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Camburn at 13:52 PM on 8 November 2010Ice-Free Arctic
muoncounter: Did you read more or just the first few paragraphs? In case you didn't: "An advantage of the EM technique is that it can be deployed from helicopters or airplanes. In the summer of 2001, a new helicopterborne EM sensor ("EM-Bird") was operated in the Arctic for the first, yielding high resolution thickness data of good quality. With the EM-Bird, we will now be able to perform systematic large-scale studies of the ice thickness distribution, improving our ability to better judge observations and predictions of possible climate changes" They took the EM and put it on Polar five and flew grids over the Arctic in 2009. The results were much thicker ice than had been anticipated. I will be the first to admit that one year does not prove anything. However, it does prove that there is large variances in ice thickness that were not expected as the 2009 data showed. -
scaddenp at 13:45 PM on 8 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
Protestant - trying the "correlation prove causation" again. Did you read responses from the last time? No, the paper attempts to show that a modelled prediction is in accordance with observation. That is how science is done. "They claim there would be almost no greenhouse effect without CO2, thats an outrageous misinterpretation." No, what you are saying is an outrageous misinterpretation. I defy you to find any scientific paper that makes such a claim. From both observations and models, water vapour is temperature-controlled. Sure, water vapour feedbacks amplifies any change in any forcing but to investigate the cause of a trend requires looking at the forcings. -
Camburn at 13:35 PM on 8 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
John: Hate to quible, but the 2009-10 El Nino IS the second strongest since 1998. Your graph shows this. Read the Murphy etal paper. The answer to your question is contained within the paper. As far as GISS, it is the outlier amongst the big 4. RSS/UAH and CRU. The Arctic temps that GISS showed the summer of 2010 in the Arctic were approx 4.0C different than DMI temps. GISSTEMP uses one sensor, DMI uses hundreds. -
Stephen Baines at 13:21 PM on 8 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
@protestant #42 "Which one of you really believes that we would lose nearly all water wapor and have over 70% cloudiness without CO2? omg..." Actually, I do...and it doesn't take a complex climate model to believe it. Let's try... If you remove all the CO2, the climate will cool as 1/5th of IR absorption by the atmosphere is due to CO2 (that is well measured). You will rightly point out that there is still water vapor present that accounts for at least 75% of the greenhouse effect including clouds (also well measured). But I also know it's raining outside my house right now. That tells me water vapor condenses when the air temperature falls below a critical threshold, and that temperatures on earth often fall below this threshold...we have water in our atmosphere precisely because that atmosphere is warm enough to allow water vapor to keep from precipitating out faster than it evaporates. What happens when we weaken the greenhouse effect by removing CO2? It would lead to a colder atmosphere, which causes evaporation to decrease and precipitation to increase, which leads to a lower greenhouse effect, which cools the earth some more, which causes more water to precipitate, which lowers the greenhouse effect....and on and on until you reach a new much colder and drier equilibrium that depends on the other control knob -- the incoming solar radiation and the earths ability to absorb it and redistribute the remaining heat. You only need the model to estimate that stabilization point and the time frame over which it is reached. You don't need it to tell you that earth would be a lot colder than now in the absence of CO2, and that water would be less abundant. All you need to know that is that it rains, that water vapor absorbs IR radiation and that earth would be a lot colder if there was no greenhouse effect. Those facts are not in dispute. Without an IR absorbing gas(or gasses) that does not condense out when it gets colder, you cannot have a stable climate on earth that is anything like ours. Of course that also means when that non-condensing gas varies in concentration, for whatever reason, climate will follow it. That can happen for natural reasons, as it has in the past, or due to human impacts, as it does now. -
Daniel Bailey at 13:11 PM on 8 November 2010CO2 has a short residence time
Here's a nice graphic to help visualize the "long tail" of atmospheric CO2 (the very long residence time):
Kinda heightens the imperative to the danger excess CO2 carries: there is no quick fix.
Temps that go up will, like the CO2 elevations, go down slowly.
On the plus side, no ice ages in our immediate futures!
The Yooper
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John Bruno at 13:03 PM on 8 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
"The El Nino of early 2010 was not "mild" according to NOAA this El Nino was the strongest one since 1998. While this El Nino was not nearly as strong as the 1998 El Nino it still met the criteria for being a moderate to strong El Nino." - Karamanski at 12:26 PM "Yes, the El Nino of 2009-2010 was the 2nd strongest according to NOAA." - Camburn at 12:34 Sorry, your'e both wrong. The 09/10 El Nino was "mild" according to NASA and was not even among the top 7 strongest of the last 50 years. Take a look at the NOAA MEI graph below and then tell me you want to argue the 09/10 El Nino was anything but mild-to-average:
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muoncounter at 12:41 PM on 8 November 2010Ice-Free Arctic
#32: "Using fixed wing aircraft, the Alfred Wegener Institute for Polar and Marine Research found the ice to be thicker than anticipated." From the AWI website: The results have been obtained by means of computations with a numerical dynamic-thermodynamic sea ice model, using six-hourly atmospheric forcing data. Perhaps some modeling is part of that work after all? "the effect of magnetic flux on high latitude temperatures." Sounds like you may have heard that its all due to cosmic rays? Been there, done that: no dice. -
John Bruno at 12:38 PM on 8 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
Camburn at 12:32 PM: please explain the relevance of your comments. -
John Bruno at 12:36 PM on 8 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
HumanityRules at 12:08 PM: Sure, if your'e interested in looking at the peak monthly low, then yes, the monthly data might be better. And why not look at daily temps? Or daily temperature in Jupiter FL? (my home town). The finer the spatio-temporal grain of the measurement, the greater the range of the values. Looking at monthly extremes isn't "more accurate". It is just a finer-grained comparison and inevitably yields a greater extreme value. In an older version of the post I had a section speculating Art was doing exactly what you suggested: start at the peak and measure the difference to the following low. To me, this seems a stretch to use this measurement to quantify how much cooler temp is during La Nina. But I suppose it is important to clarify "how much cooler than what?" My relative value was the baseline/neutral point in the cycle/running average, i.e., I suggest using the cycle amplitude, while you are suggesting a peak to valley measure. Your suggestion is always going to be biased by the strength of the preceding cycle peak: a really strong El Nino high followed by a weak La Nina low, would, by your method, be misleading in suggesting the La Nina was very cold or greatly reduced global temperature. Seems like climate cherry picking to me. Keep in mind though, it doesn't matter how great the amplitude of the cycle is, since it just sits atop of an increasing baseline. -JB -
Camburn at 12:34 PM on 8 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
Yes, the El Nino of 2009-2010 was the 2nd strongest according to NOAA. And also according to NOAA, this La Nina has recorded the fastest temperature drop of SST since records have been established. This is actually to be expected as Solar Cycle 24 seems to be sleeping. -
Camburn at 12:32 PM on 8 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
The heat graph from Murphy etal uses guestimates for the heat content of the ocean. The ARGO system is not showing the same results as projected in this paper. Also, the GISS temp data has become the outlier of all data sets. The 1200K radius is not effective at extrapolating air temperatures. One of the reasons that the GISS is showing so high is it incorporates Arctic temps that are extrapolated rather then measured. -
Karamanski at 12:26 PM on 8 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
"That is despite the facts that the El Niño that dominated the early months of 2010 was quite mild" The El Nino of early 2010 was not "mild" according to NOAA this El Nino was the strongest one since 1998. While this El Nino was not nearly as strong as the 1998 El Nino it still met the criteria for being a moderate to strong El Nino. -
Camburn at 12:11 PM on 8 November 2010Ice-Free Arctic
The St Rock sailed the northern northwest passage in 1944. Henry Larson was the captain. They left Halifax, Nova Scotia and docked in Vancourver, British Columbia 86 days later. Using fixed wing aircraft, the Alfred Wegener Institute for Polar and Marine Research found the ice to be thicker than anticipated. This was done in 2009. This is emperical data, not modeled nor guesses from the current satillites. The approx 60 year ice cycle is not dependent on the PDO. Within that 60 year cycle there is also a ten year cycle. Interesting information to study. One other thing that must be taken into consideration is the effect of magnetic flux on high latitude temperatures. There are numerous published papers that show that cause and effect. Here is something from the US Weather Bureau. "The Arctic seems to be warming up. Reports from fishermen, seal hunters and explorers … all point to a radical change in climate conditions, and hitherto unheard-of high temperatures in that part of the earth's surface. … Ice conditions were exceptional. In fact so little ice has never before been noted. The expedition all but established a record, sailing as far north as 81 degrees 29 minutes in ice-free water. … Many old landmarks are so changed as to be unrecognizable. Where formerly great masses of ice have been were found, there are now often moraines... At many points where glaciers formerly extended far into the sea, they have entirely disappeared." The date was October 1922. Antidoal evidence shows that we have a lot to learn about the Arctic and Ice. And the reasons for the increase and decrease of said ice. While co2 potentially plays a part, it is far from the only reason that the ice varies on a decadal scale. -
HumanityRules at 12:08 PM on 8 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
I don't think the annual temp record is the best tool for showing the variation in temp introduced by El Nino/La Nina. Here's the monthly data from 1996-2010.
Still not the nicest I know but it does more accurately show how much ENSO affects global temp. You can see the 1998 El Nino introduced 0.7oC of heating. From the peak in 2007 to the low point in 2008 we can see ~0.6oC of cooling in a year.
ENSO seems to have a larger short term affect on temp than you are suggesting here. It's worth considering how much the recent El Nino has contributed to the possible record temperatures for 2010.
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CBDunkerson at 11:32 AM on 8 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
Norman #46, as it happens there is more than one star in the universe. Thus, astronomers have been able to study the life cycle of stars in considerable depth. The idea that stars get hotter as they grow older is not, as you seem to imply, some vague hypothesis based on nebulous computer models... it is observed reality. As to Mars... the belief that it once had surface water goes hand in hand with the belief that it once had an Earth-like atmosphere. Just as the greenhouse effect keeps Earth habitable it could have once allowed liquid water on Mars. Now that Mars has lost most of that atmosphere it has very little greenhouse warming... and thus is too cold for liquid water. In short, the Sun is not the only thing which could have made Mars warmer in the past. Odd that you would assume that. -
johnd at 11:07 AM on 8 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
Some interested observers in Australia with vested interests in the weather, are seeing the onset of the current La-Nina as reminiscent of 1974 which was the beginning of 3 consecutive La-Nina years, even to the extent that in the late 60's, south eastern Australia suffered a severe drought that became a benchmark for droughts at the time, and as then, this drought just ended is also being seen as a benchmark drought. The only difference is that those 3 consecutive La-Nina years came to mark the end of 3 decades of generally cooler and wetter weather where there were 25% more La-Nina years than El-Nino years and the IPO was continually in a negative phase, whilst now is being forecast as marking the beginning of another 3 decades pattern of similar conditions. -
Norman at 10:56 AM on 8 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
Did not put up the link I will use Hyperlink. This chart shows the amount of IR CO2 will absorb from the IR spectrum. Chart of CO2 absorption ability. -
Norman at 10:54 AM on 8 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
#24 The Ville You post "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" I still question the "faint young Sun" hypothesis. It is based upon some solar models but are they correct? If our sun was faint in the past (when CO2 levels were in the 6000 PPM range) then how did Mars have flowing water on its surface? These two conclusions are mutually incompatible. Either the Sun was not cooler and could warm Mars or Mars could never had liquid water with a fainter Sun. From studies on downwelling IR radiation, the contribution given by current levels of CO2 is about 10%. That's it. Here is what CO2 will give you: http://www.google.com/imgres?imgurl=http://www.real-debt-elimination.com/images/lynchi2.jpg&imgrefurl=http://www.real-debt-elimination.com/real_freedom/Propaganda/Global_Warming_Myth/lynching_of_carbon_dioxide.htm&h=818&w=870&sz=73&tbnid=mooueGrTNRbqNM:&tbnh=136&tbnw=145&prev=/images%3Fq%3Dcarbon%2Bdioxide%2Babsorption%2Bspectrum&zoom=1&q=carbon+dioxide+absorption+spectrum&usg=__pSKV5BxhGfhn4yRlb1D39C9_ZWw=&sa=X&ei=ITzXTISaNM-cnwfq_fzhCQ&ved=0CB8Q9QEwAw -
muoncounter at 10:48 AM on 8 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
#42: "When climate warms, more CO2 is released from the oceans, " For starters, when atmospheric CO2 increases, climate warms and oceans become more acidic. "If some warming event coincidences with a volcanic eruption which huge releases of CO2" Sorry, no soap. CO2 volumes from most eruptions are comparatively small. Large eruptions (such as Pinatubo) cause cooling due to their aerosol volume - that's well-documented. Along with that particular early 90's cooling event came a temporary drop in the rate of global CO2 increase -- also well-documented. If you would like references for any of the above, start with SkS search. I'm with Yooper on this, you need to do some research to support your ideas. And please, try harder than the old correlation-causation canard. -
OregonStream at 10:32 AM on 8 November 2010CO2 has a short residence time
Isn't the NASA graphic a bit out-dated? 5.5 Gt carbon from anthropogenic emission? As for ATekhasski's comment, the fact remains that uptake rates in today's carbon cycle appear limited (thus the rapid accumulation). The article seems to hint that the relaxation time is a function of the excess uptake (beyond the natural exchange) vs. the amount of buildup. Don't know how up-to-date this is, but RC had some discussion of the ANTHROPOGENIC PERTURBATION lifetime: http://www.realclimate.org/index.php/archives/2005/03/how-long-will-global-warming-last/ -
Daniel Bailey at 10:23 AM on 8 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
Re: protestant (42)"Response to #18 was also a bit silly imho. The paper linked just proves how fatally flawed the climate models are, and thats it."
Um, are you referring to the linked video in the response to #18? If so, then you should really watch it and try and learn something about CO2. And the specifics about GHG's are that, without their effect, the average temp of the Earth would be 33 degrees C less than it is now (about 59 degrees F less). Since that puts the Earth well below the freezing point of water on a global basis, there would likely be no life, as the Earth would be a global iceball, pole to pole. This is well-understood and has been for over a hundred years. The majority of your posts here thus far are fraught with a lack of understanding of, well, just about anything to do with climate science, actually. And I see by the responses that many commenters have stepped in to help you gain understanding on a post-by-post basis. Have you actually read any of their references they cite? Did you have any questions or reservations on what you read? Quite frankly, I don't think you're trying. I'm not sure anyone here can help you if you're not willing to let anyone actually help you. The Yooper -
barry1487 at 10:22 AM on 8 November 2010Ice-Free Arctic
Thanks, muonocounter. There is time series data for 1870 - 2007 at that page, including extent for the 1930s. http://arctic.atmos.uiuc.edu/SEAICE/timeseries.1870-2008 According to that data set, Arctic sea ice extent (annual) first dipped below 13 million sq/km in 1960. Prior to that it was always greater than 13 mil. From 1979, annual extent has always been below 13 million sq/km, and by 2000 was starting to dip below 12 mil. In 2007, the annual sea ice extent fell below 11 million square kilometers. The first column is annual data. The following four columns are Winter, Spring, Summer and Autumn extents year by year from 1870. Although summertime extent is more variable, the 1930s were relatively stable, and the data show considerably greater extent for that period/season than today. While we have a lot of ice-edge data from the 1930s, it is quite inferior to the satellite period data. All the above should be read with the usual caveats. -
Stephen Baines at 10:11 AM on 8 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
RSVP Ya know, heroin is also biological solar energy ... just kind of processed...like petroleum. And if the point isn't clear...You judge whether something is "bad" based on it does, not where it comes from. Surely you're just taking the mickey, right? -
protestant at 09:56 AM on 8 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
And does correlation prove causation, or in this case climate sensitivity? No. When climate warms, more CO2 is released from the oceans, CO2 lags temp and thats all we know (well yes it can amplify the change but self-evidently its not _the_ control knob). If some warming event coincidences with a volcanic eruption which huge releases of CO2, that does not prove CO2 was the main cause either. The geologic history is SOOOO long it is actually evident such coinsidences occur. Response to #18 was also a bit silly imho. The paper linked just proves how fatally flawed the climate models are, and thats it. They claim there would be almost no greenhouse effect without CO2, thats an outrageous misinterpretation. Which one of you really believes that we would lose nearly all water wapor and have over 70% cloudiness without CO2? omg... Determining climate sensitivity or anything as complex as that from inaccurate paleo-reconstructions is just pop-science. When all of the forcings (including the multi-decaedal and multi-cencennial oscillations) are not known the climate sensitivity can not be determined. -
michael sweet at 09:44 AM on 8 November 2010Ice-Free Arctic
During the 1930's the Russians took extensive pictures of the ice edge during the summer from airplanes. These photos have been used to archive that side of the Arctic. I have not seen American records, but there is undoubtly something. Probably not as systematic as the Russian records. There are many towns in the Canadian and Alaskan Arctic. Those peole keep records every year, going back to the 1800's, of the local ice conditions. It is well known that the Northwest passage was only open to non-icebreakers in the past 5 years. The people who say the passage was previously open are trying to fool naive readers. Around 1900 Peary and Cook were doing their exploring. There is a lot of data about the Arctic ice before satelites were launched. -
muoncounter at 09:28 AM on 8 November 2010Ice-Free Arctic
#27: "we have little from that period corroborating the notion of significantly less sea ice coverage" The reference in Polyak goes through Kinnard et al 2007 to the University of Illinois sea ice data set. There's a slight offset to match the satellite data, but there's enough overlap to work that out. -
muoncounter at 09:17 AM on 8 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
#40: "and yet it is "a bad thing"." The bad thing in question is: we released the carbon that was stored in fossil fuels back into the atmosphere in the form of CO2. But I'm sure you knew that already. If not, you really should do some more reading. -
barry1487 at 09:17 AM on 8 November 2010Ice-Free Arctic
Here's a full version of Polyak 2010 for anyone to review. http://www.cgd.ucar.edu/oce/mholland/papers/Polyak_2010_historyofseaiceArctic.pdf -
barry1487 at 09:15 AM on 8 November 2010Ice-Free Arctic
Brutus,Isn´t it likely that minimum sea-ice extent was much lower in the 1930s when temperatures were (almost) as high as today?
While anecdotal evidence is hardly foolproof, and a lack of anecdotes even less so, still we have little from that period corroborating the notion of significantly less sea ice coverage than where we started at the beginning of the instrumental record. I'm aware of pictures from the North Pole in the 1930s of areas of open water, but this only reflects local conditions, not the entire Arctic. We also have had open water at the pole from time to time throughout the last 30 years. This is a result of various conditions, mostly to do with how winds blow the sea ice about. We've also had a longer period of warming (since 1970s) today than then, a couple of decades more of sustained warmth. Overall Arctic sea ice doesn't respond in lockstep with temps, but declines as a result of continued warmth over years until an equilibrium is reached. Thus, it is probably unlikely that sea ice coverage in the 30s was less than today's, as there wasn't the same long-term build up and sustained high temps for long-term melt. Reconstructions from observational data (which is admittedly sparse pre-1950) and proxy data support this probability. One could reasonably argue that these findings are not certain, but it would be unreasonable to posit that sea ice coverage in the 1930s was "likely" as low as today. -
Riccardo at 08:19 AM on 8 November 2010Ice-Free Arctic
Brutus no systematic observations does not mean we know nothing. Take a look at Polyak2010 fig. 2a, reproduced below for your convinience.
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CBDunkerson at 08:02 AM on 8 November 2010Ice-Free Arctic
Various points; Riccardo #14, Arctic ice volume accuracy - While the PIOMAS model results are the only continuous 'record' I am aware of it should be noted that this has been validated against submarine and ICESat records. Thus, there is a fairly strong case for the PIOMAS results being accurate within a relatively small margin of error. Camburn #17, "...we are at the end of the 30 year cycle" - What cycle are you referring to? The usual '30 year cycle' that skeptics go on about is the Pacific Decadal Oscillation... but we are actually ten years into the 'cool' phase of that rather than "at the end". Oamoe #16, Cryosat - Cryosat has actually been "collecting data" since April. They have been fine tuning the sensors and working out the kinks, but the commissioning phase actually ended a couple of weeks ago. I'm not sure whether they will release anything from prior to the end of the commissioning phase since they were still making adjustments during that period, but they should be able to tell us whether the current (remarkably low) volume reported by PIOMAS is roughly accurate. -
Rob Honeycutt at 07:48 AM on 8 November 2010Ice-Free Arctic
Camburn.... I also find this from Weather Underground regarding passages of the Northern Passage... "We can be sure the Northwest Passage was never open from 1900 on, as we have detailed ice edge records from ships (Walsh and Chapman, 2001). It is very unlikely the Passage was open between 1497 and 1900, since this spanned a cold period in the northern latitudes known as "The Little Ice Age". Ships periodically attempted the Passage and were foiled during this period, and the native Inuit people have no historical tales of the Passage being navigable at any time in the past." -
kdkd at 07:45 AM on 8 November 2010What should we do about climate change?
PL #376 The discussion certainly is pointless if you won't answer a straightforward question with a straightforward answer. I see you've written quite a large volume of stuff on energy policy, and that your evaluation of the evidence tends to a conclusion that renewable energy is not terribly viable. I had a question about this which you don't seem to want to answer. Let me repeat it for you: 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? Straightforward yes/no answer please. If the answer is "yes" then a link and possibly a page reference will suffice. I'm afraid if the aswer is no, and you haven't evaluated this aspect, then I suspect that you're missing a critical piece of the puzzle, and I would question the validity/coverage of your argument. When people ask me about things that I have written I give them the courtesy of telling them where the passage(s) they are interested in are located - I don't tell them to trawl through my entire output. -
Rob Honeycutt at 06:46 AM on 8 November 2010Ice-Free Arctic
Camburn.... Think about it for just one second. Sailing of the NW Passage, on any route, was a fantasy of traders for most of the 19th and 20th century. Lots of attempts made. Many lost ships and men along the way. The first passage by Amundsen took three years, spending two full winters stuck in the ice. This year a guy does it solo in 12 days. -
Rob Honeycutt at 06:33 AM on 8 November 2010Ice-Free Arctic
Camburn.... "Kiwi Yachtsman, Graeme Kendall, completes world sailing firsts; Arctic North West Passage solo, non stop & in a record 12 days." -
Camburn at 06:19 AM on 8 November 2010Ice-Free Arctic
The Canadians use the southern passage yearly. Usually during the month of September to re-supply towns etc in the Arctic. -
Camburn at 06:18 AM on 8 November 2010Ice-Free Arctic
Rob: He sailed the southern passage, not the northern passage. The southern passage is open most years to small boats. -
Rob Honeycutt at 06:08 AM on 8 November 2010Ice-Free Arctic
Camburn.... If look up the prior sailings of the NW Passage you'll find that these were major endeavors requiring aid from ice breakers. This past summer Graeme Kendall in the Astral Express sailed the NW Passage in a small one man sailboat in but a few weeks. The conditions of the Arctic now is not at all comparable to those of previous expeditions. -
Daniel Bailey at 05:59 AM on 8 November 2010Ice-Free Arctic
Re: oamoe (16) Not an expert, but here are some answers: 1. As soon as the calibration phase is completed. Here's the most recent (26 Oct 2010) press release on the matter. 2. As PIOMAS is a climate modeling tool used to make Arctic ice forecasts (model runs through 2049 are available on their site), then that would be a safe assumption. It may take awhile to figure out the necessary calibrations, as PIOMAS uses 7 years worth of forcings to hone its accuracy. 3. As an add-on to #2 above, PIOMAS is not a data reporting effort but a climate modeling tool. It used to be that updates would be announced every 2 weeks, but as we all know, life sometimes gets in the way of ill-funded missions. A cool thing: for the curious, you can track the current location of Cryosat-2 here. The Yooper -
RSVP at 05:26 AM on 8 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
muoncounter #39 "this is a bad thing" From what you say, the energy stored in fossil fuels is apparently from the Sun which constitutes a source of biological solar energy. The biproduct of this process that favors plant growth, and yet it is "a bad thing". I am sure I can think of worse things. -
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"? :)
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