I'll have to give it more thought. -
Utahn at 23:59 PM on 16 June 2011There's no room for a climate of denial
Eric the Red: "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 say no, unless all of the other 50% turned out to be some previously undiscovered factor... I think the H.Pylori thing is really interesting too, but even that didn't exactly overturn a consensus, as it turns out H.Pylori causes ulcers in large part by increasing gastric acid secretion. So acid is still causing the ulcers, lowering acid still treats and prevents ulcers (even if you don't kill the H.Pylori), it's just that in many cases a germ is causing the high levels of acid to be secreted, and you can better prevent recurrence of ulcers by also killing the germ. To me this would be analogous to finding that C02 still was warming the globe, that we were emitting it, but that something else was causing us to emit it besides our various desires leading to industrial and personal energy use. Maybe if God were causing us to use all these fossil fuels...which is actually probably true in some way! Do you know of any antibiotics that work on God? -
Chris G at 23:45 PM on 16 June 2011The greenhouse effect is real: here's why
Scaddenp, Glenn, Hmm, I'd figurede that the bacteria producing methane were eating plant material and that would mean the same ratios throughout. I did not remember about the C3 versus C4 pathways. Interesting, thanks. -
Ken Lambert at 23:24 PM on 16 June 2011Speaking science to climate policy
Michael Sweet #7 One of the oft used reasons for the post-WW2 cooling up to about 1975 was the masking effect of Aerosols. Do you remember the argument that the 'Clean Air Acts' - cleaned up North American and European sulphate and other emissions - had unmasked that CO2GHG forcing - hence the increase in temperatures since 1975? Well - Hansen has brought them back to explain another masking of CO2GHG forcings - the last 10 years or so. While it is feasible that unmeasured Aerosols from the Chinese and Indian and other Asian economies have taken the place of the 1945-75 lot, one wonders why the window 1975-2000 ever existed. Surely emissions from Asia are not a new thing and have been steadily increasing for the last 30 years. "According to Bart's 0.8 C/W/m2 @3, that is over 1C of committed warming in addition to what is in the pipeline due to ocean thermal inertia." What is in the pipeline? Temperature rise or a rise in sequestered heat energy? Ocean thermal inertia can only redistribute heat already sequestered as temperature rise (or ice melt) in many places and temperature drops somewhere else. This is an 'internal' forcing effect. At any instant in time, the storage of heat energy will be represented by a mass phase change (WV or Ice) and a mass temperaure increase somewhere. If Hansen's rediscovered Aerosols are masking CO2GHG forcing by closing the imbalance gap - less heat energy is being sequestered for the oceans thermal inertia to redistribute. The 'warming' is not in the pipeline - its in the time tunnel - dependent on future imbalance. -
Eric the Red at 23:01 PM on 16 June 2011Forecast: Permanently Hotter Summers in 20-60 years
No, I do not propose that. However, much research has shown (not proven) that the PDO has significant climate implications. If much of the recent warmer is attributable to decadal oscillations rather than climate feedbacks, then that needs to be incorporated into climate models. It is not the physics of climate science that is resulting in the greatest uncertainty, but rather the mathematically-modelled responses to the physics. I think you are deluded yourself if you think that testing mathematical models is alchemy. When did observation, correlation, and inference become extinct? The modern day term for model testing is called engineering. I know a new thread has started since I first brought up a potential grand minimum, but what if a combination of a negative PDO and solar minimum reduced global temperatures significantly more than modelled? -
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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