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not sure that I fully understand what you are trying to say, navegante, but there absolutely are possible negative feedback effects that will potentially slow down further ice loss, as the amount of ice gets smaller, and which might tend to cancel out positive albedo feedback. the concept of feedback here is just that as a continually increasing amount of heat is added, does the rate of ice loss speed up, slow down or continue in a linear fashion? greater venting of ocean heat in autumn due to less ice cover absolutely is an example of a negative feedback, and thinner layers of insulating snow could be another. understanding the balance of feedbacks is far more difficult than anything they teach in high school, but most ice models show slower melt rates as the amount of ice decreases, suggesting that negative effects win out. this has been discussed at some length on the forum, of course, including Chris's slow transition thread, and OSweetMrMath's ice modeling thread
Toggle Commented Oct 18, 2015 on PIOMAS October 2015 at Arctic Sea Ice
crandles has also posted an interesting figure on the forum that indicates when autumn area is low and the ocean refreezes late in the season, most of the autumn snow falls into the ocean rather than on ice - meaning the ice has a thinner insulating snow cover and therefore grows thicker over winter than it normally would (then again it has also been suggested - by Peter Ellis, I think - that thicker snow cover might delay the onset of ice melt next spring, and that the overall effect on ice freeze/melt might be weather dependent). still it does seem quite plausible that there might be some kind of multiyear cycle where big crashes are followed by a couple of years of apparent recoveries before the next crash. negative feedbacks will almost certainly slow the transition to a seasonal ice free state, but it would be pretty surprising if 2012's record wasnt comprehensively beaten before 2020
Toggle Commented Oct 17, 2015 on PIOMAS October 2015 at Arctic Sea Ice
I have nowhere asserted that it 'would' go south, only that the potential destination area away from the ice is much larger than the area over the ice. and even if it does go over the ice, how much effect will it have on ice melt if it is at altitude? I haven't read your ISPN entry, but I will
Toggle Commented Oct 10, 2015 on 2015 minimum overview, part 2 at Arctic Sea Ice
no, and the inane sarcasm is not appreciated - the most likely direction a packet of warm air will travel is vertically upwards (duh). because however lines of longitude converge at the North Pole, any horizontal movement at ground level is much less likely to take it over the ice pack than it is to take it away from the ice pack - one area is vastly bigger than the other. as an aside, it is worth pointing out that a June negative anomaly in snow cover is likely to lead to extra ice melt, either because 1) warmer than average land temps in high northern Siberia/N Am are also likely to mean that temps over the nearshore ice are above average, or 2) bcz warmer than usual air moves from over the land to over the ice (which is what you believe), and in either case this might lead to more widespread melt ponding than usual; if early melt ponding is greaterer than usual, the albedo effect kicks in and ice melt proceeds from there. the point is that once ice albedo is lowered at an earlier stage than usual, it really doesn't matter where the extra heat from lower land albedo goes for the remainder of the summer - the ice will melt faster all by itself. I suspect this is the cause of a large part of the correlation, but as I keep saying, I really don't know. just there is a lot of anomalous heat in the northern hemisphere doesn't mean the ice will melt, unless the heat comes in contact with the ice. the Pacific blob, for instance, is irrelevant for predicting arctic sea ice melt, and even anomalously warm waters in the peripheral arctic seas won't lead to greater than average melt unless the warmer water is driven under the ice.
Toggle Commented Oct 9, 2015 on 2015 minimum overview, part 2 at Arctic Sea Ice
I made two points - 1) half of the extra heat won't go north over the ice, partly because the area south of northern snow covered area is much bigger than the area to the north (isn't that obvious?), and 2) of the heat that does go over the ice, it's not clear how much of that will actually result in melting. if you interpret that as a Gish gallop, it's probably not worth continuing the discussion. of course I think the heat will go into the atmosphere (wasnt that clear from what I said?) but the question is then whether it is then eventually lost by radiation - I don't have a clear understanding of what happens next, which was the reason for my original question. but never mind
Toggle Commented Oct 7, 2015 on 2015 minimum overview, part 2 at Arctic Sea Ice
I can see the empirical argument, of course, but I'm not sure what the 'realistic physics' is. most of the directions wind can blow in from previously snow covered areas in the northern hemisphere won't take the extra heat over the ice, so 'even if only half that energy blew north' seems a bit misleading, and warmer inflowing air might tend to rise over the cold dome of air over the ice - yes this will result in some melting but I'm interested to know how much, partly because I've always been frustrated by how vague the information on arctic heat budgets always seems to be. some of this could be correlation rather than causation - a warm June over northern Siberia or North America, or both, might lead to both early snow loss and melt ponding, leading to a bigger ice melt?
Toggle Commented Oct 6, 2015 on 2015 minimum overview, part 2 at Arctic Sea Ice
'Even if only half of that energy blew north and only half of that resulted in ice melt, the snow anomaly of June 2015 would have resulted in 1 million km^2 Arctic sea ice melt.' ... this is phrased to sound like two conservative assumptions, but are they? naturally I have no idea, but does anyone?
Toggle Commented Oct 5, 2015 on 2015 minimum overview, part 2 at Arctic Sea Ice
not much point going on about this, but if wadhams didn't think there was any evidence of foul play, there was clearly no reason whatsoever to mention the possibility. just asking for trouble, especially given who he was talking to
Jim - to answer your questions, no and no, but I'm not sure how that relates to anything I said. never mind
... come on. there's no reason why a journalist shouldn't ask wadhams for a comment - he's a high profile ice scientist who isn't afraid to give a direct answer (unfortunately, in this case). it seems pretty clear he did say what has been attributed to him, and viewed together with his ridiculously low end of melt season prediction, it fits the pattern of someone who is beginning to believe what he wants to believe rather than rigorously following the evidence. as Chris said earlier, he needs to take a break (from talking to the media, at least)
according to the telegraph article wadhams actually said: 'Yes. I do believe assassins possibly murdered them but...' (you might think I'm crazy). he wasn't wrong
Le Manguier going west to east has been sailing and waiting along the east coast of Prince of Wales Island to a point further north than the Bellot Strait ... S/V Arctic Tern has almost reached Bellot as well ... Looks like S/V Catryn is also heading south of Port Leopold on the way to Bellot Strait. It will be interesting to see how they do on the west side of Bellot Strait when they get into 9+/10 concentration with 2/10 big floes of Multi-year ice in it (see chart below). When the tide is running there is a phenomenal amount of pressure at the west end of Bellot. They will need icebreakers and luck...,762.0.html#lastPost
Toggle Commented Aug 24, 2014 on ASI 2014 update 8: neck and neck at Arctic Sea Ice
Wipneus has recently commented on the high amount of ice still blocking the northwest passage - there's certainly more than in most recent years, and if it's open in a week's time I'll eat my proverbial hat :-/,382.1150.html#lastPost
Toggle Commented Aug 16, 2014 on ASI 2014 update 7: late momentum at Arctic Sea Ice
nice to see a confident prediction, but I'll believe it when I see it :-/
Hans, every country's 'major goal' is GDP growth, especially poor ones, which china still is. and expecting them to hold emissions steady while western countries emit so much per person is naive in the extreme - there is also the fact that about 25% of China's total CO2 emissions are embodied in products exported to US/EU/Japan, and another major chunk result from ongoing urbanization. what do you expect them to do, stop burning coal and carry on splashing around in the paddy fields? if high-income countries aren't taking significant action, why should anyone else?
Toggle Commented Jun 13, 2014 on The day the ice cap died at Arctic Sea Ice
saying 'they're responsible for their own population' is a bit harsh - what are they supposed to do, cull them every few years? clearly per capita emissions are the only fair comparison, however china gets far less $value for each unit CO2 emitted, and clearly coal will dominate the energy mix for plenty of time to come - nuclear n renewables are still a sideshow
Toggle Commented Jun 13, 2014 on The day the ice cap died at Arctic Sea Ice
"The coincidence is quite note worthy but could just be completely coincidental" by definition, as it were - clearly there is no causal connection :-/
Toggle Commented May 31, 2014 on Greenland 2013 in review at Arctic Sea Ice
... come on. “The origins of, and mechanisms behind, projected Arctic moistening are still unclear, however. Is it caused by an intensified local Arctic hydrological cycle19, or does it result from a global hydrological response to altered evaporation rates and moisture fluxes in lower latitudes8? This is an important issue, for several reasons: (1) if the local response dominates, Arctic precipitation may be strongly linked to Arctic warming and sea-ice retreat; (2) in that case the effect on Arctic Ocean freshening will probably be limited because evaporation and precipitation effects on surface salinity will then largely cancel out (only a remote origin will lead to overall net freshening); it's usually worth giving professional scientists (especially those who manage to get published in Nature) the benefit of the doubt
Toggle Commented May 26, 2014 on Greenland 2013 in review at Arctic Sea Ice
NSIDC's April review is out, featuring the Nature melt ponds paper: 'The size and number of melt ponds on sea ice are in part governed by the sea ice topography. First-year sea ice is smoother than multiyear ice, and the melt ponds tend to be shallower and more spread out over the first-year ice. While the melt pond fraction in May makes up about 1% of the total summer melt pond fraction, the shift to a predominantly first-year ice pack has helped to increase the number of melt ponds in spring and provides useful input into predictions for September sea ice extent.'
Toggle Commented May 10, 2014 on PIOMAS May 2014 at Arctic Sea Ice
on the one hand, all the years tend to converge in may, so low extent in april is not really a big deal. unless this indicates that melting is getting an early start (see the abstract in Boa05att's comment), of course
Toggle Commented Apr 24, 2014 on Miscellanea at Arctic Sea Ice
Jai, you are attacking a straw man, and you need a reality check - in fact it is you (handwaving attempts to dismiss the consensus view of an established scientific discipline) who is promoting views akin to climate denial "This mythology is intentionally marketed and produced because it benefits a few wealthy elites. That is the only reasoning I can come up with" naked conspiracy theory
Toggle Commented Apr 21, 2014 on Miscellanea at Arctic Sea Ice
David, no serious economist believes that 'Jevons' paradox will always happen that way', as is clear from the links that Hans has provided. Hans, I was agreeing with you, and taking issue with Jai.
Toggle Commented Apr 21, 2014 on Miscellanea at Arctic Sea Ice
the myth is that economists rely on faith based arguments - as the quote given by Hans makes clear, Jevons proposition was/is based on observation. are you saying the denial of climate change is a myth, that the invisible hand is a myth, or that reliance on the invisible hand is a myth? because the 'invisible hand effect' is certainly real
Toggle Commented Apr 20, 2014 on Miscellanea at Arctic Sea Ice
From the NSIDC writeup: 'This winter the multiyear ice makes up 43% of the icepack compared to only 30% in 2013. While this is a large increase, and may portend a more extensive September ice cover this year compared to last year, the fraction of the Arctic Ocean consisting of multiyear ice remains less than that at the beginning of the 2007 melt season (46%) when a large amount of the multiyear ice melted. The percentage of the Arctic Ocean consisting of ice at least five years or older remains at only 7%, half of what it was in February 2007. Moreover, a large area of the multiyear ice has drifted to the southern Beaufort Sea and East Siberian Sea (north of Alaska and the Lena River delta), where warm conditions are likely to exist later in the year.'
Toggle Commented Apr 3, 2014 on Forecast me not at Arctic Sea Ice
"If the sun shines directly overhead at a particular moment, that’s peak insolation, and the rule-of-thumb value for that is 1000 W/m^2. So based on that, the Greenland ice sheet could melt away from sun alone, in not much longer than a century." ... you mean, if the sun shone directly overhead, 24-7, 12 months a year? n the reason it doesn't melt so fast is that the sun doesn't?
Toggle Commented Mar 21, 2014 on PIOMAS March 2014 at Arctic Sea Ice