tag:blogger.com,1999:blog-5337555368793819627.post4685292500173772275..comments2023-06-07T09:04:36.390-04:00Comments on More Grumbine Science: Exploring Arctic Ice MinimaRobert Grumbinehttp://www.blogger.com/profile/10783453972811796911noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-5337555368793819627.post-60023458239450796502014-10-15T06:33:45.079-04:002014-10-15T06:33:45.079-04:00Sorry, here´s the link. I really didn´t mean to ha...Sorry, here´s the link. I really didn´t mean to have people go from here to my blog, because it´s mostly about politics and a bit of comedy. <br /><br />http://21stcenturysocialcritic.blogspot.com.es/2014/09/forecasting-future.html<br /><br />The post is extremely simple, but I do happen to have expertise in the subject, and I find forecasting in that particular field to be quite haphazard. <br /><br />Regarding the Arctic ice extent, I happened to work on an Arctic project in the early 1990´s. The gentleman you mentioned may not have been keeping track of long term trends. At the time we could see the Barents to Kara sector was definitely losing ice cover. We also saw a significant decrease in multi year ice. <br /><br />When I see people prepare Arctic wide figures and plots I remind them it gets much more interesting if they plot the Barents to the Kara gate, and up to just beyond Spitsbergen. Don´t you think the Barents is the key? Or am I missing something? Fernando Leanmehttps://www.blogger.com/profile/16085680730729620836noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-47034939594855643482014-09-26T16:18:38.217-04:002014-09-26T16:18:38.217-04:00(For other folks: I gave a talk in NOAA/National O...(For other folks: I gave a talk in NOAA/National Ocean Service on the 24th, titled 'sea ice question time' or some such. The pretty poster was largely someone else's photo of a banded (er, ribbon) <a href="http://en.wikipedia.org/wiki/Ribbon_seal" rel="nofollow">seal</a>, which is an Arctic animal I find cute. Had some nice discussion with folks in the talk itself and more afterward the talk proper.)<br /><br />The coffee chat, or other discussion would have been fun for me too.<br /><br />My take is that the 'new normal' I suggest in this post is probably going to be short-lived. And I might want to up the baseline figure some from that 4.7 million km^2. Mostly here I just wanted to toss up several hypotheses for a later ('real soon now') post on the method of multiple working hypotheses and our duty in science to go around slaying hypotheses.<br /><br />The 'short lived' aspect to this new normal is because I expect that at some point (homework to do before naming a time) I think we'll lurch to yet another new normal. Partly this involves things that EvanH mentioned -- the sea ice thickness changing even while area and extent aren't showing much action.Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-47017908281624692322014-09-26T12:37:11.640-04:002014-09-26T12:37:11.640-04:00Sorry I missed your talk on the 24th - somehow I m...Sorry I missed your talk on the 24th - somehow I managed to ignore the cute flyer. Seems like this line of work on minima has a real potential to be a game changer in both the sea ice realm, as well as resource management. That would have been an interesting sidebar over coffee after. Oh well.Philip Hhttp://www.districtofcolumbiadispatches.blogspot.comnoreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-24771011268786688422014-09-18T19:07:51.774-04:002014-09-18T19:07:51.774-04:00... p.s. I looked for your article and didn't ...... p.s. I looked for your article and didn't come up with anything. Just some comments to blogs that don't include the data and analysis. Please do provide a link. My link policy is pretty broad -- http://moregrumbinescience.blogspot.com/2008/08/linking.html<br />If you have substantive, relevant, comments to add that don't fit easily in a blog comment box, please do provide the link. (No ads for miracle cures, etc., but doesn't sound like that's a problem here.)<br /><br />also, sorry about my delay in approving the comment. I'm back from vacation and it's taking particularly long to catch up.<br />Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-22473620021450818412014-09-18T19:04:17.898-04:002014-09-18T19:04:17.898-04:00Fernando:
Behind the scenes, I do have some under...Fernando: <br />Behind the scenes, I do have some understanding of the clockwork machinery behind sea ice. In my follow up note(s) ('any day now') I'll say a bit more about that.<br /><br />I think we agree that one cannot _just_ play games with data -- run curves through it that we decided beforehand (one straight line, three straight lines, a parabola, ...) and declare that this is the future. As will develop, that's not what my plan is for this either. Start, though, with descriptive looks at the data we do have, and then examine some more.<br /><br />The Arctic sea ice pack, actually, is historically (up to the 1990s) pretty stable on the whole. At a professional meeting in 1993, Norbert Untersteiner, one of the grand old men in the field, observed that although one part or another of the Arctic would have more or less ice than usual (sometimes quite a bit more or less), it was always pretty nearly compensated by a deviation of the same size and opposite direction elsewhere in the Arctic. You might have exceptionally little ice in the Beaufort/Chukchi seas, for instance, but there'd be exceptionally extensive ice in the Barents/Kara seas. Arctic total held pretty steady. He based that not only on the satellites (1979-present) but on his (and others') field work in the Arctic (1950s-1990s).<br /><br />Ironically, or as an object lesson for me about being too quick to make generalizations, he made that speech in almost the last year that it could be said to be true.Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-36996592355997549932014-09-17T18:10:02.544-04:002014-09-17T18:10:02.544-04:00Read my "predicting the future" in which...Read my "predicting the future" in which I go over the pitfalls of extrapolatin' without having a sense of the clockwork machinery. I used the USA's oil production forecasts but it applies to lots of stuff. <br /><br />Arctic ice seems to be decreasing. I don't think it will allow us to use the northern sea route safely, but it may allow extreme tourism to try to reach the North Pole in an ice breaker to be a fairly routine trip. <br /><br />I do wonder, why do you fret so much over this issue? The Arctic has always been very erratic and we don't know that much about how things work in such nasty weather zones.Fernando Leanmehttps://www.blogger.com/profile/16085680730729620836noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-41452877160372293542014-08-30T11:47:44.725-04:002014-08-30T11:47:44.725-04:00Yes, that's all a fair summary.Yes, that's all a fair summary. Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-63680428017794806882014-08-29T18:48:39.142-04:002014-08-29T18:48:39.142-04:00The general idea that I had pieced together from a...The general idea that I had pieced together from assorted sources was:<br /><br />- We started (as of the beginning of the 20th century) with a big thick sheet of multi-year ice covering a large area of the Arctic.<br /><br />- As we warmed the climate, the multi-year ice began to thin, but since we were only melting a little more in summer than was forming each winter, it took a long time to melt all the way through.<br /><br />- Measurements of extent don't pick up thinning ice sheets very well until they start getting holes in them, so over most of the 20th century it didn't look like the Arctic was doing much.<br /><br />- By the late '90s, the ice sheets had thinned enough that they started getting the aforementioned big holes and shrinking around the edges. This showed up on the satellite data as a dramatic decline in ice cover even though it was really just a continuation of ongoing volume loss.<br /><br />If the above is correct, then I don't think there's any reason to believe the recent slowing of the decline is 'real'. It could be that:<br /><br />1. We're running out of 'easy' ice. It could be that what remains of the multi-year ice started out much thicker than the portions which have already melted. If so, we could still be losing volume at an alarming rate without much loss in area.<br /><br />2. We're running out of ice, period. Since the flux of energy into the ice is a function of surface area, we can't expect to keep losing volume at the same absolute rate when the surface area is reduced dramatically.<br /><br />Am I on the right track here?Evan Hhttps://www.blogger.com/profile/17951470271527674038noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-59455491419267572032014-08-29T10:28:08.074-04:002014-08-29T10:28:08.074-04:00I agree with you -- nothing proven, and we definit...I agree with you -- nothing proven, and we definitely want some physical mechanisms. <br /><br />The eyeballing and playing with lines isn't for making conclusions, just for raising questions to explore. If there really is a new normal for ice, how can we distinguish between that and a continuing trend? Is it reflected in new normals for the atmosphere or ocean? And others. <br /><br />Probably this will go the way of most hypotheses -- be tossed. But it struck me as possibly educational to pursue matters out loud. Robert Grumbinehttps://www.blogger.com/profile/10783453972811796911noreply@blogger.comtag:blogger.com,1999:blog-5337555368793819627.post-56430730913165955422014-08-28T22:48:07.253-04:002014-08-28T22:48:07.253-04:00I don't know… 2007-14 is such a short time per...I don't know… 2007-14 is such a short time period, calling it a "new normal" just because there's no trend, rather than assuming it is a continuation of a declining trend where 2007 jumped ahead of the curve… seems unlikely. Not impossible, but I'd want a physical reasoning rather than just eyeballing and random trend fitting…<br /><br />-MMM<br />Anonymousnoreply@blogger.com