Greenland 2012

[skierinvermont]

Yeah, it's on the order of -0.25 W/m2 from 2000-2009 of total solar forcing. From 2009-present, it's a little less than +0.10 W/m2 from what I can see.

Surface albedo change is also probably on the order of +.1W/m2 or less over the last few years.

[PhillipS]

I would believe that they took into account the accelerating rate per year of ice loss when they came up with 13000 year melt out and again basing off there calculation you would still be looking at a few thousand years to reach 2m SLR. Don't get me wrong i am not taking this as set stone figures.

Greenland as a whole this month is below average as William pointed out you could see by looking in the global temp thread as he stated.

You are mistaken on the highlighted sentence. The article simply took the current volume of the Greenland ice sheet, 2620000 km3, [source], and divided it by the current annual melting rate of 200 billion tons per year. Remember that a gigaton of ice is about 1 km3 so the annual melting can also be thought of as 200 km3. That is where they got the figure of 13,000 years.

But if you do the math for the assumption that Greenland's annual melt continues to accelerate by 8 km3 each year, then you'll see that the entire 2,620,000 km3 ice sheet would melt in less than 790 years. With the full 6+ meter sea level rise occurring during that same period. Of course there is a huge amount of uncertainty in that number - but the uncertainty is not one-sided. If the rate of acceleration increases with additional AGW warming then it could melt out sooner.

I'll grant that 790 years still sounds like a long time, but keep in mind that except in north and south America there are cities and their associated infrastructure that have been around far longer than that.

[SVT450R]

You are mistaken on the highlighted sentence. The article simply took the current volume of the Greenland ice sheet, 2620000 km3, [source], and divided it by the current annual melting rate of 200 billion tons per year. Remember that a gigaton of ice is about 1 km3 so the annual melting can also be thought of as 200 km3. That is where they got the figure of 13,000 years.

But if you do the math for the assumption that Greenland's annual melt continues to accelerate by 8 km3 each year, then you'll see that the entire 2,620,000 km3 ice sheet would melt in less than 790 years. With the full 6+ meter sea level rise occurring during that same period. Of course there is a huge amount of uncertainty in that number - but the uncertainty is not one-sided. If the rate of acceleration increases with additional AGW warming then it could melt out sooner.

I'll grant that 790 years still sounds like a long time, but keep in mind that except in north and south America there are cities and their associated infrastructure that have been around far longer than that.

I see thanks for the breakdown i admit math is not my subject.

[TerryM]

Does anyone know the name of the polynia off Cape Morris Jesup that has recently formed? It's visible on the Environment Canada AVHRR images. HRPT Resolute Arctic Composite updates ~every 1/2 hour.

I don't recall it in 2010 or 2011. It seems to be a flip side of the NEW Polynia with strong southerly winds in Fram Strait and katabatic winds off Greenland having opened a large shore polynia. The very high temps in the area probably aren't helping it heal

Buoys in the area have reversed direction in the past few days with 409080 particularly heading west at a high speed from just north of Independence Fjord.

It would be unusual for this large a polynia to not be named if it is in fact a regular feature.

Terry

[TerryM]

An new paper with full text not paywalled addresses the recordbreaking 2012 Melt.

"an increase in the Greenland Blocking Index (GBI, e.g. Overland et al.,

10 2012)"

Indicates that Sandy like storms with Greenland Blocking shifting the storm track westward will become more frequent.

"This suggests that the projected contribution to sea

level rise under different warming scenarios might be underestimated (and the sensitivity to temperature changes might be higher)"

So SLR can be expected to outpace past projections.

Other interesting finding indicate that past melts influenced 2012 melt - a positive feedback not unlike the Arctic sea ice feedbacks that have lead to exponential volume losses.

Most of the metrics in 2012 were ~ 3 std. dev. from the baseline, pushing the odds of this being the result of natural variability to a vanishingly small possibility.

http://www.the-cryosphere-discuss.net/6/4939/2012/tcd-6-4939-2012.pdf

Terry

[Vergent]

Smoke from Arctic wildfires may have caused Greenland's record thaw

http://tehrantimes.com/science/103883-smoke-from-arctic-wildfires-may-have-caused-greenlands-record-thaw

[TerryM]

There is a good discussion going on at Neven's Sea Ice Blog re. the article I'd posted above. Some are seeing the GIS melting out exponentially with full melt out occurring earlier than 2060. Since past melts have been found to exert a strong influence on future melts the record 575 Gt melted this year can be expected to be exceeded within the next few years.

http://cires.colorado.edu/science/spheres/arctic-meltdown/icetowater.html

Mentions a 50 Watt/m2 (not a typo) increase in absorbed shortwave radiation recorded as Swiss Camp since 1990.

Terry

[TerryM]

Does anyone expect there to be enough infrastructure left after Greenland has melted to Eemian levels (~ 5 m SLR) that the final melt out will even be recorded?

Terry

[salbers]

There is a good discussion going on at Neven's Sea Ice Blog re. the article I'd posted above. Some are seeing the GIS melting out exponentially with full melt out occurring earlier than 2060. Since past melts have been found to exert a strong influence on future melts the record 575 Gt melted this year can be expected to be exceeded within the next few years.

http://cires.colorad...icetowater.html

Mentions a 50 Watt/m2 (not a typo) increase in absorbed shortwave radiation recorded as Swiss Camp since 1990.

Terry

How does this 575 Gt figure jive with the ~200 Gt per year discussed with GRACE? To address my own question, here is a discussion paper mentioning the context, complete with GRACE data through Sept. 2012 (see Figure 8).

http://www.the-cryosphere-discuss.net/6/4939/2012/tcd-6-4939-2012-print.pdf

I like to consider an exponential calculation if you assume 200 Gt/yr baseline and 8Gt/yr present acceleration rate, then the doubling time of melt rate is about 15-20 years. Probably less than 200 years for a total melt in this scenario? I'm assuming the melt rate would continue to double every 15-20 years.

[salbers]

Greetings,

This was published in Science on Nov 30.

http://www.sciencema...t/338/6111/1183

A Reconciled Estimate of Ice-Sheet Mass Balance

Abstract

We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth’s polar ice sheets. We find that there is good agreement between different satellite methods—especially in Greenland and West Antarctica—and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by –142 ± 49, +14 ± 43, –65 ± 26, and –20 ± 14 gigatonnes year⁻¹, respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 ± 0.20 millimeter year⁻¹ to the rate of global sea-level rise.

[TerryM]

NSIDC has introduced a new site covering Greenland.

 

http://nsidc.org/greenland-today/

 

The daily melt charts alone should prove interesting.

 

Terry

[TerryM]

Greenland's getting an early start to the melting season.

 

http://nsidc.org/greenland-today/

 

Temperatures in the mid 40's at Narsarsuaq probably aren't helping.

 

http://www.ogimet.com/gsynop.phtml.en

 

Terry

[SVT450R]

  Greenland Ice Cores Reveal Warm Climate of the Past

http://www.sciencedaily.com/releases/2013/01/130123133612.htm

 

Jan. 23, 2013 — In the period between 130,000 and 115,000 years ago, Earth's climate was warmer than today. But how much warmer was it and what did the warming do to global sea levels? -- as we face global warming in the future, the answer to these questions is becoming very important. New research from the NEEM ice core drilling project in Greenland shows that the period was warmer than previously thought. The international research project is led by researchers from the Niels Bohr Institute and the very important results are published in the scientific journal, Nature.

In the last millions years Earth's climate has alternated between ice ages lasting about 100,000 years and interglacial periods of 10,000 to 15,000 years. The new results from the NEEM ice core drilling project in northwest Greenland, led by the Niels Bohr Institute at the University of Copenhagen show that the climate in Greenland was around 8 degrees C warmer than today during the last interglacial period, the Eemian period, 130,000 to 115,000 thousand years ago.

"Even though the warm Eemian period was a period when the oceans were four to eight meters higher than today, the ice sheet in northwest Greenland was only a few hundred meters lower than the current level, which indicates that the contribution from the Greenland ice sheet was less than half the total sea-level rise during that period," says Dorthe Dahl-Jensen, Professor at the Niels Bohr Institute, University of Copenhagen, and leader of the NEEM-project.

Past reveals knowledge about the climate

The North Greenland Eemian Ice Drilling project or NEEM, led by the Niels Bohr Institute, is an international project with participants from 14 countries. After four years of deep drilling, the team has drilled ice cores through the more than 2.5 kilometer thick ice sheet. The ice is a stack of layer upon layer of annual snow fall which never melts away, and as the layers gradually sink, the snow is compresses into ice. This gives thousands of annual ice layers that, like tree rings, can tell us about variations in past climate from year to year.

The ice cores are examined in laboratories with a series of analyses that reveal past climate. The content of the heavy oxygen isotope O18 in the ice cores tells us about the temperature in clouds when the snow fell, and thus of the climate of the past. The air bubbles in the ice are also examined. The air bubbles are samples of the ancient atmosphere encased in the ice and they provide knowledge about the air composition of the atmosphere during past climates.

Past global warming

The researchers have obtained the first complete ice core record from the entire previous interglacial period, the Eemian, and with the detailed studies have been able to recreate the annual temperatures -- almost 130,000 years back in time.

"It is a great achievement for science to collect and combine so many measurements on the ice core and reconstruct past climate history. The new findings show higher temperatures in northern Greenland during the Eemian than current climate models have estimated," says Professor Dorthe Dahl-Jensen, Niels Bohr Institute.

Intense melting on the surface

During the warm Eemian period, there was intense surface melting that can be seen in the ice core as layers of refrozen meltwater. Meltwater from the surface had penetrated down into the underlying snow, where it once again froze into ice. Such surface melting has occurred very rarely in the last 5,000 years, but the team observed such a melting during the summer of 2012 when they were in Greenland.

"We were completely shocked by the warm surface temperatures at the NEEM camp in July 2012," says Professor Dorthe Dahl-Jensen. "It was even raining and just like in the Eemian, the meltwater formed refrozen layers of ice under the surface. Although it was an extreme event the current warming over Greenland makes surface melting more likely and the warming that is predicted to occur over the next 50-100 years will potentially have Eemian-like climatic conditions," she believes.

Good news and bad news

During the warm Eemian period there was increased melting at the edge of the ice sheet and the dynamic flow of the entire ice mass caused the ice sheet to lose mass and it was reduced in height. The ice mass was shrinking at a very high rate of 6 cm per year. But despite the warm temperatures, the ice sheet did not disappear and the research team estimates that the volume of the ice sheet was not reduced by more than 25 percent during the warmest 6,000 years of the Eemian.

"The good news from this study is that the Greenland ice sheet is not as sensitive to temperature increases and to ice melting and running out to sea in warm climate periods like the Eemian,as we thought," explains Dorthe Dahl-Jensen and adds that the bad news is that if Greenland's ice did not disappear during the Eemian then Antarctica must be responsible for a significant portion of the 4-8 meter rise in sea levels that we know occurred during the Eemian.

This new knowledge about past warm climates may help to clarify what is in store for us now that we are facing a global warming.

[Jonger]

 

Greenland's getting an early start to the melting season.

 

http://nsidc.org/greenland-today/

 

Temperatures in the mid 40's at Narsarsuaq probably aren't helping.

 

http://www.ogimet.com/gsynop.phtml.en

 

Terry

 

That's probably possible on any day of the year.

[dabize]

 

 

During the warm Eemian period there was increased melting at the edge of the ice sheet and the dynamic flow of the entire ice mass caused the ice sheet to lose mass and it was reduced in height. The ice mass was shrinking at a very high rate of 6 cm per year. But despite the warm temperatures, the ice sheet did not disappear and the research team estimates that the volume of the ice sheet was not reduced by more than 25 percent during the warmest 6,000 years of the Eemian. "The good news from this study is that the Greenland ice sheet is not as sensitive to temperature increases and to ice melting and running out to sea in warm climate periods like the Eemian,as we thought," explains Dorthe Dahl-Jensen and adds that the bad news is that if Greenland's ice did not disappear during the Eemian then Antarctica must be responsible for a significant portion of the 4-8 meter rise in sea levels that we know occurred during the Eemian.

 

You know, that IS good news - I had been under the impression that once the GIS melts to around 80% of its current volume, it becomes unstable and will then continue melting until 25% of its original volume whatever then happens with the climate.

 

However, as noted, it doesn't change the overall flavor of the problem - it just switches the concern to the WAIS.

While 4-8 meters isn't 20 meters, it will still make it very difficult to live in functioning coastal cities.

Also, the very high current rate of melt may still bring in effects that the Eemian doesn't model.

And where do you start measuring the 8 degrees C....from 2012 or from 1950?

[SVT450R]

 

 

 

You know, that IS good news - I had been under the impression that once the GIS melts to around 80% of its current volume, it becomes unstable and will then continue melting until 25% of its original volume whatever then happens with the climate.

 

However, as noted, it doesn't change the overall flavor of the problem - it just switches the concern to the WAIS.

While 4-8 meters isn't 20 meters, it will still make it very difficult to live in functioning coastal cities.

Also, the very high current rate of melt may still bring in effects that the Eemian doesn't model.

And where do you start measuring the 8 degrees C....from 2012 or from 1950?

They state 8c warmer then today no specific year but you  would think within the past 5 years or less.

[PhillipS]

That's probably possible on any day of the year.

 

No, it's certainly unusual and possibly unprecedented, at least in recent years.  Here's the relevant plot from the NSIDC Greenland Ice Sheet page:

 

Greenland shouldn't be seeing any melting until around the end of April.

[Jonger]

That's probably possible on any day of the year.

 

No, it's certainly unusual and possibly unprecedented, at least in recent years.  Here's the relevant plot from the NSIDC Greenland Ice Sheet page:

 

Greenland shouldn't be seeing any melting until around the end of April.

Is melting just a term for exceeding 0C? I highly doubt there was a noticeable change besides wet snow at the coast. There was a +15C anomaly that brushed the SE corner of Greenland.... Considering the warm current is close by, this can't be that odd... There is a -10C anomaly forecast 5 days later.

[SVT450R]

No, it's certainly unusual and possibly unprecedented, at least in recent years.  Here's the relevant plot from the NSIDC Greenland Ice Sheet page:

 

 

Greenland shouldn't be seeing any melting until around the end of April.

 

I have to disagree jonger is correct if you take a  look at Narsarsuaq GL temps it can get above freezing any month of the year on southern coast of GL so you could see melting.

[AvantHiatus]

I have to disagree jonger is correct if you take a  look at Narsarsuaq GL temps it can get above freezing any month of the year on southern coast of GL so you could see melting.

There was not this much degree of melting compared to last year and will need to be monitored. 2013 melt season is looking rough.

 

[SVT450R]

Shouldn't be a surprise with the transition into -nao.  We also need to keep in mind that the blue dotted line is an average 1981-2010 so a single year will have a spikey look to it compared to where the running average is at that given moment.

[PhillipS]

Shouldn't be a surprise with the transition into -nao.  We also need to keep in mind that the blue dotted line is an average 1981-2010 so a single year will have a spikey look to it compared to where the running average is at that given moment.

 

Notice that the long-term 1981 - 2010 average is essentially zero for this time of year.  If years prior to 2010 had much melting before April the average would be non-zero, if only by a small amount.  if, for example, NSIDC re-baselined the chart to 1983 - 2012 the average line would look very different.

 

I stand by my comment that this year's melting is unusual and possibly unprecedented - even compared to 2012.

[TerryM]

Shouldn't be a surprise with the transition into -nao.  We also need to keep in mind that the blue dotted line is an average 1981-2010 so a single year will have a spikey look to it compared to where the running average is at that given moment.

 

Correct, but the graph posted by Weatherguy is specific to 2012 & we don't see any light under the red line until the middle of March. It's probably far to early in the season to base prognostications on what we've seen so far - but that said, it really doesn't look good.

 

I think that this new site will be the subject of much discussion as the year progresses. I hope that at some point they extend the graphic past the 100 days of melt point & having a comment section would be nice.

 

Terry

[Jonger]

No, it's certainly unusual and possibly unprecedented, at least in recent years. Here's the relevant plot from the NSIDC Greenland Ice Sheet page:

Greenland shouldn't be seeing any melting until around the end of April.

I have to disagree jonger is correct if you take a look at Narsarsuaq GL temps it can get above freezing any month of the year on southern coast of GL so you could see melting.

There was another article that mentioned it being upper 20's during the readings. Just google Greenland melting and reduce the options to the last few days.

[skierinvermont]

There was not this much degree of melting compared to last year and will need to be monitored. 2013 melt season is looking rough.

 

 

What nonsense alarmism. You and Phillip are taking a typical February Greenland heatwave and blowing it out of proportion. It will return to 0% melt before actual real melt resumes in May. 

 

Look how last year spiked to 10% of Greenland melted and then returned to completely frozen before the actual melt season began in May. 

 

 

The 1981-2010 average comes out to zero despite spikes that regularly occur in the winter months during brief heatwaves. I am sure these spikes have become more common as the world has warmed, but to say they are unprecedented, or that they portend negatively on the summer melt is rubbish.

[SVT450R]

Notice that the long-term 1981 - 2010 average is essentially zero for this time of year.  If years prior to 2010 had much melting before April the average would be non-zero, if only by a small amount.  if, for example, NSIDC re-baselined the chart to 1983 - 2012 the average line would look very different.

 

I stand by my comment that this year's melting is unusual and possibly unprecedented - even compared to 2012.

But the problem is your ignoring the fact that southern greenland can see temps above freezing even in January so you can't say you wouldn't see some melting now. 

[skierinvermont]

This is like saying a high of 50F in NYC on Feb 15th is "unprecedented" because the average is 40. 

[SVT450R]

This is like saying a high of 50F in NYC on Feb 15th is "unprecedented" because the average is 40.

I also agree with your point that it's becoming more common in our warming climate but like you say it's not something never seen before.

[PhillipS]

What nonsense alarmism. You and Phillip are taking a typical February Greenland heatwave and blowing it out of proportion. It will return to 0% melt before actual real melt resumes in May. 

 

Look how last year spiked to 10% of Greenland melted and then returned to completely frozen before the actual melt season began in May. 

 

The 1981-2010 average comes out to zero despite spikes that regularly occur in the winter months during brief heatwaves. I am sure these spikes have become more common as the world has warmed, but to say they are unprecedented, or that they portend negatively on the summer melt is rubbish.

 

Typical February Greenland heatwave?!  Puh-leeze!  If you are indeed stating that recent temperatures are typical for this time of year in Greenland you need to provide some supporting data.  "Typical" does not mean "less than record setting", it means commonplace.

 

And you do understand, don't you, that when the values on the Greenland Melt Extent drops to zero it does not mean that ice that melted has refrozen, it only means that no additional melting is taking place.  That's an important distinction.  Granted, there may well be some refreezing - for example, meltwater pools may skim over - but snow and ice that melted and ran off during the "typical February Greenland heatwave" is not magically restored.

 

And what sort of 'new math' are you using to claim that thirty years of melt extent records with values >= 0 can average to 0?  Melt values can't be negative so unless all of the values are 0 the average will be positive, right?  Let's take the 2013 melt extent record as representative.  The values have ranged from 0 to about 4%, right?  Prove you're right by making some synthetic data with thirty values of m,  where 0 <= m <= 4 and Average(m) = 0.  And, of course, share that data with us.  I'm no math whiz but I'm confident you can't do that unless all values of m = 0.

 

You generally post excellent comments - it's surprising and disappointing that you'd stoop so low on this thread.

[skierinvermont]

Typical February Greenland heatwave?!  Puh-leeze!  If you are indeed stating that recent temperatures are typical for this time of year in Greenland you need to provide some supporting data.  "Typical" does not mean "less than record setting", it means commonplace.

 

And you do understand, don't you, that when the values on the Greenland Melt Extent drops to zero it does not mean that ice that melted has refrozen, it only means that no additional melting is taking place.  That's an important distinction.  Granted, there may well be some refreezing - for example, meltwater pools may skim over - but snow and ice that melted and ran off during the "typical February Greenland heatwave" is not magically restored.

 

And what sort of 'new math' are you using to claim that thirty years of melt extent records with values >= 0 can average to 0?  Melt values can't be negative so unless all of the values are 0 the average will be positive, right?  Let's take the 2013 melt extent record as representative.  The values have ranged from 0 to about 4%, right?  Prove you're right by making some synthetic data with thirty values of m,  where 0 <= m <= 4 and Average(m) = 0.  And, of course, share that data with us.  I'm no math whiz but I'm confident you can't do that unless all values of m = 0.

 

You generally post excellent comments - it's surprising and disappointing that you'd stoop so low on this thread.

 

It was posted above that the maximum anomaly was 15C.. that certainly would not be unprecedented and would be a fairly typical heatwave. Greenland probably experiences a +15C anomaly once per winter. Unless that description is inaccurate, I will have to say its a typical heatwave.

 

 

Also the average is not zero. This is false. It is slightly greater than zero. Meaning there are likely other little melt events mixed in there. What does (2 + 29*0)/30 equal? .067. The values have clearly been above average this February, but not unprecedented. This is an inevitable conclusion from the fact that +15C anomalies are not uncommon.

 

 

Also temperatures briefly above freezing are not going to cause meltwater. They'll briefly cause the surface to appear wet from satellite but that's about it. Melt season doesn't begin until May and that's what will determine the mass balance for Greenland this summer. Not a little bit of wet snow on Feb 19 that quickly refreezes. 

 

If anything warm temperatures in winter are probably beneficial for Greenland because they are probably associated with increased precipitation, largely in the form of snow.