Video follows.
The length of the melt season for Arctic sea ice is growing by several days each decade, and an earlier start to the melt season is allowing the Arctic Ocean to absorb enough additional solar radiation in some places to melt as much as four feet of the Arctic ice cap’s thickness, according to a new study by National Snow and Ice Data Center (NSIDC) and NASA researchers.
Arctic sea ice has been in sharp decline during the last four decades. The sea ice cover is shrinking and thinning, making scientists think an ice-free Arctic Ocean during the summer might be reached this century. The seven lowest September sea ice extents in the satellite record have all occurred in the past seven years.
“The Arctic is warming and this is causing the melt season to last longer,” said Julienne Stroeve, a senior scientist at NSIDC, Boulder and lead author of the new study, which has been accepted for publication in Geophysical Research Letters. “The lengthening of the melt season is allowing for more of the sun’s energy to get stored in the ocean and increase ice melt during the summer, overall weakening the sea ice cover.”
To study the evolution of sea ice melt onset and freeze-up dates from 1979 to the present day, Stroeve’s team used passive microwave data from NASA’s Nimbus-7 Scanning Multichannel Microwave Radiometer, and the Special Sensor Microwave/Imager and the Special Sensor Microwave Imager and Sounder carried onboard Defense Meteorological Satellite Program spacecraft.
When ice and snow begin to melt, the presence of water causes spikes in the microwave radiation that the snow grains emit, which these sensors can detect. Once the melt season is in full force, the microwave emissivity of the ice and snow stabilizes, and it doesn’t change again until the onset of the freezing season causes another set of spikes. Scientists can measure the changes in the ice’s microwave emissivity using a formula developed by Thorsten Markus, co-author of the paper and chief of the Cryospheric Sciences Laboratory at NASA’s Goddard Space Flight Center in Greenbelt, Md.
Results show that although the melt season is lengthening at both ends, with an earlier melt onset in the spring and a later freeze-up in the fall, the predominant phenomenon extending the melting is the later start of the freeze season. Some areas, such as the Beaufort and Chukchi Seas, are freezing up between six and 11 days later per decade. But while melt onset variations are smaller, the timing of the beginning of the melt season has a larger impact on the amount of solar radiation absorbed by the ocean, because its timing coincides with when the sun is higher and brighter in the Arctic sky.
Despite large regional variations in the beginning and end of the melt season, the Arctic melt season has lengthened on average by five days per decade from 1979 to 2013.
Still, weather makes the timing of the autumn freeze-up vary a lot from year to year.
“There is a trend for later freeze-up, but we can’t tell whether a particular year is going to have an earlier or later freeze-up,” Stroeve said. “There remains a lot of variability from year to year as to the exact timing of when the ice will reform, making it difficult for industry to plan when to stop operations in the Arctic.”
To measure changes in the amount of solar energy absorbed by the ice and ocean, the researchers looked at the evolution of sea surface temperatures and studied monthly surface albedo data (the amount of solar energy reflected by the ice and the ocean) together with the incoming solar radiation for the months of May through October. The albedo and sea surface temperature data the researchers used comes from the National Oceanic and Atmospheric Administration’s polar-orbiting satellites.
They found that the ice pack and ocean waters are absorbing more and more sunlight due both to an earlier opening of the waters and a darkening of the sea ice. The sea ice cover is becoming less reflective because it now mostly consists of thinner, younger ice, which is less reflective than the older ice that previously dominated the ice pack. Also, the young ice is flatter, allowing the dark melt ponds that form at the early stages of the melt season are able to spread more widely, further lowering its albedo.
The researchers calculated the increase in solar radiation absorbed by the ice and ocean for the period ranging from 2007 to 2011, which in some areas of the Arctic Ocean exceed 300 to 400 megajoules per square meter, or the amount of energy needed to thin the ice by an additional 3.1 to 4.2 feet (97 to 130 centimeters).
The increases in surface ocean temperatures, combined with a warming Arctic atmosphere due to climate change, explain the delayed freeze up in the fall.
“If air and ocean temperatures are similar, the ocean is not going to lose heat to the atmosphere as fast as it would when the differences are greater,” said Linette Boisvert, co-author of the paper and a cryospheric scientist at Goddard. “In the last years, the upper ocean heat content is much higher than it used to be, so it’s going to take a longer time to cool off and for freeze up to begin.”
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I tend to take research done by Ms. Stroeve with a grain of skepticism, since she allows her work to be aided by political activists at Greenpeace.
This photo was taken on 09/11/2012:
Source: Greenpeace
But politics aside, more importantly, no evidence seems to be visible in common sea ice graphs like this one. In fact, the melt season started later than usual this year, according to NSIDC’s Arctic Sea Ice Extent Graph.
They did some CYA for that:
“There is a trend for later freeze-up, but we can’t tell whether a particular year is going to have an earlier or later freeze-up,”
National Snow & Ice Data Center (NSIDC) – click to view at source
Granted, the report mentions it to be mostly a regional effect, While there likely is some truth in the report, what isn’t explored is whether the cause of this change is part of a natural cycle, a natural cycle enhanced by some AGW effects, or purely an artifact of AGW.
Their claim…
The increases in surface ocean temperatures, combined with a warming Arctic atmosphere due to climate change, explain the delayed freeze up in the fall.
…reads like something Greenpeace would write, providing no other possibility. One thing I tend to notice about Earthly geological and atmospheric processes is that they tend to act on timespans than exceed human lifetimes, sometimes being orders of magnitudes longer. In the case of Arctic sea ice, a record going back to 1979 is shorter than that and only represent a fraction of what may be a natural cycle. Making claims that they know exactly what the cause is might very well bite them in a few years or few decades.
When I read a study summary like this one I see purposeful presumptions laced through the entirety of the “study”. All aimed at arriving where it needs to be.
They site their source of data with the implication they are merely reading the data. They are in reality arranging the data for a prescribed use.
One thing that popped was the extended period for an arctic ice free summer.
….”scientists think an ice-free Arctic Ocean during the summer might be reached this century.”
Boy that is a huge expansion of time from the predictions just a few years ago that it would already have occurred by now.
Imagine how many natural fluctuations will occur over the rest of the century.
Well, don’t imagine just look at the last century.
There’s been a lot of changes to change as changes occur.
@Magma- Not only do you seem to be a petty and bitter anonymous troll, but your poisonous snide little potshots are becoming increasingly tiresome.
You want to take SAMURAI, et al, to task.
Ok, you want to be the smartest guy in the room? Prove it:
Do winds and ocean currents and black carbon soot and the Beaufort Gyre have greater influence on Arctic sea ice area, or does global temperature cause the greatest variance in Arctic sea ice? Why has Antarctic continental ice been increasing for 150 years, while Southern Ocean sea ice area sets new growth records each year? Why is the global sea ice anomaly already positive (and will remain so for the rest of the year?)
Steve R says:
April 1, 2014 at 3:09 pm
I forget…Can someone recap again why we are supposed to be terrified of an ice-free arctic summer again? Would an ice- free arctic summer bring about climate apocalypse? And if so, in which direction (hot or cold)?
__________________
All of those Russian icebreaker/research vessels need to earn their keep and Antarctica is so very far away (and attracts the wrong sort of clientele.)
That’s not bad going. Not two weeks since the Spring Equinox and already the Arctic is doomed. Hard to decide whether they’re going for a record or just joining in the general climate clamour du jour.
@ur momisugly Alan Robertson – sure. I’m barely returning the favor. Any representative sampling of the attacks on scientists’ competence, motives and characters routinely made here would cast my mildly sarcastic remarks into the shade.
Okay, I have used the NSIDC’s own official database to prove this claim is false. Please feel free to post this anywhere anytime since this claim is made by anyone)
The actual trend is a decrease of 0.2 days per decade (as in not even measureable since we are using whole days here, not fractions of a day – so it is really Zero per decand).
http://s27.postimg.org/jo99y2i37/Length_of_Melt_Season_NH_SEI_NSIDC.png
The official Maximum dates and Minimum dates (as in days since the beginning of the year, including the impact of leap years).
http://s28.postimg.org/fw18ygh4d/Max_Min_Date_NH_SEI_NSIDC.png
The NSIDC database can be accessed here – Final includes all days from 1979 to 2013 (every second day in the first 8 years)
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/
Magma: I am the least smartest guy in the room. I’m just a layperson, BA/JD, non-scientific type, but I’d love to read your response to Alan’s questions. In spite of my non-science background, I can understand the notion of relying on data to support one’s arguments. If the data isn’t there, or if it’s questionable; or if one’s arguments are grounded not so much on observation and measurement but on questionable models and assumptions, then I think that criticizing one’s methods is quite proper. In a civil way, of course. But the response of one who is criticized, I would think, would be to counter with a valid argument. A scientist proposing an idea must not have too much of a thin skin. Doesn’t science involve questioning, examining, and scrutinizing a hypothesis or even offering other possibilities, based on data, as an alternate hypothesis to explain the observed phenomena? So, please, Magma, educate me, by answering Alan’s questions.
“Making claims that they know exactly what the cause is might very well bite them in a few years or few decades.”
Yeah, but they will be long gone by then.
It’s always the same. These people never answer any questions with science. They only try to make you confused and to drop the questions asked in the first place. It’s really hard to understand what drives them.
Like mr Cook, he make a big fuzz about water v/s ice emissions, but do not discuss what people here really is talking about and what is definitely wrong. The max and min times isn’t moving. As far as I can see this invalidate the claims,end of story.
These guys neglect to mention that the Arctic has been melting twice as fast as their model projections predict. That is because Arctic warming today is not greenhouse warming but is caused by warm Gulf Stream water carried into the Arctic Ocean by North Atlantic currents. It all started at the turn of the twentieth century, prior to which there was nothing but slow, linear cooling for 2000 years. The sudden start of the warming was due to a rearrangement of the North Atlantic current system at the turn of the century. The former pattern of currents returned for thirty years in mid-century, and with it came cooling at the rate of 0.3 degrees Celsius per decade. None of this can be attributed to greenhouse warming by carbon dioxide because there was no increase of atmospheric carbon dioxide when the warming started. We know this for sure because fortunately excellent records are available in the form of the Keeling curve and is extensions. It is particularly difficult for those who believe in AGW to explain the on again – off again – on again mid-century observations. It is clear that the authors are ignorant of these facts because they did not do their homework and read the relevant scientific literature. The full story of Arctic warming is found in E&E Volume 22, issue 8, pages 1069 to 1083 (2011).
RE: SAMURAI says:
April 1, 2014 at 10:42 am
I’m not sure that the ice is thinner, despite the milder air temperatures over the Pole north of 80 degrees.
First, the cross-polar-flow created strong winds where it is usually calmer, which created cracks in the ice that exposed water which was immediately chilled more than normal. As Ice is largely melted from below, this chilled water has a decreased ability to melt ice.
Second, the cross-polar-flow diverted the ordinary Transpolar Drift towards Canada, decreasing the amount of ice flushed out through Fram Strait and increasing the amount of ice in the Beaufort Gyre.
Third, some of the coldest air was over parts of the Arctic Ocean which lie south of 80 degrees latitude, and are not included in the DMI graph of arctic temperatures. When the cross-polar-flow shifts over towards Bering Strait, a large part of the cold air crosses south of 80 degrees. The air is coldest just as it leaves Siberia, warming as it crosses the “warmer” ice (ice only minus-thirty) and the entire coast of Siberia is south of 80 degrees. Much of the Canadian and Alaskan coasts are also south of 80 degrees, so when the flow reversed cold air hit those areas from inland.
My own sense is that the ice is thinner on the Atlantic side and towards the Kara Sea and Laptev Sea coastlines in West Siberia, but that the ice in the Beaufort Gyre is thicker, especially north of Alaska. I think it is unlikely that the waters north of Bering Strait, which were largely ice-free in recent years, will be ice-free this September.
I’ve noticed a large area of piled-up sea ice on the arctic coast on the Siberian side of Bering Strait. I’m not certain how many Manhattans its area is, (maybe 50,) but it is a big chunk of jumbled ice over fifteen feet thick. In the summer heat it will likely crumble and be spread far and wide like a small pat of butter over a large piece of toast. Because the extent-graphs do not differentiate between a small chunk fifteen feet thick and a spread-out-slush six inches thick, this single area of piled up ice has the ability to mess up ice-melt calculations royally. In fact, if the winds are right, as it spreads out the extent graphs may go up when logic tells us they should go down.
I think it will be a lot of fun watching ice melt this summer, and also listening to the hullabaloo people make about it.
RACookPE1978 You rock!
Julienne Stroeve
I suggest you ask the sailors of the 22 yachts that got stuck in ice while crossing the Northwest Passage last summer in the Arctic Sea. They say there is 60% more sea ice than previous year. BTW Larsen crossed the Northwest Passage in a single season in 1944. Probably less sea ice back then.
http://www.sail-world.com/Asia/North-West-Passage-blocked-with-ice%E2%80%94yachts-caught/113788
“… scientists think an ice-free Arctic Ocean during the summer might be reached this century. ”
Um but the Arctic was supposed to be ice free last year, now its going to happen sometime this century. This is more evidence that climate change is just politics, not science.
Samurai the ice is not that thin, the reason ice melts is warmer water currents underneath the ice, not the surface air which even if some was warmer would still be under zero and not melting the ice anytime soon at this time of year.
See Box of Rocks and maybe Caleb above
Gavin is right in one aspect, it is impossible to predict the time and extent to which Arctic sea ice will melt. He was badly burned last year as I was the other way the year before.
The Arctic ice returning to status quo will be the death knell of the warmists when it occurs. One can only hope for such an event in the next couple of years lasting for at least 2 summers along with a drop in global temp.
While this practically would be just weather and not proof of no AGW it would still be the silver bullet for AGW as they have used the reverse argument so often they will die of shame and ridicule.
There is no evidence of objectivity (such as considering alternative explanations) in this report of the study and some evidence of a pre-determined conclusion. So many studies looking for observations in support of an opinion. And that reminds me of the NYTimes article proclaiming that it is not safe to pee in your swimming pool. “says science.” Technically, a chemical is created but it is impossible to create it at levels that can be remotely toxic. Says Science. One fact, such as variable ice melt patterns, does not make for a proven conclusion of fearsome, rapid and non-reversing change.
@ur momisugly Alan Robertson, Tuduri
Do winds and ocean currents and black carbon soot and the Beaufort Gyre have greater influence on Arctic sea ice area, or does global temperature cause the greatest variance in Arctic sea ice? How do you separate (amplified) Arctic warming and other effects from the larger global picture – warmer air masses and currents and gyres, whether the Beaufort or the North Atlantic Current, warmer runoff from rivers draining into the Arctic Ocean and so on? But there’s probably not much role for black carbon here.
Why has Antarctic continental ice been increasing for 150 years it hasn’t while Southern Ocean sea ice area sets new growth records each year? Proportionately small variations in annual ice, possibly driven by fresher surface water and changing thermoclines. Why is the global sea ice anomaly already positive (and will remain so for the rest of the year?) 0.3 million km2 out of a total 17 million km2, and the year is young
Magma says:
April 1, 2014 at 4:41 pm
“@ur momisugly Alan Robertson – sure. I’m barely returning the favor. Any representative sampling of the attacks on scientists’ competence, motives and characters routinely made here would cast my mildly sarcastic remarks into the shade.”
___________________
These pages are filled with “State Pen, not Penn State” and similar remarks. These threads also contain many documented references to attacks by the very same “scientists”, educators and government officials which call for the imprisonment, “re-education” and even death of climate skeptics. The efforts to suppress our voices are legion.
Your remarks don’t get any shade, just the full glare of sunlight exposing the totalitarian underpinnings of the cause which you support.
Prove me wrong!
Magma says:
April 2, 2014 at 7:15 am
___________________
That’s more like it.
mkelly says:
April 1, 2014 at 12:04 pm
The IPCC said that the Arctic was freezing up in the 1970′s. The graph below is from the 1990 IPCC report, and shows Arctic sea ice satellite data which is conveniently omitted from NSIDC graphs that start at the 1979 peak…If the first IPCC report has ice record going back to 1974 with ’74 being low the 1979 information is a true cherry pick. We should not use it.
First, be careful comparing data sets. The earlier data was manually digitized from ice charts, and averages 10% higher than the self-consistent 1979-date satellite data. Second, it didn’t: the maximums ranged from 13.9 M km2 (1974) to 15.7 M km2 (1979) and the minimums from 6.1 M km2 (1977) to 6.9 M km2 (1978). Compare to the last ten year average of 13.3 M km2 for the maximum extent, and the 2012 historic summer low of 2.4 M km2.
But here’s the first ten years of monthly NOAA/NMC/CAC Arctic sea ice extent data if you want to play with it (in million km2)
year old
1973.042 14.234
1973.125 14.795
1973.208 14.605
1973.292 13.489
1973.375 11.814
1973.458 9.797
1973.542 8.446
1973.625 6.705
1973.708 6.570
1973.792 8.569
1973.875 10.300
1973.958 12.711
1974.042 13.307
1974.125 13.898
1974.208 13.913
1974.292 13.360
1974.375 11.932
1974.458 10.406
1974.542 8.294
1974.625 6.581
1974.708 6.521
1974.792 8.615
1974.875 11.126
1974.958 12.533
1975.042 13.848
1975.125 14.674
1975.208 14.471
1975.292 13.460
1975.375 11.648
1975.458 9.791
1975.542 8.353
1975.625 6.692
1975.708 6.542
1975.792 8.615
1975.875 10.847
1975.958 12.830
1976.042 14.015
1976.125 14.996
1976.208 14.703
1976.292 14.489
1976.375 12.501
1976.458 11.118
1976.542 8.791
1976.625 7.273
1976.708 6.748
1976.792 9.500
1976.875 11.639
1976.958 12.852
1977.042 14.445
1977.125 15.074
1977.208 15.196
1977.292 13.997
1977.375 12.727
1977.458 10.719
1977.542 7.768
1977.625 6.382
1977.708 6.106
1977.792 8.820
1977.875 10.830
1977.958 12.925
1978.042 14.344
1978.125 15.067
1978.208 15.021
1978.292 13.881
1978.375 12.344
1978.458 10.838
1978.542 8.883
1978.625 6.873
1978.708 7.380
1978.792 9.632
1978.875 11.557
1978.958 13.824
1979.042 14.650
1979.125 15.697
1979.208 15.330
1979.292 14.023
1979.375 11.946
1979.458 10.615
1979.542 8.409
1979.625 6.746
1979.708 6.240
1979.792 8.817
1979.875 10.605
1979.958 12.818
1980.042 13.883
1980.125 14.731
1980.208 14.779
1980.292 13.726
1980.375 12.392
1980.458 10.631
1980.542 8.891
1980.625 7.276
1980.708 7.285
1980.792 8.670
1980.875 11.403
1980.958 13.198
1981.042 14.474
1981.125 14.519
1981.208 14.338
1981.292 13.520
1981.375 11.932
1981.458 10.517
1981.542 8.961
1981.625 6.618
1981.708 6.446
1981.792 8.751
1981.875 11.012
1981.958 13.230
1982.042 14.424
1982.125 14.973
1982.208 15.074
1982.292 13.530
1982.375 12.097
1982.458 11.066
1982.542 8.862
1982.625 7.049
1982.708 6.449
1982.792 9.378
1982.875 11.183
1982.958 13.058
richard says:
April 1, 2014 at 2:07 pm
“Claim: NSIDC, NASA Say Arctic Melt Season Lengthening, Ocean Rapidly Warming”
and the reality,
http://www.arctic-info.com/ExpertOpinion/Page/-the-need-for-icebreakers-will-increase-after-the-year-2016-
“…..For this reason, especially in the summer, there has been an increase in the need for icebreakers on the Northern Sea Route.”
And that reason, which you conveniently omitted, was the increase in commercial transarctic traffic via the Northern sea route, which is consistent with an increased seaice melt.
Bill Illis says:
April 1, 2014 at 11:31 am
Are they using the real dates of Max and Min here or are they just repeating what they believe?
If you read the original post you’ll see that they aren’t using the Max and Min to define the melt season! They actually determine the date when ice surface starts to melt and the date when that water freezes.
Mr Green Genes says:
April 1, 2014 at 10:44 am
Les Johnson says:
April 1, 2014 at 10:26 am
Totally agree. My charts look just like yours! It would appear that Ms Stroeve is guilty of a terminological inexactitude ((c) Sir Winston Churchill).
Clearly not since you and Les are trying to compare apples with oranges!
Phil: In general, if ice extent is increasing, then there is more freezing than melting. If ice extent is decreasing, then there is more melting than freezing.
This is the method used by Bill Chapman of the U of Illinois, and host of the Cryosphere today.
If this disagrees with Stroeve, then either Stroeve or Chapman is wrong, or they are measuring two different effects.
Mssr. Occam would suggest that Chapman is right.
Those yachts are still stuck up there by the way.
http://empiricusembarks.wordpress.com/
Les Johnson says:
April 2, 2014 at 9:30 am
Phil: In general, if ice extent is increasing, then there is more freezing than melting. If ice extent is decreasing, then there is more melting than freezing.
This is the method used by Bill Chapman of the U of Illinois, and host of the Cryosphere today.
If this disagrees with Stroeve, then either Stroeve or Chapman is wrong, or they are measuring two different effects.
Mssr. Occam would suggest that Chapman is right.
If ice extent is increasing it can also be due to winds breaking it up and spreading it out over a larger area just as the opposite can occur which leads to compaction. This can happen even when melting occurs since melting is reducing the thickness of the ice rather than its extent. So yes they are measuring two different effects, Stroeve et al. are measuring surface melting.