Polar ice sheets melting at an accelerating rate

[salbers]

These results for Greenland go through 2009, I wonder if any are available for 2010?

http://cires.colorado.edu/people/wahr/

http://www.skeptical.../news.php?n=483

Also see figure 2 below that shows acceleration of land ice melting in Antarctica.

http://www.skeptical...gaining-ice.htm

[BethesdaWX]

I'm sorry, this is Bull$hit

If ice was melting rapidly, we'd have seen very cold SST anoms off the coast of greenland this summer, andn through the timeof the melting.

Not only that, but those anoms have been some of the warmest anoms on the globe. Where is this melt water going then? There must be immense amounts of it.

[skierinvermont]

I'm sorry, this is Bull$hit

If ice was melting rapidly, we'd have seen very cold SST anoms off the coast of greenland this summer, andn through the timeof the melting.

Not only that, but those anoms have been some of the warmest anoms on the globe. Where is this melt water going then? There must be immense amounts of it.

LOL the amount of melt water is trivial relative to all the water in the north Atlantic and the incredibly warm temperatures there the past year. I would not expect cold ocean temperatures because of some melt water.

[skierinvermont]

These results for Greenland go through 2009, I wonder if any are available for 2010?

http://cires.colorado.edu/people/wahr/

http://www.skeptical.../news.php?n=483

Also see figure 2 below that shows acceleration of land ice melting in Antarctica.

http://www.skeptical...gaining-ice.htm

Excellent summary from skeptical science of melt processes.

[BethesdaWX]

LOL the amount of melt water is trivial relative to all the water in the north Atlantic and the incredibly warm temperatures there the past year. I would not expect cold ocean temperatures because of some melt water.

Do you understand how this works? No you don't aparently.

How do you think the gulf stream is stopped in its tracks? Cold surface water would be evident if there was significant melting. Ask anyone.

Mel****er is what caused the gulf stream to halt....aparently there must have been alot more of it in years past.

[BethesdaWX]

Boy has this board gone down the sh*thole...... bleeping out "Melt-water"..... Y'all keep your own...k?

[Msalgado]

Boy has this board gone down the sh*thole...... bleeping out "Melt-water"..... Y'all keep your own...k?

Had you used a space or a dash then there would have been no bleep. Put the letters and see what was bleeped. No need for you to get upset.

[Msalgado]

Do you understand how this works? No you don't aparently.

How do you think the gulf stream is stopped in its tracks? Cold surface water would be evident if there was significant melting. Ask anyone.

Mel****er is what caused the gulf stream to halt....aparently there must have been alot more of it in years past.

Can you provide some information on this from a legit source?

[salbers]

Do you understand how this works? No you don't aparently.

How do you think the gulf stream is stopped in its tracks? Cold surface water would be evident if there was significant melting. Ask anyone.

Mel****er is what caused the gulf stream to halt....aparently there must have been alot more of it in years past.

Actually it's the other way around, where the warmer ocean water around Greenland is helping to melt the ice. At some point we might observe reduced salinity that I think is the main threat to the Gulf Stream. I'm unsure if the current melting is large enough to allow this to be observed, yet. Here is more information about ocean induced melting, with a mention of salinity: http://www.nature.co...ll/ngeo765.html.

It's true the current melting isn't as rapid as what happened at the end of the last Ice Age. We are though headed for temps and sea levels higher than we normally get during interglacials. It's the acceleration that is more notable at this point, how long will this acceleration continue and is it outside normal climate fluctuations? It seems suspiciously aligned with other signs of global warming. And if the acceleration continues it will make the sea level rate of rise go up significantly. Current melt rates contribute about 1mm of the 3.5mm annual rise.

Putting this another way, melting can increase exponentially. If we continue to get roughly a doubling every 10 years in melt rate, it won't be too long before major sea level rises occur. Fortunately, we have the fairly accurate GRACE measurements to tell us what is going on.

[nzucker]

LOL the amount of melt water is trivial relative to all the water in the north Atlantic and the incredibly warm temperatures there the past year. I would not expect cold ocean temperatures because of some melt water.

I think the melting on Greenland is more due to the -NAO pattern we've seen prevail rather than AGW; we've had incredible blocking there with the world's most above average temperatures often being in the North Atlantic, hence the reason for 09-10 and 10-11 being cold winters in the US and Europe. It'll be interesting to see if this is related to the powerful solar minimum because the Maunder is believed to have caused significant warming in Greenland due to the prevalence of the -NAO regime. The -NAO/-AO is generally considered good for arctic sea ice/cryosphere development but we'll see if the extreme blocking actually hurts certain areas like Greenland and Hudson Bay.

[BethesdaWX]

Actually it's the other way around, where the warmer ocean water around Greenland is helping to melt the ice. At some point we might observe reduced salinity that I think is the main threat to the Gulf Stream. I'm unsure if the current melting is large enough to allow this to be observed, yet. Here is more information about ocean induced melting, with a mention of salinity: http://www.nature.co...ll/ngeo765.html.

It's true the current melting isn't as rapid as what happened at the end of the last Ice Age. We are though headed for temps and sea levels higher than we normally get during interglacials. It's the acceleration that is more notable at this point, how long will this acceleration continue and is it outside normal climate fluctuations? It seems suspiciously aligned with other signs of global warming. And if the acceleration continues it will make the sea level rate of rise go up significantly. Current melt rates contribute about 1mm of the 3.5mm annual rise.

Putting this another way, melting can increase exponentially. If we continue to get roughly a doubling every 10 years in melt rate, it won't be too long before major sea level rises occur. Fortunately, we have the fairly accurate GRACE measurements to tell us what is going on.

What the heck? That melting Ice (freswater) is less dense, it would have to propogate to the surface....aka...Freshwater vs Salt Water! Meaning, you'd have a very cold pool(s) developing, this is what interrupts the currents.. when freshwater cannot sink.

Arctic sea ice has lower salt water content than the avg ocean....land ice is completely freshwater.

http://www.windows2u..._oceancirc.html

Your Statement would put the laws pf physics at state. Freshwater melting from greenland glaciers would be less dense, and would not sink!

Unless of course.......the greenland glaciers are sal****er!

[salbers]

Thanks for the link - I see it focuses mainly on sea ice. What's unclear to me is what are the present respective contributions of fresh water from melting sea ice and Greenland land ice?

[BethesdaWX]

Thanks for the link - I see it focuses mainly on sea ice. What's unclear to me is what are the present respective contributions of fresh water from melting sea ice and Greenland land ice?

No problem.

There is no question Sea ice, being salt water, would not have as much an effect land ice would....but it still has slightly higher "freshwater" content to it. Notice that Sea Ice is Melting alot faster than Land Ice....which fits perfectly with the warm AMO/PDO sea surface effecting land temps tosome degree, but not near what Sea Temperatures turn out to be.

The Greenland ice sheets are completely freshwater, so, being less dense than salt water, they would need to remain surfaced....this is what causes the gulf stream to shut down when this was worse back before the little ice age, after the MWP.

So.....point is, If the Greenland ice Sheets were melting at an alarming rate...we'd see a very large quantity of COLD surface SST's...which we see the opposite.

Hansens theory that the cold Euro winters are caused by melting Ice do not have any merit, because not only are the SST's up there warmer than avg, but the Sea ice that bhe speaks of does not have AS MUCH impact.

[salbers]

Well, alarming is a subjective term here. I'd suggest the melt rate isn't enough to dump too much fresh water yet, but the acceleration is of some concern if it sustains itself.

Also, if it's the warm ocean that is triggering the melting, we wouldn't necessarily have much cold water due to the melting.

[BethesdaWX]

Well, alarming is a subjective term here. I'd suggest the melt rate isn't enough to dump too much fresh water yet, but the acceleration is of some concern if it sustains itself.

Also, if it's the warm ocean that is triggering the melting, we wouldn't necessarily have much cold water due to the melting.

How would the warm ocean SST's cause direct melting of land Ice? SST's cannot Directly melt land ice Directly because...well.....Land ice is not on the water! The ocean AMO warming of the ATMOSPHERE would melt some of the ice, but that would show up as a cold pool in the northern AMO horseshoe belt.....The melting ice would Cool the surface with less-dense freshwater, thus the cycle would be broken.

Melting land ice in general HAS to cool the surface SST's. I could understand your point if the current anoms were near normal...but...the SST's near Greenland are the some of the warmest on the globe......that woud suggest that ice melt is not occuring to the extent we think it is.

[salbers]

How would the warm ocean SST's cause direct melting of land Ice? SST's cannot Directly melt land ice Directly because...well.....Land ice is not on the water! The ocean AMO warming of the ATMOSPHERE would melt some of the ice, but that would show up as a cold pool in the northern AMO horseshoe belt.....The melting ice would Cool the surface with less-dense freshwater, thus the cycle would be broken.

Melting land ice in general HAS to cool the surface SST's. I could understand your point if the current anoms were near normal...but...the SST's near Greenland are the some of the warmest on the globe......that woud suggest that ice melt is not occuring to the extent we think it is.

The ice is melting where the ice flows are in contact with the ocean, at the shoreline. The source of heat is more the oceans than the air. I hope you got a chance to read the paper I posted earlier. They are showing the temperature and salinity profiles in the vicinity of the melting ice. I suppose any colder mel* ***er (note forbidden word ) is getting diluted by the massive influx of warmer water from ocean currents. More reading is here: http://www.jpl.nasa....elease=2010-050

In other words, the warmer the anomalies in the area, the more the water can melt the glaciers at the shoreline.

[BethesdaWX]

The ice is melting where the ice flows are in contact with the ocean, at the shoreline. The source of heat is more the oceans than the air. I hope you got a chance to read the paper I posted earlier. They are showing the temperature and salinity profiles in the vicinity of the melting ice. I suppose any colder mel* ***er (note forbidden word ) is getting diluted by the massive influx of warmer water from ocean currents. More reading is here: http://www.jpl.nasa....elease=2010-050

In other words, the warmer the anomalies in the area, the more the water can melt the glaciers at the shoreline.

Yes, but the melting ice would cool the surface water, since it has to float. Even if its not MAJOR, we'd see the cool pools hugging the coastline.

Either way, those SST's are from the Warm AMO.....so, there ya go.

[Mencken_Fan]

I'm sorry, this is Bull$hit

If ice was melting rapidly, we'd have seen very cold SST anoms off the coast of greenland this summer, andn through the timeof the melting.

Not only that, but those anoms have been some of the warmest anoms on the globe. Where is this melt water going then? There must be immense amounts of it.

Your seemingly facetious question: "Where is this melt water going?" piqued my curiosity.....

Water coming from Greenland is fresh, and cold. Being fresh, this melt water should lie atop oceanic salt water (assuming all temperatures being equal.) But if the sea surrounding Greenland is relatively warm, might the colder fresh water sink and slowly mix with salt water at some depth below the surface?

Would it not take some time before the melt water had a noticeable effect on surface water temperatures?

If this is a stupid question, please pardon me; I'm just a layman trying to apply some logic. And please remember, even capable thinkers must rely on logic when a mastery of physics and mathematics is less than great.

[BethesdaWX]

Your seemingly facetious question: "Where is this melt water going?" piqued my curiosity.....

Water coming from Greenland is fresh, and cold. Being fresh, this melt water should lie atop oceanic salt water (assuming all temperatures being equal.) But if the sea surrounding Greenland is relatively warm, might the colder fresh water sink and slowly mix with salt water at some depth below the surface?

Would it not take some time before the melt water had a noticeable effect on surface water temperatures?

If this is a stupid question, please pardon me; I'm just a layman trying to apply some logic. And please remember, even capable thinkers must rely on logic when a mastery of physics and mathematics is less than great.

Its not a stupid question The fact that the ice is freshwater, it is less dense than sal****er, so it cannot sink through the sal****er. Given that this "rapid melt" is supposed to be happening for years, theres no reason we shouldn't see it by now.

[salbers]

I think that mel****er would also float since the cold water is less dense (below 4C).

In terms of "where is it", isn't the disposition of the mel****er discussed in the paper I linked to in post #9?

Probably most SST analyses are too low in resolution to see the localized areas of cooler water immediately adjacent to Greenland during melting episodes. A higher resolution look appears to show the mel****er in figure 9 of this paper: http://seaice.apl.washington.edu/Papers/BaconEtal2002-FWjet.pdf

[BethesdaWX]

I think that mel****er would also float since the cold water is less dense (below 4C).

In terms of "where is it", isn't the disposition of the mel****er discussed in the paper I linked to in post #9?

Probably most SST analyses are too low in resolution to see the localized areas of cooler water immediately adjacent to Greenland during melting episodes. A higher resolution look appears to show the mel****er in figure 9 of this paper: http://seaice.apl.wa...l2002-FWjet.pdf

No, the resolution of POES should be good enough to pinpoint where it is.

Add on the fact that the GS completely shut down after the MWP, its magnitude is obviously at a high level...

[salbers]

No, the resolution of POES should be good enough to pinpoint where it is.

Add on the fact that the GS completely shut down after the MWP, its magnitude is obviously at a high level...

Good, maybe we can look at POES or other high-resolution analyses for earlier this fall if there's any online? Current OSTIA data does show some cool water near the S Greenland coast, unless that is actually sea ice.

http://ghrsst-pp.met...latest_full.png

Is there some documentation on the GS shutting down after the MWP - where is this stated to be a fact. This seems a bit irrelevant to me in that either way it doesn't contradict the GRACE Greenland data of present ice melt acceleration.

[Snow_Miser]

NASA is a very reputable source. I agree- however, my natural skepticism told me to research the GRACE satellite. I came with an interesting result.

The problem with the GRACE satellite is that it measures fluctuations in gravity, not ice mass.

Volcanoes, Plate Tectonics and Isotasy can all cause changes in gravitational fluctuations. And you know what else is curious? Volcanic Activity is prosperous under Antarctica.

2 Volcanoes Found in Antarctica (The New York Times)

First Evidence Of Under-ice Volcanic Eruption In Antarctica (British Antarctic Survey)

Map of Antarctic Volcanoes (ICECAP)

Protective Ice Flow in Antarctica Linked to Warmth of Volcanoes (The New York Times)

Scientists Discover Undersea Volcano Off Antarctica (National Science Foundation)

Scientists Find Active Volcano in Antarctica (The New York Times)

[salbers]

Yes, GRACE does measure gravity, and the ice melting is the biggest reason for the changes around Greenland. These gravity changes just happen to be near the Greenland coasts, just as one would expect for melting ice. Glaciers are simply retreating in Greenland as well, an obvious visual indication.

I like to be skeptical too, yet it was interesting to see the pattern of ice melt in Antarctica and Greenland measured by GRACE matches that measured by laser altimeter (a different method). Sounds like a good validation (see link for Greenland, I posted Antarctic validation on Eastern Wx).

http://www.flickr.co...sfc/4384863591/

Meanwhile, we do again (as I posted examples twice above) see cooler water near the Greenland coast, maybe the melt water?

http://www.nnvl.noaa...-Greeenland.jpg

In one of your links it mentioned that volcanoes in Antarctica are just a secondary cause of ice melt. The primary cause is warm ocean currents. And I think volcanoes aren't causing gravity shifts on large enough scales to explain the GRACE data, remember the IceSat confirmation again.

[BethesdaWX]

Good, maybe we can look at POES or other high-resolution analyses for earlier this fall if there's any online? Current OSTIA data does show some cool water near the S Greenland coast, unless that is actually sea ice.

http://ghrsst-pp.met...latest_full.png

Is there some documentation on the GS shutting down after the MWP - where is this stated to be a fact. This seems a bit irrelevant to me in that either way it doesn't contradict the GRACE Greenland data of present ice melt acceleration.

#1 Thats a chunk of sea ice showing up

#2 Yes, It is actually debatable whether the GS shut down, and whether it was the Sun, The GS, or both, thar created the LIA.

#3 GRACE has not only a very large margin of error, but it picks up on Changes in Tectonics, volanism/densities, etc, and these are poorly understood.

Satellite imaging in itself reveals very littole ice loss.....some is to be expected with the warmer AMO...

[salbers]

#1 Thats a chunk of sea ice showing up

#2 Yes, It is actually debatable whether the GS shut down, and whether it was the Sun, The GS, or both, thar created the LIA.

#3 GRACE has not only a very large margin of error, but it picks up on Changes in Tectonics, volanism/densities, etc, and these are poorly understood.

Satellite imaging in itself reveals very littole ice loss.....some is to be expected with the warmer AMO...

What's the basis of this? I think at least the SE Greenland coast is clear of sea ice right now - http://www.seaice.dk...mb.20101230.gif

I'd reiterate that the melting going on is larger than the GRACE errors, since GRACE matches up with IceSat and other measurements to a convincing degree (note my post #24).

GRACE validation is also discussed here: http://adsabs.harvard.edu/abs/2009AGUFM.G53A0670A

[BethesdaWX]

What's the basis of this? I think at least the SE Greenland coast is clear of sea ice right now - http://www.seaice.dk...mb.20101230.gif

I'd reiterate that the melting going on is larger than the GRACE errors, since GRACE matches up with IceSat and other measurements to a convincing degree (note my post #24).

GRACE validation is also discussed here: http://adsabs.harvar...AGUFM.G53A0670A

Again..... disagreement is the issue. If there was large scale melting of the greenland ice sheet, we'd surely see it.....which is the whole reason we're having this discussion. GRACE is in large disagreement with most other satellite data, its an outlier in all aspects when compared to measured temperatures by UAH in the antarctic, which do not fit in with conclusions given by GRACE. ice wise.

Tectonics are a Major issue no matter what is stated accuracy wise, which is why I'd prefer actual OBS, not estimations using gravity.

It would be alot easier to figure this out if they were to actually release data on this sh*t! Why has NASA been refusing FOI requests for the "important" data?

[salbers]

Again..... disagreement is the issue. If there was large scale melting of the greenland ice sheet, we'd surely see it.....which is the whole reason we're having this discussion. GRACE is in large disagreement with most other satellite data, its an outlier in all aspects when compared to measured temperatures by UAH in the antarctic, which do not fit in with conclusions given by GRACE. ice wise.

Tectonics are a Major issue no matter what is stated accuracy wise, which is why I'd prefer actual OBS, not estimations using gravity.

It would be alot easier to figure this out if they were to actually release data on this sh*t! Why has NASA been refusing FOI requests for the "important" data?

There really isn't any disagreement since you're comparing apples and oranges. It's warm ocean currents (having of course high SST values) helping to do the melting perhaps more than air temperature. And again, GRACE agrees with IceSat - a direct measurement of ice altitude. Ice melting is confirmed by many more direct observations (e.g. SAR) than UAH temps. It doesn't necessarily follow that the melting is large enough in scale to show up in coarse-scale SST maps (particularly since the warm ocean is helping to cause the melting), just fine scale ones as we've seen. It's all consistent actually. The melt is accelerating though and is significant (in terms of being noticeable) for sea level rise.

There are GPS measurements of the Greenland tectonics that are helping to corroborate the GRACE measurements. And IceSat agrees without any reliance on gravity - as I've mentioned several times. It's pretty compelling when you look at the various lines of observational evidence using different techniques. More on the multiple lines of evidence is here: http://www.scholarsa...e-gps-ice-melt/

Looks like GRACE data are available here: http://isdc.gfz-pots...ub&tid=1&pid=35

Really, the more interesting question is whether the rate of melt is increasing on a continual annual basis or are there fluctuations from decade to decade (as I asked in post #9)?

[Snow_Miser]

Yes, GRACE does measure gravity, and the ice melting is the biggest reason for the changes around Greenland. These gravity changes just happen to be near the Greenland coasts, just as one would expect for melting ice. Glaciers are simply retreating in Greenland as well, an obvious visual indication.

So you don't think the extremely warm AMO has anything to do with it?

I like to be skeptical too, yet it was interesting to see the pattern of ice melt in Antarctica and Greenland measured by GRACE matches that measured by laser altimeter (a different method). Sounds like a good validation (see link for Greenland, I posted Antarctic validation on Eastern Wx).

http://www.flickr.co...sfc/4384863591/

Again, appears to just be natural factors of the warm AMO and Oceanic Currents.

Meanwhile, we do again (as I posted examples twice above) see cooler water near the Greenland coast, maybe the melt water?

http://www.nnvl.noaa...-Greeenland.jpg

So the tiny little area is melt water? That doesn't seem like a lot at all, considering what the GRACE satellite was initially showing. A classic -NAO is being shown in that SST map, with all of the positive anomalies centered near the NAO blocking.

In one of your links it mentioned that volcanoes in Antarctica are just a secondary cause of ice melt. The primary cause is warm ocean currents. And I think volcanoes aren't causing gravity shifts on large enough scales to explain the GRACE data, remember the IceSat confirmation again.

What could cause those warm oceanic currents? The AMO?

-Snowlover123

[BethesdaWX]

-Snowlover123

Thats kinda what I dont think he understands