No mention though of the possibility that this is all part of a natural pattern, and of course no mention of Ms. Stroeve’s Greenpeace connections to her research, which brings her scientific objectivity into question. UPDATE: A graph submitted by a commenter suggests otherwise as does recently published paper. See below. UPDATE2: data source has been added.
From NSIDC and UCL:
New data confirms Arctic ice trends: sea ice being lost at a rate of five days per decade
The ice-free season across the Arctic is getting longer by five days per decade, according to new research from a team including Prof Julienne Stroeve (Professor of Polar Observation and Modelling at UCL Earth Sciences). New analysis of satellite data shows the Arctic Ocean absorbing ever more of the sun’s energy in summer, leading to an ever later appearance of sea ice in the autumn. In some regions, autumn freeze-up is occurring up to 11 days per decade later than it used to.
The research, published in a forthcoming issue of the journal Geophysical Research Letters, has implications for tracking climate change, as well as having practical applications for shipping and the resource industry in the arctic regions.
“The extent of sea ice in the Arctic has been declining for the last four decades,” says Julienne Stroeve, “and the timing of when melt begins and ends has a large impact on the amount if ice lost each summer. With the Arctic region becoming more accessible for long periods of time, there is a growing need for improved prediction of when the ice retreats and reforms in winter .”
While temperatures have been increasing during all calendar months, trends in melt onset are considerably smaller than that of autumn freeze-up. Nevertheless, the timing of melt onset strongly influences how much of the Sun’s energy gets absorbed by the ice and sea. This in turn is affected by how reflective the surface is. Highly reflective surfaces, such as ice, are said to have a high albedo, as they reflect most of the incoming heat back into space. Less reflective surfaces like liquid water have a low albedo, and absorb most of the heat that is directed at them.
This means that even a small change in the extent of sea ice in spring can lead to vastly more heat being absorbed over the summer, leading to substantially later onset of ice in the autumn. There is also a second effect, in that multi-year ice (which survives through the summer without melting) has a higher albedo than single-year ice that only covers the sea in winter. Since the 1980s, the proportion of the Arctic winter ice that is made up of multi-year ice has dropped from around 70% to about 20% today, so the changes are quite substantial
These feedback effects, in which small changes in atmospheric temperature and sea ice lead to large changes in heat absorption, was what the team set out to study.
Stroeve’s team analysed satellite imagery of the Arctic region, dating back over 30 years. The data breaks down the whole region into 25x25km squares, and the team analysed the albedo of each of these for each month for which they had data. This allowed them to update trends and add an extra 6 years onto the most recent analysis of its kind. The new data continues the trend towards longer ice-free periods previously observed.
“The headline figure of five days per decade hides a lot of variability. From year to year, the onset and freeze-up of sea ice can vary by about a week. There are also strong variations in the total length of the melt season from region to region: up to 13 days per decade in the Chukchi Sea, while in one, the Sea of Okhotsk, the melt season is actually getting shorter.”
The amounts of energy involved in these changes are enormous – hundreds of megajoules of extra energy accumulated in every square metre of sea. This is equivalent to several times the energy released by the atom bomb at Hiroshima for every square kilometre of the Arctic ocean.
For organisations such as oil drillers operating in the Arctic region, a sophisticated understanding of when the sea will freeze up is essential. For climate scientists, this type of study helps them better understand the feedback mechanisms inherent in the Arctic climate. The results from this study are closely in line with previous work and therefore give added confidence that models of the complex Arctic climate are broadly correct.
Notes
- The research appears in a paper entitled “Changes in Arctic melt season and implications for sea ice loss”, to be published in a forthcoming issue of the journal Geophysical Research Letters. An online pre-print is available now on the journal website.
- Julienne Stroeve is a recent appointment to UCL Earth Sciences, joining the department from the National Snow and Ice Data Centre in Colorado, USA.
Related links
- Article in Geophysical Research Letters
- UCL Earth Sciences
- National Snow & Ice Data Center
- Centre for Polar Observation and Modelling
High-resolution images
Satellite view of sea ice
This image may be reproduced freely as it is in the public domain
Map of changing melt seasons in the Arctic
This image is available under a Creative Commons Attribution Non-commercial No-derivatives licence. It may additionally be reproduced for the purpose of news reporting.
Researcher profile
=================================================================
UPDATE: Gail Combs offers this graph in comments which suggests that there is no long term trend for the data back to 1979, only a recent drop. FTP Data source listed below.
UPDATE2: Les Johnson Sends over his spreadsheet with data. He writes:
This is my spreadsheet on arctic ice max/min. The data is taken from the link in the sheet. I apologize as its not user friendly, nor fully automated. I did not expect to share it. I filter by year, and take the max/min and the respective dates. That’s it. The assumption is that after max, the ice is melting, until minimum is reached.
1979-2011 arctic melt season (XLSX)
Also Greg of “climategrog” says he thinks the graph needs more context. So, here it is with his links:
The data source listed on that graph is the original data source from which it is derived. It is not the data which is shown in the plot. I know because it’s my processing of that data.
Taken out of context it is rather misleading. Indeed you seem to have (not unreasonably) misunderstood it be the data in the FTP link that is plotted directly. It would seem more appropriate to provide a link to my documentation of how it was derived.
==============================================================
By way of explaining the recent drop in days, we have this recently published paper Via the Hockeyschtick:
New paper finds lows of Arctic sea ice in 2007 and 2012 were due to storms
A new paper published in The Cryosphere finds that the 2 recent lows in Arctic sea ice over the past decade during 2007 and 2012 were strongly related to storm activity, rather than a long-term effect of climate change. According to the authors, “Strong summer storms on the Siberian side of the Arctic Ocean may have been important contributions to the recent [Arctic sea ice minimums] in 2007 and 2012.” Arctic sea ice strongly rebounded in 2013 by up to 78% in comparison to 2012, suggesting the 2007 and 2012 lows were just natural variation.
The paper adds to many other peer-reviewed publications finding Arctic sea ice extent is due to natural variability from winds and storms, not AGW.
The Cryosphere, 8, 303-317, 2014
http://www.the-cryosphere.net/8/303/2014/tc-8-303-2014.html
Cyclone impact on sea ice in the central Arctic Ocean: a statistical study
A. Kriegsmann1,* and B. Brümmer1
1Meteorological Institute, University of Hamburg, Hamburg, Germany
*now at: Climate Service Center, Hamburg, Germany
Abstract.
This study investigates the impact of cyclones on the Arctic Ocean sea ice for the first time in a statistical manner. We apply the coupled ice–ocean model NAOSIM which is forced by the ECMWF analyses for the period 2006–2008. Cyclone position and radius detected in the ECMWF data are used to extract fields of wind, ice drift, and concentration from the ice–ocean model. Composite fields around the cyclone centre are calculated for different cyclone intensities, the four seasons, and different sub-regions of the Arctic Ocean. In total about 3500 cyclone events are analyzed. In general, cyclones reduce the ice concentration in the order of a few percent increasing towards the cyclone centre. This is confirmed by independent AMSR-E satellite data. The reduction increases with cyclone intensity and is most pronounced in summer and on the Siberian side of the Arctic Ocean. For the Arctic ice cover the cumulative impact of cyclones has climatologic consequences. In winter, the cyclone-induced openings refreeze so that the ice mass is increased. In summer, the openings remain open and the ice melt is accelerated via the positive albedo feedback. Strong summer storms on the Siberian side of the Arctic Ocean may have been important contributions to the recent ice extent minima in 2007 and 2012.
Sometimes I get fatigued by the pure quantity of propagandist pseudo-science – which, of course, is the purpose of it. To wear down opposition until they beg to enter a re-education camp.
“the observed difference in freezeup between 1982–1999 and 2000–2012 is about 6 days.”
So they reduce the whole record of 40 years of daily data into two numbers and draw a straight line through them. Amazing.
I just love these people who believe they can see trends in short sections of cyclic data.
Only in Climate McScience…
In some regions, autumn freeze-up is occurring up to
11an infinite number of days per decade later than it used to.Parts of the Barents Sea aren’t freezing up any more.
Anyone can make alarmist statements that are true but pointless.
Gail’s graph is interesting, but immaterial.
Her graph basically tells us how many days each year have less total Arctic ice than the day before. it does NOT tell us whether there is less ice than the same day the year before or the decade before. Nor does it tell us how the ice is distributed.
So, yes, the date for the overall turn-around is about constant — but that is NOT what the paper is the discussing! . There has been a downward trend in the max and min, so the data that the ice melts or refreezes at a particular location can and will vary considerably. When the paper talks about the “ice-free season”, they mean the ice-free season for some specific point. Point Barrow has fewer days of ice each decade; Murmansk has fewer days ice each decade; Nuuk has fewer days of ice each decade.
Ms. Stroeve apparently agreed with the hyperbole in the press release since she didn’t change it. Therefore, in my opinion, it is perfectly acceptable – and indeed imperative – that Hiroshima-type crap needs to be highlighted and ridiculed. In ALL studies and ‘science’ press releases.
and…And…AND…GIANT VIRUSES! Coming to a theater near you!!!!!
http://www.foxnews.com/science/2014/03/04/giant-virus-resurrected-after-30000-years/
Giant amoeba eating viruses! Next week, Man eating viruses? 🙂
Maybe the artist Christo can go up there and cover the landscape with that white plastic crap and spool up the albedo.
richard says:
March 4, 2014 at 11:03 am
“Coral flourishing at Bikini Atoll nuclear test site – because humans have been driven away”
———————————————————————————————————————-
Please don’t give the crazy people any ideas.
I don’t have a problem with activists writing papers. But they only get a vote, not a veto. The number of open water days definitely increased but it has been quite a while since there was an ice-free Arctic in summer.
The growing season north of Latitude 49 has been increasing at about 2 days per decade over the same time period. When the natural cycle goes into cooling mode, it will reverse, hopefully temporarily.
The last thing the bread baskets of North America need is cooler summers!
Curt says:
March 4, 2014 at 12:38 pm
You are both very astute and absolutely correct, but incorrect at the same time. 8<)
Almost all of the sunlight hitting the open ocean near the equator at noon is absorbed. Under those conditions of solar elevation angles greater than 45 degrees at all latitudes, open ocean albedo is about 0.035 based on real world measurements, regardless of satellite elevation angles. (Wikipedia's oft-repeated 0.065 ocean albedo is for INDIRECT or DIFFUSE sunlight only, and is relatively constant across almost all solar elevation angles. Diffuse or indirect sunlight is also only a small fraction 10% too 30 of the potential direct sunlight – under clouds or fog or storms – as under 84% of the arctic days during the summer – there is no direct sunlight at all. )
Now, real world open ocean measurements of the albedo of actual open ocean under real world waves (not a lab-world perfectly flat pure water sample!) show that the albedo of the open ocean continuously increases about ten times from that 0.035 at 45 degrees SEA up to 0.35 to 0.45 at only 4-5 degrees SEA. To repeat: As the solar elevation angle gets smaller => the sun gets closer to the horizon, the albedo – as you indicate above! – gets much higher. Lower Solar Elevation Angle => Higher albedo => More energy is reflected.
But it is worse than you think!
Also, as the SEA gets smaller, the projected area that the radiation falls on gets larger and larger! The actual radiation falling on any square meter of surface is proportional to the sin of the SEA: AS the SEA gets smaller, the radiation intensity ALSO gets lower and lower.
But it is even worse than you thought you thought!
As the SEA gets smaller and smaller, the energy of the sun must penetrate more and more atmosphere to even get down to the sea level to be either absorbed or reflected at those ever smaller and smaller intensities! (This is true at all latitudes, at twilight, you can stare straight into the same sun that noon would blind you instantly.) Thus, near the horizon at 5 or 10 SEA, the same sunlight that might at noon only penetrate 2 or 4 atmosphere thicknesses at latitude 60, must penetrate 30 atmosphere thickness before it can spread out to be reflected back into space.
Now, all of the above combine in the Arctic: Very high latitudes and a varying declination angle and very high atmosphere thicknesses, AND a much higher albedo caused by those low elevation angles mean little solar energy is actually absorbed.
Not nothing, but much less solar energy is absorbed in the Arctic ocean water than what the same equations would imply if that ocean water were on the equator.
But is even worser than you thought you were thinking you were thinking you thought about the Arctic!
See, the Arctic sea ice is long-lived ice compared to the seasonal Antarctic sea ice. “Fresh” sea ice underneath “fresh” snow has a very high albedo: Fresh sea ice DOES reflect a larger amount of energy compared to open ocean waters at high angles of SEA.
But Judith Curry actually measured the Arctic sea ice as it aged over the summer months: Instead of teh oft-quoted sea ice albedo of 0.80 or 0.85 or 0.70, she found the following.
From January through early May, Arctic sea ice albedo was 0.83
From May through late August, it decreased to a low of about 0.46 on day of year = 206, then increased again until early October when new snow kept it at 0.83 until the next May.
So, remember that actual open ocean albedo of 0.35- 0.40 at low elevation angles? It turns out that the actual sea ice albedo of the Arctic is ALSO about 0.35 – 0.40 in mid-summer. So many days of the melt season, in many hours of each day, the actual albedo of old sea ice and open ocean water are just about the same! There can be NO Arctic amplification possible many hours of every day in the Arctic melt season: Both Arctic sea ice and Arctic open ocean water are absorbing just about the same amounts of solar energy.
Not every day, not every hour of every day: Across the early summer to mid-August, there is a net absorption of solar energy IF the arctic sea ice melts.
However! IF the Arctic sea ice melts, the open ocean LOSES more heat energy via evaporation, convection, and increased thermal radiation than does ice-covered arctic waters. Thus, on all, over the entire day of the late Arctic melt season, MORE ENERGY IS LOST FROM THE OCEAN THAN IS GAINED WHEN ARCTIC SEA ICE MELTS under today’s conditions.
Anthony, “UPDATE: Gail Combs offers this graph in comments ”
The graph Gail linked is my work that she found an attributed version of that I had stuck in tinypic, probably for an earlier comment on WUWT.
In fact it is the Arctic line from a combined Arctic / Antarctic plot I had already linked here. Plus a similar treatment using ice area.
http://climategrog.wordpress.com/?attachment_id=206
http://climategrog.wordpress.com/?attachment_id=210
Out of context any graph like that is pretty meaningless. It could have been created by any kind of manipulation. If I were to see a graph presented like that, without explanation, I would ignore it as useless.
The above articles give a basic description of how the graphs are derived which would seem much better than a naked graph without explanation. They also highlight the problem of using one day per year ice minimum to get excited about death spirals and the need to make full use of the daily data available.
By all means keep the plot used but it has no objective value in countering Stroeve paper, without an explanation of how it is derived.
I’m pleased this is relevant to this discussion but would appreciate a credit.
RACook says “However! IF the Arctic sea ice melts, the open ocean LOSES more heat energy via evaporation, convection, and increased thermal radiation than does ice-covered arctic waters. Thus, on all, over the entire day of the late Arctic melt season, MORE ENERGY IS LOST FROM THE OCEAN THAN IS GAINED WHEN ARCTIC SEA ICE MELTS under today’s conditions.”
Yes indeed. The simplistic albedo positive feedback hypothesis is outweighed by the other negative feedbacks. It looked like it was working during 1997-2007 when the data did roughly fit a quadratic decline. However, what has happened since 2007 is a slowing of the long term rate of change.
http://climategrog.wordpress.com/?attachment_id=496
This is totally incompatible with the idea of a dominant +ve feedback. Once a glass tumbler has reached a “tipping point” it does not slow down when it’s half way over.
Computer models, like PIOMAS are fundamentally flawed and totally fail reproduce the 50% increase in ice volume measured last year by Cryosat2. Either they are badly underestimating the negative feedbacks or there is an external periodic driver that they are not accounting for.
Possibly BOTH.
Anthony PS that should have read :” that she found an UNattributed version of ” . No criticism of Gail there. I sometimes stick things on pastebin sites until I get them written up.
March 4, 2014 at 3:17 pm | Greg Goodman says:
—–
I remember recently reading about the regeneration of the coral species at Bikini Atoll but don’t remember anything about radioactive isotopes being sequestered in place of calcium and magnesium. Both Ca and Mg in the (alkaline) water at standard concentrations are all that is required for growing the cnidarians skeletons.
You know much about coral propagation ? I’ve been doing it for a couple of decades and better than most academic research labs. It is an amazingly adaptable life form … but somehow the academics just don’t seem to be able to grasp the technique and one day when they do all will become perfectly clear to them … just as it is to advanced marine aquarists. 😉
“…but don’t remember anything about radioactive isotopes being sequestered in place of calcium and magnesium.”
Probably because whatever you read did not assess it. Strontium and Caesium are quite similar chemically to calcium and potassium and often get assimilated as drop in replacements when they are present in the environment, and the chemistry still works.
Similar things have been found in studies in the “natural park” around Tchernobyl. The result is radioactive grass, trees, mice etc. Some species, like pine mutate badly ending up as distorted bushes instead of tall straight trees. Others. like silver birch with simpler DNA, are apparently much more tolerant and show few defects.
It is quite possible the coral are equally tolerant, though I have no specific knowledge on that either way.
That of course does not mean it be equally inoffensive to other species with large and complex DNA like, say, fish, marine mammals and humans.
I was reacting to the rather stupid comment someone made that a zone so radioactive that the native population can still not return 60 years later is “pristine coral” but the whole subject of the sensitivity of different species to radio isotopes is quite fascinating.
Sadly humans do not have simple DNA like birch trees. That leaves us with a problem.
“Hiroshima bomb” seems to be the new mantra so how many Hiroshima bombs does the sun deliver to the earth over a 24 hour day?
Thanks for the reminder about the Stroeve – Greenpeace link.
Mosher thinks we should not know about it.
Interesting.
It certainly does.
But, according to Willis, English isn’t logical, therefore anything you say in English means only what you want it to mean. So black = white, yes = no, could = couldn’t. Good old Humpty Eschenbach.
“sea ice being lost at a rate of five days per decade”
But can it make the Kessel run in 12 parsecs?
Tim Folkerts says:
“Murmansk has fewer days ice each decade”
No it hasn’t, because Murmansk has zero days of Ice per year and always has had zero days of ice per year (though the ice-edge apparently did come fairly close in March 1866, the worst ice-year in recorded history).
Anthony says: UPDATE: “Gail Combs offers this graph in comments which suggests that there is no long term trend for the data back to 1979, only a recent drop. FTP Data source listed below.”
The data source listed on that graph is the original data source from which it is derived. It is not the data which is shown in the plot. I know because it’s my processing of that data.
http://climategrog.wordpress.com/?attachment_id=206
http://climategrog.wordpress.com/?attachment_id=210
Taken out of context it is rather misleading. Indeed you seem to have (not unreasonably) misunderstood it be the data in the FTP link that is plotted directly. It would seem more appropriate to provide a link to my documentation of how it was derived.
Ice extent shows melting season getting shorter since mid 90’s, ice area since 1989. That seems clearly at odds with the paper which averages the whole record of “four decades” worth of daily data down to two numbers and draws a straight line through it.
I thought any posts which contained your name got held back for personal attention by you but my earlier suggestion of a clarification about the nature of the data in that graph and a request for due credit got passed without so much as a moderator’s note.
REPLY: Well I have other things to do, and I’m not always available to handle requests, so don’t whine. I’ve added an update. -Anthony
Thanks. Not whining, just seemed odd that I got no response, not even “sorry, no time”
I thought it was important for your blog not to give the impression that it was some NOAA data about melting periods that was being presented in the graph. That was the way it looked with the tinypic graph and the ftp address on the graph.
I know you like to run a clean ship and would not want to give the opportunity to one of your many critics to say you were misrepresenting the data.
I’m sorry you saw that as ‘whining’ but at least it’s clear what the graph represents now.
Thanks for improving the clarity.
Thx appreciate it
Greg says:
March 5, 2014 at 12:10 am (Replying to RACook)
Ah, but dear sir! It is truly worse than you thought you thought you were thinking when you were told it was worse than you thought it was:
The Arctic sea ice at maximum is right at 15.0 Mkm^2 on a date ranging from 1-5 March (1980-2010 average) to 15 March (2011, 2012, 2013 and now coming up on 2014.) Odd, that would indicate conclusively that the MAXIMUM point of Arctic Sea Ice Extents is averaging 10 days LATER in the most recent years, which of course REFUTES entirely the premise of the ‘paper” cited above.
Hmmmn. Well, we will let others investigate that minor issue.
Now, that 15.0 Mkm^2 maximum Arctic sea ice extents represents a cap over the pole down to latitude 70.2 degrees. (Hudson Bay, the Baltic, and a few smaller areas are in this region as well, but they melt entirely every summer, so their impact on summertime ice extents is negligible entirely. (An interesting but minor point, the NSIDC Sea Ice Extents does NOT include the Great Lakes, freshwater lakes worldwide like Baikal in Russia, not the Antarctic permanent Ice Shelves.) Now, at maximum extents, this is a cap going down to 70.2 latitude, and at minimum, a much smaller cap only down to 80 north latitude in 2012. (Slightly further south at minimum if you use the 2011-2013 average sea ice extents rather than the 2012 record low.)
Let’s use the “worse case” scenario of 2012 record-setting low arctic sea ice extents of 3.5 Mkm^2 sea ice extents on day-of-year 245 at a latitude of 80.4 degrees north. (Note that sea ice has significantly INCREASED between 2012 and 2013 (and now into the 2014 season) so the CAGW favored theory of arctic sea ice amplification is proved false anyway.)
But in 2013, the Antarctic Sea Ice extents set a new record high at 19.5 Mkm^2 at the same time that Arctic sea ice was increasing from the 2012 record low.
In fact, that 19.5 Mkm^2 sea ice extents cannot be compared directly to the Arctic sea ice loss: The Antarctic sea ice is expanding at a latitude MUCH CLOSER to the equator at ALL TIMES of the year than the Arctic sea ice. This happens because the Antarctic Sea Ice Extents is cycling between 59.2 latitude (at maximum of 19.5 Mkm^2 in September) and a minimum of 3.8 Mkm^2 at latitude 66.4 near 14 February on day-of-year 45.
(Why does a similar sea ice area occur at such a different latitude? A “subtle” difference in land area: Antarctica = 14.0 Mkm^2 of land ice PLUS 3.5 Mkm^2 permanent ice shelf + the 3.8 Mkm^2 of sea ice. Thus, at minimum Antarctic Sea Ice Extnts, the antarctic sea ice edge is actually at a latitude corresponding to 14.0 + 3.5 + 3.5 Mkm^2 or 24.0 – 24.3 Mkm^2 of “ice cap” = latitude -66.4. And THAT 66.4 south latitude is far far closer to the equator’s solar energy than 80 north!)
But it is even worse than you think!
This Antarctic sea ice extents is
(1) present all year around – unlike the Hudson Bay, Baltic or Bering Sea ice,
(2) at latitude always exposed to the sun (since the Antarctic circle is -67.5 south)
(3) is present during the times of each year’s solar cycle so the Antarctic sea ice is exposed 24 hours per day to the MAXIMUM levels of solar energy on 5 January of 1410 watts/m^2,
(4) but the Arctic sea ice is exposed to the all-day Arctic sun at the times of MINIMUM solar energy at 5 July of “only” 1314 watts/m^2!