Arctic Ice Discussion (the Refreeze)

[cooling climate]

I wouldn't consider gains in the second half of March as anything more than a frivolous plus. Both 2011 and 2007 saw gains late in March! As for the warm spell across southern Hudson bay, I doubt it will have much of an impact. The ice usually doesn't start melting there until May, so even if there are any small losses over the next few days, chances are there will still be time for it to re-freeze.

PIT, who's suggesting a total melt out this year?

Spoken like a true disciple of G.W's. Even when sea ice is increasing you lot can not

help but add your doom and gloom spin to it. Pathetic.

[BornFromTheVoid]

Spoken like a true disciple of G.W's. Even when sea ice is increasing you lot can not

help but add your doom and gloom spin to it. Pathetic.

Doom and gloom? Haha, a typical fine and balanced contribution CC.

I was just demonstrating that some growth in sea ice extent in the second half of March means relatively little when it comes to the summer melt period. Also that the current Canadian warm spell shouldn't impact the sea ice in Hudson Bay. Did I get those horribly wrong?

If that's doom and gloom to you, then I can only presume your life must be just rainbows and butterflies!

[pottyprof]

I was just demonstrating that some growth in sea ice extent in the second half of March means relatively little when it comes to the summer melt period.

But surely every little bit of growth counts regardless of how small it is? While I admit that it seems an insignificant amount, that has to be a little more to melt out?

Yours

Mr Pedantic.....

[loafer]

Some interesting noise on blogs asking why ice data from 1979 onwards is used when the data is available from 1972, pointing out that 1979 was the peak ice point.

If true it does seem pretty cynical.

As far as doom and gloom versus rainbows and butterflies, some people are glass half full and some are glass half empty. Personally I prefer the former, but that's just me...!

[BornFromTheVoid]

But surely every little bit of growth counts regardless of how small it is? While I admit that it seems an insignificant amount, that has to be a little more to melt out?

Yours

Mr Pedantic.....

Yep, just as every little bit of growth in from September through to now will help, a little bit of ice gained in the 2nd half of March is nothing unusual. The 2 years I mentioned were just to show that there is now correlation between ice growth in late March and a slower summer melt.

I do find it odd that after the little exchange of posts, this is what you feel the need to take issue with...

Some interesting noise on blogs asking why ice data from 1979 onwards is used when the data is available from 1972, pointing out that 1979 was the peak ice point.

If true it does seem pretty cynical.

As far as doom and gloom versus rainbows and butterflies, some people are glass half full and some are glass half empty. Personally I prefer the former, but that's just me...!

Could you point me in the direction of this blog? Would be interested in looking at the sources it used.

As far as I'm aware, the period from December 1972 to October 1978 were monitored using the Nimbus 5 satellite, and after that, primarily the much more advanced Nimbus 7 satellite and others with similar technology were used. The newer satellites revealed much more detail of the main ice body, and was capable of capturing areas of low ice concentration behind the fringes. This left a discontinuity between the sea ice readings up to ~1979 and after. Rather than dealing with normalising the data and using lower a quality dataset, most studies now will just use from 1979 onwards because it's considered to have more continuity and better quality.

There are sea ice records going back before 1972 also, but it is a case of the further back you go, the less reliable and patchy the data becomes.

[BornFromTheVoid]

Cryosphere Today has updated, and as my post from last week suggested, we're almost back to a new sea ice maxima here as well, just a little over 50,000km2 off the high mark set on March 5th. There has been a spike in ice growth in Kara and Barents Sea's over the last 2 days, and conditions look like remaining similar for the next 96 hours, so hopefully a new sea ice area maximum by then.

http://arctic.atmos.uiuc.edu/cryosphere/

[loafer]

Yep, just as every little bit of growth in from September through to now will help, a little bit of ice gained in the 2nd half of March is nothing unusual. The 2 years I mentioned were just to show that there is now correlation between ice growth in late March and a slower summer melt.

I do find it odd that after the little exchange of posts, this is what you feel the need to take issue with...

Could you point me in the direction of this blog? Would be interested in looking at the sources it used.

As far as I'm aware, the period from December 1972 to October 1978 were monitored using the Nimbus 5 satellite, and after that, primarily the much more advanced Nimbus 7 satellite and others with similar technology were used. The newer satellites revealed much more detail of the main ice body, and was capable of capturing areas of low ice concentration behind the fringes. This left a discontinuity between the sea ice readings up to ~1979 and after. Rather than dealing with normalising the data and using lower a quality dataset, most studies now will just use from 1979 onwards because it's considered to have more continuity and better quality.

There are sea ice records going back before 1972 also, but it is a case of the further back you go, the less reliable and patchy the data becomes.

The original source is the 1990 IPCC Report - page 224 - which says that data is available from 1972 and generally perceived to be reliable from 1975. Report here: http://www.ipcc.ch/ipccreports/far/wg_I/ipcc_far_wg_I_full_report.pdf

I found it via a blog which referenced WUWT - http://wattsupwiththat.com/2012/03/18/sea-ice-news-volume-3-2/

I'm not a regular reader, but the submarine photo article below is fascinating (if a little paranoid in places!).

[BornFromTheVoid]

The original source is the 1990 IPCC Report - page 224 - which says that data is available from 1972 and generally perceived to be reliable from 1975. Report here: http://www.ipcc.ch/i...full_report.pdf

I found it via a blog which referenced WUWT - http://wattsupwithth...ews-volume-3-2/

I'm not a regular reader, but the submarine photo article below is fascinating (if a little paranoid in places!).

Cheers for that loafer. I guess it more or less comes down to whether everyone involved in sea ice study and analysis is part of a huge cover-up, or whether these people that have spent years in becoming experts decided that the data pre-1979 just isn't up to the right standard. Of course, the idea of good quality data will shift and change over time, as is the case with many things.

That WUWT article is extremely sly and misleading though. It repeatedly claims that the data is derived from satellites, but passes over the Arctic were quite infrequent up to 1978, and even after that, we didn't have daily coverage until the late 80s!

Sea-ice conditions are now reported regularly in marine synoptic observations, as well as by special reconnaissance flights, and coastal radar. Especially importantly, satellite observations have been used to map sea-ice extent routinely since the early 1970s. The American Navy Joint Ice Center has produced weekly charts which have been digitised by NOAA. These data are summarized in Figure 7.20 which is based on analyses carried out on a 1° latitude x 2.5° longitude grid. Sea-ice is defined to be present when its concentration exceeds 10%

As you can see from the highlighted parts above, there were numerous sources used to create the sea ice maps pre-1979. Even the threshold to include an area as covered by sea ice was different, so why he goes on to say

"It is satellite derived extent data, like Cryosphere Today’s data"

is a little baffling.

You mention that the IPCC report, which says data pre 1975 isn't reliable. Mr Watts claims that this data, which the IPCC says is unreliable (I'm just taking your word for it now, with my mobile broadband, I'll be waiting a few hours before I can download the report!), is evidence for a cyclical pattern and of some kinda cover-up.

To try and claim that few years of unreliable data from a mish-mash of sources somehow provides evidence that current ice loss is part of a cycle is a bit disingenuous imo...

[loafer]

I'm a sceptic on all sources including WUWT and the environmentalist blogs so we are on the same wavelength.

The only thing worth trusting is unadulterated data from a reliable independent source which is, unfortunately, all too rare.

[Methuselah]

A minuscule decrease and the doom-mongers are out in force; an equally minute increase and WUWT et al are touting the start of the next Ice Age...What a fuss, over a few days' natural variation? Do we count each and every fluctuation as the start a new trend?

[BornFromTheVoid]

Very true loafer. Luckily most sea ice data is freely available, so people can download it and do what they wish with it. All this could be so much easier If only both peoples minds and climate were a little less complex eh!?

Yep Pete, while the day to day or week to week changes can be fun to monitor (at least I find it fun!), they don't indicate a thing with regards to the long term, no matter how much some people would like it to.

[songster]

In the WUWT thread, Julienne Stroeve posted the link to the NSIDC's unified dataset going back to 1972. They don't generally show it because of the technical issues already covered, but it's on their site and freely accessible. She also offered to provide datasets going back even earlier to anyone that contacts her, on the understanding that these are works in progress with (likely) large and unknown errors associated with them.

ftp://sidads.colorado.edu/pub/DATASETS/nsidc0192_seaice_trends_climo/esmr-smmr-ssmi-merged/

[Gray-Wolf]

plenty of folk grabbing at the single sweetie rolled out thin........a few would prefer two rolled together even though , to the 'thinnies' it looks less. Any present 'gains' must be outside the Arctic Basin (unless things are really bad and we have poor ice conditions in the basin itself???) so will be the first to melt out over the coming weeks (shadows of 2010 fuss?).

I think that we will have a 'record low this year. Had we seen normal export of ice last year we'd have seen 07's record broken. What are the odds for a repeat of low export this year? we still have the young,thin ice making up the majority of the pack so any resumption in normal transport will obviously lead to very low ice extent/area come Sept.

[Geordiesnow]

plenty of folk grabbing at the single sweetie rolled out thin........a few would prefer two rolled together even though , to the 'thinnies' it looks less. Any present 'gains' must be outside the Arctic Basin (unless things are really bad and we have poor ice conditions in the basin itself???) so will be the first to melt out over the coming weeks (shadows of 2010 fuss?).

I think some of the gains are coming from the Barents sea itself and I would not be surprised if that area see a bit more ice growth with the cold conditions being more persistant than it has been during the winter. Of course, southern Hudson Bay is going to face a very warm spell for the time of year so any ice loss there will probably mean that the extent may level off or even go down but we shall see.

In terms of summer extent then what sources do you have to back up that the pack is still very thin? Of course I also expect it to be a thin pack but have we seen less ice exiting fram and therefore perhaps there could be more thicker ice up there because of the persistant southerlies during the winter? As I said earlier, it could be an interesting melt season.

[Nights King]

plenty of folk grabbing at the single sweetie rolled out thin........a few would prefer two rolled together even though , to the 'thinnies' it looks less. Any present 'gains' must be outside the Arctic Basin (unless things are really bad and we have poor ice conditions in the basin itself???) so will be the first to melt out over the coming weeks (shadows of 2010 fuss?).

I think that we will have a 'record low this year. Had we seen normal export of ice last year we'd have seen 07's record broken. What are the odds for a repeat of low export this year? we still have the young,thin ice making up the majority of the pack so any resumption in normal transport will obviously lead to very low ice extent/area come Sept.

So who won last years ice minimum contest? Will you be going for 3.5m or less again?

[VillagePlank]

I think that we will have a 'record low this year. [sic]

One year you will certainly be right!

[Gray-Wolf]

We have had 'masked records' over the 'collapse and spread ' years Boar old hog, The 3 years where we witnessed the Barberistic phenomena have not been documented (yet) but the documentation of 'rotten ice' would suggest that this occurrence was widespread in the 'old paleocryistic' and the subsequent 'refreeze' into FY ice made the extent of the phenomena difficult to spot from the satellites (did they ever write an algorithm to enable it to be spotted?).

I'd suggest we had record low 'volumes' in 09',10, and 11? As for 'Area/Extent' I strongly suspect that 2010 challenged 07' and that in 2011 the margin from being a record should have been far smaller as old 'shelf ice' (normally not included in extent) was thrown in the mix with large 'ice islands' of the stuff heading out toward Beaufort from Ward hunt?

[jethro]

I find it difficult to be alarmed about every square mile of ice gained or lost in this christmas pudding when we have HH Lamb documenting this back in the 1970's. Seems to me, the only real difference between now and back in the early 20th century is that we can measure in finer detail today; I'm not altogether convinced that intense scrutiny is a good thing for anything in life.

• Computations in the United States from surface air temperature observations all over the world show that from the 1880s to some time after 1940 the Earth’s climate was becoming generally warmer. The global warming over those years amounted to about half a degree Centigrade, but in the Arctic it was much stronger and amounted to several degrees between 1920 and 1940.
  
• The ice on the Arctic seas decreased in extent by about 10 per cent and decreased in general thickness by about one third. Glaciers in all parts of the world were receding, opening up new pastures and land for cultivation.
  

http://unesdoc.unesco.org/images/0007/000748/074891eo.pdf

[BornFromTheVoid]

I find it difficult to be alarmed about every square mile of ice gained or lost in this christmas pudding when we have HH Lamb documenting this back in the 1970's. Seems to me, the only real difference between now and back in the early 20th century is that we can measure in finer detail today; I'm not altogether convinced that intense scrutiny is a good thing for anything in life.

• Computations in the United States from surface air temperature observations all over the world show that from the 1880s to some time after 1940 the Earth’s climate was becoming generally warmer. The global warming over those years amounted to about half a degree Centigrade, but in the Arctic it was much stronger and amounted to several degrees between 1920 and 1940.
  
• The ice on the Arctic seas decreased in extent by about 10 per cent and decreased in general thickness by about one third. Glaciers in all parts of the world were receding, opening up new pastures and land for cultivation.
  

http://unesdoc.unesc...48/074891eo.pdf

As always jethro, it's the trend that counts. I think by this stage we've lost a lot more than 10% of ice extent and well over a third of the thickness, which is a significant difference imo.

With dwindling resources, increasing food prices and increasing numbers on the poverty line, I think anything that could have potential negative global impacts (whether it be from man made or natural sources) should be closely scrutinised in the hope of gaining an improved understanding and prediction methods.

As Dr Stroeve mentioned on the WUWT comments sections

"One comment from the modeling results from the CMIP5 archive, the models do show trends of sea ice loss during the 1920s/1940s consistent with the warming trend during that time-period. I don’t see this in the sea ice records that date that far back (i.e. Chapman and Walsh), but that’s in large part because the ice cover has observational gaps and has been filled in with climatology. These trends rival some of what we saw in the 1990s, but not what we’ve seen the last decade. I know these are model results so some here may disregard them all together."

[VillagePlank]

As always jethro, it's the trend that counts. I think by this stage we've lost a lot more than 10% of ice extent and well over a third of the thickness, which is a significant difference imo.

This is where I get all confused.

It is a big difference compared to the what other difference? Clearly it's small compared to ice-age to not ice-age, but massive if it happens over an hour? Do we know the variances expected at this point between the ice ages? Given that we know ice ages act (sort of) sinusoidally, are trends even relevant unless they are of sufficient length - ie over a number of ice age cycles - to show the pattern?

I'm not being funny, here; these are important questions.

Edited March 21, 2012 by Boar Wrinklestorm

[BornFromTheVoid]

This is where I get all confused.

It is a big difference compared to the what other difference? Clearly it's small compared to ice-age to not ice-age, but massive if it happens over an hour? Do we know the variances expected at this point between the ice ages? Given that we know ice ages act (sort of) sinusoidally, are trends even relevant unless they are of sufficient length - ie over a number of ice age cycles - to show the pattern?

I'm not being funny, here; these are important questions.

When I mentioned the trend, it was more in agreement with part of what jethro said...

"I find it difficult to be alarmed about every square mile of ice gained or lost"

rather anything else.

As for the difference part, I just meant that the sea ice volume/extent loss experienced in the last few decades is significantly more than that which HH Lamb mentioned occurred between 1920 and ~1945, as well as the fact that accuracy of sea ice data from back then questionable.

Of course it's all relative and what people consider significant or not will vary from person to person. I mainly consider the changes in sea ice, such as an 80% volume loss and >30% extent loss in September since the late 70s, significant because it has the potential to alter global weather patters quite drastically.

[stewfox]

Here is the updated figures, maybe another very late max figure ?

http://arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html

[BornFromTheVoid]

Here is the updated figures, maybe another very late max figure ?

http://arctic.atmos....nteractive.html

It's still stuck on the 17th or 18th methinks, but I agree otherwise, a late peak seems very likely.

EDIT: Here's the Sea Ice Extent from the NSIDC updated to the 20th

Edited March 21, 2012 by BornFromTheVoid

[ghrud]

As always jethro, it's the trend that counts. I think by this stage we've lost a lot more than 10% of ice extent and well over a third of the thickness, which is a significant difference imo.

With dwindling resources, increasing food prices and increasing numbers on the poverty line, I think anything that could have potential negative global impacts (whether it be from man made or natural sources) should be closely scrutinised in the hope of gaining an improved understanding and prediction methods.

As Dr Stroeve mentioned on the WUWT comments sections

"One comment from the modeling results from the CMIP5 archive, the models do show trends of sea ice loss during the 1920s/1940s consistent with the warming trend during that time-period. I don’t see this in the sea ice records that date that far back (i.e. Chapman and Walsh), but that’s in large part because the ice cover has observational gaps and has been filled in with climatology. These trends rival some of what we saw in the 1990s, but not what we’ve seen the last decade. I know these are model results so some here may disregard them all together."

10% of what... what is the starting point. 10% of an average of the last 30 years data? 30 years in climate is like the blink of the eye.

[BornFromTheVoid]

10% of what... what is the starting point. 10% of an average of the last 30 years data? 30 years in climate is like the blink of the eye.

Compared to the late 70s/early 80s levels. Your right, and the existence of the planet is but the blink of an eye when compared to the galaxy.