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>there will be open water all along the American coast of the Arctic Ocean. My guess is this could happen within two weeks or maybe even faster, which would be extremely early, given that the earliest time this has happened in the past decade (and probably much, much beyond that), was between July 1st and 7th in both 2009 and 2011." Think we can call this to have happened now. ;)
Toggle Commented Jul 11, 2016 on Beaufort final update at Arctic Sea Ice
>"I was not aware that the IPCC had included sea ice extent projections in their publications" Yes AR5 says things like: Sea Ice Continuing the trends reported in AR4, the annual Arctic sea ice extent decreased over the period 1979–2012. The rate of this decrease was very likely1 between 3.5 and 4.1% per decade (0.45 to 0.51 million km2 per decade). The average decrease in decadal extent of Arctic sea ice has been most rapid in summer and autumn (high confidence2), but the extent has decreased in every season, and in every successive decade since 1979 (high confidence). {4.2.2, Figure 4.2} The extent of Arctic perennial and multi-year sea ice decreased between 1979 and 2012 (very high confidence). The perennial sea ice extent (summer minimum) decreased between 1979 and 2012 at 11.5 ± 2.1% per decade (0.73 to 1.07 million km2 per decade) (very likely) and the multi-year ice (that has survived two or more summers) decreased at a rate of 13.5 ± 2.5% per decade (0.66 to 0.98 million km2 per decade) (very likely). {4.2.2, Figures 4.4, 4.6} The average winter sea ice thickness within the Arctic Basin decreased between 1980 and 2008 (high confidence). The average decrease was likely between 1.3 and 2.3 m. High confidence in this assessment is based on observations from multiple sources: submarine, electro-magnetic (EM) probes, and satellite altimetry, and is consistent with the decline in multi-year and perennial ice extent {4.2.2, Figures 4.5, 4.6} Satellite measurements made in the period 2010–2012 show a decrease in sea ice volume compared to those made over the period 2003–2008 (medium confidence). There is high confidence that in the Arctic, where the sea ice thickness has decreased, the sea ice drift speed has increased. {4.2.2, Figure 4.6} It is likely that the annual period of surface melt on Arctic perennial sea ice lengthened by 5.7 ± 0.9 days per decade over the period 1979–2012. Over this period, in the region between the East Siberian Sea and the western Beaufort Sea, the duration of ice-free conditions increased by nearly 3 months. {4.2.2, Figure 4.6} It is very likely that the annual Antarctic sea ice extent increased at a rate of between 1.2 and 1.8% per decade (0.13 to 0.20 million km2 per decade) between 1979 and 2012. There was a greater increase in sea ice area, due to decrease in the percentage of open water within the ice pack. There is high confidence that there are strong regional differences in this annual rate, with some regions increasing in extent/area and some decreasing {4.2.3, Figure 4.7} Projections would likely be CMIP3 or CMIP5 analysis? I doubt that should be described as an IPCC projected range. It is more like what the models show and the models may not be good enough for the IPCC to agree that that is what will happen.
Toggle Commented Jun 21, 2016 on 2016 melting momentum, part 1 at Arctic Sea Ice
Melt ponds suggest no Arctic sea-ice record this year Seems to also be covering Dr David Schröder's melt pond fraction SIPN submission. Similar conclusions reached.
Toggle Commented Jun 17, 2016 on 2016 melting momentum, part 1 at Arctic Sea Ice
DMI SST map back up.
Toggle Commented May 27, 2016 on ASI 2016 update 1: both sides at Arctic Sea Ice
Chris, Thanks for the explanation. We seem agreed on Oct to Dec temps being caused by summer sea ice area. A step down in area then levelling of area results in a step up in Oct-Dec temperatures then a less steep rise or levelling of temps. For Jan-Mar, I am more inclined to suggest different drivers for the temperature: GHGs and warmer air flowing in from lower latitudes. (0.9m thick ice or 1m ice makes little difference compared to 0m or 0.1m so summer sea ice area effect is greatly reduced.) Displacing polar vortex or not (maybe also wavier jet stream) can then cause increased volatility in temperatures. I will accept that it is possible that there is a less steep rise hidden by noise and could take several years before this is revealed. I see Screen et al say "However, the presence of amplified warming aloft hints that processes in addition to the increased transfer of heat from the ocean to the atmosphere resulting from sea ice loss have had a contributing role in winter." Maybe enough wriggle room to stick to my inclination for different drivers of Jan-Mar temps and to expect them to continue upwards without a slowing in the rate.
>Sam Wrote "So hope is useless at this point. Fear on the other hand, fear may serve us." Perhaps it might depend on the audience and maybe a bit of both is needed. Maybe the fear is more important: I would suggest possibly most important audience is people who make investment decisions. With renewable becoming cheaper it is a matter of deployment that takes investment. Do they put huge amounts into a safe but relatively small return over long period from renewables or something more exciting and riskier? If they are convinced that economy will collapse or at least there is significant risk of collapse unless the problem is dealt with then the exciting and riskier investments will look a lot less attractive. That doesn't work unless there is some hope that massive investments deploying renewables might work to avoid the problems.
>"Do you know what Oct to March surface temperatures north of 70degN (NCEP/NCAR) have been doing over the last 10 years? They have levelled - apart from this year which is a clear outlier." Jan to March seems to be continuing upward possibly accelerating. Oct to Dec does seem to have levelled as you indicate. Is there some explanation for this or is it just noise like ENSO that doesn't really affect what you would predict for trend going forward? Oct and possibly later might be affected by heat absorbed by oceans over summer which is then given up before ocean freezes over. So I might give Oct a lower weighting when considering effect of temperatures on reducing winter volume. Last 3 years Oct might be low because ice extent at minimum was high, possibly partly explaining the levelling off? Change to Nov to Mar and the levelling off is much less clear. Perhaps also changing to 75N to 90N.
David Madsen said "CO2 levels are going to exceed 450 ppm by 2030 (not may exceed, will exceed)" I see a couple of problems with this rhetoric. It seems to say there is nothing we can do about it therefore we may as well not bother. A more hopeful message is that we are gearing up renewables as they are now becoming cheaper than fossil fuels. Even without carbon price or subsidies that creates incentive. There is a lot of deployment to do but starting to cut emissions to keep atmospheric level to less than 2.5ppm increase per year may be possible as long as sinks don't suddenly weaken. 407ppm+2.5*14=442ppm. Last 10 years increase was 23ppm only 2.3 ppm per year. Given possibility of such a challenge to what you are saying, if you are going to maintain a 'will' not 'may' stance, isn't it better to slightly reduce the claim to what is certain so you don't get challenged is this way?
Rob said: "Chris said : if April volume loss stalls then summer loss extent stalls. This does not make any physical sense to me. If summers keep on warming (due to global warming), then more and more ice (volume) will melt out during the summer." Try the following for an explanation: Summer extent declines for 2 reasons: 1. GHGs, warming of air and oceans. This reason continues to apply. 2. Less volume at maximum means thinner ice which disppears more quickly allowing albedo effect resulting in more heat absorbed and more melt. If volume at maximum levels out a bit then reason 2 reduces in its effect. Reason 1 continues but looks fairly linear and reason 2 declines in effect. Together this looks to give a reduced rate of decline.
2016.1453 .. 14.2208595 might be the minimum with Arctic just having increased 138k and typical Antarctic minimum just a couple of days away. It seems global area usually increases from now on.
2016.0986 -1.5609524 14.3651371 15.9260893 2016.1013 -1.4567810 14.4637003 15.9204817 2016.1041 -1.3401810 14.5634079 15.9035893 2016.1068 -1.2670890 14.6249723 15.8920612 2016.1096 -1.2674983 14.6272812 15.8947792 2016.1123 -1.2934796 14.6033812 15.8968611 2016.1151 -1.4321671 14.4693680 15.9015350 2016.1178 -1.5083036 14.3738375 15.8821411 Less than 9k higher than record of one week ago. With Arctic gaining just 14k a new record is within reach again.
Toggle Commented Feb 15, 2016 on Global sea ice area record minimum at Arctic Sea Ice
Stan, re broken link: To get to the page intended by John Christensen delete the ), that has been added to link by mistake.
Toggle Commented Feb 11, 2016 on PIOMAS February 2016 at Arctic Sea Ice
>"Winter has had its best time." Per a few sources like coldest time is mid Feb to mid March when ice extent is high and winds have to travel a long way over ice and snow if they are to bring warmth to Arctic. Doesn't this mean winter hasn't had its best time yet this year? More unusually mild weather in next month would really eat into the remaining potential recovery time.
Toggle Commented Feb 11, 2016 on PIOMAS February 2016 at Arctic Sea Ice
Very close: 2016.0959 -1.5473126 14.3929777 second lowest day ever after 2006.0850 -1.5731411 14.3918705 Just over 1k above, obviously not statistically significant difference. Arctic rose just over 33k so need an Antarctic fall of 35K with the next datum. Yesterdays Antarctic fall was 42k and typical for this day is 35k. So looks like an even better chance than today is coming tomorrow.
2016.0931 -1.5001982 14.4575024 66k above record and 4k higher than 2 days previously. But this time we have an arctic drop of 22k so antarctic drop of just 44k would be enough. (Last day antarctic fall was 68k and typical fall for time of year is 42k. Looks possible bordering on probable.)
2016.0876 -1.5149544 14.4531231 is now lowest ever for time of year (being below 2006.0876 -1.4466151 14.5214624 2011.0876 -1.2477340 14.7203436 ) less than 62k more than lowest ever 2006.0850 -1.5731411 14.3918705
>"And the volume is? They're not saying," Per BBC "This February, Cryosat saw average sea-ice floe thicknesses of just over 1.7m, giving a volume across the Arctic of nearly 24,000 cubic km. Back in the winter of 2013, following strong melting during the previous summer, floe thicknesses averaged 1.5m and the volume fell below 21,000 cu km." For comparison PIOMAS has 2015 32 20.348 2015 60 22.524 avg 21.502 2013 avg Feb 19.376 so Cryosat continues to have more volume in winter.
Toggle Commented Apr 18, 2015 on CryoSat-2 sea ice thickness maps at Arctic Sea Ice
First, second and fourth look much more sensible odds to me. Third looks a bit mean, I might offer 25:1 unless 'top 5' extent means lowest 5 extent when betting at 10:1 would look like good value. I might be interested in 10:1 Not in top 5 extent but probably only a small amount for a bit of fun and only if 'top 5' means lowest 5. If it means highest 5 then odds look a little low but again what record is to be used? By NSIDC, I get the following years to result in a pay off 2014 2013 2001 1997 1996 1994 1992
Toggle Commented Mar 11, 2015 on Mad max? at Arctic Sea Ice
>"Current odds are as follows for September of 2015: 400:1 Continuous ice from NW Passage to Siberia 200:1 Ice remaining in Hudson Bay 12:1 2015 Extent lowest year on record 8:1 2015 Extent within lowest 2 years on record 5:1 2015 Extent within lowest 3 years on record 3:1 2015 Extent within lowest 4 years on record 2:1 2015 Extent within lowest 5 years on record NOTE: Race will be cancelled if Krakatoa, Pinatubo and the Yellowstone Caldera all erupt within the next few weeks!" Serious or in jest? What does "Continuous ice from NW Passage to Siberia" mean? At those rates, I think I would like to place a few hundred pounds on Extent within lowest 5 years and some more on some of the others. Which extent data is involved?
Toggle Commented Mar 11, 2015 on Mad max? at Arctic Sea Ice
I can see that 'tumbling' as in turning 90 degrees at a time would impede brine rejection. However that requires very small pieces of roughly same width as depth. Isn't that unlikely and repeatedly turning upside down more likely? If just repeatedly turning upside down, doesn't the brine have an easy path back down along the route it has carved when going in the opposite direction? Does that impede brine rejection all that much?
Toggle Commented Jan 4, 2015 on Fram Strait 2014 at Arctic Sea Ice
What Tilling and colleagues see in the data is a very strong link between autumn thickness and the degree of melting in a year. "You might think, for example, that wind conditions would be important because they can pile the ice up and make it less susceptible to melting, while at the same time exposing more water to freeze," the University College London researcher explained. "But we've looked at this and other factors, and by far the highest correlation is with temperature-driven melting." Am I following this correctly? If there is a lot of melt during spring & summer then autumn thickness tends to be thin. Err, yes I think I would expect that not only for the obvious reason but also because lower ice at maximum tends to cause more melt. Presumably there is something a little more subtle than that she is trying to get at?
Toggle Commented Dec 16, 2014 on In the meantime: CryoSat at Arctic Sea Ice
D has linked the Average for month the end of month figures are Day 151 31 May: 2014 20.288 4th lowest 2013 20.498 2012 19.591 2nd lowest 2011 19.483 lowest 2010 20.229 3rd lowest 2009 22.431 2008 22.878 2007 21.891
Toggle Commented Jun 3, 2014 on PIOMAS June 2014 at Arctic Sea Ice
>"Looking at the data I see that modelled volume reached 23,104 km3 on April 15th, which is slightly more than the 292,900 mentioned. Maybe the folks over at the PSC calculated the max differently." The average of the 30 days in April comes to 22.931 so I suspect this is a rounded monthly average rather than a single day maximum. Probably best not to expect too much accuracy at one day level so I would expect scientists to look more at monthly average than a one day max. Whether you use a monthly average or single day this is second lowest, above 2011 by about 0.42 or 0.427. So little difference. Shape of curve in April this year is unusually flat ending month at 3rd lowest. Not really sure why this is. Any ideas?
Toggle Commented May 8, 2014 on PIOMAS May 2014 at Arctic Sea Ice
If updating ASIGs, displaying piomas v2.1 and current year would be better; the image to display should be: Thanks for this and all the work you do.
Toggle Commented Apr 15, 2014 on PIOMAS April 2014 at Arctic Sea Ice
>"I thought it'd be a nice way to pass our time while we wait for the latest PIOMAS update." Which is now out 31 March 14 value 22.609 just below 2011 minimum maximum of 22.677, is second lowest for 31 March 14.
Toggle Commented Apr 7, 2014 on Research for a novel at Arctic Sea Ice