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David Horton at 18:01 PM on 27 July 2010Waste heat vs greenhouse warming
No no Doug, the undersea volcanoes that are warming the sea. Surely you know about them? Plimer does. No, seriously, good to see "waste heat" put into context, I have seen it presented seriously as an argument on threads relatively recently. Including, unless I am going crazy, waste heat from air conditioners near monitoring stations. Actually warming the planet that is, not just the nearby thermometer. These kinds of propositions are put forward with never any research into the relative proportions concerned, and it is good to see John's diagram. Not, of course, that it will stop someone, on the very next thread, from again saying "what about waste heat?"> -
Paul D at 17:52 PM on 27 July 2010Waste heat vs greenhouse warming
A waste heat discussion at RealClimate: http://www.realclimate.org/index.php/archives/2009/10/an-open-letter-to-steve-levitt/ -
Doug Bostrom at 17:50 PM on 27 July 2010Waste heat vs greenhouse warming
Any difference between a warm rock and a warm engine, thermally speaking, RSVP? -
RSVP at 17:41 PM on 27 July 2010Waste heat vs greenhouse warming
0.028 W/m2 is derived by dividing the total worldwide energy consumption... 1.5 x E13 W by the total surface area of the Earth. These are at least Watts we can be sure are "real". Furthermore they represent direct heating of the atmosphere (non GHGs) and the water supply, which are not the best IR emitters. (Exactly how much IR could be coming out water below its surface?) In terms of accounting, this is very different from the 2.9 W/m2 that is being "slowed" down by GHGs but eventually makes its way up and out. Seen this way, I would even venture to suggest that the real comparison should be between 0.028 and zero. If not, what part of the 2.9 W/m2 is not making its way out? -
Doug Bostrom at 17:22 PM on 27 July 2010It's waste heat
RSVP I believe we're all clear on that. Flanner is at any rate and since his number is the operative one here we're all on the same page it seems. One more time: AHF (Anthropogenic Heat Flux) is something like 1% of expected forcing from anthropogenic green house gases. As I explained earlier, estimates of AGHG forcing expectations could be too large by a factor of 10 and would still dwarf AHF. "There's no there, there." Meanwhile you still seem to be worrying over the relationship of N2 and O2 w/waste heat. It's not a unique or special connection. Ned explained the commonality here. -
RSVP at 17:01 PM on 27 July 2010It's waste heat
Marcus said "heat from within the Earth is going to find its way to the great beyond regardless of birthright, ultimately via radiation. " I agree 100%, but then you go on... "There's really not much to work with here for a so-called skeptic, to the point that one is left wondering how to speak patiently in the face of arguments to the contrary, once they've been repeated several times by the same person. " I have also asked more than several times how N2 and O2 radiate? I have still to see anyone acknowledge this difficulty. There have been some indirect responses about CO2 acting as an antenna! in which case, according to this explanation CO2 is helping to cool the atmosphere, and if this were the case, all latent energy would actually be attributed to waste heat. But lets not go there for now please. I would just like to see an explanation on how N2 and O2 (the non GHG portion of the atmosphere) are understood to cool radiatively, as I have been saying that they cant do this and will only generally cool by convection. And only by convection to "cooler" objects such as water and ice, implying a "selective" route for energy exchange. There was that question of why poles warm faster (for instance). At any rate Marcus, I also agree with your statement, "so much of this "debate" is ultimately driven by complete and total intractability"... This is obvious. I am not sure why, as we are all in the boat together. -
RSVP at 16:39 PM on 27 July 2010It's waste heat
I would hope that the term "waste heat" is not being understood simply as that portion of energy that is not delivered to the load. I can see how the word "waste might lead one to think this... thoughtout this discussion, I was referring to the broader concept. For say an automobile, waste heat should be understood as heat exchanged to cool the engine, the car's friction in all moving parts, the kinetic energy increase in the atmosphere left by drag, and combustive heat going out the tail pipe in the form of CO2 and water vapor. Similarly, house heating waste heat is not the percent of heat that escapes though a building's insulation, but every calorie used to heat the inside of a home or building; as this heat is eventually released into the environment. It is actually equivalent to the total worldwide energy consumption... 1.5 x E13 W http://en.wikipedia.org/wiki/World_energy_resources_and_consumption Hope this helps. -
Doug Bostrom at 16:36 PM on 27 July 2010Waste heat vs greenhouse warming
David, you jumped the gun, in a manner of speaking. See John Chapman's post just above yours. Something like 1/30th of the amount in question, and of course as it's already been present all along is not really relevant, which is why it's not factored in the first place. Important to remember, the issue is "anthropogenic warming." -
David Horton at 16:15 PM on 27 July 2010Waste heat vs greenhouse warming
And of course you have forgotten all the heat released by those volcanoes John, on land and undersea. Massive amounts of heat, stands to reason. You'd know that if you were a geologist. -
muoncounter at 15:09 PM on 27 July 2010Assessing global surface temperature reconstructions
#36: " the conclusion that the UHI effect is negligible is not an effective way of looking at this issue." Seems to me that a necessary step in researching something is a consideration of whether or not it is likely to be of negligible significance. But the more important point was somehow missed: If GISS/HAD/GHCN etc are as consistent with UAH/RSS as Ned has shown, then any major revision of one had better also apply to the other. If UHI can profoundly flatten surface temperature measurements, then what 'correction' will do the same to the satellite data? As far as I can discern, UHI doesn't apply to satellite measurements of atmospheric temperatures. "about the ocean temperatures, lets be real, " Point was: Looking at Ned's fig 8, all blue bars are of comparable height. Again, different data sources and interpretations are consistent with one another about the trend. #37: " no surprise that if you run the same core data through a software processing package - you might get similar results." It would require significant explanation if the results were not similar. Ned has shown that the conclusion all competent measurement systems show increasing temperatures on a global scale during this time period is well-founded. But Mr. Lambert's criticism can be inverted: It is no surprise that if you run the same set of selectively chosen points out of a large data volume through a set of preconceived notions, you get the same tired denialist arguments. What is disappointing, however, is how quickly those arguments revert to mere name-calling and accusation. What makes this blog different is, for the most part, the discussion stays on a higher plane. -
John Chapman at 14:46 PM on 27 July 2010Waste heat vs greenhouse warming
Just for completeness, in case someone wonders about other factors, the contribution from another nuclear source - the decay of radioactive elements in the Earth's crust (40TW) - amounts to near 0.1 W/m2 which is much more significant than the waste heat. -
Doug Bostrom at 14:09 PM on 27 July 2010Waste heat vs greenhouse warming
I originally thought that "waste heat" as it pertained to anthropogenic global warming was a blanket term to describe Sisyphean discussion of the AGW affair on the Internet. Once again, Skeptical Science sets the record straight! -
Joe Blog at 13:06 PM on 27 July 2010Waste heat vs greenhouse warming
Im still at a lil o a loss as to some o the figures ive seen turn up here in regards to anthropological radiative forcing.... I followed the link to the ipcc page, and there in the table it has total human contributions listed as around 1.6W/m2 with error bars putting it out as far as possibly around 2.4W/m2. And ive generally seen it stated as 2W/m2. Where does the 2.9W/m2 figure come from? But, yeah, it should be pretty obvious we arnt going to compete with that big ole fusion furnace in the sky as far as putting energy into the climate system.Response: The total radiative forcing from man-made greenhouse gases is 2.9 W/m2. But this is partly cancelled out by man-made aerosols which have a cooling effect. The net effect that humans have on climate is around 1.6 W/m2.
Probability distribution functions (PDFs) from man-made forcings. Greenhouse gases are the dashed red curve. Aerosol forcings (direct and indirect cloud albedo) are the blue dashed curve. The total man-made forcing is the solid red curve (IPCC AR4 Figure 2.20b)
Yes, the sun produces almost all the energy in our climate system. But if the sun's output stays the same, it contributes no radiative forcing. The sun only causes a change in global temperature if the solar output changes. Remember that the sun has actually been cooling in recent decades so the sun's net effect on climate has been a slight cooling. -
Marcus at 13:04 PM on 27 July 2010Waste heat vs greenhouse warming
As I've said elsewhere. If waste heat were such a significant contributor to the warming of the planet, then why didn't the far less thermally efficient factories & power stations of the 19th century generate a significant warming trend? Why did temperatures rise so "fast" during the Great Depression decade of the 1930's, yet fall slightly during the Wartime/post-war Industrial Boom decades of the late 1940's & 1950's? Why have temperatures risen faster during a period of increasing thermal efficiency (which means less waste heat generated) than in decades when thermal efficiency was much lower? It seems to me that this is one skeptic argument which doesn't even bear up to even distant scrutiny! -
Marcus at 12:57 PM on 27 July 2010It's waste heat
Another problem with the "Waste Heat" theory. Why did the planet continue to warm (due to increased solar activity) during the Great Depression, when industrial activity-world wide-fell, yet temperatures fell during the first decade of the post-war industrial boom?Response: Marcus, just to play devil's advocate on this line of argument, couldn't you likewise say "why was there no global warming during mid-20th century while CO2 levels were rising?" or "why was there global warming in the early 20th century while CO2 levels weren't rising that steeply?" :-)
To fully address the question of waste heat during the industrial revolution and Great Depression, you would need to calculate the radiative forcing from waste heat over these periods. It's not that hard to work out - we do have figures on energy use over these periods (I link to the CDIAC data from here). Working this out is left as an exercise for the reader (eg - I'm too lazy to do it myself). -
Marcus at 12:55 PM on 27 July 2010It's waste heat
There is one obvious problem with the whole "waste heat" argument which is this-why was there little to no measured warming between 1850 & 1900, given the amount of factories & power stations which were pumping out heat during this time? By today's standards, these factories & power stations were incredibly inefficient-meaning they gave off the vast bulk of their energy as waste heat. Yet strangely, in the last 60 years, we're expected to believe that waste heat generation is actually inversely proportional to improvements in thermal efficiency. i.e. the skeptics would have us believe that, even though thermal efficiency has improved over the last 60 years, the contribution of waste heat to global warming is increasing! That's *hilarious*. From my calculations, its fair to say that waste heat contributes somewhere around +0.006 degrees (& falling) to total global warming for the last 60 years. -
Doug Bostrom at 11:32 AM on 27 July 2010It's waste heat
Actually this thread is helpful because it's serving as a remarkably clear and concise example of how so much of this "debate" is ultimately driven by complete and total intractability on the part of some of the discussants. This is a very simple situation. "AHF" is capable of adding something like 1% of the quantity of solar heat being retained by additional impedance due to C02 and knock-on effects, working from mainstream estimates of anthropogenic GHG climate sensitivity. Just to make things clearer, let's imagine for a moment that we're somebody akin to Dr. Roy Spencer, a highly-qualified scientist able to make a start on articulating an alternate hypothesis to anthropogenic warming as an explanation for recent observed temperature increases. Under our Dr. Spencer-style hat, we believe that effective AGHG forcing is only 10% of more commonly accepted figures. In this circumstance we're looking at AHF forcing still being just 10% of anthropogenic GHG forcing. Even if we assume mainstream estimates are off by a full order of magnitude, AHF still pales in significance compared to anthropogenic GHGs, is still yet another order of magnitude less. Meanwhile, as has been pointed out, heat is mindless and does not care from where or to where it's going. Whatever heat is added to the pool here on Earth whether by anthropogenic liberation or arriving from the sun or for that matter emerging from retained and radioactive decay heat from within the Earth is going to find its way to the great beyond regardless of birthright, ultimately via radiation. Nothing about the origin of heat specifies its subsequent behavior. Heat flux from energy liberated as a part of human activity by any measure appears by all accounts to be a minor constituent of Earth's radiative energy budget. Even if one looks at the thermal impedance properties of the atmosphere from various outlier perspectives, AHF still does not measure up in a significant way. There's really not much to work with here for a so-called skeptic, to the point that one is left wondering how to speak patiently in the face of arguments to the contrary, once they've been repeated several times by the same person. -
Ned at 10:58 AM on 27 July 2010The nature of authority
Berényi Péter writes: You may expect that, but unfortunately reality does not seem to conform. Can you explain, in words, what that figure shows and how precisely it contradicts the claim from chris's post? Thanks. -
Ned at 10:52 AM on 27 July 2010It's waste heat
johnd writes: Ned at 22:36 PM, part of the issue being discussed was whether waste heat accumulates or not, and whether accumulative it's effect is more than negligible. There is no magic mechanism that removes heat from the atmosphere if it originally came from radiation but lets it accumulate if it originally came from combustion or whatever. IMHO these analogies to revolving doors and traffic jams seem to have no effect other than clouding the issue. How about some actual evidence, please? Doug B. gave a reference to a paper with quantitative comparison of the two sources way back in comment #2. That was very helpful, I think. -
chris at 09:42 AM on 27 July 2010The nature of authority
not sure why I wrote "longitude" when I meant "latitude" in my post just above! -
chris at 09:38 AM on 27 July 2010The nature of authority
Berényi Péter at 09:14 AM on 27 July, 2010 "You may expect that, but unfortunately reality does not seem to conform." Careful Peter. One location does not define an entire longitudinal band. You really need to look at the paper I cited (Zhang et al., 2007; link in the post that you mined my sentence from). The 20th century has seen a decrease in rainfall in the equatorial regions from around 0 o longitude to 30 o N, and an increase in rainfall in the high latitudes. Pretty much as expected from models. X. Zhang et al. (2007) Detection of human influence on twentieth-century precipitation trends Nature 448, 461-465 -
KR at 09:34 AM on 27 July 2010It's waste heat
johnd - False distinction logic error: thermal energy is thermal energy, none of it is 'pregnant' or otherwise distinguishable from the other. This is akin to the G&T arguments where some skeptics thought that an object would somehow 'know' that certain photons came from colder objects, and would not therefore contribute to energy balances. Photons (and joules) don't carry ID cards, unlike Arizona citizens. Thermal energy gets distributed by the usual suspects - conduction, convection, latent heat, and radiation, with radiation measured to be the dominant pathway. The source of the energy is irrelevant to how it leaves. As per the thread, however, only ~1% of that thermal energy comes from energy usage, the other 99% comes from GHG entrapment of solar energy. Bad analogies don't change that. If nothing else, this thread has been a delightful example of logic errors... -
Berényi Péter at 09:14 AM on 27 July 2010The nature of authority
#101 chris at 09:17 AM on 25 July, 2010 We expect in a warming world that rainfall will decrease in the equatorial regions of the Earth You may expect that, but unfortunately reality does not seem to conform.
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johnd at 09:06 AM on 27 July 2010It's waste heat
RSVP at 06:35 AM, perhaps another analogy may help. A well designed and up to date maternity hospital has been built and access is via a revolving door that is designed to maintain an efficient environment and minimize heat losses by operating only with one person entering and one person leaving at the same time. Only 1% of those entering the hospital do so to give birth, the bulk of those entering, and leaving are visitors or staff. At what point does the hospital board have to go back to the engineers who did the original design calculations, and ask them if the assumption they made that as only 1% of those entering the hospital were pregnant, and so could be considered negligible, was a indeed a valid assumption? -
johnd at 08:34 AM on 27 July 2010It's waste heat
Ned at 22:36 PM, part of the issue being discussed was whether waste heat accumulates or not, and whether accumulative it's effect is more than negligible. Obviously if the total heat losses from your dining room, being well insulated one hopes, remains less than that being provided by the burning candles, then it is the total accumulated heat that is relevant in any quantitative comparison at any point of time. Naturally, if at some point of time someone opened a door introducing a period of increased heat loss, that is a period of cooling, then a portion or perhaps all the accumulated heat of the burning candles would be lost. -
KR at 07:21 AM on 27 July 2010It's waste heat
Also take a look at Common Sense error, strongly related to the Dunning-Kruger effect -
KR at 07:16 AM on 27 July 2010It's waste heat
RSVP - queuing theory, with its associated transition points at certain flow rates, has absolutely nothing to do with this topic, and can only be considered an (rather poor) attempt to change the subject. Your waste heat issue is 1% the effect of GHG entrapment, negligible in comparison. You have shown no evidence whatsoever to the contrary. This is a science blog site - Appeals to Belief and Red Herring logical errors really don't hold up to actual numbers or physics. -
Doug Bostrom at 07:07 AM on 27 July 2010It's waste heat
RSVP, imagine that as cars from the rock concert move down the congested highway the mayor of the local city connected to the highway announces that an asteroid is approaching and will strike the center of the city within hours. Many residents respond to the announcement by "getting out of Dodge," ironically jumping into their Dodge automobiles and hightailing it for the proverbial hills. Proportioning the public panic to the relative numbers of AHF forcing versus forcing by a doubling of C02, the highway must then cope with not only the increase of traffic from the concert but a panic stricken flood of drivers representing over 100 times more additional vehicles beyond that created by the concert traffic. Not to put too fine a point on it, you're obsessing over a very tiny number. -
Ned at 06:55 AM on 27 July 2010The nature of authority
Actually, I don't know that. It sure seems like that's the impression you're trying to convey in this thread. If not, you might want to try to write more clearly. In particular, using repeated expressions like "According to AGW" and "I am being told that ..." when referring to the basic physics of infrared spectroscopy does not convey the impression of confidence in said spectroscopy. Most people, when writing about something they genuinely believe in, don't feel the need to add a continual stream of parenthetical qualifiers. -
RSVP at 06:35 AM on 27 July 2010It's waste heat
An metaphore to "queue threoy" may help you all... There is a highway that goes into the city. The flow is constant everyday (no weekends in this theoretical land). The flow of cars depends on the amount of traffic since the channel (the highway) but in generally is usually constant and flows well. One day Road Maintenance needs to paint the lines on the side of the highway and places cones on the right lane. This slows traffic down slightly. (This might be effects of elevated CO2... perhaps). On top of this however, there is a special event that day (rock concert) and the number of cars increases, but only by 1%. (waste heat) Since the flow was basically optimal before these two occurrences came about, the traffic almost comes to a complete halt. There is now a traffic jam and cars are moving bumper to bumber. Someone in a car wants to see a huge accident to justify this inconvenience. As he passes the cones, he is dissappointed that there is nothing dramatic to see. (AGW guy, asking me for numbers to justify the effects of man made waste heat). -
KR at 06:08 AM on 27 July 2010It's waste heat
Here's another summary on this topic, with some references: Global Warming Waste Heat -
KR at 05:50 AM on 27 July 2010It's waste heat
In the medium concentrations we have for GHG's in Earth's atmosphere, a doubling of CO2 concentration increases the width of the blocked LWIR band enough that the Earth's surface must be 1oC hotter for the integrated spectrum at the top of the atmosphere to sum to the energy coming in. Increased GHG concentrations slow the escape of the LWIR energy from the atmosphere. The 10^9 collisions/second ensure that the GHG's maintain the same temperature as the rest of the air mass - you can't separate N2 and O2 temps from the air mass as a whole, and it's rather silly to claim so. Back to the point of the thread - Human energy use releases energy at a rate 2 orders of magnitude less than the GHG entrapment. Unless you provide some evidence to the contrary, which you have not done so far, waste heat is not an issue worth worrying about. -
RSVP at 05:47 AM on 27 July 2010The nature of authority
Ned "In another thread RSVP is questioning basic laboratory measurements of the spectral properties of gases that have been known since the 1850s" That is not what I am doing and you know that. -
Ned at 05:41 AM on 27 July 2010It's waste heat
Maybe this will help. RSVP, think of each individual CO2 molecule as a tiny machine, taking in fuel (IR radiation) and giving off waste heat (vibrational energy transferred by collisions with other molecules in the atmosphere). Every year, we add billions of tons of those tiny machines to the atmosphere. The waste heat they produce is two orders of magnitude greater than the heat from our clunky mechanical devices down here on the surface. Does that help? -
Ned at 05:37 AM on 27 July 2010It's waste heat
The concentration of CO2 in the atmosphere affects the absorptance of longwave IR. It doesn't particularly affect the rate at which the energy from that absorption is shared with the rest of the atmosphere. Those are two entirely different processes. You really don't understand how this works, do you? -
RSVP at 05:30 AM on 27 July 2010It's waste heat
Ned "Likewise, most of the heat from GHG absorption will also be transferred to O2 and N2 molecules, thanks to the fact that each CO2 molecule collides with N2 or O2 molecules roughly one billion times per second. " Why does GHG concentration matter? Does it go to two billion times per second as concentration doubles? My point is you make it sound like all the energy captured by CO2 goes directly into the surrounding molecules (one minute), but concentration "modulates" this process another minute when it comes to justifying the reduction of GHG emissions. -
RSVP at 05:25 AM on 27 July 2010It's waste heat
Ned "I'm confused by all the references to N2 and O2. Why do you think there's some kind of distinction there? " What makes a GHG a GHG? N2 and O2 are not greenhouse gasses by definition, otherwise the atmosphere would be 100% GHG and there would be no problem with emission of GHGs. How can you ask this question? -
RSVP at 05:23 AM on 27 July 2010It's waste heat
KR "The air mass as a whole, containing GHG's, is not transparent to IR - it heats and cools depending on the IR in/out balance. What exactly is not clear about that?!?" The crux of the AGW theory (and the campaign to control GHGs concentrations) rests on the assumption that the efficiency of "The air mass as a whole" to "emit/absorb IR" is a function of concentration. Making this kind of a blank statement about how air gets rid of heat ignores the premises upon which AGW is based on. -
Ned at 05:17 AM on 27 July 2010It's waste heat
RSVP, the point that Doug and KR and I keep emphasizing is the main one -- you need to provide some evidence here. But aside from that, I admit I'm confused by all the references to N2 and O2. Why do you think there's some kind of distinction there? Most of the waste heat from anthropogenic sources will be carried in the atmosphere by O2 and N2. Likewise, most of the heat from GHG absorption will also be transferred to O2 and N2 molecules, thanks to the fact that each CO2 molecule collides with N2 or O2 molecules roughly one billion times per second. Perhaps you're under some misimpression that when a greenhouse gas absorbs IR radiation it only raises the temperature of the GHG molecules themselves? If so, that's wrong. The atmosphere is not a mix of gases each with its own distinct temperature. -
KR at 04:55 AM on 27 July 2010It's waste heat
N2 and O2 are transparent to IR. However, the CO2 and H2O content of the air mass can and does absorb and emit IR. GHG's at air temperature will lose/gain energy as they emit/absorb IR, and through molecular collisions will cool/heat the air mass as a whole, including the N2 and O2. And that thermal exchange is very efficient, very fast. The air mass as a whole, containing GHG's, is not transparent to IR - it heats and cools depending on the IR in/out balance. What exactly is not clear about that?!? I've got nothing more to say here, unless RSVP comes up with a measurement supported number comparable to Flanner's. -
Doug Bostrom at 04:52 AM on 27 July 2010It's waste heat
I think we can conclude that this is a dead end, unless RSVP can produce a number for "AHF" more useful and much larger than Flanner's. -
RSVP at 04:47 AM on 27 July 2010It's waste heat
N2 and O2 are transparent to IR. These gases do not radiate since they are not GHGs, and therefore have a hard time loosing their heat outside of convective cooling with water and ice. The cooling of manmade heat engines raises the temperature of N2 and O2 directly. This heat is carried around the planet and is being discharged and dissipated in the cooler regions since convection requires a lower temperature for heat to be transferred. -
Ned at 04:39 AM on 27 July 2010It's waste heat
RSVP, you could simplify this whole process a lot if you would just point us to a paper, a study, or anything, really, that quantitatively shows waste heat being equal to or greater than radiative forcing from GHGs. Once we have such a source, we can debate the data, methods, interpretations, etc. But until you give us something that at least remotely resembles a shred of evidence, what's the point? -
Doug Bostrom at 04:39 AM on 27 July 2010It's waste heat
RSVP, I'm (honestly) still uncertain about what point you're making. I -think- you're saying that observed increases in global temperature are significantly affected by anthropogenic liberation of heat energy. If that's the case, your argument is stuck here Nearly all energy used for human purposes is dissipated as heat within Earth's land–atmosphere system. Thermal energy released from non-renewable sources is therefore a climate forcing term. Averaged globally, this forcing is only +0.028 W m−2... until you can provide a substitute number for Flanner's calculated result that is both much larger and more correct. If you're driving at something else, different matter of course. -
RSVP at 04:27 AM on 27 July 2010It's waste heat
CBDunkerson I have tried to answer your questions. It would seem fair that you try to answer some of mine. 1. Can energy be destroyed? 2. Where exactly does the Urban Heat go? 3. What does the word energy dissipation mean to you in this context? 4. What are the radiative properties for cooling of N2 and O2? 5. How do these properties differ from GHGs? -
Doug Bostrom at 04:23 AM on 27 July 2010September 2010 Arctic Ice Extent Handicapping Via ARCUS
Those still following this topic may be interested to read a very informative post by Dirk Notz, here at RealClimate. For me it was interesting to see my intuition seconded by somebody with some expertise: Because of the very low thickness of much of the Arctic sea ice, it wasn’t too surprising that at the end of the winter, sea-ice extent decreased rapidly. This rapid loss lead up to the lowest June sea-ice extent since the beginning of reliable observations. After this rapid loss of the very thin ice that had formed late in winter, the retreat slowed down substantially but the ice extent remained well below the long-term mean. Currently, the ice covers an area that is slightly larger than the extent in late July of the record year 2007. However, this does not really allow for any reliable projections regarding the future evolution of Arctic sea ice in the weeks to come. The reason for this is mostly that sea ice in the Arctic has become very thin. Hence, in contrast to the much thicker ice of past decades, the ice now reacts very quickly and very sensitively to the weather patterns that are predominant during a certain summer. This currently limits the predictability of sea-ice extent significantly. For example, in 2007 a relatively stable high-pressure system formed above the Beaufort sea, towards the north of North America, leading to rapid melting of sea ice there. If again such stable high pressure system forms in the Arctic throughout the coming weeks, we might well experience a sea-ice minimum that is below the record minimum as observed in 2007. However, if the summer should turn out to be colder than during the previous years, a sea-ice minimum similar to that observed in 2009 would not be too surprising. Hence, at the moment all that remains is to wait – and to check again and again the latest data of Arctic sea-ice extent. Emphasis mine. Probably what many of us suspected. -
Mal Adapted at 03:48 AM on 27 July 2010The nature of authority
Thingodonta:Good quote from Charles Darwin.
I chose that quote because it was Darwin's formulation of the Dunning-Kruger Effect, 128 years before it was named. -
KR at 03:44 AM on 27 July 2010It's waste heat
Previous comment, last sentence - that should be *provided*, not *proved*; I believe that makes more sense. ...must...practice...typing... -
CBDunkerson at 03:43 AM on 27 July 2010It's waste heat
RSVP #26 1: Your answer makes no sense. Heat spreading through atmospheric Nitrogen and Oxygen does not explain why the poles are heating faster... there is not more Nitrogen and Oxygen there. 2: Your answer is clearly false. Yes, the Urban Heat Island effect (which has very little to do with waste heat) causes cities to be warmer (though nowhere near enough so to explain the GLOBAL temperature increase), but it does not result in warming of the rural areas around these urban centers as we would expect if global warming were simply the spreading out of heat from urban sources. Hence the 'island' part of the name... it is a sharply localized effect. 3: Again, your answer makes no sense. How are atmospheric Nitrogen and Oxygen responsible for a decrease in the rate of heat escape? Especially as they have not themselves changed significantly? As to 'more heating oil in Winter'... I thought you had claimed that measured warming was due to ACCUMULATED waste heat because it is magically prevented from escaping the atmosphere. Thus, when the heating oil was burned is irrelevant... the heat should still be there in the Summer. 4: Here you seem to simply deny the data. -
Ned at 03:24 AM on 27 July 2010Assessing global surface temperature reconstructions
Berényi Péter writes: It is not as simple as that. The effect of adjustments on overall GHCN trend may be negligible relative to the raw dataset, but it is not so with USHCN which is a subset of it. Even if that were the case, the US represents approximately 2% of the surface area of the Earth. There is no way that the USHCN adjustment process is going to have a detectable influence on the global temperature record. As Figure 5 shows, at the global scale you get virtually no difference using raw or adjusted data. BP continues: This difference in adjustments for the US vs. the rest of the world either does not make any sense from a scientific point of view or it has such a subtle explanation, that it has escaped all the wise people attending to this blog. Peterson & Vose 1997 make it clear that different adjustment processes are used for USHCN and non-USHCN stations. The NCDC website FAQ explains that NOAA has detailed station history information for USHCN stations that it does not have for non-USHCN stations. BP continues: An even more serious question is why to waste time and effort to adjustments that have no substantial effect whatsoever on a global scale? Maybe because they want to make individual station records as accurate as possible for local to regional-scale studies, even if those corrections largely get lost in the noise when averaging data globally? Or maybe nobody could be certain there would be no effect at the global scale until actually trying it? Or maybe there's some other explanation.
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