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thingadonta at 15:49 PM on 15 August 2010NASA-GISS: July 2010-- What global warming looks like
The reference to 43% below avergage temperature from ~West Africa to Japan is here, courtesy WUWT. http://wattsupwiththat.com/2010/08/14/more-of-the-moscow-heat-wave-satellite-analysis/#more-23439 Its still cooler than normal in SE Asia, and for the last several months. -
stormhunter27 at 15:39 PM on 15 August 2010NASA-GISS: July 2010-- What global warming looks like
Hey thanks muon - appreciate it. Being a met means I've had some climatology training, but it takes some searching to find the data I need and often the deniers are already off and runnng with a totally new argument before I can rebutt the original. BTW - there's a new paper at WUWT that is causing quite a stir. I'd love to see a real analysis of it: http://wattsupwiththat.files.wordpress.com/2010/08/mcshane-and-wyner-2010.pdf -
miekol at 15:38 PM on 15 August 2010Newcomers, Start Here
Ok John, you got me hooked :-) I will take a look at your scepticism Michael Gold Coast -
muoncounter at 14:05 PM on 15 August 2010NASA-GISS: July 2010-- What global warming looks like
#62: "There is no warming, summers are cooling. It's milder winters that is increasing the average of the yearly mean " How about this response? That is just flat wrong. See the seasonal RSS temperature anomaly graph at the Has Global Warming Stopped? thread. Summer and winter anomalies are on the same upwards trend; but I agree, that does give the appearance of warming. -
muoncounter at 13:56 PM on 15 August 2010NASA-GISS: July 2010-- What global warming looks like
#60: "only 43% of the land area extending from West Africa through to Japan is above average T. ... This means that is cooler than average, overall," Your conclusion is Utter Nonsense. Example: Take the integers 1 thru 10. Their average is 5.5; half are above and half below. Now take these integers: 1,2,3,3,4,5,7,9,10,12; their average is 5.6, which is higher than the prior average. Only 40% of the new integers are higher than either average, yet the average has gone up! If those were temperatures, would that be warming or cooling? No cherries picked here. -
michael sweet at 12:43 PM on 15 August 2010More evidence than you can shake a hockey stick at
Johnd: "The heat content of the atmosphere, primarily carried by the greenhouse gases" was discussed at great length here: waste heat thread. This is a misconception that you and RSVP share. Absorbed heat is carried by all molecules in the atmosphere and not just by a select few. The heat absorbed by CO2 (and H2O) is shared to the rest of the N2 and O2. This is very basic, long well understood, physics and chemistry. AGW theory will not make sense until you understand heat transfer in the atmosphere. I suggest you review the waste heat thread.Moderator Response: I second that suggestion to take further discussion of that particular topic to that other thread. -
michael sweet at 12:12 PM on 15 August 2010NASA-GISS: July 2010-- What global warming looks like
Thingodonta, In figure 1 above when I draw a line from west Africa to Japan there are only two small spots where the temperature is below normal and the vast majority of the area is red. One small spot near Kenya in the ocean and the low end of the cold area in Northern Asia. Where did you get the 43% figure? Can you explain to me from Figure 1 how you see July as cooling? The reddish colors are hot in the figure and the cold are blue. -
stormhunter27 at 11:52 AM on 15 August 2010NASA-GISS: July 2010-- What global warming looks like
Ok, here's a new argument I've never seen and they pertain to this topic: There is no warming, summers are cooling. It's milder winters that is increasing the average of the yearly mean to give the APPEARANCE of warming. How would this even work? BTW - ths guy also says that "there is no climatic event that is outside the normal" and expects that this is an argument of some type. -
Typhoon_ at 11:48 AM on 15 August 2010More evidence than you can shake a hockey stick at
New paper on the Mann temperature proxy reconstruction: to be published in the Annals of Applied Statistics . A Statistical Analysis of Multiple Temperature Proxies: Are Reconstructions of Surface Temperatures Over the Last 1000 Years Reliable? http://tinyurl.com/AAS-paper Abstract. Predicting historic temperatures based on tree rings, ice cores, and other natural proxies is a difficult endeavor. The relationship between proxies and temperature is weak and the number of proxies is far larger than the number of target data points. Furthermore, the data contain complex spatial and temporal dependence structures which are not easily captured with simple models. In this paper, we assess the reliability of such reconstructions and their statistical significance against various null models. We find that the proxies do not predict temperature significantly better than randomseries generated independently of temperature. Furthermore, various model specifications that perform similarly at predicting temperature produce extremely different historical backcasts. Finally, the proxies seem unable to forecast the high levels of and sharp run-up in temperature in the 1990s either in-sample or from contiguous holdout blocks, thus casting doubt on their ability to predict such phenomena if in fact they occurred several hundred years ago. We propose our own reconstruction of Northern Hemisphere average annual land temperature over the last millenium, assess its reliability, and compare it to those from the climate science literature. Our model provides a similar reconstruction but has much wider standard errors, reflecting the weak signal and large uncertainty encountered in this settingModerator Response: A perfect topic to take to the "How reliable are climate models" thread. Please continue discussion of this paper at that thread.
Thanks! -
johnd at 11:32 AM on 15 August 2010More evidence than you can shake a hockey stick at
doug_bostrom at 10:27 AM, when considering the heat energy being carried by water vapour we should confuse the heat content itself with how it may manifest itself. Latent heat and sensible heat are not two different types of heat but rather the means of describing different conditions involving the transfer of heat energy. What is relevant to the subject of how the weather, and thus the climate varies, is how the heat content of the atmosphere may vary. With weather and climate both being subject to the balancing of various forces, any factor does not have to be the dominant reservoir, but rather the one most sensitive to any underlying changes, and this is the function of water vapour. This subject is leading I believe into the recent argument, put I think by RSVP, who IIRC, argued that all the gases in the atmosphere could be considered greenhouse gases if they absorbed IR, against much opposition, again IIRC. -
JMurphy at 10:48 AM on 15 August 2010NASA-GISS: July 2010-- What global warming looks like
thingadonta wrote : "According to NASA, only 43% of the land area extending from West Africa through to Japan is above average T a the time of Russia's hewatwave. This means that is cooler than average, overall, but you have managed to cheery-pick Moscow simply for the purposes of highlighting warm temperatures." Is it really the case that there are no average temperatures at all, or are you saying that average temperatures are only present in 6% or less of that land area ? -
thingadonta at 10:10 AM on 15 August 2010NASA-GISS: July 2010-- What global warming looks like
"WMO takes note of the conspicuous nature of this year's weather in Russia......." You state "Russia" and then go on to make a quote which refers only to Moscow. "July 2010 is the warmest month ever in Moscow....." According to NASA, only 43% of the land area extending from West Africa through to Japan is above average T a the time of Russia's hewatwave. This means that is cooler than average, overall, but you have managed to cheery-pick Moscow simply for the purposes of highlighting warm temperatures. So, you have convinced me, global warming looks like cooling. This site constantly states how skeptics cherry pick data while ignoring the bigger picture, well you have just done the same. -
Dikran Marsupial at 09:47 AM on 15 August 2010Has Global Warming Stopped?
fydijkstra "Yes, the oscillation in Akasofu’s model is super-imposed on a linear trend. We don’t know how long this trend will continue. Not to infinity of course, because nothing in the climate goes on to infinity." Yes, and the same could be said of a linear model used to determine more recent trends. It seems to me that you are being a little inconsistent there. "Here we see a multi century oscillation with a wavelength of about 1400 years" The human eye is great at picking out cycles that are merely the result of random variation. That is why science has developed the use of probability and statistics to guard against such mistakes of intuition. Again there isn't even two full cycles shown in the graph, so projecting forward on that basis is a guess, nothing more. BTW, Roy Spencer isn't the only person to have come up with a 2000 temperature reconstruction - what do the others say? "It is not possible to calculate error bars with only 10 points on a flattening curve." Nonsense, if you were fitting using maximum likelihood based methods, of course it is possible to calculate error bars. "I used this flattening function only to show, that the data fit better to a flattening curve than to a straight line." I think I may have mentioned that fitting the calibration data better doesn't mean the model is better because of over-fitting. This is especially relevant when there are only a handful of data. "When it is said that ‘global warming has stopped’ this is only about the data onto the present. Nobody denies that it is possible that global warming will resume." The principal cause of variability is ENSO, which involves a transfer of heat between the oceans to the atmosphere. That means you can't unequivocally tell if global waring has stopped by looking at air temperatures alone, as there may still be a net warming of the Earth as a whole but a transfer of heat from the atmosphere to the oceans. The test does show that air temperatures haven't risen much (if you choose the start date in the right place). -
Doug Bostrom at 09:22 AM on 15 August 2010Why I care about climate change
Sorry, truncated my remark there. I've been looking at the whole adaptation thing (which, no surprise we're going to be doing more or less, regardless of how we feel about mitigation) and among other factors in adaptation costs is how to account for direct impacts of a transitional climate. For example, there are twenty million people out of their houses today in Pakistan due to the recent flooding there, apparently much of the housing stock being destroyed beyond repair. Now, rather than argue about whether this is entirely due to climate change or entirely because of natural variability, we can take a statistical perspective and say that some proportion of these people need new homes due to a change in climate. Let's take a conservative approach and say that only five million are homeless due to climate forcing, arguably a reasonable number when the flood probability itself is taken into account. That number has to be entered into a ledger and stacked against benefit. There are myriads of details like this to take account of, "detail" perhaps being a poor choice of word. I use it because the intricacy and scale of this situation makes some millions of persons forced out of their homes into a "detail." See Tol, Stern and their citations for more information. -
chris at 09:13 AM on 15 August 2010Has Global Warming Stopped?
fydijkstra at 05:48 AM on 15 August, 2010 To me that's simply too much ad hoc-ery to be realistic fydijkstra. (i) Braun et al (2005) explicitly rule out the 1470 year cycle for Holocene events. Their tentative conclusion for the driving of Dansgaard Oescher phenomena relates to the possibility of threshold events resulting from meltwater pulses involving massive N. Hemisphere ice sheets that result in large temporarily perturbation of the thermohaline circulation with dramatic and rapid effects on temperature in the N. Atlantic. We know these processes have nothing to do with current global warming. In any case the current warming is out of phase with the supposed "cycle" (if the peak of the last cycle was around 800-900 AD then we shouldn't be getting a new peak until 2300-2400). Or are you suggesting that we've got another 300-400 years of relentless warming due to some uncharacterised putative cycle? (ii) This seems a little unlikely in the context of the Spencer/Loehle and Akasofu's notions. Firstly, if one were to take the Spencer/Loehle sketches at face value, then we should take on board that their sketches only go to 1935. If we add on the real world warming since then, current temperatures are already well above the supposed maximum of the Loehle/Spencer sketch you reproduced. We're surely much warmer than we should be if our temperatures were dominated by your 1500 year cycle which projects a substantial warming from natural causes still to come... (iii) Akasofu proposes a linear "recovery" from the LIA that continues to this day and through the next ~ 100 years. That seems astonishing to me. It implies that the Earth has a much higher sensitivity to changes in forcings than current understanding would support, and that the climate system has such an extraordinary inertia that "recoveries" (from temperature perturbations) are dominated by processes with time constants on the century timescale or longer (how can this possibly be true?). Let's hope that Akasofu isn't correct else we're probably in a lot more trouble than we think we are! (iii) Of course we probably don't believe Akasofu's ad hoc-ery if we think about it for a bit. Looking at the temperature record (reconstructions and direct measurements from the mid 19th century) indicates that "recovery" from the LIA was largely complete by the early 19th century. (iv) I suppose the other problem inherent in ad hoc-ery is that the ad hoc decision to project the "Braun et al" cycle into the Holocene (where Braun et al state it doesn't apply) seems entirely incompatible with Akasofu's ad hoc construction. Akasofu's sketch doesn't show any of these supposed 1500 year cycles? And while according to Akasofu, we should be already heading into a cooling phase which will continue for another 20-odd years, according to the 1500 year cycle idea we should still be on a rather relentless warming "curve" that should continue for another 300 or more years... (v) Is there a good reason for rejecting everything we know about the climate system, and basing our ideas on mutually incompatible ad hoc notions? I can't think of one! -
Doug Bostrom at 08:49 AM on 15 August 2010Why I care about climate change
GC, you're speaking of net benefit, aggregate so to speak?Moderator Response: Great discussion to take into detail on the thread It’s Not Bad (Positives and Negatives of Global Warming). -
gallopingcamel at 08:46 AM on 15 August 2010Why I care about climate change
scaddenp (#140), Good question---"What would convince me that AGW is real?" Actually, I am already convinced but as I have said several times on this blog, I see it as a small beneficial effect rather than a problem (see #111 in this thread for example). You are probably right to suggest that next year will be cooler. The ENSO and PDO cycles will drive temperatures down for a while but in 20 to 30 years the trend will be up again. That is what I think of as Mother Nature revealing herself. Adding another 20+ years to the existing ~37 years of satellite data will greatly improve our ability to critique predictions by the IPCC and others. -
Doug Bostrom at 06:15 AM on 15 August 2010Has Global Warming Stopped?
Presuming for a moment Akasofu were right, I'm sure I'm not the only one to point out that what we're doing to the atmosphere will be added to whatever Akasofu's model might predict, which in turn is paltry in comparison to the GHG effect. So ~0.015 degrees C warming per decade per Akasofu will be added to the observed ~0.13 degrees per decade per anthropogenic forcing. Of what relevance is Akasofu's work right or wrong? Much? Little? -
fydijkstra at 05:48 AM on 15 August 2010Has Global Warming Stopped?
Dikran (#65) your 5th remark: “but it is super-imposed on a linear function of time, so it too goes on to infinity.” Yes, the oscillation in Akasofu’s model is super-imposed on a linear trend. We don’t know how long this trend will continue. Not to infinity of course, because nothing in the climate goes on to infinity. We can look at Roy Spencers reconstruction of 2000 years of global temperatures. I gave the link in my previous posting, but here is the graph.
“it would be interesting to see the error bars on your flattening model. I suspect there are not enough observations to greatly constrain the behaviour of the model beyond the calibration period, in which case the model [is] not giving useful predictions.”
It is not possible to calculate error bars with only 10 points on a flattening curve. I used this flattening function only to show, that the data fit better to a flattening curve than to a straight line. This is only about the data onto the present, it is not a prediction. When it is said that ‘global warming has stopped’ this is only about the data onto the present. Nobody denies that it is possible that global warming will resume.
SNRatio (#69): “The simple Akasofu formula "anomaly = LIA recovery + MDO" predicts falling temperatures now - and therefore I wonder if it is not already partly falsified.”
No, the Akasofu model does not exactly predict the year when the falling temperatures should continue. Moreover, just as with the model of ever rising temperatures, there is noise in the data. Akasofu’s model perfectly fits with the data so far.
“The trend also seems rather speculative: What is the physical basis for this continuing "LIA recovery" in the 21st century?” See my above given reply to Dikran.
Moderator Response: See the Skeptical Science posts are "We’re coming out of the Little Ice Age" and "Climate’s changed before." -
Doug Bostrom at 05:06 AM on 15 August 2010NASA-GISS: July 2010-- What global warming looks like
I should add, Eric, that if you want to get calibrated against the level of effort required to mount a useful discussion here, look for examples by Berényi Péter. Péter puts a serious amount of hard work into teasing out quibbles he has with climatology. Meet or exceed the metric Péter provides when it comes to showing how a substantive argument against expert knowledge can be attempted and you're doing ok. Again, "I doubt it" is not an argument. -
Doug Bostrom at 04:53 AM on 15 August 2010NASA-GISS: July 2010-- What global warming looks like
Eric, you're hypothesizing about Meehl's paper without doing any work to support your hypothesis. "I appeal to myself as an authority, take my word for it." Not persuasive. Rumor has it that Meehl replies to polite inquiries. Why not ask a real expert? As to record high minimums clearly you can type, you've got an Internet connection, you're capable of performing your own literature search. You'd nonetheless like to send somebody (me, for instance) beavering away to produce some references for you thereby supplying you with fresh opportunities for making lazy assertions. Forget it; I did a good faith effort for you once, not again on this topic. Do your own work. -
witsendnj at 03:15 AM on 15 August 20103 levels of cherry picking in a single argument
#34, I agree. David #3 wonders if the problem with deniers is they can't read charts. Probably they can't - but they can read tea leaves, and they tell what most scientists won't say outright - fixing this problem (it's no longer fixable) would have required radical sacrifice in lifestyle on the part of every citizen of developed countries, and a universal one-child (or less) policy. The scientists and climate change activists who promise that we can convert to clean energy and restore the economy without giving up our fuel-gobbling toys are making a huge mistake. The deniers know instinctively that isn't true. You don't need charts or graphs to see where how this movie is going to end. Scientists should stop pussyfooting around and demand that fuel be rationed on a per-person basis, and restricted to only the most essential purposes until it is replaced with sustainable sources for electricity. Don't you have kids too? -
muoncounter at 01:36 AM on 15 August 2010Extreme weather isn't caused by global warming
#2: Something the Bush admin said in 2008 seems to be correct? "As options dwindle for negotiating a global pact to fight climate change, the United Nations is pointing to today's "extreme conditions." "As global temperature records have been set for the early summer months, states and cities are also setting hundreds of temperature records. ... Unfortunately, climate models indicate that an average summer in 2050 will have even more days topping 90°F if global warming continues unabated." -
muoncounter at 01:16 AM on 15 August 2010Increasing CO2 has little to no effect
That good friend of AGW, Dr. Roy Spencer, has empirical evidence for the greenhouse effect. "Particularly difficult to grasp is the concept of adding a greenhouse gas to a COLD atmosphere, and that causing a temperature increase at the surface of the Earth, which is already WARM. This, of course, is what is expected to happen from adding more carbon dioixde to the atmosphere: “global warming”. ... This [Spencer's experiment] shows that the addition of an IR absorber/emitter, even at a cold temperature (the middle level clouds were probably somewhere around 30 deg. F), causes a warm object (the thermopile [in his IR thermometer]) to warm even more! This is the effect that some people claim is impossible. -
lgilman909 at 23:51 PM on 14 August 20103 levels of cherry picking in a single argument
Scaddenp writes (first comment), apropos of why there is so much climate denial, "There must be a lot of people with shares in fossil fuel industry." We _all_ have shares in the fossil fuel industry. Not necessarily stock, but a frightening, radical dependency. Coal and oil feed us, light us, clothe us, entertain us, truck and ship all our crap and necessities around the planet, move us back and forth to our jobs and vacations, build our homes -- keep the whole industrial circus from collapsing into apocalyptic chaos and mass death. Denialism's reassurance that all is basically well, that all will continue to be well, that we can all continue to do our familiar things and burn our familiar fuels and live our familiar way and be safe forever, that there is nothing fundamentally, fearfully wrong with the planet or with our dream of technology-driven prosperity and progress . . . it's very tempting. -
muoncounter at 23:34 PM on 14 August 2010Why I care about climate change
#139: "When a student finds something in a science text book that makes no sense he asks his teacher for an explanation." These days, students go to the interwebs (and each other) well before asking their teachers. That's why 'science' via echo-chamber-blogosphere is so dangerous and why your next statement so important. "I hope we can agree that widespread scientific illiteracy is dangerous when our survival depends on sophisticated technology. " Amen to that. Illiteracy is dangerous in all forms, but scientific illiteracy is like not knowing which is the business end of a loaded gun. -
RSVP at 22:51 PM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
michael sweet The average temperature on the Moon is fairly meaningless in this context given temperature swings that take minutes relative to daylight and night hours on Moon that last roughly 300 hours. Please check the curves here and see temperature transitions... in evacuated tubes... on the Earth. http://en.wikipedia.org/wiki/Solar_thermal_collectorModerator Response: Your comments on this topic belong on the thread CO2 effect is weak. -
Eric (skeptic) at 22:33 PM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
Doug, am I not going to get any links about studies of the effect of urbanization on record high minimums? If not, why not? I can obviously see why higher *average* minimums might be interesting to some, and the Easterling links are convincing enough. But this thread is about records, not averages. Am I not going to get an answer to why Meehl did not have any discussion of urbanization in producing his chart in the head post, even just a sentence referring to Weber? It would not be directly relevant since Weber studied the effect of urbanization on a city by city basis with all of his available data (no selection bias), but at least it would be something. Appeals to authority only work if the authority has shown some thoroughness, otherwise you need a new authority. -
Garrett at 18:43 PM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
miekol at 17:35 PM on 14 August, 2010 I'm getting a distinct feeling this is not a science site. Its as its title says,"skeptical about global warming skepticism," This is a science site. When you have any concpt of science maybe you will be taken seriously. Until then, whatever. -
miekol at 17:35 PM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
I'm getting a distinct feeling this is not a science site. Its as its title says,"skeptical about global warming skepticism," and unless one is pro GWers its pointless posting because any negative posts to pro warming get deleted. [further thoughts off-topic for this thread deleted]Moderator Response: To the contrary, Skeptical Science deals with a multitude of arguments and as long as they do not degrade into insults, accusations of dishonesty, hypotheses of general corruption of the entire scientific community or the like they are allowed to follow their natural course. However, in the interest of encouraging useful conversation, Skeptical Science does not entertain bundled collections of misconceptions but instead deals with each misconception individually. By using the "Search" function at upper left, you will most likely be able to find a suitable location to take your concerns. More information on expectations for comments may be found at the Comments Policy page. -
Garrett at 17:03 PM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
I don't mind my comments being removed by moderators, and I was right-on-target wiuth mine. And I am on "your side" whatever that may be. But. If you are going to remove my post at least have the courtesy to send me an email which I use to register with your site so I b) know what it is I said that offended your moderator. I know what am talking about and I ave te shingle to prove it.Moderator Response: We apologize for any unintended offense. It may be that your comment was one of several diverging into a discussion of the role of C02 as a GHG which were removed after the pointer to Miekol upthread. If you feel your comment was removed in error please feel free to post it again. -
Doug Bostrom at 15:45 PM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
Interesting perspective there, Eric. The Weber paper was about the Alps in Europe, found minimum and maximum temperatures to be increasing at both low-lying stations in Central Europe as well as mountain tops. The mountain tops of the European Alps are not urbanized and of course are quite distant from Washington, D.C. which although a sprawl has not yet grown across the Atlantic. As to Meehl, can you show that the change in ratio is due to urbanization? Remember, when you convey the impression you know better than experts on a given topic, you incur a sort of debt against your credibility. You can't just create an argument out of thin air by implying you're more expert than Meehl and his coauthors, you have to show how, specifically by improving his results. That's how you pay for credibility, by doing the work necessary to back up assertions. Not an assertion? Simple doubt is not an argument. -
Eric (skeptic) at 13:55 PM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
Doug, thanks for the links. The Weber paper (last link) confirms what one forecaster alluded to here in DC in a July forecast discussion (actually the Sterling VA office) which was that the record high minimums are affected by urbanization in DC. The Weber paper says there is little effect on record high maximums. I see the Meehl paper used 1800 stations out of 11,000 or so. There's no discussion of that possible urban bias in the paper for station selection. As with the record high mins, an increasingly urbanized area is also less likely to reach new record low mins. RBW, for the record I am referring to urbanization (the process), not urban versus rural (static). Records, unlike averages, cannot be homogenized. -
scaddenp at 13:41 PM on 14 August 2010Why I care about climate change
"I guess we will continue locking horns until Mother Nature reveals herself. I suspect we will not have to wait much longer." Hmm, could I be hopeful in reading this, or do you actually mean that you believe that suddenly AGW is going to get away and are expecting a down trend any day? Well I can predict with considerable confidence that next year will be cooler than this year. However, the interest will be comparing temperature with previous La Nina's of same magnitude. Not the start of the cooling trend - El Nino will return. GC - can you tell us what data would finally convince you that AGW is real? 10 year from now and warming continues apace, will you still be finding reasons why its not largely due to us? With so many predictions from AGW it is easy to see what data would could me and others to rethink our position. What would it take from you? -
The Skeptical Chymist at 11:28 AM on 14 August 2010On Statistical Significance and Confidence
Barry @46 Don't stop asking questions, even if you think they are naive, that's how we learn. Looking at your question, if you are saying the graph suggests the rate of warming in each decade is increasing I think you are over-interpreting the results. But I do think the results suggest that the climate has continued to warm each decade for the last 30 years. There were several decades last century when (due to aerosol buildup) the climate didn't warm. Therefore, adding recent decades where warming occurred will increase the proportion of decades showing warming and increase the century trend. I think this result would occur even if the most recent decade had warmed at the same or a slower rate as past decades. At the same time, the fact that the trend keeps increasing when you add in the most recent decade does show that warming continues. -
muoncounter at 11:25 AM on 14 August 2010Has Global Warming Stopped?
Any thought that warming 'stopped' should be quashed by the July RSS temperatures.
This graph shows global (-70 thru 82.5 lat) temperature anomalies. I've calculated an average for Jan-Feb-Mar and one for Jun-July-Aug, setting the times for each average accordingly. The dreaded straight line trend is the same for both, representing 0.17 degC/decade. I like the seasonal averages: nobody remembers what the average temperature was for a given year, but we sure do take note of the extreme summers and winters. Despite the three cold winters ('85,'89,'93) and corresponding mild summers (one cooled by Mt. Pinatubo), its inconceivable that anyone looking at this graph could not see the upward trend.
Yeah, its a short time frame (although 30 years is, by most accounts, a generation). So the predictable next step is to condemn all satellite data, as discussed in #67-68 above.
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miekol at 11:18 AM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
Even though Mars’ atmosphere is 97% CO2, there is no runaway greenhouse effect on that cold planet. But there should be if the proposition of high levels of CO2 can cause a runaway greenhouse effect. It doesn’t so how could Earth’s 0.038% CO2 cause such an effect?Moderator Response: Miekol please note the link above directing you to a suitable thread for discussing the potential effects of C02 on atmospheric temperature. Better yet, here it is: How do we know more CO2 is causing warming? Thanks! -
kdkd at 11:03 AM on 14 August 2010On Statistical Significance and Confidence
Dikran #57 is correct - there are procedures to correct the number of degrees of freedom (and thus cause a corresponding loss of power) when you think there's something up with the normality of a distribution. This can cause less power loss than the use of a non-parametric statistic, so can be desirable. There are also statistical tests available which can tell you if a non-normality correction is justifiable. In the case of the two charts that BP has posted in this thread, I can pretty much guarantee by eye (from a decade or so of experience) that you'd just be losing power for the sake of it if you insisted on correcting their linear model statistics for non-normality. Generally the linear model stats are pretty robust to moderate deviations from normality, so no need to throw the baby out with the bathwater, unless the p value based diagnostics tell you otherwise. -
Doug Bostrom at 11:00 AM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
Actually Miekol there are not two sides to every debate, in fact some things are effectively beyond debate and to take some positions may be something adults do but will yield no improvement in understanding. Regarding the effect of C02 as a trace gas, here's where to go with that: How do we know more CO2 is causing warming? -
CBW at 10:58 AM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
What's kinda funny is that the denialists who are citing the UHI effect don't seem to know what it is. Hint: it isn't the fact that the middle of a big city is warmer than the nearby rural areas. That's a pretty well-established, well-understood phenomenon that no scientist disputes. RSVP: Thermal inertia can be viewed as the rate of change in the temperature of a system as a function of the rate of heat input. Compare the heat capacity of the planet's oceans to the current planetary energy imbalance. One is a big number, the other is quite a bit smaller. fydijkstra: 12 months isn't irrelevant for a running average, it's the length of time that will average out the seasonal variations. 11 years is useful, too, as it will tend to average out the solar cycle. Somewhere in the 5 to 7 year range is useful, too, since it will average out the ENSO cycle. Also, since we're talking about GISS measurements, 2005 was the warmest year, not 1998. 2009 and 2007 were both slightly warmer than 1998 and 2002, but the four years are probably statistically tied for second-warmest. You must think it a remarkable coincidence that all five of those years came in the last 11 of a 130 year history, and that the 9 warmest years on record came within the last 11 years. -
miekol at 10:54 AM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
Its called being adult and having an adult conversation David. And doug, I've not said "I disagree." There's two sides to every debate. I enjoy trying to understand the world around me. I find it difficult to accept that its man made CO2 that is the cause of climate change. Do you know that in every 85,800 molecules of dry air only 33 are CO2. And of those only 33 is man made. That's one in 85,000. If you include water vapour its even less. http://en.wikipedia.org/wiki/Atmosphere_of_Earth#Composition How is it possible a one in 85,800 atmospheric molecules can be the cause of climate change? -
Doug Bostrom at 10:44 AM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
Miekol it's worth stopping and considering (honestly-- step back, calm down, think about it) that your opinion w/regard to our ability to perform useful measurements on the behavior and direction of our climate is quite divorced from what our best experts tell us. "I disagree" is not an argument, not a means of improving our understanding. "I disagree and here's how, specifically, coherently and constructively" using means and methods specific to the case in consideration is a better approach as well as actually being a complete attempt at argument. Ideology or politics really have nothing to useful to say about what the physical world of instrumentation tells us. -
michael sweet at 10:33 AM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
David Horton: It is striking to see posts like Miekol's right after yours. There are several people like him/her posting on Skeptical Science right now. How can you reply to a post like that? -
michael sweet at 10:28 AM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
Miekol: Is the ice core data for 400,000 years a long enough record for you? Or do you insist we wait for 5,000 years to get direct temperature measurements? These data show that current warming is not natural and can cause serious problems. Your last post is too extreme for me to reply to. You need to read less denial websites and become familiar with the science. This web site has a lot of good information for the novice.Moderator Response: Miekol's last post was moderated out because it was off-topic and primarily ideological/political. Please try to stay on topic. -
Doug Bostrom at 10:27 AM on 14 August 2010More evidence than you can shake a hockey stick at
JohnD, water vapor can store heat in both latent and sensible forms. Latent heat is not what's measured w/a thermometer. What's the capacity for sensible heat of water vapor in comparison w/the rest of the gases in the atmosphere? Water vapor in our temperature realm has a specific heat capacity of ~1.8kJ/kg K versus dry air at ~1.0 kJ/kg K. The mean mass of water vapor in the atmosphere is something like 1.27 × 10^16 kg, the dry air mass 5.13 × 10^18 kg. We don't need to work the arithmetic to see that water vapor is not the dominant reservoir of sensible heat in the atmosphere. -
Esop at 10:14 AM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
#42: better tell that to the vast number of "skeptics" who declared that temps would continue to decline and that we were rapidly headed for a Maunder Minimum when the global average temps had a slight La Nina induced drop in 2008. Looking at the 2009 and 2010 data, it seems that their prediction didn't quite come true. -
miekol at 10:06 AM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
A period that spans only five decades is nowhere near long enough when it comes to the study of planet climate. As the writer says, "we're looking at a system with enormous inertia and so climate shifts will generally show up as incremental creep over a long period of time." Even centuries will not encompass the BIG PICTURE. A minimum would be five millennium. -
johnd at 09:57 AM on 14 August 2010More evidence than you can shake a hockey stick at
doug_bostrom at 09:18 AM, doug, I take it then that you do not accept that the atmosphere could be warmer because of the increase in heat content bought about by an increase in water vapour. What carries the heat content that determines the measured temperature of the atmosphere if not primarily water vapour? -
muoncounter at 09:36 AM on 14 August 2010NASA-GISS: July 2010-- What global warming looks like
#32: "In Deniaworld it seems there is no measurement, no series of measurements; no extreme unprecedented weather event, no series of such events; no series of different extreme events in different regions; ... there is nothing, literally nothing that can't be arbitrarily dismissed," You're forgetting the two weather events that Deniaworld uses to set its clocks: the 1998 high temps (hence no warming since then) and the 2007 min ice extent (hence the Arctic hasn't melted at all since then). When you stake your position on only those facts you want, life is sweet. And hence all others must be wrong. -
Doug Bostrom at 09:31 AM on 14 August 2010Of satellites and temperatures
BP, sounds like a literature search is in order. I see something like 11,000 hits on Google Scholar using the term "derivation atmospheric temperature microwave sounding." Adding "calibration" winnows the list down to about 5,000 hits. For sure some duplicates and ringers I'll bet, but somebody appears to be on the case.
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