Let me endorse OLN's comments above. This is a new concept for (all?) of us & there are going to be bumps along the path. I just recieved a message from the folks that want the presentation for a First Nations education project so I'll have to get started in that direction. I'm typing between doctors appointments so don't have time to address each of the posts just yet. There is a problem about the latest modified versions not being visible from the posted URL - if anyone is familiar with Google Drive and how to share things properly - please advise. Terry

S Latham I think you may be right. WhatI'd been considering was the latent heat uptake and release during the freeze/melt cycles. During todays melting months, say from April to September, enormous amounts of sensible heat are being used to melt ice while in winter the freezing of Arctic ice stabilizes ocean temperatures at about -2C. In a seasonally ice free situation: In months without ice starting in September, then progressing through August and July the latent energy now melting ice will be released as sensible heat so cooler spring and summer temperatures with ice should be accurate. In the months when freezing now occurs from October through to March freezing will still be occurring at about the same rate as today so no change in fall or winter would be more accurate. In a constantly ice free Arctic - which may be impossible due to long winter nights: The present melting months of April through September will be exhibiting an increase in sensible heat so the Arctic ice is providing cooling in spring and summer. In the months when freezing now occurs from October through to March the lack of ice would mean no change of phase. Without the phase change temperatures would be colder, but since this will only occur in warmer conditions the phrase "Arctic ice keeps winters warmer", while accurate probably conveys the wrong message. Trying to synopsize this into one sentence may be beyond my limited literary prowess. "Arctic sea ice acts as a buffer, cooling our summers & warming our winters." might be better as "Arctic sea ice acts to stabilize Arctic Ocean temperatures to ~-2C which affects Northern Hemisphere weather year round." I've changed slide #64in the NiagaraModified presentation using the new sentence. Terry

Thanks for the kind words - and especially thanks to all that helped with the graphics that made up the bulk of the presentation. I'm inviting criticism so that this can evolve into something that the Arctic Sea Ice community can take pride in, even if no presentation is ever made in your area. I'll try to respond to all suggestions made & those I feel comfortable with will be incorporated into the NiagaraModified presentation which is the version I'll be using next time the opportunity arises. Terry

3.0 Extent is the least important metric IMHO. Area is far more important & Volume tells the story. PII2012 may delay Nares Strait advection but I believe that the CAA will again swallow up any MYI that approaches. I'd be more surprised by 4 than 0 but 2015 is still my best guess for hitting bottom.(for 1 day) Larry - I'll be interested in seeing what can be extrapolated from the poll. Can geographic data be extracted so that we could compare say Canadian guesses as opposed to American or European? Terry

Amazing! Terry

Thanks to everyone for the time and thought you've put into answering my question. I really thought that someone, somewhere would have worked this out and that I was just unable to find the results of their studies. I didn't think that a 100 ppb difference in CH4 cover would make a large difference, but then I wouldn't consider a 100 ppb difference to constitute much of a plume either. When S&S were reporting kilometer wide outflows in the ESAS I assume that the CH4 readings in or close to the plume would be much, much higher than the diffused clouds that were eventually picked up at Barrow. The 100ppb was only thrown out as a metric to work from. It's entirely possible that equating hot spots with high methane levels is either all in my imagination, or more likely a chicken egg scenario where the heat is causing the CH4 outgassing and there is no feedback. I'm going to continue to watch these areas during the next melt season though, especially now that A4R has been publishing the satellite methane maps regularly. I've posed my question on a few more boards & if anyone comes up with a solid figure I'll post it here. Terry

Lodger & A4R "As long as methane levels continue to increase, the methane oxidation rate is irrelevant, as any CH4 decomposed is automatically measured as CO2. No modeling or estimating required." I'm not sure why increasing levels are necessary for this to be true. If levels are static, rising or lowering, the greenhouse effect at that moment should independent of how much longer the CH4 will be with us. I see the oxidation rate a hugely important when we're concerned with the cumulative effect of CH4 releases over long periods of time. When we're concerned with how the Arctic ice is behaving during a particular melt season, and being cognizant of the fact that much of the radiative energy won't be measurable as sensible heat & may in fact be hidden in the following season's freeze, having a number that we can plug in indicating how much additional long wave radiation will be trapped because a cloud of CH4 is over an area might be helpful. Actually the number that would be most helpful to me would be similar to the albedo ratio but indicating the ratio of outgoing radiation that could be expected to be reflected back towards earth for each increase of 100 ppb of CH4. Not over any particular period of time, but for any time that the CH4 concentration was at that level. Terry

Lodger "However, it is appropriate to use the current concentration of CH4 for climate forcings in this year. The 1 year C02e for CH4 is about 120x." Intuitively it seems as though the 1 yr 120x CO2e is far too low. If you can provide a link or an explanation of how you arrived at that figure I'd appreciate. While it's interesting to know what the effect will be compared to CO2 over a 20 or 100 year period, it would also be interesting to know what the effect will be over the particular melting season that we are watching - and perhaps over a shorter time period over a particular ice formation that happens to lie beneath a dense "cloud" released from a short lived plume. If I'm lying in bed for 100 min with two blankets over me and after 12.4 min, one of the blankets is removed the effect that the second blanket had over the first 20 min, or over the whole 100 min period might be of far less importance than the effect it was having while it was actually in place. As you stated oxidation rates should be irrelevant if what we are interested in is the real time effect that an increased level of CH4 is having on temperatures directly beneath a plume or cloud that is not yet mixed with the rest of the atmosphere. A4R's charts seem to indicate high levels of CH4 over ice free areas. Is it possible that these are ice free areas simply because they lie under high level concentrations of CH4 or more likely that these areas are exuding more CH4 which is in turn trapping more long wave radiation which again is causing more CH4 to be released? A positive feedback mechanism working in a possibly very small geographical area & over a short time period. Terry Sorry but for some reason I can't seem to control the italicize function - looks fine until I check it in preview - hope it's clear enough this way.

Please ignore the above - I was trying to figure out the HTML tags and hit post instead of edit. Sorry Terry [Fixed, N.]

Lodger The 1 year C02e for CH4 is about 120x. Intuitively it seems as though the 120x CO2e is far too low. If you can provide a link or an explanation of how you arrived at that figure I'd appreciate. "As long as methane levels continue to increase, the methane oxidation rate is irrelevant, as any CH4 decomposed is automatically measured as CO2. No modeling or estimating required." I'm not sure why increasing levels are necessary for this to be true. If levels are static, rising or lowering there has to be greenhouse effect at that moment that is independent of how much longer the CH4 will be with us. While it's interesting to know what the effect will be compared to CO2 over a 20 or 100 year period, it would also be interesting to know what the effect will be over the particular melting season that we are watching - and perhaps over a shorter time period over a particular ice formation that happens to lie beneath a dense "cloud" released from a short lived plume.

A Question: The greenhouse potential for CH4 in given as 25 x CO2 over 100 yrs or as 72 x CO2 over 20 yrs, yet the atmospheric lifespan is only 12.4 yrs. What is the equivalency for CH4 during 12.4 yrs, or over much shorter time frames when presumably almost all of the gas is viable? If a "cloud" of CH4 bubbled out of the ESAS and drifted over the Karla Sea, what effect would this have directly under the "cloud" during the week, month or season that it remained in place? Simply running the 20 and 100 year figures backwards to 12.4 yrs gives hugely divergent results so I assume this isn't the correct methodology. It seems intuitive that the short term effects are going to be much stronger than in longer term, but I have no idea how much stronger. Hope this isn't a double post! Terry

Lodger The date you mention is spooky in so many ways. Terry

Ghoti Sadly it's not a "once again", but rather a "still". Our Conservative gov. believe's that AGW is a "Liberal Myth" & uses it's sweeping powers to ensure that facts don't interfere with ideology. Terry

While I don't see the loss of mankind as a likely outcome of what we have unleashed, I also don't see much hope for the survival of any civilization remotely comparable to our own. 70k yrs ago the material culture that survived was capable of being reproduced by family groupings & I've no doubt that scattered remnants of our species will be able to retain these & possibly even more complex tool making capabilities - but not much more complex. When the last LED, vacuum tube, ball point pen or ball bearing has been salvaged, it won't be replicable. I'll save the rest of my rant for Neven's eagerly awaited new blog, but I fear my contributions on that side will give little comfort to those that see this as a mere blip on the road to human progress. Terry

Very well put Werther. Anyone who has been following the volumetric side of Arctic ice decline has to have seen the writing on the wall. I'm an old man by most reckonings & I'm quite sure that I'll be around long enough to see an ice free Arctic. This isn't a problem that I can pass of to my children or my grandchildren, this is something my generation will face. We've played with the figures for sensible heat release in an Arctic without ice to melt, not because we believe these figures to represent a large part of the heat budget, but because they're so easy to calculate. The energy entrapped by albedo change in a cloud covered, greenhouse gas infused Arctic will dwarf the latent heat of fusion's release of sensible heat. Even if this somehow was not the case, the sensible heat released is enough to cook things within a matter of decades at the most. I'm very aware that at this point I'm expected to write a paragraph about how, with enough care, self sacrifice or good governance we'll be able to weather this unscathed. I'd consider such a paragraph to be delusional & don't really care to spread a message of false hope. We've had a good ride, but it's time to pay the piper. Terry

What strikes me as unusual is the dearth of MYI north of Greenland this year. Even if the Petermann ice island acts to keep Nares blocked until deep in the melt season, it won't make too much difference. 2013 is going to be an interesting year. Terry

Espen The NOW Polynya does seem larger than usual this year, but I'm more concerned with PII 2012-A-1 I wonder if the largest chunk of the Petermann ice island that grounded in Kane Basin might disrupt the flow of ice through Nares Strait for the next few years. It's in an area where the passage is fairly wide, but a blockage between the grounded ice island and Ellesmere Island could possibly form some sort of bottleneck. I think the Hall Basin gyre directs most of the thick ice towards the western side of the strait & the Kane Basin gyre may also act to direct ice flow into the area that could be blocked. Once the ice island melt enough to float over the Kane Basin sill things should be back to normal & it's certainly possible that ice flow won't be effected anyway. Still something to watch in 2013. Terry

Wasn't there a finding last year that dark colored bacteria were infecting the ice at higher elevations than previously? Terry

Rob I think we usually assume that when ice has reached 0C & more energy is added the end result will be water, but it requires a huge amount of energy to effect the phase transition. What I'm postulating is that in fall there may be vast quantities of ice at 0C or -1,6C that has taken in so much latent heat that even with atmospheric temperatures of -20C some considerable time will be required before the temperature of the ice can drop. Without phase change I think the only way for the energy to escape would be by convection to the surfaces of the ice, then either convection or radiation from there. Neither process would be very efficient with relatively low deltas so I can imagine that a thick, uncracked mass of ice could require considerable time before it dropped below the freezing point and accretion could begin. Another thought just struck me. Is it possible that in large solid ice masses some of the latent heat could remain trapped through the winter season leading to a more rapid melt the following spring? If this were so it might help explain the preferential melt of MYI. Terry

As a youngster I was always fascinated by the Burma Shave road signs. They were small with one line per sign & everyone would try and guess the upcoming rhyming line. While probably not great for Freeway signage, PCH (Pacific Coast Highway), old Route 66 or any of the other heavily traveled byways might be an appropriate venue & it's not impossible that some might be noticed by the media in a nostalgia piece. My skills as a writer of doggerel are lacking but I threw out a few to demonstrate Now ice is white And water's blue The Arctic's melting What can you do Articulate! When ice is gone In Santa's realm The coastal tides Will overwhelm Articulate! The Arctic ice Will melt away It won't come back For many a day Articulate! We're almost out Of Arctic ice Don't take the chance Don't roll the dice Articulate! With sea ice gone Our future's clear Things won't go well On this small sphere Articulate! Our future's clear When ice is gone We'll cook ourselves And blame Chevron Articulate! The Arctic once was full of ice When Burma Shave made driving nice Those day are gone The ice is too The Arctic Ocean Will soon turn blue Articulate! Terry

Larry A new context for the phrase "Fair weather friends." Terry

Rob Rather than "the ice remaining will be filled with water, rather than being solid ice" is it possible that the absorbed insolation is simply moving the ice through the latent heat range without changing ice temperature at all? What if rather than requiring enough energy to raise the temperature of the ice by 80c before it will melt, a large portion of the remaining ice would need only an additional 10c or 20c to complete the phase change? This would leave us with solid ice, still at 0c requiring far less energy to complete it's transformation to the liquid state. The ice sheet would have to shed itself of this hidden (latent) energy before it could begin to expand again in the winter, possibly explaining the lag until late December that you have noted. Terry

The Eisenman paper is going to take some time, but assuming Rob's interpretation to be correct it seems a virtual certainty that we'll make a rapid transition from seasonally ice free to perennially ice free. At present we're melting & freezing ~ 18.6K Km3 of ice on an annual basis. The energy diverted during melt season, then released during fall and winter cools Arctic summers and warms Arctic winters. If we're looking at a scenario where latent heat of fusion is taken out of the equation & where winter Arctic temps still remain >0 doesn't this imply summer temperatures in the NH that are far above even the most extreme projections? Terry

HELP!! I need a speaker for the first weekend in May on the Canadian side of Niagara Falls. Anything related to the recent changes in Arctic ice and/or the ramifications of these changes would be acceptable as subject matter. Can't provide transportation of lodging, but expect an audience of 50-150 Mensans and a very good lunch at the Falls Marriott Hotel. Need to complete our program as soon as possible. For more information: TWEMoran@GMail.Com

Wipneus Another great graph for us to work with! Am I correct that you're projecting average September area not minimum? I'd have expected quite a drop when minimum = 0 and the next year all the ice is FYI with the albedo, melt point and mechanical problems that implies. Terry