NASA: Warm Ocean Currents Cause Majority of Ice Loss from Antarctica

What sea level rise, and where is all that glacial ice coming from?

just to say that, regardless of the scientifico/politico conclusions, that that is a beautiful picture of an unknown region of our planet.

Well floating ice melts and contributes nothing to sea level rise. If what we are dealing with is a migrating glacier which is what they do, how does the ocean speed it up? The glaciers moving into the ocean cause sea level rise their melting just makes them less obvious.

So sea ice cover measurably increased over the chosen time period but they used models to “prove” that the ice got thinner. Please explain how the warm currents managed to thin the ice without effecting it’s coverage.

I have a simple experiment I would recommend to anyone who has doubts about how Antarctic ice sheets “melt”.
You need a stop watch, and a thermometer that includes zero deg C on its scale, and you need to find something like a mid west or similar cold lake that gets ice on it in winter. Night time is preferred to eliminate spurious “heat” sources like the sun.
So part one of the experiment requires waiting for a wind free night, with the air and water Temperature at the lake right at zero deg C, so there should be chunks of ice floating on the water.
You srtip down to your pre-natal suit, and start the stop watch as you stand alongside the lake shore.
Time how long it takes for you to freeze to death, or preferrably abandon this phase of the experiment, before that time.
Phase two of the experiment is identical to phase one, with one slight experimental difference in procedure.
Before you start the stop watch, as in phase one, go and jump in the lake.
Record the new time to expiration.
Then write a short essay, on the relative thermal conduction of air and water.
[Moderator’s Note: George, while there is a certain elegance to this experiment, don’t you think, maybe, you might have suggested that no one try this at home? -REP]

What happened to the sticky Svensmark paper story….itv has dissapeared off WUWT current list???!!!

Ah, now I understand! The missing heat was hiding under Antarctica, wringing its hands together and laughing to itself with all the devious intent of a silent film villain!
need I say /sarc?

That’s one for the history books surly? NASA in 2012 announces that they have discovered that Ice melts. (Yea of course, “and don’t call me surly”).
The usual culprits will have headlines like,
“ocean driving Antarctic ice loss”.
“Antarctic Ice Melting From Warm Water Below”.
“Warmer seas behind Antarctic ice shelf melt, study finds”
The spin on ice melting is very much on Que at the end of this this summer in the SH.
I wonder why? (hmm… scratches chin!)

And to pre-empt some of the icesheet -sea ice confusion. On the east side of the Antarctic Peninsula, where the Larsen icesheets are, you can see from the graphic below that sea ice extends far beyond the icesheets (300+ kms) even at this time year, the late Austral summer.
You can also see ice free areas along the coast, so warm ocean upwelling along the coast is certainly occuring. The question is whether it has increased.
http://nsidc.org/data/seaice_index/images/daily_images/S_bm_extent_hires.png

So… ocean currents have changed, bringing more warm water to the ice sheet, causing it to melt from below. Assuming that is correct:
1. Where did the warm water originate from?
2. What replaced the warm water? Presumably less warm water from somewhere else?
3. Since the warm water left where it was, and was replaced by other presumably colder water, did some area of earth experience cooling as a consequence?
4. If the volume of water melting from the ice sheet is in fact large enough to cause a measurable rise in sea level, then the obvious question is, where does that water go once it melts? Being at freezing point, it would be colder than any other water it flowed toward.
So, unless the study can show corresponding cooling to account for the change in warm water currents and the results of new cold water entering the ocean in vast quantities, all they’ve shown is…that something changed. Oh my. Like that’s never happened before.

Whoops my second plot above one should be …
http://nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png
Just “kissing” the historical average too. Go, baby ice, go!

It’s Nature. I hate to ad hom, but in this case the stain on the rep is inky extreme. Lie to me a few hundred times, and I tend to lose confidence.
The floating ice is melting! It’s melting! Oh no!!!!!
Yeah, well, as the Award Winning Best Science Blogger points out: Antarctic ice mass in total is increasing. Good thing if some of the edge ice melts. There’s way too much ice in Antarctica anyway.
Ice is death. Nothing alive in frozen H2O, because Life requires liquid water. Anarctica is a Continent of Death. We pro-lifers (as opposed to pro-deathers) are not happy about that. What the Big World Gummit types ought to be doing is bombing the ice shelves and towing the bergs to places that could use it. Circulate and melt that dead ice. Do something useful with it.
WARMER IS BETTER. FIGHTTHE ICE.

So, the inference is that CO2 is now causing changes in winds. I am assuming less wind (exception would be Al Hansen). This is back to the old El Nino/CO2 connection that has already been shown to be FALSE.

In the graphic above colour represents ice thickness, not as you might assume ocean temperature or ocean temp change.
Having read the NASA PR. There is no mention that they measured increased warm water upwelling.
The logic is icesheets are melting, warm water is upwelling, therefore upwelling warm water has caused the icesheet melt (in the sense of icesheet retreat).
Either the press release is badly written or the claim is junk.

ICESat was the first satellite specifically designed to use laser altimetry to study the Earth’s polar regions. It operated from 2003 to 2009.
=======
This is one of the biggest problems with any science that depends on nature cooperating….
They based everything on the info they have from 2003 – 2009….
….by the time they get their paper out there
it’s changed……
http://nsidc.org/data/seaice_index/images/daily_images/S_bm_extent.png

I don’t imagine that the same authors are responsible for this other paper published at the same time (well the names are exactly the same).
“Corrected ICESat altimetry data, surface mass balance, and firn elevation change on Antarctic ice shelves”
http://doi.pangaea.de/10.1594/PANGAEA.775982
Of course, the ICESat data needed to be corrected for … “We have modified the original ICESat data by applying an improved tide model (CATS2008a) as well as the recommended corrections for saturation and surface air pressure (the inverse barometer effect). … The original reported elevation relative to WGS84, as defined …. “

looks like real-science.com is out of commission once again….
[Reply: Works for me. ~dbs, mod.]

“Studies have shown Antarctic winds have changed because of changes in climate,” Pritchard said. “This has affected the strength and direction of ocean currents. As a result warm water is funnelled beneath the floating ice. These studies and our new results suggest Antarctica’s glaciers are responding rapidly to a changing climate.”
A different picture is seen on the Antarctic Peninsula, the long stretch of land pointing towards South America. The study found thinning of the largest ice shelf on the peninsula can be explained by warm summer winds directly melting the snow on the ice shelf surfaces. The patterns of widespread ocean-driven melting and summer melting on the Antarctic Peninsula can be attributed to changing wind patterns.
=
In what is it different? It’s the winds and really too bad for warmists, from Antarctica the number of depressions below 980hPa coming out is increasing and the depressions are deeper -i.e. associated anticyclones are more powerful-… Leroux, Dynamic Analysis of Weather and Climate, Springer 2010 figures 14.10 and 14.11 and page 350 the conclusion is “the warming of the Antarctica peninsula is of dynamical origin”. Intensification of meridional exchanges causing transfer of additional warm, moist air to the Pole as a result of reinforced MPHs. This dynamic is precisely the opposite of what a global warming world should create. What the satellite offers is a confirmation and a precision on the various processes at work, not at all any confirmation of CO2 induced warming… quite the opposite!

“”””” Geoff Sherrington says:
April 25, 2012 at 10:04 pm
Re Lake Vostok being liquid, can I ask again please, why are deep ocean waters so close to freezing point. “””””
What is the big mystery ? sea water of greater than about 2.47% salinity, increasess in density right down to its freezing point , and since it is denser when colder it sinks below warmer waters, so the deeper waters tend to be colder, until you get down to where the internal heating from the mantle, takes over and the cooling stops.
No mystery at all.

“Studies have shown Antarctic winds have changed because of changes in climate,”
Or;
“Studies have shown Antarctic winds have changed the local climate,”

Steve from Rockwood says:
April 25, 2012 at 4:20 pm
I’m not sure how going from radar to laser helps you measure the removal of the underside of the ice.
You use a blue-green laser.
It’s amazingly accurate — if you sit on the bottom of the ocean and aim upwards…

Willis, is that the igloo effect? /jk

I must confess that I never really understood how ‘warm’ air, which is below (and usually very much below) freezing could be driving ice sheet melt. Same point applies to the Himalaya Glaciers.
Given that approximately 90% of ‘floating’ ice is below water, the obvious candidate for melting ice sheets would be a trend in slightly warmer water temperatures.

richard verney says:
April 26, 2012 at 1:38 am

I must confess that I never really understood how ‘warm’ air, which is below (and usually very much below) freezing could be driving ice sheet melt. Same point applies to the Himalaya Glaciers.
Given that approximately 90% of ‘floating’ ice is below water, the obvious candidate for melting ice sheets would be a trend in slightly warmer water temperatures.

The sea ice page shows Arctic mean temperatures below freezing until May while winter ice peaks in March and then starts its inevitable melt – a full 30-60 days before air temperatures are above freezing. Why does the ice start melting when air temperatures are still below freezing? Is it warmer water or does the ice sublimate as the sun returns to the Arctic?
What does “slightly warmer temperatures” mean? Above freezing? Or from -2 to -1.5?

Let’s hope the old icebridge between Antarctica and South America never materializes again. The ice extent is way out there right now but fortunately East of the strait. If that same broad tongue of extent were IN the strait, more of the circumpolor current of cold water would be pouring into the Atlantic instead of harmlessly circling the Antarctic continent.

And because the oceans are thermally stratified, warmest at the top and coldest at the bottom, the sun never gets to warm the bottom waters …
Ahhh, Willis, IIRC while they are thermally stratified, that stratification all occurs in the top 1 km, or even the top 500 meters. Underneath that the water temperature is a nearly uniform 4 degrees C, is is not?
Not that this makes your point incorrect. Below roughly 200 meters, it is very, very dark. And many wavelengths (as has been pointed out in other threads) are absorbed almost entirely in the top centimeter of water — IR in particular. Visible light penetrates much farther and warms as it does, but its significant heat content is probably absorbed in the top few tens of meters.
This does raise an interesting point re the article. Earth’s “climate” arguably consists of self-organized patterns of circulation that are all driven by thermodynamic forces that change the efficiency of the Earth at losing its dynamic energy input. That is, the bulk of the Sun’s energy is absorbed during the day, by the oceans, in or near the tropical band around the equator, simply because the Sun doesn’t shine at night, the Earth is 70% ocean, and the tropics are precisely the band of latitudes where the sun is directly overhead (incident at 90 degrees upon the surface of the land or water) at least once during the year, maximizing the flux of the Poynting vector through/into any given patch of surface.
Moving the heat around changes the rate at which the Earth cools, given any input. Because outgoing radiation intensity from the surface in the water window bands scales roughly like surface temperature (in Kelvin) plus radiation from in the IR bands from top of troposphere CO_2 and other GHGs at much cooler and much more globally uniform temperatures, and because radiated power scales like the area, the rate at which energy is lost is greater when the daily dose of heat is spatially concentrated. When the tropics are warmer and the poles are cooler, the planet should maintain an average temperature that is colder than it is when the surface temperature is more uniform. The moon is an extreme case of this (although not usually a very good/comparable one as it doen’t rotate as fast as the Earth does and has no thermal “ballast” comparable to the ocean of water or air quite outside of transport issues) as it is much hotter where it is hot, rapidly cools to much cooler as it cools, and has in the end an average surface temperature that is much less than Earth’s.
The efficiency of the transport of heat from the equators to the poles might well be the primary factor responsible for determining the Earth’s mean temperature once the basic balance of the GHE is taken into account. It could even be a major factor in stabilizing interglacials in the current (Pliestocene) ice age. When heat transport to the poles is slowed, not only do the poles cool but on average, so does the entire planet because the tropics only have to warm a little to compensate for a lot of temperate zone/polar cooling due to the . They have a much larger surface to radiate from, and the poles are already much colder, on average, so cooling them has a much smaller marginal impact on global heat loss rates.
When heat transport to the poles is enhanced, the planet warms because the tropics comparatively cool. If the tropics cool (on average) by a small temperature shift $\Delta T$, the poles have to warm by a much larger shift in order for total outgoing radiation to still balance incoming radiation.
Note the positive feedback that can maintain ice age/glacial conditions. In an interglacial, the glaciers melt (decreasing albedo) and surface temperatures become more uniform, with enhanced transport from equator to poles. This improved heat transport is itself equivalent to degrees of “global warming” as the more uniform surface temperature has to be, on average, higher to maintain balance from an also higher net insolation due to the reduced surface albedo. When an ice age/glaciation period cometh, “something” changes conditions and tips the balance towards a lower mean (something possibly being the sun, possibly being some mix of Milankovitch/Precession/Obliquity, possibly being the appearance and disappearance of oceanic circulation modes as the continents drift around and eventually move enough that a major current “suddenly” changes and alters the poleward transport of tropical heat). As the poles get colder, the tropics might even actually get a bit warmer but the average decreases. Albedo increases, net surface insolation decreases, and if there is any feedback that further slows heat transport, one can get kicked over into a protracted cold phase.
That’s why this paper is indeed very interesting. We already know that there are strong correspondences between decadal oscillations and surface temperature. The connection between transport efficiency and mean temperature is a possible explanation — when the phases are such that they improve transport from tropic to poles, the poles warm, the tropics cool, and the planet warms a bit on average. When they reduce the net transport from equator to poles, the poles cool, the tropics warm, and the planet cools a bit. In general, when the Earth exhibits maximum thermal inhomogeneity it cools most efficiently, and when it is most thermally homogeneous it cools less efficiently and hence has to be slightly warmer, on average, in order to maintain energy balance.
Polar heat transport is highly multimodal, of course. Ocean currents are a huge factor. Decadal atmospheric circulation is a huge factor. The moisture content of the transported air is a huge factor — droughts in the tropics reduce the heat content in the transported air and are net cooling (a conclusion that I think has good empirical support) — it not only cools the poles by reduced transport but causes the tropical land surfaces to quickly lose at night most of the heat they gained during the day, increasing the temporal diurnal inhomogeneity (net cooling). And somewhere on top of all of this (quite literally) one has modulation of surface radiation due to cloud albedo and the GHE due to humidity, cloud albedo, and complex feedbacks associated with e.g. ENSO — the decadal oscillations not only affect polar heat transport but vertical heat transport and the height of the tropopause.
Finally, everything is coupled in nonlinear ways. A pretty problem! But this paper points to a piece in the puzzle. Net growth in Antarctic ice suggests reduced polar transport in the southern hemisphere, net cooling. For a while — perhaps 30 years — northern polar ice has been diminished, suggesting net warming of the northern hemisphere. However, the PDO has changed phase, and its effect was quite manifest this winter with Alaskan sea ice strongly increased and much colder temperatures in the West/Northwest continental US. The NAO has not yet shifted phase — and is much more irregular so we don’t really know when or if it will — but if/when it does it may well reduce heat transport to the Atlantic side of the Arctic. Or a fluctuation of any one of several Arctic currents might manage it even before that. And behind all of this is the “something” — all of the factors that somehow drive the entire system inexorably into an instability region where feedbacks back to glaciation become positive and we tumble back down to ice.
Personally I think that it is very likely that we have already turned the corner on the Holocene. The LIA was reportedly the coldest century since the Younger Dryas ended, suggesting that “something” is moving us to where cold phase fluctuations are enhanced and prolonged, a probable precursor of cold phase shift. We should be so lucky as to stabilize warm phase for another few hundred or few thousand years, but the Earth’s climate is really remarkably headstrong and responds to something that sets the thermostat in a way that resists natural variability far greater than anything anthropogenic.
It might be nice to eventually understand that something.
rgb

The concern here is that loss of the ice shelves will reduce their butressing effect on inland glaciers, and hence accelerate the flow of inland glaciers into the sea.
I can see how grounded ice shelves provide buttressing, but not how floating shelves do.
To take a classic example, Notre Dame Cathedral in Paris has vaults that exert a diagonally downward thrust that has both a vertical and a horizontal component. The walls hold up the vertical component just fine, but without buttresses, the walls would be pushed over by the horizontal component of the vault thrust. The flying buttresses come up at an angle and are anchored solidly in the ground, and hence provide the required horizontal component at the base of the vaults, offset by their horizontal thust in the opposite direction at ground level.
But now if each flying buttress were set on a pontoon, and the level of the Seine raised until the pontoons were just floating, the buttresses would no longer provide the required horizontal thrust, and would just slide out, allowing the walls to topple.
The grounded portion of the shelves drags against the ocean floor, and hence provides back-thrust to hold the inland glaciers in. But since it is the floating shelves that are affected by warm currents, it is hard for me to see how their reduction would significantly reduce the buttressing of the inland glaciers.
Of course, melting the floating ice by itself would have no direct effect on sea level. There might be an indirect effect via ocean temperature, but I think that would be small.

And I thought my “jump in the lake” experiment would adequately demonstrate why, when the floating sea ice melts, the sea level will FALL !.
The 80 Cal per gram latent heat of freezing, comes right out of the ocean, and cools an astronomical amount of sea water, causing it to shrink. If you assume that the coefficient of expansion of sea water, is independent of Temperature near zero (which it isn’t), then it is a trivial exercise to prove that the change in sea level is independent of how the heat gets distributed. you either cool a lot a little or you cool a lot a little; or somewhere in between.

The newspaper alarmists have said this melting will cause sea levels to rise. Have they never tried the famous experiment of putting some ice cubes to float in a glass of water and watching them melt without any rise whatoever in the level of the water?

Did anyone notice how dishonest the video is? The red is the thickest ice shelves.
“The shelves are indicated by the rainbow color; red is thicker (>550m), while blue is thinner (<200m)."