In the latest ARCUS Sea Ice Outlook, WUWT, Stroeve (NSIDC), and Meier (NSIDC) agree at 4.5 million square km. Whether those values turn out to be high due to the recent ice loss as a result of a strong Arctic storm which broke up a lot of sea ice remains to be seen. Here is the storm report from NASA:
==============================================================
Image mosaic of Arctic storm. (Credit: NASA/Goddard/MODIS Rapid Response Team)
› Related image and story from NASA’s Earth Observatory
An unusually strong storm formed off the coast of Alaska on August 5 and tracked into the center of the Arctic Ocean, where it slowly dissipated over the next several days.
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this natural-color mosaic image on Aug. 6, 2012. The center of the storm at that date was located in the middle of the Arctic Ocean.
The storm had an unusually low central pressure area. Paul A. Newman, chief scientist for Atmospheric Sciences at NASA’s Goddard Space Flight Center in Greenbelt, Md., estimates that there have only been about eight storms of similar strength during the month of August in the last 34 years of satellite records. “It’s an uncommon event, especially because it’s occurring in the summer. Polar lows are more usual in the winter,” Newman said.
Arctic storms such as this one can have a large impact on the sea ice, causing it to melt rapidly through many mechanisms, such as tearing off large swaths of ice and pushing them to warmer sites, churning the ice and making it slushier, or lifting warmer waters from the depths of the Arctic Ocean.
“It seems that this storm has detached a large chunk of ice from the main sea ice pack. This could lead to a more serious decay of the summertime ice cover than would have been the case otherwise, even perhaps leading to a new Arctic sea ice minimum,” said Claire Parkinson, a climate scientist with NASA Goddard. “Decades ago, a storm of the same magnitude would have been less likely to have as large an impact on the sea ice, because at that time the ice cover was thicker and more expansive.”
Aqua passes over the poles many times a day, and the MODIS Rapid Response System stitches together images from throughout each day to generate a daily mosaic view of the Arctic. This technique creates the diagonal lines that give the image its “pie slice” appearance.
In the image, the bright white ice sheet of Greenland is seen in the lower left.
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My best guess is that because of this storm breaking up ice packs, the September minimum will be lower than 4.5 million sqkm. The median of August ARCUS outlooks is 4.3, but the possibility exists that it will come in lower than that.
The value for the JAXA plot is similar:
And the most recent JAXA value for 8/13/2012 is 5,152,969 sqkm (data source here). More maps and graphs exist on the WUWT Sea Ice Reference Page.
Here’s the August ARCUS report compiled by Helen Wiggins:
With 23 (thank you!) responses for the Pan-Arctic Outlook (plus 5 regional Outlook contributions), the August Sea Ice Outlook projects a September 2012 arctic sea extent median value of 4.3 million square kilometers, with a range of 3.9–4.9 (Figure 1). The quartiles for August are 4.1 and 4.6 million square kilometers, a narrow range given that the uncertainty of individual estimates is on the order of 0.5 million square kilometers. The consensus is for continued low values of September 2012 sea ice extent. The August Outlook median is lower by 0.3 million square kilometers than the July estimate, consistent with low summer 2012 observed values. According to the National Snow and Ice Data Center (NSIDC), the arctic sea ice extent for July 2012 was the second lowest in the satellite record behind 2011; the ice extent recorded for August 1st of 6.5 million square kilometers is the lowest in the satellite record. Twelve of the contributions give a value equal to or lower than the 2007 record minimum (monthly average) extent of 4.3 million square kilometers.
Individual responses are based on a range of methods: statistical, numerical models, comparison with previous rates of sea ice loss, composites of several approaches, estimates based on various non-sea ice datasets and trends, and subjective information.
Again, we are comparing these Outlook values to the September average sea ice extent as provided by NSIDC. NSIDC is not the only data source for ice extent; their estimate is based on a long-term time series and we use their value as an operational definition.
Download High Resolution Version of Figure 1.
DEVELOPMENT OF SUMMER 2012 SEA ICE CONDITIONS AND RECENT WEATHER
The NSIDC time history for 2012 compared with previous years is shown in Figure 2. As noted in previous Sea Ice Outlook reports this year, sea ice extent in May started higher than several previous years and there were indications of increased thickness on the North American side. But late May and the first half of June had the Arctic Dipole (AD) Pressure pattern that is favorable for ice loss, resulting in a record trend in sea ice loss. At the end of June the AD was replaced by low sea level pressure. At this point, the sea ice loss showed more of a historical loss trend, but because of the low June value it has remained below the previous lowest value from 2007. The sea level pressure field for the second half of July and early August (Figure 3) shows that the low pressure centered along the dateline has persisted for most of the summer. This a a fairly typical historical summer pattern, if perhaps a bit stronger.
The pattern in Figure 3 is favorable for sea ice loss near the Canadian side of the North Pole and in the Kara Sea, but not in the Pacific Arctic as in previous summers. The recent NSIDC sea ice chart from 9 August (Figure 4) shows major open water areas in the eastern Beaufort Sea, East Siberian Sea, and Kara Sea, and a strip of sea ice continuing in the Chukchi Sea. These areas opened up quickly in the last few weeks. Also note the open areas within the ice pack.
Except for early June, the weather was not particularly favorable for sea ice loss in summer 2012 as it was in 2007 and some other recent years. Given the lack of meteorological support and several indications that the sea ice was rather thin, we note that thermodynamic melting of thin, mobile sea ice is now a dominant process, justifying the low sea ice predictions in the Sea Ice Outlook.
KEY STATEMENTS FROM INDIVIDUAL OUTLOOKS
Wang et al, 3.9 +/-0.3, Model
The outlook is based on a CFSv2 ensemble of 40 members initialized from Jul 27-Aug 5, 2012. The model’s systematic bias, forecast RMS errors, and anomaly correlation skill are estimated based on its historical forecasts for 1982-2011. The CFSv2 has shown long-term decrease of sea ice extent during the past 3 decades, as in the observation. The CFSv2 was also found to have some skill in predicting year to year variability at seasonal time scales.
Arbetter, 4.0, n/a, Statistical (updated 13 August)
Using conditions from week 30 of 2012 (ie August 1, 2012), a revised minimum Arctic sea ice extent of 4.03 million km2 is projected for the week of September 7, 2012. This is substantially lower than the earlier estimates, reflecting both lower than average sea ice extent used as initial conditions this summer and a persistent downward trend in sea ice extent over the past decade (and longer). The output continues to suggest 2012 will be at or below the previous record minimum September ice extent, recorded in 2007 and repeated in 2011.
Klazes, 4.0 +/- 0.7, Statistical
Extent is predicted by first estimating minimum ice volume for September. Using a linear minimum ice volume-extent model the extent is calculated. Only data up to 2011 is used. The method is statistical, based on mean September ice extent and minimum September ice volume (PIOMAS, Zhang and Rothrock, 2003).
Hamilton, 4.0 +/- 0.3, Statistical
A simple regression model for NSIDC mean September extent as a function of mean daily sea ice area from August 1 to 5, 2012 (and a quadratic function of time) predicts a mean September 2012 extent of 4.02 million km2, with a confidence interval of plus or minus .32. This supersedes an earlier year-in-advance prediction based on a Gompertz (asymmetrical S curve) model that used data only through September 2011.
Beitsch et al, 4.1 +/- 0.1, Statistical
The KlimaCampus’s outlook is based on statistical analysis of satellite derived sea ice area.
We introduced the following method: use of near-real-time (SSMI/S) sea ice concentration data combined with long data sets (SSM/I: 1992{2011), a time-domain _lter that reduces observational noise, and a space-domain selection that neglects the outer seasonal ice zones. The daily estimate of the September extent, the anomaly of the current day and a time series of daily estimates since May 2012 can be found on our ftp-server: ftp://ftp-projects.zmaw.de/seaice/prediction/2012/
Folkerts, 4.1 ± 0.2, Statistical
A variety of publicly available monthly data from 1978 forward (including area, extent, volume, regional extent, NCEP Reanalysis Data, and various climate indices) was collected. For each year, monthly data up to 24 months before the September minimum extent was organized and correlated with the minimum extent. Multiple regression analysis was also performed on a variety of combinations of these explanatory variables, seeking sets of data that correlate well with September extent, while trying to avoid overfitting. In addiction, analysis was also performed using the annual change in extent as the dependent variable (which, together with the extent the previous September, also allows predictions of the upcoming minimum).
Andersen, 4.1, n/a, Statistical
Same as last month.
Morison, 4.2, n/a, Heuristic
Same as last month.
Randles, 4.2, ± 0.7, Statistical
I use an average of two methods. One is as used in my previous submissions this year of a linear regression to predict the expected residual from a gompertz fit of September Extent using the residual from a gompertz fit of Cryosphere Today area. The other method is to calculate a weighted average of Cryosphere Today area and NSIDC Extent giving 1.5 weight to area. The difference between this and the NSIDC September average extent is calculated and estimated with a linear trend.
Naval Research Laboratory, 4.3 +/- 0.6, Model
The Arctic Cap Nowcast Forecast System (ACNFS) was run in forward model mode, without assimilation, initialized with a July 1, 2012 analysis, for nine simulations using archived Navy atmospheric forcing fields from 2003-2011. The mean ice extent in September, averaged across all ensemble members, is our projected ice extent. The standard deviation across the ensemble mean ice extents is an estimate of the uncertainty of our projection given we do not know the atmospheric conditions that will occur this summer. Please note, this is a developmental model that has not been fully validated in non-assimilative mode, but the assimilative system has been validated to provide an accurate ice forecast [Posey et al. 2010].
Netweather.tv, 4.3, n/a, Heuristic
The prediction method was based on a poll of Netweather.tv forum members. The question was “What do you think the MEAN September sea ice extent will be?” The mean (4,338,095km2) of the…votes was rounded to the closest 100,000 and used to form the prediction.
Lukovich et al, 4.3, n/a, Heuristic
It is hypothesized that the 2012 fall sea ice extent will attain values comparable to those of 2011 based on a heuristic assessment of sea ice and surface atmospheric dynamics, with regional losses governed by local wind and ice conditions.
Zhang and Lindsay, 4.4, +/- 0.4, Model
These results are obtained from a numerical ensemble seasonal forecasting system. The forecasting system is based on a synthesis of a model, the NCEP/NCAR reanalysis data, and satellite observations of ice concentration and sea surface temperature. The model is the Pan-Arctic Ice-Ocean Modeling and Assimilation System (PIOMAS, Zhang and Rothrock, 2003). The ensemble consists of seven members each of which uses a unique set of NCEP/NCAR atmospheric forcing fields from recent years, representing recent climate, such that ensemble member 1 uses 2005 NCEP/NCAR forcing, member 2 uses 2006 forcing …, and member 7 uses 2011 forcing…In addition, the recently available IceBridge and helicopter-based electromagnetic (HEM) ice thickness quicklook data are assimilated into the initial 12-category sea ice thickness distribution fields in order to improve the initial conditions for the predictions.
Keen et al (Met Office), 4.4, +/-0.9, Model
Same as last month.
Kauker et al, 4.5, +/- 0.4, Model
Sea ice-ocean model ensemble run – For a more detailed description we refer to our July report. The ensemble model experiments for the August outlook all start from the same initial conditions on July 30th 2012. The simulated daily ice extent for all 20 realizations of the ensemble is shown in Figure 1 from the initialization until end of September. Note that August and September atmospheric conditions similar to 2007 would result in a September minimum of 3.6 million km2 (thick black line in Figure 1). Atmospheric forcing similar to the years 2008 and 2010 would give a September mean of about 4.0 million km2 .The mean September value of the ensemble mean is 4.46 million kmÇ (bias corrected). The standard deviation of the ensemble is 0.38 million km2 which we provide as uncertainty estimate of the prediction.
Meier et al, 4.5, +/-0.3, Statistical
This statistical method uses previous years’ daily extent change rates from August 1 through September 30 to calculate projected daily extents starting from July 31. The September daily extents are averaged to calculate the monthly extent. Rates from recent years are more likely to occur because of the change in ice cover. Thus, the official projection is based on the rates for 2002-2011, yielding a September 2012 average of 4.47 million square kilometers; the range however is still quite large with a standard deviation of 335,000 square kilometers. Using all years (1979-2011) yields a slightly higher estimate of 4.66 million square kilometers, but a similar range of 337,000 square kilometers. Five out of the 33 scenarios (using rates from 1979, 1999, 2004, 2007 and 2008) would yield a new record minimum September extent. This suggests the chance for a record low this year is ~15%, though this probably underestimates the probability because recent years have tended to follow faster decline rates.
WattsUpWithThat.com, 4.5, n/a, Heuristic
Reader poll.
Stroeve et al, 4.6, range 4.1-5.2, Statistical
Same as last month.
Tivy, 4.7, +/-0.5, Statistical
A persistence forecast based on anomalies in July extent where the mean period is defined as the average of the previous five years. Persistence is a benchmark for more sophisticated techniques.
Kay et al, 4.7, range 4.0-5.7, Heuristic
An informal pool of 23 climate scientists on June 1, 2012 estimates that the September 2012 Arctic sea ice extent will be 4.68 million sq. km. (stdev. 0.32, min. 4.00, max. 5.70). In 2008, 2009, and 2011, our informal pool estimates of the mean September ice extent were within 0.10 million sq. km. of the corresponding observed value, making our informal method competitive with more sophisticated prediction efforts.
Canadian Ice Service, 4.7, n/a, Multiple Methods
As with CIS contributions in June 2009, 2010 and 2011, the 2012 forecast was derived using a combination of three methods: 1) a qualitative heuristic method based on observed end-of-winter Arctic ice thicknesses and extents, as well as an examination of Surface Air Temperature (SAT), Sea Level Pressure (SLP) and vector wind anomaly patterns and trends; 2) an experimental Optimal Filtering Based (OFB) Model which uses an optimal linear data filter to extrapolate NSIDC’s September Arctic Ice Extent time series into the future; and 3) an experimental Multiple Linear Regression (MLR) prediction system that tests ocean, atmosphere and sea ice predictors.
Wu et al, 4.7, +/-0.3, Model
Same as last month.
Blanchard-Wrigglesworth et al, 4.9, +/-0.6, Model
Same as last month.
barry says:
August 14, 2012 at 4:17 am
Winter sea ice cover has declined, but not as much as summer time sea ice loss (over the satellite record). If this pattern continues – summer time decline greater than wintertime – then the area of sea ice formation will continue to get larger, inevitably breaking records. This is what is expected to happen under the scenario predicted by the mainstream observers, where the Arctic pack becomes thinner over time. With a modicum of thought, it makes complete sense.
What scenario predicted by which observers?
The thinning is an effect of record melt + record ice formation, not a cause.
Greenhouse gas warming theory predicts most warming in the Arctic winter. Thus the greatest effect should be on the ice maximum extent, not on the ice minimum extent. We should be seeing sea ice reduction because of reduced winter ice formation. That we see record melt in the summer and record ice formation in the winter, is compelling evidence greenhouse gas warming is not the cause of decreased summer sea ice.
Mervyn,
Roald Amundsen’s NW Passage transit was possible only because it took him a couple years to do it after his ship got iced in. He also did not go through all of what is commonly considered the Northwest Passage today, instead opting for a warmer, more southerly route along the Canadian mainland south of Victoria Island. So you’re right, it had nothing to do with man-made global warming. It had to do with the fact that he was able to survive two Arctic winters while stuck in place until the ice broke up enough for him to navigate to safety.
BTW, there are several good books out there on the history of Arctic exploration and the politics surrounding it. I highly recommend “Arctic Labyrinth” by Glyn Williams.
As Joachim Seifert sez above, the arithmetic of warming from the LIA max ice extent is that the ice coverage hasn’t “caught up” to the centuries-long trends. At some point the equilibrium curve and the actual ice will match (but probably only for a moment). In the meantime, the average must continue to fall.
izen says:
August 14, 2012 at 2:02 am
“The early melting of ice that has occurred this summer within the Arctic has exposed more ocean surface to solar warming during the 24/7 arctic ‘day’. ”
izen, the Earth is not flat as depicted in CAGW energy budget papers but closer to a sphere.
In the north the sun is comming at a very small incidence, which is going down day by day, in September the switch to the south emisphere happens and the north starts to get night 7×24.
The most energetic sunrays like UV are already reflected at a more steep angle by water, the lower energetic at smaller angles – see water reflection.
For the ocean subsystem less ice coverage in the north would mean a huge heat loss during fall and winter, ice is a natural thermal shield – see igloos.
I see the arctic rather as a thermostat ensuring heat loss and no heat gain – only in the month of May – August net heat gain, all other month net heat loss – you need to do proper calculation balance, subtract first reflection then compare sin() with radiated value. In addition to this take clouds into account – see above picture.
Don’t add “backradiation” as thermal input, but do a proper heat transfer calculation as for any thermal calculation with several strata and radiation to space. I never saw insulation calculation being replaced with backradiation in any thermal calculation in any engineering work.
If the “death spiral” hypothesis of ever warming arctic would be a viable hypothesis it would have happened long ago when it was warmer, but this was invalidated all the warmer periods before.
The Earth is not flat and we are not going to fry.
kadaka (KD Knoebel) says:
August 14, 2012 at 6:39 pm
“Arctic death spirals.”
I note that these are all media links. I have learned to be careful of journalists. One’s slightest looseness of speech gets amplified out of all proportion in search of a good story. Lokk how an off-the-cuff comment to a journalist turned into a countdown to zero ice cover on WUWT!
Thanks for the Cryosphere information. Differences in the details of data analysis can produce differences like that between the NSIDC and Cryosphere Today graphs.
I like having two data sets. As long as each is internally consistent,they can give independant confirmation of trends.
Philip Bradley says:
August 14, 2012 at 11:05 pm
“Greenhouse gas warming theory predicts most warming in the Arctic winter. Thus the greatest effect should be on the ice maximum extent, not on the ice minimum extent.”
I’m not familiar with this argument. Could you provide a reference?
Observed winter ice extents in recent years have been close to the 1979-2000 average, suggesting that there has been no long term change in maximum extent since satellite measurement started. I would expect this, since with very little insolation through the Winter, there is little infrared to be backscattered by greenhouse gases, and no opportunity for any increase in their concentrations to have any effect.
http://nsidc.org/arcticseaicenews/files/2012/07/N_stddev_timeseries2.png
Indeed GWPF got egg on its face earlier this year by suggesting that an April 2012 winter ice extent close to the average was evidence that global warming had stopped.
Average Arctic temperatures during the winter are very, very cold, about -40°C. AGW is posited to have raised average temperatures by about 0.8°C. Double that figure for polar amplification and then, very generously, double it again for faster winter warming and you get winter warming in the Arctic of 3.2°C, which would raise the average temperature to -36.8°C. That is not going to inhibit winter ice formation except at the very lowest Arctic lattitudes.
By comparison, the Arctic summer has an average temperature a little over 0°C. Increase that by a mere 1.6°C and you suddenly have very good conditions for melting a lot of ice, even at much higher lattitudes.
No, but that you think this is compelling evidence that your understanding of the climate does not even extend to the seasons. I would recommend you review your reference materials because this is really basic stuff.
Kevin MacDonald says:
August 15, 2012 at 4:35 am
I’ll quote the linked below synthesis of Arctic amplification.
This mechanism of Arctic amplification will hence have a
pronounced seasonal expression, strongest in the low sun period,
especially autumn, and weaker in summer.
and
<i.Serreze et al. (2009) examined the evolution of temperatures over
the Arctic Ocean from 1979 to 2007 using data from two different
atmospheric reanalyses. Anomalies were computed with respect to the
period 1979–2007. Starting in the late 1990s, surface air temperature
anomalies over the Arctic Ocean were seen to turn positive in autumn,
growing in subsequent years, and building into winter. Development of
the autumn warming pattern was found to align with the observed
reduction in September sea ice extent, with the temperature anomalies
strengthening from the lower troposphere to the surface. The recent
autumn warming was found to be stronger over the Arctic Ocean than
over Arctic land areas and lower latitudes. No enhanced surface
warming signal was found in summer.
http://www.colorado.edu/geography/class_homepages/geog_4271_f11/readings/week_12_13_serreze_barry_arctic_amp.pdf
I’ll suggest your understanding of the Arctic climate is rather more deficient than mine.
Philip Bradley @ur momisugly here
Successful wintertime recovery was predicted at least as early as 1995, in this paper, where summer time declines were more extreme than wintertime in the model simulation (CO2 increase 1% per annum over a centennial model run).
This showed up in subsequent simulations, and makes physical sense. Even though winter warms more than summer in the Arctc, it is still well cold enough for ice to form, and we should expect strong recovery each season while temperatures remain well below freezing. The dynamics are complex – for instance, warmer winters may equate to more snow, and more thickness, but the ocean is warmer, reducing the growth season, and there are salinity changes etc.
But if we assume simply that the behaviour we have seen is what will continue – that winter ice cover will decline slower than summer ice cover – then we can expect to see “record ice reformation” going into the future. It’s simple arithmetic, and no indication at all of any long-term recovery. To the contrary, an indication of long-term recovery might be that the ice reformation is reduced over time, as the difference between wintertime and summertime ice cover becomes less (as it was 10, 20, and 30 years ago).
I’m not sure that the cause of warming would make much of a difference to these metrics.
[edit] I see Kevin MacDonald has put it a little more succinctly.
Strawman! I didn’t against argue against a seasonal expression of Arctic amplification (in point of fact, I overstated it), I illustrated why it would not be strong enough to significantly inhibit winter freezing in the Arctic Ocean.
Given the above logical fallacy, I’d suggest it is not just your understanding of climate that is deficient and that your comprehension generally is poor. Whether this is from lack of effort or lack of ability only you and those closest to you will know.
The NSIDC data supports Sereze et al. (2009). Increased amplification from warmer and more extensive open water is delaying ice growth, giving lower extents for the date. (It means, too, that I have underestimated the probable effect of increasing greenhouse gas concentrations on back radiation from warmer seas.)
It is also pushing the maximum extent later in the year.The 1979-2000 average winter extent peaks in late February. Four of the last five years show the peak occuring well into March, with a shorter time cold-soaking at minimum temperature. The effect of this does not show as a reduction in maximum extent, but may explain why the multi-year ice and total ice volume have both declined in recent years.
It may also help explain why the Spring and Summer thaw has become so much more extensive, even without extra amplification in Summer, with a smaller volume of ice to be melted and a greater extent change per unit of energy input.
http://nsidc.org/arcticseaicenews/files/2012/04/Figure2.png
While the usual suspects are freaking out because of ice melting (really?!?), other countries are making preparations to exploit the wealth of resources hidden under the arctic.
http://www.wired.com/dangerroom/2012/08/arctic/
Again, catastrophists, an open arctic is bad, how? The arctic has been ice free numerous times throughout history and guess what life on earth made it through. Even the polar bears looked like they did alright, and they’re currently at record-breaking levels.
Kevin MacDonald says:
I would suggest thinking a little deeper abut this.
1) the temperature gets down to about -30C for area above 80N. If you extend the boundaries out to 70N, the average is “only” ~ -25C in the dead of winter.
2) Summer warming (70N – 90N) has been about 0.3 C/decade, or about 1C. Warming for Sep, Oct, Nov, Dec, Jan & Apr has been at least 1.0C/decade –> 3-5 C warming. So your estimate of 3.2 is not bad (but is certainly not “generous”.)
3) The gradient is less than 30C from the top to the bottom of the ice (~ 0C to ~ -25C) for most of the Arctic Ocean. A warming of 3C is more than 10% of this gradient. Since this gradient determines the flow of energy by conduction up thru the ice,there will be ~ 10 % reduction in the energy flow by conduction (and hence in the depth of ice that freezes in the winter). A ~ 10% reduction sounds like it is inhibiting ice formation!
4) If there are 3C – 5C changes over large areas ‘around the margins’, then the margins of the ice will freeze more slowly and less deeply.
5) Large areas of open Arctic water in the summer will absorb more sunlight than ice and warm up. When the temperatures *do* inevitably drop in the fall, energy must first be lost to cool the warm water, which further inhibits ice formation.
From Entropic man on August 15, 2012 at 3:37 am:
ThinkProgressive!:
Indeed, a stunning example of an innocent statement being “…amplified out of all proportion in search of a good story.” Surprising really, given Joe Romm’s history as an accurate reliable journalist.
BTW, the last link is to a New Scientist graphic using PIOMAS volume data. You know, the PIOMAS model results that were well researched, well verified, and widely cited by the alamist community as proof of Arctic sea ice decline. Then the PIOMAS model collided with reality, leading to the less-alarming PIOMAS v2.0 found here, which is equally as well researched, well verified, and widely cited by the alamist community as proof of Arctic sea ice decline. Which is why the next to last link goes 404.
Temps today are higher than during the LIA in the 17 Century…. when ice mass grew….
IT is NORMAL, that ice melts today, it would be unnormal if it stayed the same…One day, when
temps will be down again, in about 100 years, the ice volume will grow again….crystal clear….
This process is normal……
Then fail to take that advice, why?
I am referring to Philip Bradley’s assertion about what the Arctic sea ice maximum should be, I am not discussing when it should be, yet it is the latter your points address.
No Kevin, my points are exactly about the extent and volume of ice as it refreezes each year. Warmer winters will limit the thickness of the ice. Warmer winters will limit the edges of the ice. Both of these will affect both the maximum and the minimum extents.
Lars P. says: August 15, 2012 at 3:07 am
“the Earth is not flat as depicted in CAGW energy budget papers but closer to a sphere.”
What? Where can you find any paper claiming the earth is flat, or making calculations assuming the earth is flat?
“The most energetic sunrays like UV are already reflected at a more steep angle by water, the lower energetic at smaller angles – see water reflection.
Perhaps you mean ‘refraction’? All light reflects at the same angle (ie the angle of incidence). Now it is true that violet (and UV) would refract at a higher angle, but that wouldn’t matter anyway
“For the ocean subsystem less ice coverage in the north would mean a huge heat loss during fall and winter, ice is a natural thermal shield – see igloos.”
OK I can agree with that. This would provide a form of negative feedback. Of course, this would never allow a year with
“I see the arctic rather as a thermostat ensuring heat loss and no heat gain – only in the month of May – August net heat gain … “
This depends a lot on what you are including in your calculations.
* If you mean simply EM radiation heat sources, then I suspect you are close to right. During the winter, there is thermal IR leaving the surface and thermal IR arriving at the surface. The thermal IR leaving will indeed be greater than the thermal IR arriving. During the summer, the thermal IR leaving is STILL greater than the thermal IR arriving, but the incoming sunlight will eventually make up the difference (May-Aug sounds about right).
* For ALL heat sources, the net gain is positive whenever there is net warming (or melting of ice). in that sense, there is a net gain from ~ March–>Sept, and a net loss from Sept–>March.
(The difference would be due to transport of heat from the south via air and ocean currents.)
“Don’t add “backradiation” as thermal input, but do a proper heat transfer calculation … “
What?? That is like saying “do a proper calculation for the flight of a baseball, but don’t add in air resistance”! A “proper” calculation of heat transfer has to include all sources of heat, which would include incoming radiation (eg incoming IR radiation or “back-radiation” as it is colloquially called).
I never saw insulation calculation being replaced with back radiation in any thermal calculation in any engineering work.
Well, that would be because back-radiation and insulation are two different things. Have you ever seen insulation being replaced with sunlight? Or insulation being replaced with an electric heater? It’s not done because it would be incredibly bad engineering!
“If the “death spiral” hypothesis of ever warming arctic would be a viable hypothesis it would have happened long ago when it was warmer, but this was invalidated all the warmer periods before.
I never liked the hyperbole of the term “death spiral”. The hypothesis is for some degree of feedback whereby melting ice helps ensure more melting ice. No one that I know of ever predicted an “ever warming arctic.” If you can find such a reference (in a scientific publication), I’d enjoy seeing it
Every bit of evidence we have says the ice is thinning. That means there’s less energy needed to melt it out than there used to be.
What would cause Arctic sea ice to thin faster than it reduces in extent? Or put another way, what would cause thicker ice to melt faster than thinner ice?
Would increased atmospheric temperatures cause this? Nope.
Nor would increased downwelling LWR, or increased sea temperatures.
What would cause it is black carbon and particulate deposition, because as the ice melts at the surface, the BC accumulates decreasing the albedo and accelerating the melt. Thus, the thicker the ice the faster it melts.
This mechanism has no effect on ice formation, which is why we are seeing record ice formation.
I was wondering why extent took such a huge nosedive.
http://ocean.dmi.dk/arctic/icecover.uk.php
The COI shows extent is already almost at 2007 minimum level. The storm practically guarantees a new record minimum.
I accept that warming winters will limit the edges of the ice, I said as much (which is why you suggesting I think a little deeper and then pointing at things I’d already thought on seemed bogus), but the position you are defending is that the Arctic maximum sea ice extent should retreat quicker Arctic minimum sea ice extent. None of the points you raise support that, all they tell us is that freezing will generally occur later in the season, but no one was arguing that this wouldn’t happen.
To add to Kevin’s comment, Philip Bradley, in reply to me, suggested that wintertime sea ice extent should decline quicker than sumertime sea ice extent. This is not what was anticipated and not what is actually occurring. Kevin is reinforcing my point. tjfolkerts, you are making a different point, which no one has talked about or is disagreeing with.
tjfolkerts, unless you are arguing that wintertime sea ice extent should decrease faster than summertime sea ice extent, I’m not sure what your point relates to. If you agree with Kevin and I on that point, by all means let us know.
To restate the point I made in response to an erroneous comment upthread – “record sea ice formation” is expected in a scenario where summertime extent declines faster than wintertime extent. As the difference between maximum and minimum increases, obviously we will see a greater area of sea ice reforming, even while both minima and maxima are decreasing (at different rates over the years). Contrary to opinions above, a decrease in sea ice reformation would be an indicator of long-term recovery.
(Except in the case where summertime sea ice bottoms out to zero extent, then decreasing wintertime extent would see less sea ice reformation over time.)
Kevin MacDonald suggests:“but the position you are defending is that the Arctic maximum sea ice extent should retreat quicker Arctic minimum sea ice extent. “
No I don’t think I am defending that. You said “That is not going to inhibit winter ice formation except at the very lowest Arctic lattitudes.” That is a very clear statement about ice formation. I was disagreeing. I think that the warmer winters WILL inhibit (to some degree) winter ice formation throughout the Arctic. And by extension, warmer winters will reduce summer extents. Nothing in what I said was directed at the specific question of WHICH of those two would retreat more quickly.
NSIDC have updated their sea ice page and commented on the storm as well as recent events.
http://nsidc.org/arcticseaicenews/2012/08/
That has a context.
Ignoring the context to make some idiotic semantic point is worthless and counter to site policy which discourages:
None of which contradicts anything I said. I had already stated that extent would be inhibited at lower latitudes and I made no claims about ice thickness because it was not part of the terms of reference. So, given that you’re agreeing with me, what, exactly, is it you believe I need to think deeper on?
Jim says:
August 15, 2012 at 9:21 am
While the usual suspects are freaking out because of ice melting (really?!?), other countries are making preparations to exploit the wealth of resources hidden under the arctic.
http://www.wired.com/dangerroom/2012/08/arctic/
Again, catastrophists, an open arctic is bad, how?
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Canadians and Alaskans whose houses are sinking into melting permafrost, or whose coastline undergoes more rapid erosion, might not be too keen.
The real problem is Greenland’s ice cap. The sea ice around Greenland has insulated it from recent warming elsewhere, an effect which recent events suggest may be less effective than it once was. If a significant portion of that ice volume melts, the ensuing sea level rises may be damaging to our civilization based on coastal plains
This is probably a foolish question, but it highlights the choice we may already have made, all unwitting. Would you regard access to Arctic resources and open sea lanes sufficient recompense if the accompanying sea level rise forced you to evacuate Manhatten?