Arguments
Recent Comments
Prev 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 Next
Comments 78701 to 78750:
-
Andy Skuce at 04:08 AM on 25 July 2011Thinning on top and bulging at the waist: symptoms of an ailing planet
John Russell: The melt water from the ice sheets is distributed (to a first approximation, it's always more complicated!) evenly over the entire ocean surface of the world. The reason the planet's shape changes is because the ice at high latitudes is removed. Simply adding water to the oceans from some other source wouldn't necessarily increase the oblateness. The shape of the Earth, referenced to sea level, the Geoid, is not a smooth or simple geometric surface but is actually lumpy, due to gravity variations arising from the uneven distribution of density in the Earth. It would be harder to visualize the oblateness of the Earth if there were no oceans but the shape of the geoid is a useful and measured quantity, even in the center of continents. Other planets and the Moon (in fact, any body that spins on its axis) also have known oblate shapes, despite having no oceans. -
Rob Honeycutt at 02:45 AM on 25 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Kevin... Thank you for stopping in to make comments and clarifications. I just want to quickly say that we know you take a lot of fire out there in the media but your hard work and dedication to the science of climate change are greatly appreciated by all. -
Kevin Trenberth at 02:29 AM on 25 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
As has been noted, I have been traveling, and I have quickly gone through the 67 comments. A few responses follow. There seems to be some confusion over Fig. 3. This represents the total net radiation from CERES EBAF and so it does include effects of clouds. It is not just the clear sky component (that is a lot more uncertain). Ironically the working definition of "clear sky" used in the community excludes clouds but includes aerosol. Since aerosols affect clouds (the indirect effect), I find this rather unsatisfactory. Still it does not affect things here. There is discussion in the comments of the supposed finding that increasing aerosol (pollution) from China may be the explanation for the stasis in surface temperatures and I do not believe this for a moment. Similarly, Jim Hansen has discussed the role of aerosol as a source of discrepancy. However, the radiation measurements at the top of the atmosphere from satellites (CERES) include all of the aerosol effects, and so they are not extra. They may well be an important ingredient regionally, and I have no doubt they are, but globally they are not the explanation. How did the imbalance occur (comment 2) can be seen from Fig 3 broken into ASR and OLR (not shown here). ASR increased, suggesting fewer clouds as occurs in La Nina over the tropical Pacific, but OLR decreased. The latter seems to be mainly a temperature signal: colder conditions mean less radiation to space. This is often a complex relationship because the biggest variations occur in the Tropics and there is typically a large offset in OLR and ASR signals in association with variations in convection that largely relate to albedo effects being offset by the radiation to space from tops of clouds. Thus fewer clouds means more ASR and more OLR (since the radiation to space comes from warmer lower levels). But that works only in the tropics. At higher latitudes OLR is dominated by surface temperature effects. Comment 17 asks about "back radiation" which is really "downwelling radiation" that is the downward component emitted from the atmosphere in all directions. Clouds, water vapor, and all the greenhouse gases play a key role and the emissions correspond to the temperature of the air. For clouds, the key temperatures are the cloud top temperature for emissions to space and the cloud bottom temperature for emissions back toward the surface. An important point is that to understand the energy flows (which include radiation), the full three (or really four) dimensional structure of the atmosphere is needed, and the simple Figure 1 does not show the vertical structure of temperature. In response to 26: yes melting permafrost can take up some energy but the amount turns out to be very tiny. The last topic I'll touch on is the ocean heat content (OHC). A couple of references were made to the von Schuckmann and Traon paper, which was nice to see, but has some flaws. For instance the data down to 2000 m in the ocean have increased since 2002 and since the beginning of that analysis, yet their error bars are constant. New analyses will be of considerable interest and are underway. I discussed this in this article here in Nature: Trenberth, K. E., 2010: The ocean is warming, isn't it? Nature, 465, 304. http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/NatureNV10.pdf ENSO involves a redistribution of OHC and losses to the atmosphere in the latter part of El Nino, and gains during La Nina, so this is internal to the climate system, not external (comment 31). The southern ocean is clearly playing a role (comments 48, 49)in taking up heat and mixing it deep, even though the magnitude of the observed warming is small. But the data are fragmentary and unsatisfactory in many respects. Nonetheless, the southern oceans, while playing some role, are not the main place where the heat goes in our model. We have a paper submitted that describes and documents that in more detail so it is premature to go into detail here. A nice paper is in press in GRL by Palmer et al (UKMO) using two Hadley climate models that details the relationship between SST and OHC to different levels in their model. Going all the way to the bottom accounts for all of the OHC but the upper OHC in the top 300 m and the SST (which relates to that) are not always good indicators of total OHC. So they also find that energy can go missing into the deeper ocean, and moreover the main phenomenon in their model associated with this is La Nina. [This latter point is not in their article]. The bottom line is that the ocean plays a major role in climate and especially in interannual and decadal variability, and a lot more will be written on this topic. Maintaining an adequate observing system is extremely important. Kevin TrenberthResponse:[DB] Hot-linked URL.
-
John Hartz at 02:21 AM on 25 July 2011Rising Oceans - Too Late to Turn the Tide?
I have alerted the three authors of the paper summarized in this news release about this posting. They may choose to chime in on this comment thread. -
John Hartz at 01:43 AM on 25 July 2011Rising Oceans - Too Late to Turn the Tide?
@Apiratelooksat50#2: Exactly which figures do you disagree with? Have you read the published paper that this news release is summarizing? -
muoncounter at 01:41 AM on 25 July 2011Rising Oceans - Too Late to Turn the Tide?
pirate#2: "I disagree" Let's see, for this study, UA team members analyzed paleoceanic records of global distribution of sea surface temperatures ... then compared the data to results of computer-based climate models simulating ocean temperatures ... The team found that thermal expansion could have contributed no more than 40 centimeters – less than 1.5 feet – to the rising sea levels during that time ... That means almost all of the substantial sea level rise in the Last Interglacial must have come from the large ice sheets For the dissenting 'study,' we see a graph covering an 18 year period and an extrapolation to 89 years. Yeah, I'd say that's disagreeable. -
muoncounter at 01:24 AM on 25 July 2011Gripping video of Arctic sea ice melting away before your eyes
pirate#4: "it is designed to play on emotions ... " Odd. An emotional response to the title of an article? Rather than what is described in that article? "... and imply something other than a natural cycle that occurs annually. " That 'natural cycles' gambit is more of a dead-ender now than the past few times you've trotted it out. It is on you to substantiate those 'cycles'. For example, how does the July 14 Icelights fit into a natural cycle? So far this summer, Arctic sea ice has been melting at a record pace. ... ice extent is currently lower than it was at the same time in 2007, the year that went on to shatter all previous records for low ice extent in September There's something about living more than 2 standard deviations below the mean that just ain't natural. But no doubt you can rationalize that away. And the subtitle to Icelights, 'Your Burning Questions About Ice & Climate,' was surely designed to play on your emotions. -
Bob Lacatena at 01:02 AM on 25 July 2011Milankovitch Cycles
To elaborate on scaddenp's comment at 17 (not sure if this has already been clearly stated elsewhere in the thread), my own understanding is that current theory states that the changes in insolation do not actually affect much themselves except to shorten/cool NH summers at the onset of a glacial, or to lengthen/warm NN summers at the onset of an interglacial. This warming is enough to cause a slow (meaning a lot slower than what we're doing to the Arctic) advance or retreat of northern hemisphere snow cover. Because of the amount of land in the NH, this results in a substantial change in albedo, which of course drops temperatures, and advances/retreats snow cover further. The drop in albedo further results in other feedbacks, primarily CO2, through things such as vegetation changes and ocean temperature changes. These, of course, evoke further feedbacks, as is well described by current climate science literature. The fact that changes in TSI are so minimal, and yet the glacials/interglacials occur, is an important clue that climate sensitivity is high. Ultimately, these effects all combine enough to cause the level of climate change required. The main problem I've seen in the literature is in trying to identify the cause/mechanism behind what appears to be an abrupt release of CO2 (which is both detected in ice core measurements, and also required for the degree of climate change seen) early in the termination of a glacial period. There's a lot of literature to be found just by searching for "CO2 glacial termination."Response:[DB] Fixed original text.
-
Tom Curtis at 00:51 AM on 25 July 2011Gripping video of Arctic sea ice melting away before your eyes
Seeing apirate wants to play silly-buggers, I think it's appropriate to look at the mean sea ice extent for September as shown here (pink line):
The interesting thing is that the location of the buoy from which the video was made is well inside that pink line. So in late July of 2011, it is already melting back beyond the mean September sea ice extent for 1979 to 2011.
This can be confirmed in the picture below of sea ice extent on July 17th
Apirate may want to attribute the fact that the summer melt has already reached a stage it normally takes two more months to achieve simply to an annual cycle. Others may suspect, at least a little bit, that if the annual cycle was the sole factor involved than this current melt extent would be the July mean rather than near the September mean.
-
Neven at 00:10 AM on 25 July 2011Gripping video of Arctic sea ice melting away before your eyes
apriatelooksat50, the video is gripping, if you're interested in this kind of stuff. And it does simply show ice melting in the Beaufort Sea. Nothing wrong with that title, unless you're having a hard time thinking things through.Arctic sea ice melting in the summer is hardly news. I am not saying that annual Arctic sea ice extent has not declined.
Indeed, Arctic sea ice has declined in summer. So fast even that it is very big news. Unless you don't want it to be news, of course. -
apiratelooksat50 at 23:29 PM on 24 July 2011Gripping video of Arctic sea ice melting away before your eyes
DB @ 3 When one reads the title "Gripping video of Arctic sea ice melting away before your eyes", it is designed to play on emotions and imply something other than a natural cycle that occurs annually. Note: I am not saying that annual Arctic sea ice extent has not declined.Response:[DB] The title clearly and succinctly tells a story, the story of what the OP is about. It is an example of "Not burying the lead".
When one reads things into that beyond what is actually said, as you do, that is an example of Confirmation Bias/Cognitive Bias. Your intransigence on adhering to a narrative (the "natural cycles" meme) being displayed here is a textbook example of what denialists do: rushing in to defend any perceived real or imaginary attack on anything that endangers their world of rose-coloured skies and green firetrucks.
Well-done, sir. As the Great One said, "It's 5-O'clock Somewhere".
-
apiratelooksat50 at 23:24 PM on 24 July 2011Rising Oceans - Too Late to Turn the Tide?
I disagree with a lot in this paper. Mainly, I don't agree with how they arrived at their figures. If we take empirical data maintained by the University of Colorado, and do some simple math, we get the following (I will even use the upper range). 89 years X 3.6 mm/year = 320.4 mm 320.4 mm = 12.6 inches That is hardly 3 feet.
-
apiratelooksat50 at 23:00 PM on 24 July 2011Gripping video of Arctic sea ice melting away before your eyes
This technology is really impressive. However, arctic sea ice melting in the summer is hardly news.Response:[DB] "arctic sea ice melting in the summer is hardly news"
In your busy waving of straw you conveniently neglect that no one on this post has claimed that it was.
-
Doug Mackie at 21:29 PM on 24 July 2011OA not OK part 9: Henry the 8th I was (*)
Bern, I hope you are not too much like Ken - take a minute to search out some previous comments by Ken (those that moderators did not delete). At the end a booklet with added bonus material, a centrefold widescreen version of figures 13 and 14, and discount coupons will be published here as a free download. Yes, as we said at the outset, this series is intended to allow readers to understand some of the more technical posts here and elsewhere. We saw phrases like "carbonate compensation depth" bandied around and we felt that few would have been able to actually explain or derive it. -
Bern at 21:10 PM on 24 July 2011OA not OK part 9: Henry the 8th I was (*)
I think perhaps Ken, like myself, is falling victim to the instant gratification that is so prevalent in modern society, so having to wait for the whole story to be revealed is almost excruciating... On the other hand, I quite like the pacing of the series of articles, and the bite-sized nature of each post. Are you planning to post an omnibus version when all the installments have been published, or let it stand as linked posts? Re the overall question - well, I think there have been enough studies published on the matter that it's pretty clear the oceans are a net sink of CO2 - and that this series is about explain just why that is so, rather than merely asserting it. -
Bern at 20:58 PM on 24 July 2011Gripping video of Arctic sea ice melting away before your eyes
For those who missed the link in the earlier post, there are some webcams located much closer to the North Pole, which can be seen here. Note that Webcam2 seems to have fallen over at a steep angle yesterday as it's supporting ice melts. This image from a couple of days ago shows plenty of meltwater & open seawater. -
newcrusader at 20:05 PM on 24 July 2011Rising Oceans - Too Late to Turn the Tide?
A foot rise of sea level along the Connecticut coast would prove very costly. Most of the states public parks would be in deep trouble. 1 foot rise would leave Rocky Neck state park http://www.ct.gov/dep/cwp/view.asp?a=2716&q=325256 and Hammonasset Beach State Park, http://www.ct.gov/dep/cwp/view.asp?a=2716&q=325210 Both In deep trouble. Both beaches are now suffering from severe erosion. The cities of New London & Groton (home of the US Sub Base) would face serious flooding during storms. With New London seeing permanent sections under water. New Haven, home to Yale would see flooding from winter storms and sewage problems. Bridgeport would see its deep water port extend into downtown!! With 2 feet of sea rise- possible by 2050. the costs for mitigating this are exponential. Yet we have many in the US Congress fighting over the chump change deficits we have now. Power in the hands of fools. -
Tom Curtis at 18:33 PM on 24 July 2011China, From the Inside Out
Agnostic @74, absolute levels of emissions are the only relevant factor at a global level, but at a national level, per capita emissions are crucial. The alternative thesis, that at a national level absolute emission levels are the only relevant factor leads directly to the absurd conclusion that in whatever final emissions mix is finally negotiated, the Vatican should be permitted the same absolute emissions level as Italy, and that Tuvalu (pop ten thousand) should be permitted the same absolute emissions level as China or the United States. Clearly that supposition is absurd, and the insistence on not using per capita emissions as the metric for international agreements and national targets is equally absurd - and can be shown to be so by simple reasoning about fairness. If, however, we commit to a limited per capita budget of CO2e emissions, then the equation becomes fairly simple:
As you can see, on a per capita basis, with a target for only a 2 degree increase above industrial levels, China can increase its total emissions by almost 50%, so long as it peaks around 2020, and eliminates all emissions by 2030. In contrast, the US and Australia need to peak now, and eliminate all emissions by 2020. That rigorous target can be ameliorated by an international trade in emission rights. But if we are not in an a global agreement that provides for such trade, there is no excuse for not reducing emissions to zero in a decade (and that would involve negative economic growth).
In the meantime China is clearly tracking very close to its appropriate target, even without trading. Whether they will continue to do so remains to be seen.
-
scaddenp at 16:23 PM on 24 July 2011Milankovitch Cycles
"Rapid" being 10x slower at least than current warming rates. -
Em at 15:48 PM on 24 July 2011China, From the Inside Out
The lifestyles of those AuStralians is pretty luxurious in comparison as well! -
Em at 15:44 PM on 24 July 2011China, From the Inside Out
I enjoyed the insight into the Chinese way of life. The demonisation of the Chinese in the current Carbon Tax debate has been quite ludicrous when you compare the lifestyle described in the article with that of most Autralians. In relation to the one-up-manship over who is allowed to comment on climate issues based on their personal carbon footprint; while it is pretty obvious that air travel in its current form is not carbon nuetral there is very little that is. I have read in the Guardian that use of the Internet produces 300m tonnes of CO2/yr, so maybe once we have stopped flying anywhere we should also then turn off our computers for ever more as well. And as possibly I don't use my computer as much as Pierre does, do I then get to have more authority to propound my views? My point is that I have no idea what steps Rob or Pierre take in their day to day life to cut or offset their carbon use, but it is possible that Rob has reduced his to a point where a yearly flight to China to maintain family contact can be justified. Is this not what we all have to do? Reduce our carbon footprint, but we can make the choice over what is neccessary to our lives and work our reductions on those that are not. -
Rob Honeycutt at 15:17 PM on 24 July 2011China, From the Inside Out
Agnostic... Definitely not trying to claim that all is well with China. There are clearly massive hurdles that face them. What encourages me is that they are actually doing things. They are taking things seriously while we in the west (yes, mostly the US) are trapped in political discord. My major point is that they are better positioning themselves to address the issue of carbon emissions. It more than ironical when I hear anyone complaining about China and what "they have to do" when we can't manage to do much anything at all. We (US again) are losing incredible opportunities to take action and move forward with every day that passes. China is moving forward every day. -
Karamanski at 15:00 PM on 24 July 2011Gripping video of Arctic sea ice melting away before your eyes
From which region of the Artic Ocean was this footage taken?Response:[DB] The buoy is approximately in the location of the crosshair placed on the map below:
-
Riduna at 14:09 PM on 24 July 2011China, From the Inside Out
An interesting article, though I would challenge its conclusion that “the West” will be playing catch-up to China before the end of the century – unless of course “the West” is an euphuism for the USA. It is true that in an effort to reduce visible pollution, the dirtiest emitters are either being closed or are being ordered to fit scrubbers to reduce their emissions. This of course refers to emission of particulates, not greenhouse gases which are steadily rising and are destined to do so for at least 50 years. Reducing aerosol emissions is commendable for popular health but it will result in an increase in the level of solar radiation reaching the earths surface which, in combination with growing CO2-e emissions, will result in escalating global warming. The primary problem facing China, India, in fact all major CO2-e emitters is clear and simple. It is to provide growing national energy needs while reducing the need to burn fossil fuels and by 2050, burning none. China has made a good but far from adequate start in this regard. Both fixed and mobile plant and equipment, including all forms of transport, need to transfer from oil-based fuels to electricity, a fact China is aware of as evidenced by its R&D into efficient electric vehicles, notably cars and trains. All very well you may say – but where is the increased level of electricity coming from, if not fossil fuels? Most of it will come from sunlight. The technology to achieve cost-efficient conversion of sunlight to electricity is not quite here yet but it is being developed in a number of countries albeit in a fragmented and inefficient way. When available, it will be willingly embraced by countries such as China which loath being increasingly dependent on the vagaries of supply and growing cost of imported fossil fuels. It is dangerously misleading to talk of how well China is doing with its low per capita CO2-e emissions. They are irrelevant as evidenced by the fact that Australian annual emissions, the highest per capita in the world, equate in total to a few days emissions by China. With regard to effect on global warming and climate change, the only relevant figure is the total emissions per country, not per capita. We delude ourselves if we “China has one of the lowest levels of CO2-e emissions per capita, so all is well with the world and China”. All is not well when China’s total emissions were over 7.7 billion tones in 2009. All is not well when China intends to increase those emissions every year for the next 40 years. Per capita, China does very well but in total it very clearly does not and it must do better – a lot better with power generation and industry which is largely unregulated and 40 years out of date when it comes to emissions. -
Eric the Red at 12:49 PM on 24 July 2011Milankovitch Cycles
Rob, The timing correlates fine. It is the rapid warming that has me puzzled. One would think that since the changes in eccentricity occur slowly, that the temperature would follow at a similar pace. Yet, that does not appear to be the case. At least, according to the ice core data. -
Rob Honeycutt at 12:08 PM on 24 July 2011Milankovitch Cycles
Camburn... Are you really trying to suggest that there is no relationship between the pace of glacial-interglaicals and Milankovitch cycles? Eric... Same question. -
DSL at 11:46 AM on 24 July 20112nd law of thermodynamics contradicts greenhouse theory
Must be a slow news day if everyone's willing to re-heat (ha ha) this thread. May I suggest a new article: "Heating up the Lexicon of Physics" or "HaIRNET: Heat and Infrared Radiation / Net Energy Transfer -- Could Be Important" or the new skeptical argument "GHE doesn't exist because you don't accept my definition of 'heat'." -
Camburn at 11:15 AM on 24 July 2011Milankovitch Cycles
That is also one of the problems with the Milankovitch theory. That was my point, the correlation does not mean causeation. However, there may be a sudden force that we have as of yet not recognized. The force seems to initially drive global climate equally between hemispheres. -
Doug Mackie at 10:33 AM on 24 July 2011OA not OK part 8: 170 to 1
JeffT, the algebra gets a wee bit tricky but it is easy to define the fraction of each species only in terms of K1, K2 and [H3O+]. Try googling dissociation of a diprotic acid. If there is huge interest we may consider an extra post to go through the equations. -
Tom Curtis at 10:32 AM on 24 July 20112nd law of thermodynamics contradicts greenhouse theory
Thankyou mc. The link should be http://web.mit.edu/16.unified/www/SPRING/propulsion/notes/node119.html -
Christina McGraw at 10:29 AM on 24 July 2011OA not OK part 9: Henry the 8th I was (*)
Ken Lambert @5. Skeptical Science - and other blogs - have plenty of good short posts on the impacts of OA. However, as we stated in the introduction to the series (and have mentioned several times since), the purpose of these posts is to give readers interested in the chemical and physical processes of OA the background information they need to understand the commentary on the web. We are certainly not introducing graduate-level concepts, but high school and 1st year university chemistry is helpful. Perhaps it was not clear that we would answer the How can we... question in the next post. The post has been modified to state this clearly. -
Eric the Red at 10:29 AM on 24 July 2011Milankovitch Cycles
Whatever the effect of Milankovitch-driven cylces, on thing is clear from the temperature record - Earth slowly slips into an ice age over tens of thousands of years, followed by a sudden rise into a warm interglacial. Can Milankovitch theory explain this? This appears to be opposite to the bifurcation diagram. -
Doug Mackie at 10:26 AM on 24 July 2011OA not OK part 9: Henry the 8th I was (*)
Oh dear Ken. Haven't you been paying attention? The series will run to about 20 parts by the time we are done. Sit back and enjoy. -
muoncounter at 10:02 AM on 24 July 20112nd law of thermodynamics contradicts greenhouse theory
damorbel#1098: "If this 'ignorance of source temperature' on the part of photons is the basis of your science then I suggest you think again. " Please, not that again. You've already contradicted yourself on the topic of 'photon temperature' on this thread.Response:[DB] Perhaps a new rule: Damorbel's Law (ala Godwin's Law).
When someone repeats/resurrects a point already refuted on the same thread by that selfsame poster, Damorbel's Law is invoked declaring the argument forfeit and all subsequent comments by that poster on that thread may be safely ignored.
One may safely then consider it already invoked on this thread.
-
LazyTeenager at 09:58 AM on 24 July 2011OA not OK part 9: Henry the 8th I was (*)
Keith Hunter at 13:35 PM on 23 July, 2011 LT @1: they amount to the same thing. Henry's Law describes the equilibrium solubility of a gas for a given atmospheric concentration. --------- Are you sure? Henry's law only applies at low partial pressures. So at high partial pressure of CO2 what happens? Does the amount of CO2 dissolved in water reach a maximim limit in the same way that a dissolved solid reaches a limit?Moderator Response: Given the current atmospheric concentration of CO2, your line of questioning is not relevant to ocean acidification. Please stay on topic. Thank you for your help in this. Doug -
Tom Curtis at 09:42 AM on 24 July 20112nd law of thermodynamics contradicts greenhouse theory
With indulgence:"If in the interior of the same solid we imagine a plane M parallel to those which bound it, we see a certain quantity of heat flows across this plane during unit of time..."
(My emphasis) Joseph Fourier, "The Analytical theory of Heat", 1878; p 105."The concept of heat 'flowing' went out with the 'fluid' concept of heat i.e. caloric."
Damorbel's theory of pedantary, 2011."Did Fourier get it wrong?"
"Title: Heat flow in the solidification of castings Author: Adams, Clyde M Advisor: Howard F. Taylor. Department: Massachusetts Institute of Technology. Dept. of Metallurgy Publisher: Massachusetts Institute of Technology Issue Date: 1953"
"Title: Heat flow over the equatorial mid-Atlantic ridge. Author: Folinsbee, Robert Allin Advisor: Gene Simmons. Department: Massachusetts Institute of Technology. Dept. of Geology and Geophysics Publisher: Massachusetts Institute of Technology Issue Date: 1969"
"Title: Heat flow in solidification of alloys. Author: Campagna, Alan John Advisor: Merton C. Flemings. Department: Massachusetts Institute of Technology. Dept. of Metallurgy and Materials Science Publisher: Massachusetts Institute of Technology Issue Date: 1970"
Heat flow and material degradation during laser metal forming 1985 16.5 Steady Quasi-One-Dimensional Heat Flow in Non-Planar Geometry So not only is "heat flow" a concept used in various MIT dissertations throughout the 20th century, it is a concept used in MIT lectures on Thermodynamics in 2007.Moderator Response: [mc] Closed italics tag. Link to '16.5 Steady Quasi' missing. -
scaddenp at 09:22 AM on 24 July 2011Milankovitch Cycles
Well lets see. Milankovitch-driven change in TSI causes much bigger changes in albedo for NH compared to SH, that is clear. It also can cause a much bigger change in CO2 and CH4 because of vegetation change, methane hydrate location, and swamp sources of both gases. The change in GHG concentration particular creates a global forcing, not just a hemispheric one. The hypothesis is testable by doing the maths and seeing how the forcings work out. See Ch6 of AR4 for the numbers on change from LGM. The inter-hemispheric connection is only a "problem" if you wish to ignore GHG forcings. On the 100k problem with milankovitch, I do agree that we have too many theories and not enough data to test them. Not much of relevance to current climate change however. -
Camburn at 07:36 AM on 24 July 2011Milankovitch Cycles
Rob: As good a guess as any. I have read so many theories on this, with none of them proveable. I know this article works on TSI basically because of the orbital changes. One thing this article does not mention, which I think at least bears thinking, is what effect does the magnetic field have? As we orbit with the Mil cycle, we are also doing a baycenter orbit. Then there is the stage 5 question when the cycle does not match the timing. I think the theory is interesting, but the lack of matching further back historically causes one to ponder the actual cause/effect question. The good thing is it causes one to think. -
Rob Honeycutt at 07:04 AM on 24 July 2011Milankovitch Cycles
Camburn @ 14... How about ice albedo feedbacks? Melting ice in the Arctic is going to cause a more rapid albedo feedback that would Antarctic land ice. The total ice mass in Antarctica is many times what it is in the Arctic. Same reason we get Arctic amplification as a result of warming. Presumably the reverse would be true of cooling. This is just a quick guess on my part. Admittedly I'd have to do some research to justify the claim. -
Philippe Chantreau at 07:01 AM on 24 July 20112nd law of thermodynamics contradicts greenhouse theory
Damorbel is at it again, after demonstrating how willing he was to contradict himself for the sake of argument. "How do you suppose a remote sensing infrared thermometer works if it doesn't relate the photon energy to the temperature of the emitter?" The hot plate of my stove emits IR photons. So does the Sun. No "IR thermometer" can tell whether an IR photon comes from one or the other. We've been there already. Damorbel's total confusion with Wien's law was clearly exposed on that occasion. Now the confusion is back, this time with gravity. It never ends.Moderator Response: (DB) Everything has an ending, including one's patience in allowing PRATT to continue to be bandied about. -
Bob Lacatena at 06:53 AM on 24 July 20112nd law of thermodynamics contradicts greenhouse theory
1098, damorbel,All these arguments about 'back radiation' and the like appear to be based on this idea of heat as a fluid substance and the preictions do not fit the observations.
This statement is not only wrong, but demonstrates a woefully poor understanding of the subject matter. You appear to be completely oblivious to radiative and molecular physics, and trapped in a 1960s mode. Please educate yourself.If this 'ignorance of source temperature' on the part of photons is the basis of your science then I suggest you think again. How do you suppose a remote sensing infrared thermometer works if it doesn't relate the photon energy to the temperature of the emitter?
You clearly failed to comprehend anything I wrote. Please go back and reread it. At the same time, this statement also represents a complete lack of understanding of radiative physics. Again, go study.it applies not only at the microscopic (molecular) level but to the sub-molecular i.e. quantum level.
No. Go study.But how can you have 1 (red) unit going from the atmosphere at 2deg. to the Earth at 5deg. How so? Did Fourier get it wrong?
No, Fourier didn't, but you do. Go study.Any object, including volumes of air, moving in a gravitational field, changes its potential and kinetic energy according to...
But we're not talking about moving parcels of air. We're talking about stationary air....but these movements must conform tho the conservation of momentum, potential and kinetic energy, don't you think?
Okay, this makes it pretty clear that you're one of those people who thinks they know what they are talking about to the point that they are hopelessly lost. Hence, this is all a complete waste of time. Enjoy applying your personal version of physics to the world. -
Camburn at 06:45 AM on 24 July 2011Milankovitch Cycles
From some final words of the article: "It seems that the Earth listens to the Northern Hemisphere when deciding to have an ice age. If the North and South are alternatively near and far from the Sun during summer, why has glaciation been globally synchronous?" This question was asked in the article, so I won't dig for references as the article states this as well. That is why I posed the question as there is really no known physical mechanism that would explain this phenomina which indiates we are missing something in the cause/effect relationship. -
damorbel at 06:26 AM on 24 July 20112nd law of thermodynamics contradicts greenhouse theory
Re #1095 Sphaerica you write:- "In thermodynamics there is no such thing as "net heat flow". Yes, there is. Go study." The concept of heat 'flowing' went out with the 'fluid' concept of heat i.e. caloric. There have been many attempts to describe heat and the idea that heat is conserved was gradually replaced with the conservation of energy during the 2nd half of the 19th century. All these arguments about 'back radiation' and the like appear to be based on this idea of heat as a fluid substance and the preictions do not fit the observations. You write:- "If a molecule emits energy in the form of a photon, the receiving molecule does not and cannot know if the emitting molecule was warmer or cooler. The energy of a photon has the relationship E = hv, this is at the basis of quantum theory laid down by Max Planck and further developed by A Einstein, Werner Heisenberg etc., etc. in the early 20thC. This discussion has raised this point about 'photons not knowing the source temperature - I'm sure I have seen it before and it just isn't true! In this respect photons are no different to any other particles. If this 'ignorance of source temperature' on the part of photons is the basis of your science then I suggest you think again. How do you suppose a remote sensing infrared thermometer works if it doesn't relate the photon energy to the temperature of the emitter? Again you write:- "thermodynamics does not apply on an individual molecular level. It applies in aggregate (i.e. at the macroscopic level)." Since thermodynamics is base on the conservation of energy, not heat, it applies not only at the microscopic (molecular) level but to the sub-molecular i.e. quantum level. I suggest you are thinking of statistical mechanics which is indeed very useful for understanding ensembles of freely interacting particles. But statistical mechanics relies just as much on the conservation of energy and the conservation of momentum (both angular and linear) as does themodynamics and quantum mechanics. Further you write:- "I simplified the "temperatures" to 5 for the surface and 2 for the atmosphere, but they are clearly there. The surface temperature should be 4 (the amount coming from the sun) but it is 5. The extra "ray" is the red one, coming from the atmosphere." I am not sure of your meaning here. According to Fourier heat transfer is between two bodies according to the temperature difference you have in your diagram 2 units of heat going from the Earth at 5deg. to the atmosphere at 2 deg - quite possible. But how can you have 1 (red) unit going from the atmosphere at 2deg. to the Earth at 5deg. How so? Did Fourier get it wrong? You write:- "Thermodynamics does not allow gravity to violate (or suspend) the 2nd Law of Thermodynamics, any more than anything else might. [Did you even realize that when you argue that gravity maintains the temperature differential, it is in fact you who are violating the 2nd Law of Thermodynamics?]" What is missing from your argument is the conservation of energy, both potential and kinetic. Any object, including volumes of air, moving in a gravitational field, changes its potential and kinetic energy according to the strength of the gravitational field and the (vector) distance it moves; this is the argument that got Galileo into trouble. As for a volume of gas, it loses kinetic energy as it rises in a gravitational field, changing into potential energy therefore it cools, it is as simple as that. No need to talk about compression and expansion, gas is free to move as it likes in an atmosphere, but these movements must conform tho the conservation of momentum, potential and kinetic energy, don't you think? -
Steve Brown at 05:56 AM on 24 July 2011The Last Interglacial Part Two - Why was it so warm?
Steve #15 - You've raised a very interesting question, which I can't answer. It would make a very good topic for a future post, which I'll look into. -
Camburn at 05:52 AM on 24 July 2011Milankovitch Cycles
Dikran: I am working from memory at this point. One thing that always stuck to me was also called the Stage 5 problem. I will dig for the Northern/Southern thing. I thought this was common knowledge to anyone who has reserached the Milankovitch cycle.Moderator Response: [Dikran Marsupial] Fine, once you can find the data, we can discuss it, but until then it would be better not to distract from discussion of the existing issues. -
Camburn at 05:40 AM on 24 July 2011Milankovitch Cycles
Dikran: I understand there are other forcings at work. But for the Milankovitch theory to hold up, the match between the hemmispheres should not be so.Moderator Response: [Dikran Marsupial] As I said, present some data that show on what timescale and to what degree they match. That way some meaningful discussion might result. -
Steve Brown at 05:39 AM on 24 July 2011The Last Interglacial - An Analogue for the Future?
Andrew #30 - My statement in the post was intended to be ironic. I don't disagree with your explanation. -
Camburn at 05:24 AM on 24 July 2011Milankovitch Cycles
There are still questions about exactly how changes in the earth's orbit affect the climate, and especially in why the climatic changes match in the Northern and Southern Hemispheres. Does anyone have an answer to this question? The match in climate changes on both hemispheres indicates that there are other forces in play as well.Moderator Response: [Dikran Marsupial] See CO2 is not the only driver of climate. Solar forcing (inlcuding Milankovic cycles) isn't the only forcing either. In addition, you would be better off stating on which timescales you think climatic changes match in the two hemispheres, preferably by refering to a specific dataset. -
muoncounter at 04:41 AM on 24 July 20112nd law of thermodynamics contradicts greenhouse theory
damorbel#1083: "distinguish between this compressive heating of the surface and the GH effect?. For me this is critical to the understanding of atmospheric physics and not often discussed." Perhaps an idea is 'not often discussed' because it is clear to most that it has little merit. You appeared as the champion of this idea as far back as comment #125 on this very thread, where the "death knell of the GHG hypothesis really is the effect of gravity on the atmosphere." Rumors of the 'death knell' of the 'GHG hypothesis' have been greatly exaggerated. This is not your personal soapbox; if you have nothing new to contribute, no one really enjoys reruns. -
DaneelOlivaw at 04:10 AM on 24 July 2011Why Wasn't The Hottest Decade Hotter?
I've made a spanish version of the first graph for my blog. http://i.imgur.com/Vs9ls.jpg
Prev 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 Next
