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Comments 105151 to 105200:
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Camburn at 05:16 AM on 8 November 2010Ice-Free Arctic
One would expect the ice conditions to be low at this time as we are at the end of the 30 year cycle. The northern northwest passage was sailed in 1944. As low as the ice was during the past 6 years, that voyage has not been repeated. There are numerous stations showing the current air temps of the Arctic are very simliliar to the temps of the late 30's and early to mid 40's. Geomagnetic research is showing that solar winds and the sun's cycles play an extremely important role in the placement of the jet streams. There also seems to be a link between geomagnetic levels and placement of global ocean circulation. And not least, is the tremendous amount of soot that China spews that lands in the Arctic. Mr. Schmidt etal published a paper in Science expressing that co2 has a minor effect on the Arctic verses the culmination of soot etc. -
oamoe at 04:52 AM on 8 November 2010Ice-Free Arctic
Several questions: 1) When will cryosat 2 begin collecting data? 2) Will cryosat 2 data serve to calibrate the PIOMAS model? 3) Why the big time lags in PIOMAS web updates? -
Brutus at 04:39 AM on 8 November 2010Ice-Free Arctic
There are no (systematic) observations from 1900 till 1950 (according to the IPCC-curve). How do they know that minimum sea-ice extent was above 8 mill km2 all these years? Isn´t it likely that minimum sea-ice extent was much lower in the 1930s when temperatures were (almost) as high as today? -
Riccardo at 04:21 AM on 8 November 2010Ice-Free Arctic
CBDunkerson I think we all agree that ice volume is the real quantity of interest. The problem is that we do not yet have good measurements. Hopefully in a few years we'll have enough to hindcast past conditions accurately and eventually redo this kind of estimates. Crispy I don't like betting, but I know many people do. Grumbine's estimate using a logistic function is easy to reproduce, but before showing the results I'd like to emphasize that it's a purely probabilistic approach, no physics whatsoever behind it.
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Rob Honeycutt at 03:52 AM on 8 November 2010Ice-Free Arctic
Riccardo and _Flin_.... You might look at Dr. David Barber's lecture here. If you go to minute 19:40 Dr Barber is predicting ice free summers sometime between 2013 and 2030. And this is a very recent lecture. -
Riccardo at 03:06 AM on 8 November 2010Ice-Free Arctic
Thank you MichaelM and NickD, I made the necessary corrections. _Flin_ as you may have noticed, the post didn't focus on the timing. I think it's more important to focus on the process itself and to know that it's a matter of decades, not millennia. -
Crispy at 02:57 AM on 8 November 2010Ice-Free Arctic
Thanks Riccardo, very clear. I've been lurking at this site a long time... thank you John for all the work. Robert Grumbine has a discussion of the timing for an ice-free arctic September. He estimates 2035, plus or minus seven years, based on a probabilistic prediction. Which starts with a logistic curve as a best fit for the data, I think. RG is an infrequent blogger, but always worth a look. He has a lot to say about arctic ice. -
CBDunkerson at 02:54 AM on 8 November 2010Ice-Free Arctic
The article suggests that ice-albedo feedback will eventually reach a point of diminishing returns which should cause the currently accelerating decline in extent to level off. How certain is it that the trend is being driven primarily by ice-albedo feedback? Pikaia brings up the much steeper ice VOLUME trend (declining an average of about 1000 km^3 per year for the past decade, Sept minimum 5800 km^3 in 2009 and 4000 km^3 in 2010)... which might suggest that the melt is being driven by ocean temperature change. Yes, ice albedo factors into the ocean temperature, but ice volume has dropped even in years that extent has increased. Each of the past three years has had ice extent greater than 2007, but ice volume has continued to decline to new record lows each year. To me that suggests that what we are seeing is part of the effect of global warming on world ocean temperatures. The water flowing into the Arctic ocean is warmer than it was in decades past and that is accelerating the breakup of the Arctic ice cover. This causes old thick ice to break into smaller chunks which can then spread out to continue 'filling' extents similar to past years... but eventually that thick ice will be gone and extent will drop as sharply as volume has been. If the ice volume trend is going to level off it only has a few years left in which to do so before hitting zero. We should be starting to get Cryosat 2 data soon now. Hopefully that will dispel any questions about the accuracy of ice extent and volume estimates. -
pikaia at 01:49 AM on 8 November 2010Ice-Free Arctic
If you look at the volume instead of the area it looks like the Arctic will be ice-free sooner rather than later. The average volume in September is 13,500 cubic Km, and the bottom of this graph equates to an anomaly of 13,500: http://psc.apl.washington.edu/ArcticSeaiceVolume/images/BPIOMASIceVolumeAnomalyCurrent.png http://psc.apl.washington.edu/ArcticSeaiceVolume/images/PIOMAS_daily_mean.png -
NickD at 01:32 AM on 8 November 2010Ice-Free Arctic
"Catastropism"? :) -
muoncounter at 01:08 AM on 8 November 2010Ice-Free Arctic
Some are betting on sooner, rather than later: Shell is pressing the Interior Department to grant final approval for its Arctic projects by the end of this year so that the company has enough time to move the necessary equipment to drill next summer, when the waters offshore are free of ice. -- New York Times, 5 Nov 2010 (emphasis added) -
muoncounter at 00:55 AM on 8 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
#38: "there must have been a steady stream of CO2 being liberated from somewhere and for some reason" Yes, its called the Carbon Cycle. There are numerous discussions of it here, which you can no doubt find on your own. "(lets assume the ocean)." Why? "But in order for plants to thrive, and for CO2 to be released, temperatures need to go up." Again, why? There is always some CO2 in the atmosphere; the amount moved around the photosynthetic cycle doesn't necessarily cause temperature increase -- that's why today's climate change is called Anthropogenic. A large percentage of the fossil fuels we've burned recently was formed at times in the geologic past when CO2 was much higher than it is today: That's why this is a bad thing. We've put back into the atmosphere the stuff that was put away long ago. "How could this have happened if the plants where continually sequestering the CO2?" Perhaps read up on how fossil fuels are formed and then come back to the Carbon Cycle. -
_Flin_ at 00:36 AM on 8 November 2010Ice-Free Arctic
Thank you, Riccardo. Looking at accelerating arctic sea ice loss the question one asks is: "When will the arctic be ice-free in September?". The first graph supports the impression: "Oh, in 2020, or maybe even a bit earlier". Which is of course not true, and differs from your text as well. Thank you for providing the other graph, I really do appreciate it. It helps for pointing people over here without having to discuss things like "Oh, the alarmists over there use misleading scales." -
muoncounter at 00:23 AM on 8 November 2010The value of coherence in science
#82: Nice to see this repeated. Your 'logic' is really the bottom of the barrel in terms of arguments: A general swipe at a class of individuals. You might as well say 'all plumbers are crooks' or 'all cops are out to get you'. No way to deny, no way to verify, because it doesn't apply to anyone in particular. Nice. Of course, my earlier note still stands: This sword cuts both ways. By your 'logic', climate deniers must be just as computer illiterate as climate scientists. Have you posted same at W@tt$ and Co. or clim@te @udit or any of the others? Let us know how 'Hey $teve, you're computer illiterate' goes. "My post was 100% accurate." Accurate, yes: as quotes from a 'News Feature', which is not a scientific paper. The 'feature' is based solely on anecdotal evidence (and part of that provided by someone who owns a company in the business of fixing just this problem!) Does the author have a degree in computer science and is therefore qualified to assess even this anecdotal evidence or is she a freelance journalist and author? -
MichaelM at 00:14 AM on 8 November 2010Ice-Free Arctic
I'm terribly sorry. My previous message was very curt. I should have added my thanks to Riccardo for all the work he put into writing the article. -
Phil at 00:09 AM on 8 November 2010The value of coherence in science
Poptech's argument also depends on a rather idiosyncratic view of the research environment (as indeed does the original Nature article, to some extent). Development of software in research groups was (in my day) carried out by graduate students and post-docs. It almost certainly still is today (as in the case of "Harry"). Like any organisation, a research group will be made up of specialists whose expertise is not shared throughout the group. Therefore, it seems to me, the idea of making scientists more "computer literate" misses the point. What is really needed is for the research group as a whole to be aware of good software practises, whether it is test-driven-development, pair-programming, peer-review and documentation standards. Poptech's assertion that by "dealing with university scientists" he understands the software culture of a research group seems dubious to me. -
MichaelM at 00:04 AM on 8 November 2010Ice-Free Arctic
The Copenhagen Diagnosis link is broken. There is an extraneous space at the end i.e 'LOW.pdf_' -
Paul D at 23:32 PM on 7 November 2010Ice-Free Arctic
I'd forgotten the Copenhagen Diagnosis! I think that is because it coincided with the CRU email theft. -
Riccardo at 23:14 PM on 7 November 2010Ice-Free Arctic
_Flin_ you don't say what that figures apparently implies, so forgive me if I misinterpret your thought. What I wanted to show, and as explicitly said in the text, is that the downward trend has accelerated. If you think that by having the y axis starting at 3 I'm suggesting that we will have an ice-free arctic when the extent reaches the x-axis, it would be in contraddiction with what I wrote. I'd also like to underline that a polynomial fit is an interpolation technique, I hope no one will try to extrapolate it to zero without good (physical) reasons to believe it will continue. As I said in the text, we have good reason to believe it won't. Anyways, if you're happier with the y-axis starting at zero, here's the graph:
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MichaelM at 22:29 PM on 7 November 2010The value of coherence in science
Poptech: Using your logic, scientists not formally trained in English would likely be illiterate. Their training in English after High School is very much self-taught. Your argument does depend on a very narrow definition of 'illiterate', Scientists have indeed been criticized for their use of english and have been asked to improve their communication skills. I have no doubt English professors would view some of their scientist colleagues as illiterate barbarians. In its more common usage, calling out climate scientists as computer illiterate is a shallow attempt to mislead. -
_Flin_ at 21:35 PM on 7 November 2010Ice-Free Arctic
I don't like the NSIDC graph. Y-axis should start at 0. As it is, it implies wrong things. Facts are bad enough without a distortion like that. Of course the graph is correct, y-axis correctly labeled, nevertheless starting at 0 might show better where we are heading. -
JMurphy at 21:13 PM on 7 November 2010Models are unreliable
A nice demonstration of how models work is given here, at Steve Easterbrook's site - it is of French origin and you can access the original video through that site also. -
Richo at 21:10 PM on 7 November 2010It's cooling
To the Yooper, Thanks for the links above, re #65, excellent way to get a good base, very interesting info. I have some questions that I will post in the appropriate threads. -
erikbays at 18:43 PM on 7 November 2010CO2 effect is saturated
After thinking on this I think I understand the IPCC argument better. I think the idea is there are two areas of increased warming. One is the outer atmosphere which is caused by CO2 as this article talks about. The second is the area between the troposphere and stratosphere, which is caused by H2O feedback. This increased H2O would supposidly prevent radiation from the troposphere to the relatively still stratosphere. The problem with the H2O feedback idea is it brings us back to the "skeptic" arguments raised in this article. H2O can approach (but never reach) saturation just like CO2 can. So each additional amount of H2O does less warming. Except now we don't have the counterarguments that the H2O is getting farther apart or that the H2O that is radiating is getting cooler and therefore radiates less (because it's getting warmner). I tried to be brief so I hope that makes sense. -
RSVP at 17:20 PM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
Daniel Bailey #36 "...an immense bolus of formerly sequestered (i.e., removed from the carbon cycle's closed budget) fossil-fuel derived CO2 back into circulation in the carbon cycle" In order for hydrocarbons to have accumulated over the eons, there must have been a steady stream of CO2 being liberated from somewhere and for some reason (lets assume the ocean). But in order for plants to thrive, and for CO2 to be released, temperatures need to go up. How could this have happened if the plants where continually sequestering the CO2? What''s good for goose, must also be good for the gander. -
erikbays at 16:17 PM on 7 November 2010CO2 effect is saturated
This page makes the argument that the lower layers of the atmosphere are ruled by convection, and that it's the "temperature of this 'last' layer" that is important for radiation of energy. However, the majority of the warming projected by the IPCC is caused by water vapor feedback in the troposphere. The outer layers of atmosphere do not have water vapor. So the argument on this page seems counter to any argument of water vapor feedback. -
Albatross at 16:17 PM on 7 November 2010Models are unreliable
Poptech, Oh now it is "natural scientists"...need I remind you of your original headline? Anyhow, you demonstrated above that you not only cherry picked your cut and pasts, but you distorted the content of the article to suite your means. Yes, that is poor form. EOS. Do all scientists (with the obvious exception of computer science) need to hone and improve their computer skills? Yes, I can certainly agree with that. -
erikbays at 15:58 PM on 7 November 2010It's cooling
Yooper, I agree with pretty much every point you make @ 74, but it is a strawman argument. To rebut me you would need to show how historic temp data encompasses the total Earth heat content. That is what this page is talking about and that is what my post was about. Nitpicking about what years of temp data the NAS has confidence in has nothing to do with my point that historical temp data doesn't encompass total Earth heat content. -
Peter Lang at 14:28 PM on 7 November 2010What should we do about climate change?
kdkd, The discussion is pointless. You need to have some understanding of electricity generation system. Understand the overall picture first, then progress to lower levels of detail one you understand how the part you want to discuss links into the overall picture. Trying to discuss a partluclar item when you don't understand how it fits, or what effect (proportional contribution) it has on the overall system is simply a diversion. Please don't waste time on this. If you are genuinely interested you will do some research. You could start by going through the psosts on this thread, or you could go to Brave New Climate or you coluld take your own route. My suggestion is to read the authoritative reports not the nonsense on the media and Greenpeace type stuff. -
kdkd at 13:58 PM on 7 November 2010What should we do about climate change?
PL #373 So do you have anything to say about demand management synergestic effects, and renewable generation site optimisation? Have you accounted for these in your conclusions? Can you show me where? -
Peter Lang at 13:16 PM on 7 November 2010What should we do about climate change?
Michael sweet, I believe I have answered you, but perhaps you do not want to hear the message. I think this sums up your position: I also don't like to see all the eggs in one basket, but your nuclear proposal looks like a bad idea that should go to the end of the line. In otherwise, you are not prepared to do any objective research. I've provided sufficient on this thread to get you started if you are interested. If you are not, then so be it. -
Peter Lang at 13:13 PM on 7 November 2010What should we do about climate change?
kdkd, I don't agree with your assertion that I have not challenged my own assumptions. You are not prepared to look at the links. There is too much background to get across to you in a blog field. -
muoncounter at 11:33 AM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
#34: "You take one location and say it is a reasonable representation of global effects." No, this is a global event. See Bohaty, cited in #35, who used OSDP cores; see Luciani et al 2010, who studied samples of Tethyan oceanic sediments now exposed in northeastern Italy. -
Daniel Bailey at 11:28 AM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
Re: RSVP (27), Bodo (28, 25) To augment Bodo's excellent response to you, RSVP, at 28 above, remember that temps are a sum of forcings and feedbacks, of which CO2 is one (but the principal one). If CO2 levels spike, say due a methane clathrate/hydrate release as is theorized occurred during the PETM, then it would be reasonable to expect a temperature response of about 3 degrees per doubling of CO2 from baseline. But if that CO2 spike were accompanied by a lowering of TSI (as occurred during the Ordovician) and also some large volcanic aerosol releases in the tropics (where volcanoes have their greatest impact), than the global temperature response to CO2 will be more muted We know with certainty that CO2 is a greenhouse gas, that a certain increase in concentration will, other forcing and feedbacks remaining constant, drive a certain global temperature increase. Slow changes in Milankovich orbital cycles drive slow changes in temperatures, which can then change CO2 levels in response (an example of CO2 acting as a feedback to drive a limited secondary temperature increase). In this case, CO2 lags temps. How the modern era differs from past comps is this: we have injected an immense bolus of formerly sequestered (i.e., removed from the carbon cycle's closed budget) fossil-fuel derived CO2 back into circulation in the carbon cycle. So, despite a quiet sun with a flat TSI, despite some of the strongest La Nina's on record, global temps are up, Arctic ice area (and extant and volume) are down, Greenland, the WAIS and the EAIS are losing mass and sea levels are rising - all within ranges of predictions based upon the physics of greenhouse gases...CO2 in specific. In this case, CO2 is acting as a forcing to drive temperature increases, which then drive secondary CO2 releases which act as feedbacks; temps lag CO2 increases. As a result, the nearest analogue to the current spike in atmospheric CO2 levels is probably the PETM (which will be a worst-case scenario for us). If we continue BAU for long enough and spike temps high enough, the probability of a methane hydrate/clathrate release goes from a remote possibility to a probability. Hence the need to further study the PETM (per Bodo's question). The more we know about the PETM, the better able we may be to gauge how near the cliff's edge we actually are in this fog of lack of knowledge about climate response we are in. Given that, to say"it is clear that cart is in front of the horse, and neither are going anywhere"
as RSVP says is specious and anything but helpful. The Yooper -
lweinstein at 11:27 AM on 7 November 2010Compendium Maps: a visual summary of the climate debate
May I suggest you make a similar Compendium Map of the specific claims supporting that humans are the cause of the present warming, and that it is leading to a problem of significant size. Note, I did not say show there is warming, and this is a problem, but that it is human caused. It would be best if these are falsifiable claims so they can be tested.Moderator Response: As far as the human attribution of the warming, please see the skeptic argument rebuttal It's Not Us - Intermediate. -
muoncounter at 11:25 AM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
32:"where you get 5 C as the temperature change." Since this figure is a stratigraphic record, time advances towards the present from bottom up. Below the MECO (yellow), the red is at 23C, during the MECO red is in excess of 28C. "if you start at the earlier time on the graph, the maximum increase in MECO is only about 2.5 C for the red " By the definition in this paper, the MECO is a short duration 'transient' event. Bohaty et al 2009 provide additional context: The identification of the δ18O excursion at sites in different geographic regions indicates that the climatic effects of this event were globally extensive. The total duration of the MECO event is estimated at ∼500 ka, with peak warming lasting <100 ka. Assuming minimal glaciation in the late middle Eocene, ∼4°–6°C total warming of both surface and deep waters is estimated during the MECO at the study sites. ... The synchroneity of deep-water acidification and globally extensive warming makes a persuasive argument that the MECO event was linked to a transient increase in atmospheric pCO2. -
lweinstein at 11:09 AM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
Another comment to John Cook: You take one location and say it is a reasonable representation of global effects. I won't dispute that, but it is weak. Now let us look at the Greenland ice core going back the last 10,000 years, and even back it up with an ocean floor core in the Sargasso sea. These (and other sources) show that the temperature was warmer several times and cooler several times by up to 2 C or more. The present temperature at these sites, which appears to be a natural recovery from a cool period called the little ice age, is actually slightly below the average peak for the last several thousand years. The speed of change was as high or higher for many of these variations. Yet the CO2 is indicated as constant to a narrow level. What do you propose as the cause of the variations, which make the present 150 year variation seem as typical? I would be glad to input the curves, but I am sure you have seen them. -
lweinstein at 10:57 AM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
#31, Bodo, I agree with your comment. 15 ppm per 1 C it is. Going back to the post by John Cook: John, I look at figure 1 and ask where you get 5 C as the temperature change. It appears the temperature and CO2 were going in opposite directions up to the beginning of MECO. Explain that. Also the 5 C assumes the red proxy case is the correct one, and the value was used at the low at the beginning of MECO and the high within it. However, if you start at the earlier time on the graph, the maximum increase in MECO is only about 2.5 C for the red and near zero for the purple proxy (based on the earlier maximum than MECO). In addition, there is a slow peak after MECO in CO2 but a dropping temperature. It clearly appears something happened, but the deduction shown is not a strong one. -
Bodo at 09:39 AM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
@Iweinstein: For example the interglacial/glacial cycles, there you have enough time (5000 years ca.) and the feedback is about 15 ppm/K. Furthermore oceans were ventilated during that time, biological pump was more efficent during the glacials. Check also the Frank et al 2010 Nature paper. They state that there is only a limited time dependece of the co2 feedback. -
lweinstein at 09:28 AM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
#28, I am curious where you came up with the figure of 15 ppm CO2 caused by 1 C temperature increase. Consider that only the upper 10% or so of the ocean has time to respond to a 1 C temperature change in just 100 or so years. In a few thousand years, all of the ocean would be affected, so about 10 times the CO2 would be released. Actually, since the deep ocean is far colder than the surface, and since the solubility of CO2 is far higher in cold water, I expect even more than 10 times the CO2 would be released for a 1 C increase. You are welcome to try to refute this. -
muoncounter at 08:39 AM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
#25: "I havent heard of MECO " MECO shows up in literature as early as Bohaty and Zachos 2003 This isotopic event is designated as the middle Eocene climatic optimum, and is interpreted to represent a significant climatic reversal in the midst of middle to late Eocene deep-sea cooling. The lack of a significant negative carbon isotope excursion, as observed during the Paleocene–Eocene thermal maximum, and the gradual rate of high-latitude warming suggest that this event was not triggered by methane hydrate dissociation. Rather, a transient rise in pCO2 levels is suspected, possibly as a result of metamorphic decarbonation in the Himalayan orogen or increased ridge/arc volcanism during the late middle Eocene. -
OBAFGKM at 08:35 AM on 7 November 2010Abraham reply to Monckton
AWoL. You found Monckton's rebut 'pretty impressive'? I on the other hand, thought of a line by Shakespeare. I'd describe is as "... full of sound and fury, signifying nothing." If you find the scientists responses lacking in passion, perhaps it's because they are concerned primarily with precision, accuracy and facts. Remove the many colourful ad hominem attacks by Monckton in his rebut and you'll find that while it may have style, it's sorely lacking in substance. -
kdkd at 08:07 AM on 7 November 2010What should we do about climate change?
Peter Lang #368 My hot water heater may not be an electricity generation system, but as it replaced an immersion heater, it certainly has a substantial impact on demand (reduced our household consumption by about one third). I'm concerned that your argument is geared towards confirming your assumptions. That is, you're aggressively arguing your case, without examining if the assumptions of your argument hold up to scrutiny. If you start making the assumption that some of the premises of your argument are incorrect, and use that to test the quality of your argument, then I'm going to be in a much better position to accept the veracity of your position. For example, what effect would a smart grid have on peak demand if 'discretionary' heating and cooling activities could be moderated through demand side management? What synergistic effects would this have if wind and solar sites were placed to reduce the problems of intermittency? And so on. Right now, I see you agressively defending your own argument with no evidence that you've challenged your own assumptions. Once the small scale safe nuclear stuff is clearly viable, and commercially available, I will be writing to my politicians by the way. -
Bodo at 08:05 AM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
RSVP: The CO2 feedback (you increase the temperature 1°C, how much does CO2 rise?) is about 15 ppm/K. In MECO temperature increase was according to Bijl et al 2010 6°C or less, thus an increase of 2000 ppm or more is difficult to explain with CO2 outgassing as an feedback. Another point is that there are many different ways to estimate climate sensitivity, they ALL come up with about 3°C, read for example Knutti 2008 -
RSVP at 07:54 AM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
moderator #18 Thanks for your answer. michael sweet #20 Thanks for listening so keenly. Again, the stronger one assumes the coupling between CO2 and climate, the less change in CO2 level needed to affect climate (i.e., CO2 has great leverage)..., or the inverse; the weaker the coupling between CO2 and climate change, the more change in CO2 level needed to affect climate (i.e., CO2 has little leverage). This paradox makes it difficult to know with certainty that CO2 has any effect, because in the first case any correlation may be completely false, and in the second, if true, the coupling is weak and might as well be ignored. If, as has been stated, CO2 is released with higher temperature, it is clear that cart is in front of the horse, and neither are going anywhere. -
Bodo at 07:38 AM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
As it seems this CO2 increase was even lager than PETM (about 700 ppm), and no knows source (but lower temperature increase)? Seems to be an interesting research topic ;-) -
Bodo at 07:34 AM on 7 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
Very interesting paper! Perhaps you could add a few clarifying words about the CO2 increase. The fact that there was not a strong signal in carbon isotopes is stunning. The source of carbon must be an different as in PETM (probably methanhydrates). PS Does anyone know why reasearch focuses so much on PETM? I havent heard of MECO until a few minutes ,while PETM is discussed for a long time in journals? -
Daniel Bailey at 06:01 AM on 7 November 2010Sea level rise is exaggerated
Re: Karamanski (103) Not accounting for an additional rise due to an unknown level of thermal expansion, if it all goes at some unknown point in the future, Greenland contains enough water to raise sea levels by 7.2 meters while Antarctica (WAIS + EAIS) has enough to raise sea levels by 61.1 meters for a total of 68.3 meters (224 feet). Dunno where you got those figures (not cited in my powerpoint of the same name), but that total amount is approximately the vertical interval between the lowest of the sea levels during glacial max and that if all the ice melted. Perhaps that is what they meant. As far as thermal expansion, my understanding is that per each 1 degree C of ocean temperature rise will be accompanied by 1 meter sea level rise just from thermal expansion. Unless memory is deserting me. The Yooper -
Karamanski at 05:20 AM on 7 November 2010Sea level rise is exaggerated
What is the maximum possible sea level rise if all of the glaciers and ice sheets melted, and how much sea level rise can we get from thermal expansion? I read in "Global Warming FOR DUMMIES" that the maximum possible sea level rise from global warming is 650ft(200m) is this correct? -
Paul D at 23:58 PM on 6 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
Miekol: "The fossil fuels that was once living organisms had to get their CO2 from the atmosphere, so early on the atmosphere must have been loaded with CO2." Even at a basic level that is incorrect. You are confusing carbon with CO2. A lot of CO2 would have been sequestrated by life at the time and held as carbon. As a poster pointed out you need to understand the carbon cycle. Apart from that, the faint young Sun and the CO2 thermostat would have taken care of long term CO2 effects and levels over hundreds of thousands of years.
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