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Berényi Péter at 08:36 AM on 21 September 2010The significance of past climate change
Posted by John Cook on Wednesday, 21 April, 2010 at 19:56 PM Climate changes when it’s forced to change. When our planet suffers an energy imbalance and gains or loses heat, global temperature changes. You mean surface temperature, of course. However, surface temperature depends not only on the heat content of the climate system (atmosphere+hydrosphere+soil), but also on surface pressure (via lapse rate). If surface temperature is increased by 1%, surface temperature goes up by 0.5°C. Therefore while it is true a positive energy imbalance implies surface warming, it does not work in the reverse direction. You can have warming with no net heat energy gain, just by increasing pressure. It has no direct consequences on our present situation, for the volume of atmosphere is pretty stable on historic timescales. However, on geologic timescales the situation is radically different. In the late Carboniferous - early Permian atmospheric oxygen level is assumed to be much higher than today, perhaps as high as 35% per volume. If N2 partial pressure is held constant (at 0.754 atm), it implies an overall atmospheric pressure 24% higher than today. This pressure increase alone would make surface temperatures some 12°C higher. Of course according to the Standard Solar Model luminosity of the Sun was 2-3% lower 300 million years ago than it is today. But it would make surface temperatures only 2°C cooler at most. On the other hand we do know surface temperatures in that epoch were about the same as they are today (with slightly more CO2 in the atmosphere).
We have 10°C unexplained lack of warming here (and a permanent polar ice cap). That's more than we asked for.
The only way out is to assume surface pressure was also about the same as it is today. However, in this case N2 partial pressure must have been about 20% lower than its present value.
As average residence time of N2 in the atmosphere is ~20 million years (due to biological nitrogen fixation) and there is about sixty times more Nitrogen in the crust than in air, it seems to be entirely possible, especially because sequestration of organic detritus was particularly intense in those times.
However, if N2 partial pressure can vary on a multi-million year timescale, we should be extremely cautious in interpreting the paleoclimate record, for as far as I know, there is no reliable reconstruction in the literature of past atmospheric pressure changes so far.
The upshot is that it is rather difficult (or should we say impossible?) to derive climate sensitivity from paleoclimate data while one of the major ingredients is indeterminate. Understanding the nitrogen cycle should be given high priority.
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Rob Honeycutt at 08:34 AM on 21 September 2010The contradictory nature of global warming skepticism
pbjamm.... Science journalist Peter Hadfield (aka PotHoler54) does a really good job of explaining it here. In fact, he has a series of videos on climate change that is really good. Highly recommended. -
Sense Seeker at 08:30 AM on 21 September 2010A detailed look at Hansen's 1988 projections
A night's sleep does help. I can see what you were trying to do. You are comparing the inputs of Hansen's scenario B (translated into forcings) and the actual changes in the input variables (as 'observed' forcings), and then compare Hansen's output (= projected temperatures) with the real output (= realised temperatures). From that you conclude that Hansen's model was 24% too sensitive. It is a pity that the detour via forcings is there, but I guess that is the best way to summarise all different emissions? (I cannot judge that.) You could consider explaining why the translation into forcings is necessary and justified; it was not obvious to me when I first read it. To guide the reader, you could also consider indicating somewhere in the beginning of your explanation what you are going to do, in broad terms. (Determine difference in input values (GHGs) and compare to differences in output (temp) between Hansen's model and reality.) PS: typo "global surface temperature (dF)" should be (dT)? -
Spaceman Spiff at 08:21 AM on 21 September 2010Global warming and the unstoppable 1500 year cycle
@thingadonta: You've just commented on a website dedicated to countering with scientific evidence 121 largely disparate, mostly contradictory, and definitely not unified "arguments" placed against climate science ( http://www.skepticalscience.com/argument.php ) -- often made by the same people. The contrast between that situation and the one found in the present state of climate science that unifies wide-ranging physical phenomena and finds multiply converging lines of evidence is utterly striking. If there is any confusion concerning the state of "skeptical arguments", it's certainly not John Cook's fault. -
hadfield at 08:05 AM on 21 September 2010A South American hockey stick
John, can you correct the mis-spelling of Moberg's name in the article, please.Response: Fixed. You'd think I'd have noticed the correct spelling in the graph :-( -
archiesteel at 08:00 AM on 21 September 2010The contradictory nature of global warming skepticism
@Baz: " I have said before that I display confirmation bias (a perfectly human trait)" So, you recognized you are biased, but will not try to correct that bias? And you wonder why we don't take you seriously? It's human to be biased, but it's rather stupid to continue being in the wrong once your errors have been pointed out to you. -
scaddenp at 07:50 AM on 21 September 2010The contradictory nature of global warming skepticism
"KR. I didn't agree with the 20-30 period at all, I accepted that's what the general consensus of opinion is on this site." Umm, but the 20-30 year period is determined objectively from the statistical study of internal variability. I notice that you have given links to this long ago. The point of doing such studies is to have an objective basis for that "consensus opinion". Can you think of a better way? -
CoalGeologist at 07:36 AM on 21 September 2010The contradictory nature of global warming skepticism
@Baz #314 You have stated:"KR. I didn't agree with the 20-30 period at all, I accepted that's what the general consensus of opinion is on this site. I have said before that I display confirmation bias (a perfectly human trait), but I'm in good company here."
Will you also accept that the reason this is the general consensus on this site is because this is how the term "climate" is defined within the scientific community? Specifically, here is the definition of climate from the AR4 Synthesis Report Glossary:Climate "Climate in a narrow sense is usually defined as the average weather, or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. The classical period for averaging these variables is 30 years, as defined by the World Meteorological Organization. The relevant quantities are most often surface variables such as temperature, precipitation and wind. Climate in a wider sense is the state, including a statistical description, of the climate system. In various parts of this report different averaging periods, such as a period of 20 years, are also used.
Scientific dialog is most meaningful when participants are using well-established terminology in a consistent manner. There may be other web sites that would be more amenable to your redefining established terminology to suit your argument. Confirmation bias may be a perfectly human trait, but it is poison to scientific reasoning. I don't know to what degree any other bloggers at this site might be guilty of this offense, but if you, personally, are guilty of it AND aware of it, then you relinquish any credibility to valid scientific reasoning. This site is supposed to be about scientific evidence, not to validating preconceived conclusions. -
scaddenp at 07:14 AM on 21 September 2010The contradictory nature of global warming skepticism
Baz, why dont you look at individual model runs? - (predictions for climate are made from average of many runs because it isnt possible to accurately initialise models and the internal variation in models is highly dependent on initialization). An individual run shows you an example of what normal climate physics will produce on a year by year basis. And surprise, you have periods of cooling, slow warming - and rapid warming, but giving 30 year trends. Nothing that contradicts model going on. -
Skepticalenergyguy at 07:02 AM on 21 September 2010Human CO2 is a tiny % of CO2 emissions
I agree that we need to be more environmentally responsible, no I'm not an industrialist, I am an engineer. My job is to reduce energy usage for my clients, increase energy awareness, promote environmental stewadardship, and develop creative ways for my clients to do all of these things economically. Thank you all for your input, it gives me stuff to think about. -
Daniel Bailey at 06:58 AM on 21 September 2010The contradictory nature of global warming skepticism
Re: pbjamm (317) I, too, came to his defense to allow him more time to make his case. As you state, I believe he has now made it. I would, however, make the point that most skeptics do not necessarily disagree with the scientific method or even some of the basic tenets of global warming or the greenhouse gas effects; they usually differ in terms of interpretation of various niggling points. There is a different term for those who make an unscientific case for their position. But thank you for taking the time to make your voice heard here. New voices, and the different perspectives they offer, are always welcome. The Yooper -
muoncounter at 06:57 AM on 21 September 2010Video update on Arctic sea ice in 2010
CBD: Clearly, this is more evidence of how warming has stopped (or is flat or is taking a few years off) or whatever. :) At least some people are taking things seriously. "Russia has no plans to deploy troops in the Arctic. We want to strengthen Russia's means of securing maritime security in the region," the Russian Foreign Ministry's Arctic representative Anton Vasilev said at the press conference. -
pbjamm at 06:50 AM on 21 September 2010The contradictory nature of global warming skepticism
re: Rob Honeycutt (315,310,etc) Thank you for making the math of this clear. I am neither a statistician nor mathematician so the notion of what constituted "statistical significance" was never completely clear to me until reading your last few posts. re: Daniel Bailey (316) I was one of the first to come to the defense of Baz but after reading this ENTIRE thread I am having a hard time believing that he is a genuine skeptic. It has become tiresome rehashing the same points over and over. Despite that I feel I have learned a great deal in the course of the discussion so I thank all who contributed. -pbjamm -
Daniel Bailey at 06:45 AM on 21 September 2010Should The Earth Be Cooling?
Re: Ken Lambert (63) Dude, I have to offer up a concession. You usually DO have sources to back up your contentions, unlike others who post here with only opinion for a wingman. I was reminded of this a bit ago when Baz said you were wrong. As his accuracy meter has flat-lined, it was actually a testimony on your behalf! Anyway, where were we? Oh, yeah. In your post #56 above, you focus on a statistically insignificant period of time (i.e., too short of a time period to base any scientific supposition on) and also refer to: "SLR flattening by nearly all analyses". Those were the two points I objected to. If you want to make the statement that it is your "opinion" that there is a "flattening" of temperatures in such a short period of time as you reference, then fine. Baz will make room for you. SLR is what it is. If you wish to contend with The University of Colorado, then go for it. There are various areas in which you have demonstrated a clear understanding of the subject at hand in your various comments I've read on Skeptical Science. I wish there was a way to get around the disconnect on these two items I objected to in my original comment. You are clearly an intelligent person, so I hope that at some point we can work to figure it out. Oh, one other thing. Upon re-reading my comment at 58 above, it comes across a little more strident than I meant it to. I apologize for that tone. I was a little worked-up still from sorting things out with a, um, different commenter; I will try to be more even in tone in the future. The Yooper -
Daniel Bailey at 06:03 AM on 21 September 2010The contradictory nature of global warming skepticism
Re: Baz (305) It is truly difficult to take you seriously anymore. Your contention that Phil Jones introduced the period 1995 to the present is contradicted by your source. Here's Harrabin's questions to Jones:"A - Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical? B - Do you agree that from 1995 to the present there has been no statistically-significant global warming C - Do you agree that from January 2002 to the present there has been statistically significant global cooling? D - Do you agree that natural influences could have contributed significantly to the global warming observed from 1975-1998, and, if so, please could you specify each natural influence and express its radiative forcing over the period in Watts per square metre."
Nowhere in his response to question A does Jones introduce the period 1995 to the present. Therefore, it is Harrabin who introduces your period in question into the interview, not Jones as you contend. This has become completely tiresome. I leave it to the reader to decide if you have said anything germane or of value at any point. At the very least, it is to be hoped that someone, somewhere, has picked up something of value from this exchange. The Yooper -
Rob Honeycutt at 05:56 AM on 21 September 2010The contradictory nature of global warming skepticism
Baz... Yes, that is exactly right. Given the general noise in climate you need 20 to 30 years of data to rise above a 95% confidence level. 1995 to 2009 falls just short of statistical significance, not because of the 0.12C figure, but because it's only 14 years. That's why the question was framed with that specific time frame. That does not mean that there has been any statistically significant warming or cooling (or flattening) in the past 10 years. It can't yet be reliably distinguished from the noise. This was my point. You call out the warming of 1995 to 2009 as not being statistically significant but at the same time you're telling us that the last 10 years are showing us that global warming has stalled or stopped. In this case you can't have your cake and eat it too. -
The contradictory nature of global warming skepticism
Rob, actually he said, "Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods." KR. I didn't agree with the 20-30 period at all, I accepted that's what the general consensus of opinion is on this site. I have said before that I display confirmation bias (a perfectly human trait), but I'm in good company here. CBD. Genuine thanks for all your input. If I wanted to be like some on here are to me, I'd have to say you cherry-picked those time-frames to start from the Little Ice Age ending. But of course, I'd never do that! http://www.co2science.org/articles/V12/N10/EDIT.php Ooh, I bet some here are going to love that link! JMurphy. See graph at terrible website link above. Thanks all. I think I'll conclude my contributions here. However, I'm afraid I will be back. :) -
Climate change: Water vapor makes for a wet argument
johnd - IR is more dominant as an energy pathway than latent heat (evaporation/condensation). Latent heat moves 80 W/m^2 into the atmosphere, while IR moves 356 W/m^2 into the atmosphere (Trenberth 2009). Atmospheric emissions of IR to space are 169 W/m^2, with an estimated 30 W/m^2 from clouds. Evaporation is not the dominant energy pathway, not by a factor of 4. Your statements contradict the actual measurements. -
CBDunkerson at 03:57 AM on 21 September 2010Video update on Arctic sea ice in 2010
Some interesting developments the past few days. First, what the NSIDC thought was the end of the melt season after 9/10 turned out to just be a 5 day bump. Since then extent has begun declining again and is now below the 9/10 'minimum' and just a hair's breadth above the 2008 low extent. If it drops any further it will tie 2008 for the 2nd lowest result after 2007. Second, PIOMAS just updated their anomaly graph thru 9/14 and shows an anomaly of about -9,500 km^3. Subtracting that from the 13,400 km^3 September baseline would yield 3,900 km^3. However, that baseline value is a monthly average while the anomaly is a daily value and 9/14 is likely close to the minimum for the month. Thus, when the 2010 monthly average is computed it will probably be around 4,000 km^3... still FAR below the previous record low of 5,800 km^3 set in 2009. I did some math based on various statistics they cite on the main page (e.g. "September Ice Volume was lowest in 2009 at 5,800 km^3 or 67% below its 1979 maximum") and came up with some stats on ice loss rates; Max (1979): 17,600 km^3 Mean: 13,400 km^3 Min (2010): 4,000 km^3 Rate: -425 km^3 per year Given that long term rate the ice would be gone in September in 10 years. If the rate over the past decade (~-1000 km^3 per year) continued it'd be four years. If the rate continued to increase as it has been it's just two years. So, I'm calling 2016 +/- 4 years for the Arctic sea ice to be gone except for a few bits and pieces. If the long term trends continued then there'd be no ice even in APRIL (the maximum extent) in about 50 years. -
JMurphy at 03:49 AM on 21 September 2010The contradictory nature of global warming skepticism
CBDunkerson wrote : "If you look at the graph you can pretty easily come up with alternating periods of about 30 years each with 'increasing' and 'decreasing' temperatures; 1850-1880: increasing +0.1 C 1880-1910: decreasing -0.25 C 1910-1940: increasing +0.5 C 1940-1970: decreasing -0.1 C 1970-2000: increasing +0.5 C 2000-2010+: 'flat'" Actually, and without trying to be sarcastic and belittling, we can use the 'Baz' scale to determine the reaction to each of those trends, just by using the sort of logic Baz has used to assert that he no longer believes the earth is warming : 1850-1880: increasing +0.1 C ("Hm, looks like AGW is real") 1880-1910: decreasing -0.25 C ("Hang on, it's not warming !") 1910-1940: increasing +0.5 C ("OK, it is happening. I'm a 'believer'") 1940-1970: decreasing -0.1 C ("Wait a minute, it's not warming...again") 1970-2000: increasing +0.5 C (Oh, perhaps it is. I'll give it another 5 years") 2000-2010+: 'flat' ("Ah ha - it's not warming. Prove it, using a 5 to 10 year trend !) -
CBDunkerson at 03:04 AM on 21 September 2010The contradictory nature of global warming skepticism
CBD #309: "The reason I didn't choose 1940 to 1950 is because the first period of warming was entirely natural!" Not precisely accurate. MOSTLY natural yes, but not "entirely" natural. Most of the 1910 to 1940 warming was due to increased solar activity, but the enhanced greenhouse effect was also starting to have an impact during that timeframe. I like to turn the 'natural cycles' bit back on the 'skeptics'. If you look at the graph you can pretty easily come up with alternating periods of about 30 years each with 'increasing' and 'decreasing' temperatures; 1850-1880: increasing +0.1 C 1880-1910: decreasing -0.25 C 1910-1940: increasing +0.5 C 1940-1970: decreasing -0.1 C 1970-2000: increasing +0.5 C 2000-2010+: 'flat' From this, it seems like the 'increasing' periods are showing more warming over time while the 'decreasing' periods are showing less cooling... or in the current cycle NO cooling. Which is the sort of pattern you would see if an accelerating warming trend were overlaid onto a regular oscillation. The temperature varies up and down due to a lot of different factors. If the 1910 to 1940 warming had ONLY been solar forcing then temperatures should have dropped back down to the prior level when solar activity declined... they didn't. That 1940 to 1970 period also had alot of aerosol pollution that is believed to have contributed to the cooling. Sorting out all the factors and how much of an impact they've had is a complicated mess... but if we were only dealing with various natural oscillations overlaying each other the long term average would be flat. Instead, it shows pronounced warming. If we ignore the underlying science you are correct... no one can say from the graph alone whether this is a brief fluctuation like others in the past which will be followed by a return to warming OR if we have now hit a peak and temperatures will begin to go back down. But we don't have JUST the graph alone to base our decisions on. We know from direct satellite measurements that there is currently an energy imbalance with more energy coming in to the climate system than is going out. We know that wavelengths of IR blocked by greenhouse gases are being measured in increasing concentrations at the surface and decreasing amounts in space. We know that long settled (~140 years) physics tells us that the increasing CO2 levels we are measuring will produce continued warming. In short, we know for a fact that the total climate system of the planet is continuing to accumulate heat. It has been settled unquestioned science for over a century and we are getting direct measurements of it happening. The fact that the SURFACE AIR TEMPERATURE hasn't reflected that ongoing accumulation much for the past decade is something we call 'weather'. The historical record shows that such fluctuations happen all the time. Right now the heat mostly isn't in the lower atmosphere (though the poles are an obvious exception)... but we KNOW it is still accumulating and thus it is inevitable that it will eventually impact surface air temperatures. -
The contradictory nature of global warming skepticism
Baz - you have been continuing to claim that 10 years of data is enough for you to conclude that warming has stopped. Given the noise in the data, seasonal variations, the Pacific oscillation, etc., 10 years provides very little statistical significance. You agreed with the 20-30 year range earlier in this thread; what happened to that agreement? Essentially you are arguing that the 10 years you have focused on (low statistical significance, very little support for anything but short term noise variations, still within the 2 sigma variations around the previously established trend) is more relevant than the 30 year, highly statistically significant (99.9999 confidence? Way less than a fraction of a percent chance that it's not warming, and we've just picked up noise?) record of a warming trend. That argument really doesn't hold up, Baz. At all. I suspect you're suffering from confirmatory bias. If we don't see warming over 20-30 years, then we'll have strong support for the trend to have stopped or paused. That just hasn't happened yet. What you're looking at is equivalent to a a few cool days in early June (weather) - and from those claiming that summer isn't coming. -
dana1981 at 02:54 AM on 21 September 2010A detailed look at Hansen's 1988 projections
Sense Seeker - I didn't provide the actual atmospheric concentrations of the various GHGs, but I did provide the actual radiative forcing associated with them, which is what matters for these calculations. Also Hansen '88 provided his formulas for dT but not dF, so I used Myhre for the dFs, which are reasonably close to Hansen's values. Ken Lambert - as the GISS forcing link only provided data up to 2003, I extrapolated to 2010 to get a value of approximately 1.06 W/m2. Several commenters have stated that the actual temperatures have run close to Scenario C, which completely misses the point, and I would suggest re-reading the rebuttal. Actual emissions have not been very similar to Scenario C, so comparing to Scenario C rather than B doesn't make sense. Albatross - yes, Scenarios B and C were very similar (perhaps identical, I'd have to go back and look) up until 2000. -
Rob Honeycutt at 02:36 AM on 21 September 2010The contradictory nature of global warming skepticism
Baz... What Phil Jones was saying is you'd need a few more years of data to achieve statistical significance, not that the rate would need to be higher. -
The contradictory nature of global warming skepticism
CBD. I've only read the first page so far, but it seems I'm leaning against Ken Lambert at post 12. The reason I didn't choose 1940 to 1950 is because the first period of warming was entirely natural! Man-made warming began in 1975 according to Tamino. When I see this: http://woodfortrees.org/plot/hadcrut3vgl/from:2001/plot/hadcrut3vgl/from:2001/trend ...I see a flattened temperature. I see no warming for 10 years. I see warming stalled, maybe stopped. Now we can argue about one data set, or the 'science' of only using 10 years until we're both blue, but THAT is what I see. I see that black line in the graph above and I wonder if the warming has stopped - and I'm not the only one. If there's no heat in the oceans then me, and others who think 'unscientifically' like me, are going to be right; and you, and others here, are going to be wrong. You cannot say at this stage that I am wrong in that belief, neither can I say you are. Only time will tell the truth. -
CBDunkerson at 02:25 AM on 21 September 2010The contradictory nature of global warming skepticism
Baz #306: "I don't accept 10 years of flattened temps is conducive to continued global warming." Take a look at the full HadCrut temp graph back to 1850;
This clearly shows DECLINING temperatures from 1940 to 1950. Why didn't that 'disprove man made global warming'? Or the 'flat' period from 1960 to 1975? Why didn't the steep rise (0.2 C per decade) from 1980 to 2000 'prove' that we were in for 2 C additional warming by 2100 even assuming no acceleration of warming? Ditto the 0.5 C rise from 1910 to 1940... surely that meant we were in for continued 0.167 C per decade warming, right? Yet the drop in temperatures from 1880 to 1910 clearly indicated that we were heading into an ice age.
There have been fluctuations, both up and down, more pronounced and/or prolonged than the 10 year 'level' period you are stuck on... so what is so 'special' about this particular minor fluctuation?
Even setting aside the statistical issues... your position just isn't consistent with the historical record.
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The contradictory nature of global warming skepticism
CBD, I need some time to read that! -
The contradictory nature of global warming skepticism
JMurphy. "Irrational". The two sentences are not the same. Read them again. Re continuing warming. If you've read my posts then you'll see that I've said quite a few times that I accept bumps in temp along the way. I don't accept 10 years of flattened temps is conducive to continued global warming. -
CBDunkerson at 02:04 AM on 21 September 2010A detailed look at Hansen's 1988 projections
angusman #22, scenarios B and C and the actual temperature record are all very similar to each other through 2005. Since 2005 actual temperatures have been roughly in line with scenario C (below in some years, above in others). However, that is FAR too short a time frame on which to judge the validity of the model. If actual results continued tracking along scenario C for 15+ years then the model would be off significantly. If the warming being seen this year continued then we'd be back 'on track' closer to scenario B. That said, Hansen's 'short term' climate sensitivity factor in 1988 was definitely too high and thus his results should be expected to go further off as time goes by. Hansen 2006 essentially explained HOW the 1988 analysis got it wrong... so to say that 2006 is itself wrong... would seem to be arguing that Hansen 1988 was correct. :] -
The contradictory nature of global warming skepticism
Daniel Bailey. Oh dear, you seem to have missed B in that BBC link and gone straight to C. Try again, Daniel, because YOU ARE WRONG. See MichaelM's quote above your post. MichaelM. Thanks, but I'm not confusing anything with everyday use! Prof Phil Jones states that the trend from 1995 to 2009 is not statistically significant. I didn't say it, he did. -
Albatross at 01:23 AM on 21 September 2010Global warming and the unstoppable 1500 year cycle
Addressing even the most bizarre myths put forward by "skeptics" is important, and IMO, does not amount to arguing a straw man as some are suggesting here. Only the other day I was reading a CBC forum on the Arctic ice and "skeptics" were parroting Singer. How he can claim to have any credibility (and even more astounding, how people can still buy into his "science") on climate science is truly bizarre. -
angusmac at 01:22 AM on 21 September 2010A detailed look at Hansen's 1988 projections
A close look at Figure 3 shows that temperatures are actually running below Scenario C - the zero-increase in CO2 from 2000. This decline has not happened. Therefore, the only conclusion that can be made from present day temperature readings is that Hansen (1988 & 2006) got it wrong. -
Albatross at 01:19 AM on 21 September 2010A detailed look at Hansen's 1988 projections
Wonder if Michaels is going to retract the misleading and erroneous testimony that he gave before US House of Representatives? I mean in the spirit of accountability,transparency and rigor that he demands of the IPCC? Excellent job Dana. Am I correct in understanding that emission scenarios B and C were the same up until 2000? -
archiesteel at 01:14 AM on 21 September 2010The contradictory nature of global warming skepticism
@Baz: "Please retract the "liar", and I've never said I am irrational." I'm not retracting anything, as you keep repeating the same debunked fallacious statement. Oh, and you did claim to not being rational. Not rational = irrational. "Re 'Where's the heat?' So 3 years is good enough for you?" Of course not, it's not statistically significant. It should be enough for you, however, since you originally claimed a five-year period was enough for you to change your mind about the warming. I can't believe you walked right into that one, too. What are you hoping to achieve, here, exactly? Get on people's nerves until they become rude so you can then complain how AGW proponents are ill-mannered? "I say again, the last 10 years of HadCRUt is flat." And I say again, that is cherry-picking, especially since other cycles (such as the PDO and TSI) are having a cooling effect during that period. Please pick a statistically-relevant period and base your opinion on this, otherwise my choice of the last three years (which shows where the "heat" is) is just as good as your choice of five or ten years. You've been unmasked, Baz. At this point, the wise thing to do would be to just stop commenting on the science until you've shown you actually understand it. Anything else is just digging yourself deeper in your own hole. "I didn't "carefully cherry-pick" that period, it was done by Phil Jones here" Another lie? The period was picked by the BBC journalist, not Phil Jones. Jones made a point of saying the warming trend was still there during that period, though it really was at the 92% degree of confidence. Of course, this was all before 2010, one of the warmest years on record, so who knows. Again, you've exhausted everyone's patience, here. Come back when your argument is scientifically relevant. -
Rob Honeycutt at 01:09 AM on 21 September 2010The contradictory nature of global warming skepticism
Baz... I think you're actually not understanding the definition of "statistically significant." Statistical significance in climate is less a function of the rate of warming or cooling and more a function of the length of time. If you look at the current warming from the past couple of years it's coming at a very high rate. I don't know the figure off hand but say it's 0.45C/decade. That is still not statistically significant because it's just part of the noise. The up and down normal to the climate signal. Statistical significance is this: Confidence = signal over noise X square root of the sample size. That essentially means the climate is very noisy so in order to have confidence that you are looking at the actual "signal", and not just noise, you have to have a fairly large sample. In climate it's 20 to 30 years of data. That's why I said, when you're talking about the "flattening" temps you are talking about data that is not statistically significant. -
rzwilling at 01:05 AM on 21 September 2010Hansen's 1988 prediction was wrong
Hi there - I'm relatively new to commenting here so apologies if I'm missing something. I've read through dana1981's Advanced and Basic versions of this rebuttal, and something important appears to be omitted from this Basic version - namely that Pat Michaels was misleading in saying that "That model predicted that global temperature between 1988 and 1997 would rise by 0.45°C." Together with Peter Hogarth's updated chart (above), it appears that even though Hansen overestimated the sensitivity parameter, his Scenario C projection is not far off from the GISS measured temperatures. I'm not sure if it's too late to make any updates to the rebuttal, but the key conclusion here might be that Hansen's 1988 projections - even though based on far less data than we have now - were within the range of what has actually been observed. Furthermore, the measured warming provides support that Hansen had the fundamentals of climate science correct, namely that human factors are driving GHG emissions and causing global warming that is significant enough that it can be directly measured over just a few decades - not centuries from now. -
Tom Dayton at 01:00 AM on 21 September 20102nd law of thermodynamics contradicts greenhouse theory
KnuckleDragger, it's best to not use the term "reflect" at all, even as a convenient shorthand, because as Riccardo wrote it has a particular meaning that is different from absorption-emission. CO2 does effectively zero reflection at the wavelengths we are concerned with here, at CO2's concentrations in our atmosphere. -
archiesteel at 01:00 AM on 21 September 2010Should The Earth Be Cooling?
@KL: So, in other words, your entire argument rests on admittedly incomplete/imperfect ARGO readings? Given the overwhelming evidence in support of AGW theory, it seems to me this would indicate deficiencies in measure OHC, not problems with AGW theory. Unless, you know, you already have decided in your mind AGW theory is wrong, then I guess confirmation bias will cloud your judgement regarding this issue... -
archiesteel at 00:53 AM on 21 September 2010Global warming and the unstoppable 1500 year cycle
@Ann: you won't see this happening, because many "skeptics" change positions depending on the current argument. The goal is to keep an aura of confusion around the debate. Now, there is a small minority who holds steadfast views on AGW, but you don't often hear from them on Internet forums... -
Riccardo at 00:23 AM on 21 September 2010A detailed look at Hansen's 1988 projections
Scrooge, natural cooling is ignored in GCM. It happens on a time frame of millennia which usually is not considered. -
Riccardo at 00:19 AM on 21 September 2010A detailed look at Hansen's 1988 projections
Ken Lambert, still confusing forcings and feebacks, do you? Anyway, Hansen calculation also are "the result of ALL the forcings - both radiative and feedbacks." (sic). And within 5%. -
Scrooge at 00:09 AM on 21 September 2010A detailed look at Hansen's 1988 projections
First I want to say that to be able to come up with those projections in 1988 is remarkable. I think I was still using an Atari 800 at the time. Now this may be a stupid question but as discussed in a previous post, is the idea that we should be naturally cooling incorporated into the model. Of course I assume it is but just one of those nagging questions. -
Ken Lambert at 23:55 PM on 20 September 2010A detailed look at Hansen's 1988 projections
Riccardo #16 Unfortunately the measures 'air surface temperature' and GISS and HADCRUT3 temperature anomalies are the result of ALL the forcings - both radiative and feedbacks. Claiming that Hansen was out by only 5% on half the story when the feedbacks (particularly WV and CO2 interaction) are the least understood is the missing part of this article. So we are closest Scenario C with the temperature record?? -
Howard at 23:54 PM on 20 September 2010It's the sun
I say the Sun is the dominant factor in climate change. If you read the new work by Frederick Bailey, on the soon to launched web site www.solarchords.com and his books, you will see the background to two discoveries, one is, what drives sunspot production, the pattern has been discovered and this led to a much greater discovery i.e. It has been cleary shown that the generally accepted value of 1AU for the Earth - Sun distance around the ecliptic plane has been found to be wrong. This work clearly shows that sunspots per se do not influence climate change but because the way they are produced, they are indicators that the AU value is changing and it is this that affects the climate. Because the two events are closely linked in time, people thought that sun spots cause climate change, they do not. This also led on to investigate why does not the TSI measurements reflect the findings made. This site clearly states here; http://www.skepticalscience.com/acrim-pmod-sun-getting-hotter.htm "There is no single continuous satellite measurement of Total Solar Irradiance" In researching the this and other sites I soon realised why the TSI variation that should be seen has not been identified, because only the variation in the output of the Sun is being measured, not the total output or TSI. The variation is then appliked to the standard figure of 1368w per Sq M and allowing for the expected orbital position. Bailey's work clearly shows the reason for the historical hot and cold periods etc. -
Ken Lambert at 23:39 PM on 20 September 2010Should The Earth Be Cooling?
Yooper #58, #61 The critical measurement is the TOA imbalance which nets all the heating and cooling forcings. Ref Fig 2.4 of AR4 which gives a total net anthropogenic forcing of +1.6W/sq.m. To this number is then added the climate responses which mainly consist of radiative cooling (from a raised Earth temperature of 0.75 degC as per S-B) of about -2.8W/sq.m and WV and Ice Albedo Feedback of about +2.1 W/sq.m. (Ref Dr Trenberth Fig 4 'Tracking the Earth's global energy) The sum is then +1.6 -2.8 +2.1 = +0.9W/sq.m All the heating and cooling forcings are acting in concert. S-B is emitting IR, Aerosols and clouds are reflecting incoming Solar heat, while CO2GHG are supposedly trapping Solar heat at lower levels (the mechanism is more correctly slowing down the transfer rather than 'trapping' heat) which tends to raise the equilibrium temperature as the analogy of a better insulator increases the T1-T2 temperature difference for a given heat flux transferred. What is certain is that CO2GHG forcing (currently claimed at about 1.6W/sq.m) is logarithmic with CO2 concentration, and S-B radiative cooling is exponential (proportional to T^4). Where these forcings and the others cross is where the forcing imbalance is zeroed and the new equilibrium temperature approached. The CO2GHG theory hangs on the interaction of WV and CO2 in the atmosphere and what will be the surface temperature rise for a unit rise in the IR emitting temperature of the Earth as seen from space. For the first law to be satisfied, most of heat flux 'imbalance' of 0.9W/sq.m should show up in the oceans due to the tiny relative storage capacity of the land and atmosphere (about 5%). OHC is proving most elusive to measure but Argo is the best we have at the present and the latest Willis analysis is not finding the 'missing heat' below 1000m. Here is the story on sea level rise: Thanks to HumanityRules nice summary: quote; "I've found 4 papers looking at closing the sea-level budget around 2003-2007. The latest is from this year. Basin patterns of global sea level changes for 2004–2007 You-Soon Chang, Anthony J. Rosati, Gabriel A. Vecchi Journal of Marine Systems 80 (2010) 115–124 Chang, like the others, calculate the steric and mass components using ARGO and GRACE and compare it to the total change calculated from altimetry. They handily summarize the 4 published attempts to close the sea-level budget in a table. Chang et al (2010) STERIC −0.11±0.22 MASS 0.70±0.34 TOT 2.67±0.52 Willis et al. (2008) STERIC −0.5±0.5 MASS 0.8±0.8 TOT 3.6±0.8 Leuliette and Miller (2009) STERIC 0.8±0.8 MASS 0.8±0.5 TOT 2.4±1.1(2.7±1.5) Cazenave et al. (2009) STERIC 0.37±0.1 MASS 1.9±0.1 TOT 2.5±0.4 Chang and Willis fail to close the budget and interestingly fail with pretty much the same numbers. Leuliette and Cazenave manage to close the budget but by very different means. Leuliette through an equal contribution from steric and mass. Cazenave primarily (80%) through mass." Note Leuliette is the only one of the 4 analyses to get equal mass and steric. Error bars are very wide on all analyses. More mass means less OHC content increase and most coming from ice melt which sinks very ittle heat compared with the claimed imbalance. Yooper - when you have supped on this - please refrain from belching on about my 'misunderstandings', Happy to debate you on any or all of the above. -
Riccardo at 23:37 PM on 20 September 2010A detailed look at Hansen's 1988 projections
Ken Lambert, it's way too easy to talk about apologia without even bothering to look at the details on how things work. This attitude just highlight the unwillingness to learn the science but still dismissing it. The feedbacks are, indeed, feedback, not forcings. Why should they be listed in the same table as the forcings? The albedo, water vapour feedbacks and others are the results of the full calculations and are not parametrized. -
CBDunkerson at 23:29 PM on 20 September 2010The contradictory nature of global warming skepticism
Baz, I dug around in the archives for a good writeup I remembered on statistical significance in the temperature data set. If you read the linked article you may better understand why these 'short term trends' you are relying on are not considered statistically valid trends at all. Ironically, you are dismissing a warming trend since 1995 which has greater than 90% confidence in favor of a 'flat' trend since 2001 which has much lower statistical significance. -
Riccardo at 23:27 PM on 20 September 2010A detailed look at Hansen's 1988 projections
Sense Seeker, #10 in this post there's a comparison of Hansen's calculation in 1988 not a thorough comparison of model results. How could he know the actual emissions in the future? Someone else could do now some new calculations with actual emissions and best available model now, but this is a different story. A good idea for a new post ;) #13 the model is not on radiative forcing alone, it's much more than this; it is called a General Circulation Model (GCM). Radiative forcings come from radiative tranfer codes that are pluged into the GCMs. I think you should dig a little bit more on GCMs; NASA GISS provide a lot of informations (and the code itself) that I'm sure you'll find intersting. -
CBDunkerson at 23:05 PM on 20 September 2010The contradictory nature of global warming skepticism
Baz #296: "Okay, there seems to be some mis-reading here again. Rob, first of all, 0.12 c per decade is NOT statistically significant - ask CBD if you don't believe me." Ask me? Ok. You appear not to know what "statistically significant" MEANS. It has nothing to do with the degree of warming, only the confidence that this warming represents a statistically valid trend rather than merely being an artifact of random fluctuations. A warming trend of 0.12 C per decade could be either statistically significant (the usual confidence level is 95%) or not depending on the data from which it is derived. -
Ken Lambert at 23:04 PM on 20 September 2010A detailed look at Hansen's 1988 projections
I clicked the link to NASA-GISS for the +1.1W/sq.m 2010 relative to 1984 forcing here: http://data.giss.nasa.gov/modelforce/RadF.txt and found data only to 2003 and nothing like +1.1. Please explain the calculation? My eyesight must be playing tricks for I see the actual temperatures running close or below Scenario C not Scenario B. Is that what you meant? And what of the climate responses - where is the estimate of WV and Ice albedo feedback and radiative cooling feedback? Seems like a contrived Hansen apologia with only half the story to me.
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