Greenland 2012

[SVT450R]

A lot of +NAOs would likely cool Greenland back down from levels they have experienced recently, but likely warmer than the last period in the 70s/80s/early 90s with the underlying anthropogenic trend.

 

Greenland temps are more affected by the Atlantic Multi-decadal Oscillation than the NAO when it comes to natural factors...at least going by the historical record.  

+1

[bluewave]

Take this Quote that Friv posted above for example.  No i don't think we will go back to normal but i would go out on a lib and say we could see a slow down in melting.

 

From 20 March – 20 April, the snow drought drove ice sheet reflectivity well below values in 13 years of (NASA MODIS sensor) satellite observations since 2000 (Figure 4). Negative North Atlantic Oscillation (NAO) has promoted Greenland heating, melting and snow drought for now 6 summers in a row (Tedesco et al. 2013; Fettweis et al. 2013). Negative late winter NAO packs a similar punch. Negative NAO has prevailed much of the past decade and is largely to blame for Greenland’s astonishing melt increase. Whether negative NAO is promoted by an earlier loss of snow on land and declining Arctic sea ice area is something I’ve been wondering about.

 

It's going to be interesting to see if we extend it to a seven year streak this summer or there is a break in the pattern.

 

 

http://www.noaanews.noaa.gov/stories2012/20121010_arcticwinds.html

 

http://onlinelibrary.wiley.com/doi/10.1029/2012GL053268/abstract

 

[1] The last six years (2007–2012) show a persistent change in early summer Arctic wind patterns relative to previous decades. The persistent pattern, which has been previously recognized as the Arctic Dipole (AD), is characterized by relatively low sea-level pressure over the Siberian Arctic with high pressure over the Beaufort Sea, extending across northern North America and over Greenland. Pressure differences peak in June. In a search for a proximate cause for the newly persistent AD pattern, we note that the composite 700 hPa geopotential height field during June 2007–2012 exhibits a positive anomaly only on the North American side of the Arctic, thus creating the enhanced mean meridional flow across the Arctic. Coupled impacts of the new persistent pattern are increased sea ice loss in summer, long-lived positive temperature anomalies and ice sheet loss in west Greenland, and a possible increase in Arctic-subarctic weather linkages through higher-amplitude upper-level flow. The North American location of increased 700 hPa positive anomalies suggests that a regional atmospheric blocking mechanism is responsible for the presence of the AD pattern, consistent with observations of unprecedented high pressure anomalies over Greenland since 2007.

 

 

NAO

 

2007 0.22 -0.47 1.44 0.17 0.66 -1.31 -0.58 -0.14 0.72 0.45 0.58 0.34

2008 0.89 0.73 0.08 -1.07 -1.73 -1.39 -1.27 -1.16 1.02 -0.04 -0.32 -0.28

2009 -0.01 0.06 0.57 -0.20 1.68 -1.21 -2.15 -0.19 1.51 -1.03 -0.02 -1.93

2010 -1.11 -1.98 -0.88 -0.72 -1.49 -0.82 -0.42 -1.22 -0.79 -0.93 -1.62 -1.85

2011 -0.88 0.70 0.61 2.48 -0.06 -1.28 -1.51 -1.35 0.54 0.39 1.36 2.52

2012 1.17 0.42 1.27 0.47 -0.91 -2.53 -1.32 -0.98 -0.59 -2.06 -0.58 0.17

2013 0.35 -0.45 -1.61

 

[The_Global_Warmer]

It's going to be interesting to see if we extend it to a seven year streak this summer or there is a break in the pattern.

 

 

http://www.noaanews.noaa.gov/stories2012/20121010_arcticwinds.html

 

http://onlinelibrary.wiley.com/doi/10.1029/2012GL053268/abstract

 

[1] The last six years (2007–2012) show a persistent change in early summer Arctic wind patterns relative to previous decades. The persistent pattern, which has been previously recognized as the Arctic Dipole (AD), is characterized by relatively low sea-level pressure over the Siberian Arctic with high pressure over the Beaufort Sea, extending across northern North America and over Greenland. Pressure differences peak in June. In a search for a proximate cause for the newly persistent AD pattern, we note that the composite 700 hPa geopotential height field during June 2007–2012 exhibits a positive anomaly only on the North American side of the Arctic, thus creating the enhanced mean meridional flow across the Arctic. Coupled impacts of the new persistent pattern are increased sea ice loss in summer, long-lived positive temperature anomalies and ice sheet loss in west Greenland, and a possible increase in Arctic-subarctic weather linkages through higher-amplitude upper-level flow. The North American location of increased 700 hPa positive anomalies suggests that a regional atmospheric blocking mechanism is responsible for the presence of the AD pattern, consistent with observations of unprecedented high pressure anomalies over Greenland since 2007.

 

 

NAO

 

2007 0.22 -0.47 1.44 0.17 0.66 -1.31 -0.58 -0.14 0.72 0.45 0.58 0.34

2008 0.89 0.73 0.08 -1.07 -1.73 -1.39 -1.27 -1.16 1.02 -0.04 -0.32 -0.28

2009 -0.01 0.06 0.57 -0.20 1.68 -1.21 -2.15 -0.19 1.51 -1.03 -0.02 -1.93

2010 -1.11 -1.98 -0.88 -0.72 -1.49 -0.82 -0.42 -1.22 -0.79 -0.93 -1.62 -1.85

2011 -0.88 0.70 0.61 2.48 -0.06 -1.28 -1.51 -1.35 0.54 0.39 1.36 2.52

2012 1.17 0.42 1.27 0.47 -0.91 -2.53 -1.32 -0.98 -0.59 -2.06 -0.58 0.17

2013 0.35 -0.45 -1.61

 

 

I am not a stats guy.  But in terms of our entire modern record.  This would indicate that the likeliness that this is a random climate oscillation is not likely. We will see.

 

 

On top of that for the up coming 2013 melt season.  Maybe a lot of snow will fall in the next couple weeks, I don't know.  If not.  It's not going to take much warmth at all to quickly get to the dark ice layer and see albedo plummet.

 

 

Which really makes it irrelevant to a large extent because the dirty layer has been reached on the W/SW side and it has slowly been uncovered further up the ice slope.  It doesn't mean the entire ice sheet would end up like that.  And since the material doesn't wash out well at all.  There is no way enough snow and cold would take over even in a multi-year run to cover it back up and keep it from being quickly exposed.

 

If the incredible amount of extra absorbed energy that is melting ice and being released back into the atmosphere is a big part of the -NAO's that would be really bad news.

[ORH_wxman]

I am not a stats guy.  But in terms of our entire modern record.  This would indicate that the likeliness that this is a random climate oscillation is not likely. We will see.

 

 

On top of that for the up coming 2013 melt season.  Maybe a lot of snow will fall in the next couple weeks, I don't know.  If not.  It's not going to take much warmth at all to quickly get to the dark ice layer and see albedo plummet.

 

 

Which really makes it irrelevant to a large extent because the dirty layer has been reached on the W/SW side and it has slowly been uncovered further up the ice slope.  It doesn't mean the entire ice sheet would end up like that.  And since the material doesn't wash out well at all.  There is no way enough snow and cold would take over even in a multi-year run to cover it back up and keep it from being quickly exposed.

 

If the incredible amount of extra absorbed energy that is melting ice and being released back into the atmosphere is a big part of the -NAO's that would be really bad news.

 

 

It very well may not be natural oscillations...but it could certianly be aided by it. In fact, 1947-1952 saw a very similar period of summer -NAOs.

.

..

.

2007   1.1  -0.2   3.1  -0.1   2.9  -3.5  -1.0  -0.2  -0.1   0.9  -1.2   0.92008   1.4   0.4   1.6  -2.8  -2.1  -0.6  -0.6   1.4  -0.2   2.8   1.1   0.32009   1.5  -0.3   1.5   2.5   2.3  -4.3  -2.7   1.6   1.0  -2.5   2.2  -4.42010  -1.9  -3.6  -1.5  -2.2  -0.9  -0.7   1.0  -2.0  -0.5  -0.9  -1.5  -5.52011  -1.2   2.0   0.4   2.0   1.8  -0.9   0.3  -1.3   1.2   1.7   1.3   3.5

.............................................................................................................................................................

1947  -0.2  -4.2  -2.8   3.3  -0.2  -0.1   0.5  -0.2   2.4  -0.2  -1.9  -2.11948   0.6  -0.5   2.0   1.6  -0.4  -0.4  -0.6  -0.2   0.1   1.5  -1.6  -0.51949   0.9   1.9  -0.2   2.5  -0.1  -1.7  -0.8  -1.1  -0.8   0.1   1.6   0.41950   0.0   1.5   0.0   1.6  -2.2  -0.1  -0.1   1.4   3.0   1.2  -0.6  -1.01951   1.0   1.4  -2.1  -1.6  -1.8  -2.8  -0.3   2.2   0.2   1.5  -0.1   2.41952   2.0  -1.2  -2.1   2.2  -2.0  -0.2   0.9  -0.5  -1.8  -0.2  -1.8  -0.8

..

.

 

This is using Hurrell SLP NAO data since we don't have reliable CPC data back that far. 2012 isn't updated on that dataset, but it doesn't change the similarities much if at all.

[The_Global_Warmer]

The first two images represent 2011 Surface temperature anomaly's in May on top.  And then June-Aug on bottom. 

 

After the then modern record GIS ice mass loss during 2010.  By late May into the first week of June.  There was a lot of talk on here about things

 

Here is 2010 same thing as above.  We can see in the first image Greenland torched in May.  In the second image we see 2010 and 2011 had similar Summer melt season temperatures. 

 

Now we know 2010 had more land ice loss than 2011.  But not by very much.  2012 was warmer than both years.  Not by epic proportions but 1-2C and the ice sheet dropped a heck of a lot more ice.

 

What is important however is that if the ice wasn't filled with so much impurity to help albedo plummet the ice mass loss wouldn't be anywhere near it is at this point.

 

CLICK HERE FOR MODIS IMAGES BACK TO THE EARLY 2000'S.

 

We can see that back a decade ago the dirty layer of ice barely made an appearance. Over-time it has slowly grown.  By 2009 it was pretty visible but not very wide.  Then 2010 broke the doors off this thing.  And caused enough melt to melt out the snow from the winter before then melted the cleaner more recent seasonal compacted snow before burning through that and getting down to ice and dirtier ice.  Either way ice or dirtier ice has a much lower albedo than fresh snow or mulch-seasonal snow.  Now the Winters can not recover from this and whiten up the GIS enough to prevent the dirty layer from being exposed throughout 2-3 months during Summer.  Like Arctic Sea Ice being limited to a certain amount of growth during one winter.  The GIS can only recover with so much fresh snow to slow things down.  And if the pattern is more favorable for it then it can have an effect to delay the exposure of the dark ice.  But it will become fully exposed and big melt will take place Summer in and Summer out.  Some worse than others, some less.  But I can't see how a switch to more +NAO would be enough to stop this at this point.  Unless the dark ice magically get's cleansed as things warm larger and larger area's of the GIS  will be exposed lowering GIS wide albedo. 

 

 

 

 

Recent period 2007-2012 vs 1948-1952.

 

I know one period is 6 years vs 5 years.  But it's a fairly close comparison.  I wanted to get a visual representation of what the numbers represent.

 

To put it bluntly.  The top image look's like what you would expect natural variation to look like during a period of weather patterns like we have seen recently.

 

Then below looks like Aliens or a Secret Govt Agency has some Ray Gun that could create such a crazily anomalous consistent pattern.  It's so consistent it may even show just looking at this general representation thart something local is a major influence.

 

 

 

 

 

Lastly.  Comparing surface temperature anomaly's from the two periods.  We can see pretty clear how global warming is changing things. 

 

The arctic is expected to warm much faster the rest of this century than the rest of the globe.  I don't think natural variation is going to have much of a say going forward in the whole season to season schemes VS it's impacts on smaller scales like weeks or up to a month.

 

As always we will see.

 

 

 

 

[ORH_wxman]

Global warming provides an underlying trend, but it clearly shows that Greenland had positive temp anomalies back then...they were even higher in the late 30s/early 40s.

 

There's a reason that happens. Natural variability is a huge influence. So is the AGW trend there, but to ignore the natural variability is assinine. Its one of the reasons so many climate models are failing...they assumed the warming from 1975 was almost purely anthropogenic when there's solid evidence that a significant portion of it was natural variability.

 

So I think its important to look at the natural variation. If we fail to understand that, then we fail to ever understand our climate. Its a very important piece in climate science. AGW isn't everything even though it is the "hotter" topic when discussing the arctic.

[SVT450R]

Global warming provides an underlying trend, but it clearly shows that Greenland had positive temp anomalies back then...they were even higher in the late 30s/early 40s.

There's a reason that happens. Natural variability is a huge influence. So is the AGW trend there, but to ignore the natural variability is assinine. Its one of the reasons so many climate models are failing...they assumed the warming from 1975 was almost purely anthropogenic when there's solid evidence that a significant portion of it was natural variability.

So I think its important to look at the natural variation. If we fail to understand that, then we fail to ever understand our climate. Its a very important piece in climate science. AGW isn't everything even though it is the "hotter" topic when discussing the arctic.

Excellent post Will couldn't agree more. Sometimes I get the feeling that some believe natural variability is no longer there and that you automatically are labeled a denier. If you don't believe natural variability plays a major role in our climate then you are just as bad as the guy who believes co2 is a myth.

[Snow_Miser]

Looks like the melt hasn't begun yet in Greenland. This is a new feature from NSIDC. Should be interesting to see what it shows throughout the melt season.

 

[Sugarloaf1989]

Aren't there other areas in the Arctic to be concerned with and studied for the affects of climate change other than the Greenland Ice Cap. It seems like the Penny, Barnes and Devon Ice Cap's would be far more susceptible to climate change in a shorter period of time, given their smaller size?

[The_Global_Warmer]

Aren't there other areas in the Arctic to be concerned with and studied for the affects of climate change other than the Greenland Ice Cap. It seems like the Penny, Barnes and Devon Ice Cap's would be far more susceptible to climate change in a shorter period of time, given their smaller size?

 

This is a great blog covering most of the worlds major glaciers:

 

http://glacierchange.wordpress.com/

 

 

GIS is so important because a tiny fraction of the ice sheet is responsible for 500GT+ ice mass loss each of the last three Summers.  The potential amount of melting is enormous.  And the main melt region is between 60-68N which is pretty far South. 

 

[TerryM]

Global warming provides an underlying trend, but it clearly shows that Greenland had positive temp anomalies back then...they were even higher in the late 30s/early 40s.

 

 

I'm quite sure this is not true. Could you tell us how you came to that conclusion & possibly explain why the ice cores do not show a melt similar to 2012's during this period?

 

Natural variability is of course a factor that everyone is aware of. Pretending that anyone doesn't acknowledge of this does nothing to forward your argument & in fact makes it appear that you are grasping at straw men, which make very insubstantial handholds.

 

Certainly there were warm periods that have come and gone affecting the coastal regions where SSTs are dominant. This is no longer the case. I'd refer you to Dr Box's graphs from last year.

 

Terry

 

Terry

[ORH_wxman]

I'm quite sure this is not true. Could you tell us how you came to that conclusion & possibly explain why the ice cores do not show a melt similar to 2012's during this period?

 

Natural variability is of course a factor that everyone is aware of. Pretending that anyone doesn't acknowledge of this does nothing to forward your argument & in fact makes it appear that you are grasping at straw men, which make very insubstantial handholds.

 

Certainly there were warm periods that have come and gone affecting the coastal regions where SSTs are dominant. This is no longer the case. I'd refer you to Dr Box's graphs from last year.

 

Terry

 

Terry

 

 

I never claimed the late 30s/early 40s had a melt equal to 2012. You have to go back to the 1800s to find one (WRT the 97% melt coverage at its max).

 

I said the late 30/early 40s had warmer temps than the already above average temperatures of the 1947-1952 period in context to the NAO periods we were discussing further up in the thread...and they certainly rivaled the temperatures there in recent years.

 

 

The accusations of strawmen get pretty old. It seems to be a tired and unoriginal accusation around this forum when anyone dares bring up that there's a lot more to climate change than AGW. Its okay to discuss natural climatic changes too.

[tacoman25]

Excellent post Will couldn't agree more. Sometimes I get the feeling that some believe natural variability is no longer there and that you automatically are labeled a denier. If you don't believe natural variability plays a major role in our climate then you are just as bad as the guy who believes co2 is a myth.

 

There were climate scientists a couple decades ago who believed natural variability would be overwhelmed in the temperature trends by now.

[ORH_wxman]

There were climate scientists a couple decades ago who believed natural variability would be overwhelmed in the temperature trends by now.

 

 

There's a lot of change even over a period of a decade of peer reviewed research....we already documented the papers that claimed in the late 1990s and early 2000s that the rapid upward trend from the 1970s in the NAO was due to global warming and that it would generally become more positive as we warmed....now most of the conclusions are opposite saying global warming has helped induce the big -NAOs recently.

[The_Global_Warmer]

I think Greenland temperatures are not that important.  Most of the ice sheet contributes very little to the ice mass loss.

 

but here is the graph:

 

 

What is important is that the area of dirty ice that has been exposed is growing.  What I mean by that is, no multi year snow pack is left between it and the previous winters snow.  It would have to snow an incredible amount and be incredibly cold all Summer to even begin to hope for any shot this region get's whitened over again.

 

I feel like local albedo changes in parts of the cryosphere get way over looked by many because it's impact is far greater on melting ice than warming the local atmosphere. 

 

Most of this dark area is between 60-70N along the Western Coast.  Last year and 2010 it expanded all the way 80N.  Which means that area will just require melting of last seasons snow fall to be in direct contact with land ice melt and much lower albedo.

 

 

 

 

Figure 3. April 2013 surface albedo (a.k.a. reflectivity) anomaly. Substantially lower albedo anomalies on land are due to the dearth of snow revealing a much darker underlying tundra. The red areas across the northern 1/3 of Greenland are uncertain due to low solar illumination angles.

 

 

 

 

I would love to see this summer have a negative NAO.  I bet the ice mass loss would still be at least 500GT.  This is an excerpt from the expert who has dedicated his life to studying Greenland.

 

He and his colleagues completely recognize what the extreme NAO's have done.  But they don't see how natural variation is going to restore the ice pack to the point it needs to be to reverse this trend at all because the damage has been done at the surface.
 

 

Greenland ice sheet mass loss has accelerated responding to combined glacier discharge and surface melt water runoff increases. During summer, absorbed solar energy, modulated at the surface primarily by albedo, is the dominant factor governing surface melt variability in the ablation area. NASA MODIS data spanning 13 summers (2000 – 2012), indicate that mid-summer (July) ice sheet albedo declined by 0.064 from a value of 0.752 in the early 2000s. The ice sheet accordingly absorbed 100 EJ more solar energy for the month of July in 2012 than in the early 2000s. This additional energy flux during summer doubled melt rates in the ice sheet ablation area during the observation period.

Abnormally strong anticyclonic circulation, associated with a persistent summer North Atlantic Oscillation extreme 2007-2012, enabled 3 amplifying mechanisms to maximize the albedo feedback: 1) increased warm (south) air advection along the western ice sheet increased surface sensible heating that in turn enhanced snow grain metamorphic rates, further reducing albedo; 2) increased surface downward shortwave flux, leading to more surface heating and further albedo reduction; and 3) reduced snowfall rates sustained low albedo, maximizing surface solar heating, progressively lowering albedo over multiple years. The summer net infrared and solar radiation for the high elevation accumulation area reached positive values during this period, contributing to an abrupt melt area increase in 2012.

A number of factors make it reasonable to expect more melt episodes covering 100% of the ice sheet area in coming years: 1) the past 13 y of increasing surface air temperatures have eroded snowpack ‘cold content’, preconditioning the ice sheet for earlier melt onset. Less heat is required to bring the surface to melting; 2) Greenland temperatures, have lagged the N Hemisphere average in the 2000s, need to increase further for Greenland to be in phase with the N Hemisphere average. 3) Arctic amplification of enhanced greenhouse warming is driven by albedo feedback over sea ice, terrestrial environments, and through autumn-winter heat release from open water areas. Likely melt area increases is despite a second order negative feedback operating in the accumulation area identified statistically from more summer snowfall (brightening effect) in anomalously warm summers. Without this negative feedback, the accumulation area complete surface melting may have happened sooner than in 2012.

While it has been shown that the ice sheet dynamics can adjust rapidly to ice flow perturbations, a negative feedback responsivity, the mass imbalance of the ice sheet in the coming decades is likely to be increasingly negative because of the positive feedback from surface albedo with air temperature. Surface melting may therefore increasingly dominate ice sheet mass loss, as glaciers retreat from a marine termini and the area of low albedo expands over the gradually sloping ice sheet. The albedo feedback ensures an increasing solar energy absorption. What could shut the positive feedback down would be a combination of an anomalously cold winter and anomalously thick snowpack. This scenario is possible given the cooling effect of a major N Hemisphere volcanic eruption or some other event to reduce surface heating.

 

 

 

 

I would like to see some hard evidence of how natural variation is going to reverse this. 

 

Other regions all over the NH where land glaciers are present have all seen incredible accelerations of ice mass loss as well regardless of the state of the NAO.  It's also regardless of the global temperatures, ENSO state, solar state, PDO went negative and has had no effect. 

 

Over the next decade methane, co2, and water vapor will all get stronger globally but also in the cryosphere where GHG forcing is amplified.

[ORH_wxman]

 

 

I would like to see some hard evidence of how natural variation is going to reverse this. 

 

Other regions all over the NH where land glaciers are present have all seen incredible accelerations of ice mass loss as well regardless of the state of the NAO.  It's also regardless of the global temperatures, ENSO state, solar state, PDO went negative and has had no effect. 

 

Over the next decade methane, co2, and water vapor will all get stronger globally but also in the cryosphere where GHG forcing is amplified.

 

 

Natural variation likely won't "reverse" it...at least not soon. But there's a good chance it will slow it down at some point with a period of +NAO summers.

[TerryM]

Natural variation likely won't "reverse" it...at least not soon. But there's a good chance it will slow it down at some point with a period of +NAO summers.

With the increasing influence of global warming if "natural variability" doesn't reverse it soon, it won't be reversed within any time that makes a difference on a human timescale. The albedo changes that Friv has pointed out are in part due to biological changes on the ice surface. The bugs have always been on the ice but they're migrating to higher altitudes and latitudes. The old studies showing a Greenland melt out in a thousand years are as far off as the studies that missed the 2007 decline in Arctic Sea ice.

 

Don't plant an orchard on the East Coast. Roots don't respond well to salt water.

 

Terry

[ORH_wxman]

With the increasing influence of global warming if "natural variability" doesn't reverse it soon, it won't be reversed within any time that makes a difference on a human timescale. The albedo changes that Friv has pointed out are in part due to biological changes on the ice surface. The bugs have always been on the ice but they're migrating to higher altitudes and latitudes. The old studies showing a Greenland melt out in a thousand years are as far off as the studies that missed the 2007 decline in Arctic Sea ice.

 

Don't plant an orchard on the East Coast. Roots don't respond well to salt water.

 

Terry

 

 

The Greenland ice sheet didn't melt out during Eemian Period with temps as much as 8C higher than during today about 120-130k years ago. It melted out by 25%. I'll take the over on 1,000 years on a melt out.

[tacoman25]

With the increasing influence of global warming if "natural variability" doesn't reverse it soon, it won't be reversed within any time that makes a difference on a human timescale. The albedo changes that Friv has pointed out are in part due to biological changes on the ice surface. The bugs have always been on the ice but they're migrating to higher altitudes and latitudes. The old studies showing a Greenland melt out in a thousand years are as far off as the studies that missed the 2007 decline in Arctic Sea ice.

 

Don't plant an orchard on the East Coast. Roots don't respond well to salt water.

 

Terry

 

Vague...but alarming and disconcerting none the less!

[TerryM]

ORH

 

"Temperatures at the North and South Poles “” critical for triggering ice melt “” could return to Eemian levels again if the global temperature rises about 4 degrees (2 degrees Celsius), the researchers said." - From Nature in 2012

 

That's quite a way from the 8C you posted isn't it?

 

Was the Eemian (when ocean levels were 8 to 9 M - >26 to 30 ft above todays) a period when NH summers were affected by orbital wobbles, or a period in which GHG's were driving winter temperatures up?  A situation where summers warm as winter's chill is expected to cause less polar ice loss than the situation we face with GHGs doing damage all year round.

 

​For you personally I'd recommend investing the whole nest egg in North Carolina beachfront property. The views are wonderful and legislation is in place so you won't have to worry about those pesky regulations about how close to the ocean you can build. 

 

Terry

[ORH_wxman]

ORH

 

"Temperatures at the North and South Poles “” critical for triggering ice melt “” could return to Eemian levels again if the global temperature rises about 4 degrees (2 degrees Celsius), the researchers said." - From Nature in 2012

 

That's quite a way from the 8C you posted isn't it?

 

Was the Eemian (when ocean levels were 8 to 9 M - >26 to 30 ft above todays) a period when NH summers were affected by orbital wobbles, or a period in which GHG's were driving winter temperatures up?  A situation where summers warm as winter's chill is expected to cause less polar ice loss than the situation we face with GHGs doing damage all year round.

 

​For you personally I'd recommend investing the whole nest egg in North Carolina beachfront property. The views are wonderful and legislation is in place so you won't have to worry about those pesky regulations about how close to the ocean you can build. 

 

Terry

 

 

This paper covers it.

 

http://www.jamstec.go.jp/frsgc/research/d5/jdannan/cp-9-621-2013.pdf

 

 

They actual estimate at one point that summer max temps in Greenland was double digit positive departures about 125-130k years ago. The "as much as 8C warmer" than today covers that type of uncertainty in my post.

 

Regardless, temperatures were much much warmer than today for thousands of years and the Greenland Ice Sheet melted by 25%. So again, I'll take the over on 1,000 years.

 

 

The study, if anything, showed potential more danger for the WAIC.

[TerryM]

ORH

 

 

 

This paper covers it.

 

http://www.jamstec.go.jp/frsgc/research/d5/jdannan/cp-9-621-2013.pdf

 

 

They actual estimate at one point that summer max temps in Greenland was double digit positive departures about 125-130k years ago. The "as much as 8C warmer" than today covers that type of uncertainty in my post.

 

Regardless, temperatures were much much warmer than today for thousands of years and the Greenland Ice Sheet melted by 25%. So again, I'll take the over on 1,000 years.

 

 

The study, if anything, showed potential more danger for the WAIC.

 We experienced double digit positive departures from the norm last summer in many Arctic locals. The paper you posted actually says

 

"Further evidence from proxy data located in the Arctic and European regions suggests the LIG climate featured temperatures, at least regionally, several degrees warmer than today"

 

Hardly an endorsement of your contention.

 

The melting at that time was from the north and was concentrated in summer months as Malkovich discovered. Todays melt is year round and the warmth is not centered on the pole. - Could I suggest even a cursory read of some of Dr. Box's findings?

 

​The 30 foot max SLR in the Eemian requires a strong Antarctic component, and in fact the PIG is possibly in jeopardy as we speak. The WAC wasn't much of a problem in the Eemian - but it's certainly a player today.

To base the GIS melt on a period that was 2 degrees warmer, but without the anthropomorphic forcings seen today is exactly the kind of reasoning that lead to studies showing that the Arctic Sea Ice would last a thousand years.

Try reading Dr. Bauch on this

 

Terry

[ORH_wxman]

ORH

 

 

 

 We experienced double digit positive departures from the norm last summer in many Arctic locals. The paper you posted actually says

 

"Further evidence from proxy data located in the Arctic and European regions suggests the LIG climate featured temperatures, at least regionally, several degrees warmer than today"

 

Hardly an endorsement of your contention.

 

The melting at that time was from the north and was concentrated in summer months as Malkovich discovered. Todays melt is year round and the warmth is not centered on the pole. - Could I suggest even a cursory read of some of Dr. Box's findings?

 

​The 30 foot max SLR in the Eemian requires a strong Antarctic component, and in fact the PIG is possibly in jeopardy as we speak. The WAC wasn't much of a problem in the Eemian - but it's certainly a player today.

To base the GIS melt on a period that was 2 degrees warmer, but without the anthropomorphic forcings seen today is exactly the kind of reasoning that lead to studies showing that the Arctic Sea Ice would last a thousand years.

Try reading Dr. Bauch on this

 

Terry

 

 

In Greenland? First I've ever heard of that.

 

Given the warmer temperatures for thousands of years only melted 25% of the Greenland Ice Cap, I still see no way how you could justify it melting out in 1,000 years.

[AvantHiatus]

In Greenland? First I've ever heard of that.

 

Given the warmer temperatures for thousands of years only melted 25% of the Greenland Ice Cap, I still see no way how you could justify it melting out in 1,000 years.

Assuming the study in question is accurate. Such a temperature differential in that time period is hard to prove because the Earth has been going through some aggressive ice age periods in the last few million years. Judging by the temperature profile, it sounds like something you would see in the Eocene rather than the Holocene.

 

8c Warmer? No way...and as one would guess, the extreme warmth anomalies were confined to a very small area on the planet.

[bluewave]

The most recent estimates that I saw for various temperature rise levels came from PIK.

 

http://www.pik-potsdam.de/news/press-releases/gronlands-eismassen-konnten-komplett-schmelzen-bei-1-6-grad-globaler-erwarmung

 

 

03/11/2012 - The Greenland ice sheet is likely to be more vulnerable to global warming than previously thought. The temperature threshold for melting the ice sheet completely is in the range of 0.8 to 3.2 degrees Celsius global warming, with a best estimate of 1.6 degrees above pre-industrial levels, shows a new study by scientists from the Potsdam Institute for Climate Impact Research (PIK) and the Universidad Complutense de Madrid. Today, already 0.8 degrees global warming has been observed. Substantial melting of land ice could contribute to long-term sea-level rise of several meters and therefore it potentially affects the lives of many millions of people.

 

 

The time it takes before most of the ice in Greenland is lost strongly depends on the level of warming. “The more we exceed the threshold, the faster it melts,” says Alexander Robinson, lead-author of the study now published in Nature Climate Change. In a business-as-usual scenario of greenhouse-gas emissions, in the long run humanity might be aiming at 8 degrees Celsius of global warming. This would result in one fifth of the ice sheet melting within 500 years and a complete loss in 2000 years, according to the study. “This is not what one would call a rapid collapse,” says Robinson. “However, compared to what has happened in our planet’s history, it is fast. And we might already be approaching the critical threshold.”

In contrast, if global warming would be limited to 2 degrees Celsius, complete melting would happen on a timescale of 50.000 years. Still, even within this temperature range often considered a global guardrail, the Greenland ice sheet is not secure. Previous research suggested a threshold in global temperature increase for melting the Greenland ice sheet of a best estimate of 3.1 degrees, with a range of 1.9 to 5.1 degrees. The new study’s best estimate indicates about half as much.

 

 

Feedbacks between the climate and the ice sheet - a tipping element in the Earth system

“Our study shows that under certain conditions the melting of the Greenland ice sheet becomes irreversible. This supports the notion that the ice sheet is a tipping element in the Earth system,” says team-leader Andrey Ganopolski of PIK. “If the global temperature significantly overshoots the threshold for a long time, the ice will continue melting and not regrow – even if the climate would, after many thousand years, return to its preindustrial state.” This is related to feedbacks between the climate and the ice sheet: The ice sheet is over 3000 meters thick and thus elevated into cooler altitudes. When it melts its surface comes down to lower altitudes with higher temperatures, which accelerates the melting. Also, the ice reflects a large part of solar radiation back into space. When the area covered by ice decreases, more radiation is absorbed and this adds to regional warming.

The scientists achieved their insights by using a novel computer simulation of the Greenland ice sheet and the regional climate. This model performs calculations of these physical systems including the most important processes, for instance climate feedbacks associated with changes in snowfall and melt under global warming. The simulation proved able to correctly calculate both the observed ice-sheet of today and its evolution over previous glacial cycles, thus increasing the confidence that it can properly assess the future. All this makes the new estimate of Greenland temperature threshold more reliable than previous ones.

 

[ORH_wxman]

Assuming the study in question is accurate. Such a temperature differential in that time period is hard to prove because the Earth has been going through some aggressive ice age periods in the last few million years. Judging by the temperature profile, it sounds like something you would see in the Eocene rather than the Holocene.

 

8c Warmer? No way...and as one would guess, the extreme warmth anomalies were confined to a very small area on the planet.

 

 

8C warmer regionally...not globally. In the general arctic region, they had anomalies in the 3-5C warmer than present day...at least in their study.

 

There isn't much to support a complete meltout of the Greenland ice sheet within 1,000 years unless you believe the most extreme temperature scenarios and then sustain them for hundreds of years.

[PottercountyWXobserver]

8C warmer regionally...not globally. In the general arctic region, they had anomalies in the 3-5C warmer than present day...at least in their study.

There isn't much to support a complete meltout of the Greenland ice sheet within 1,000 years unless you believe the most extreme temperature scenarios and then sustain them for hundreds of years.

It doesn't matter, even a 1/10 of the ice sheet melting will have severe consequences. A 1/4 melted will cause extreme global warming. We could possibly be looking at 1/8 melted out in 100 years. Someone will have to do the calculations, but I'm assuming an 1/8 of the ice melt on Greenland over 100 years would raise sea levels at least a 5 feet. And 5 feet of sea level rise will be traumatic for those along the coast. With Trillions worth of damage around the world.

[SVT450R]

I think to many hug the Grace ice mass chart showing the sharp decline when first it's a short period of a decade (cherry picked) as that this is the new set in stone rate of melt and that we can't see any slow down in the melt.

[ORH_wxman]

It doesn't matter, even a 1/10 of the ice sheet melting will have severe consequences. A 1/4 melted will cause extreme global warming. We could possibly be looking at 1/8 melted out in 100 years. Someone will have to do the calculations, but I'm assuming an 1/8 of the ice melt on Greenland over 100 years would raise sea levels at least a 5 feet. And 5 feet of sea level rise will be traumatic for those along the coast. With Trillions worth of damage around the world.

 

 

We're already locked into a large sea level rise over hundreds/thousands of years...but 5 feet by 2100 has little basis to go on. 5 feet just by Greenland's contributon alone by 2100 is even more outlandish.

[The_Global_Warmer]

I think to many hug the Grace ice mass chart showing the sharp decline when first it's a short period of a decade (cherry picked) as that this is the new set in stone rate of melt and that we can't see any slow down in the melt.

 

 

Unless the dirty ice magically goes away.  A slow down would be like the 2006 melt. 

 

Even with the current run of -NAO in Summer if the ice was clear of impurities albedo would lower slightly from the heights of the pure fresh snow cover because of snow grain changes but it would be pretty little. 

 

The reason the ice mass loss has dramatically accelerated is the exposure of the dirty layer.  Which isn't exactly like one sheet of impurities.  But as the ice melted impurities at different layers instead of washing out don't  They stay embedded with the mushy ice.  As the ice continues to melt more impurities gather to the point that the surface of the ice sheet almost look's black.

 

This is from 2005:  Since then the Dirty Ice layer size has more than doubled. 

 

The only way that this can be reversed is for new snow accumulation to not melt out during a Summer.  Unless the Northern Hemisphere and it's ocean's cool to levels only a volcano could produce right now it can't happen.  It might have taken a relatively short period of time during very extreme conditions vs recent CLIMO for this to be uncovered.  But once it's uncovered it is now apart of the equation. 

 

So far no matter how much I talk about this or link to the Professional's who actually have been on the GIS Ice sheet core digging an examining this phenomenon that has exploded onto the scene it's pretty much ignored here.  Yet the people working up there have been watching it expand the last decade and a big part of that is the -NAO Summers.  Which no one is debating whatsoever. 

 

However one it is has been uncovered it's impacts are way beyond a -NAO or +NAO.  since a +NAO pattern in today's warmer climate could only delay the Summer on-set of the dark layer exposure it's only effect would be a seasonal lowering of ice mass loss because wherever the dark layer has appeared the season before all of the snow on top of it will melt the next season even in a highly +NAO.  In that season maybe the rest of the higher albedo Greenland has very little or no ice mass loss.  Or some snow at lower elevations above the dark layer doesn't melt out completely.  Which is still going to take the perfect pattern. 

 

This dark layer is still here and as the Earth warms and more -NAO Summers bring the sunshine it will grow again. 

 

 

 

http://bprc.osu.edu/wiki/Greenland_Ice_Albedo_Monitoring

 

http://www.meltfactor.org/blog/?cat=74