By Steven Goddard,
The headline reads “NASA Satellites Detect Unexpected Ice Loss in East Antarctica”
ScienceDaily (Nov. 26, 2009) — Using gravity measurement data from the NASA/German Aerospace Center’s Gravity Recovery and Climate Experiment (GRACE) mission, a team of scientists from the University of Texas at Austin has found that the East Antarctic ice sheet-home to about 90 percent of Earth’s solid fresh water and previously considered stable-may have begun to lose ice.
Better move to higher ground! NASA also reported :
In 2007, NASA generated this map (below) of Antarctica showing just how hot it is getting down there in the land of Penguins.
Now I am really worried! But wait……. There are a few minor problems.
Assume for a minute that we accept the GRACE numbers. The first problem is Antarctica contains a lot of ice : 30 × 10^6 km³. At 100 km³ per year, it will take 300,000 years to melt.
The next problem is with the NASA temperature map. From the NASA article “The scientists estimate the level of uncertainty in the measurements is between 2-3 degrees Celsius.” They are claiming precision of better than 0.05°C, with an error more than an order of magnitude larger than their 25 year trend. The error bar is large enough that the same data could just as easily indicate rapid cooling and blue colors. That will get you an F in any high school science class.
And that is exactly what happened. The hot red map above was preceded by a cold blue map which showed Antarctica getting cooler. What motivation could NASA have had to change colors without mathematical justification?
NASA justified their heating up Antarctica with this comment :
This image was first published on April 27, 2006, and it was based on data from 1981-2004. A more recent version was published on November 21, 2007. The new version extended the data range through 2007, and was based on a revised analysis that included better inter-calibration among all the satellite records that are part of the time series.
As I have already pointed out, this is absurd. Their error bar is so large that they could have painted the map any color they wanted. Apparently someone at NASA wanted red.
But why are we looking at temperature trends anyway? The real issue is absolute temperatures. Some of the regions in which GRACE claims ice loss in East Antarctica average colder than -30°C during the summer, and never, ever get above freezing. How can you melt ice at those temperatures?
http://en.wikipedia.org/wiki/File:Antarctic_surface_temperature.png
I overlaid the Antarctica summer temperature map on the GRACE “melt” map, below. As you can see, GRACE is showing ice loss in places that stay incredibly cold, all year round.
The problem with GRACE is that it measures gravity, not ice. Changes in gravity can be due to a lot of different things beneath the surface of the ice. Antarctica has active magma chambers. Plate tectonics and isostasy also cause gravity changes.
We should be clever enough not to be blinded by technology. The claims that ice is melting in East Antarctica don’t have a lot of justification.
George E. Smith says:
July 1, 2010 at 11:00 am
“But following the same principle, the bottom of glaciers, where they contact their rock enclosures is under very high pressure; so arguably the melting point of the ice is lower there so that interfacec ould melt; and allow the solid to slide further down on a liquid interlayer.”
The depression of the melting point by pressure is very slight, amounting to around -2C at the base of an ice sheet, a few degrees more at high pressure contact points. However, that doesn’t matter ; for a deep ice sheet, the base is not at -30C (or whatever the mean surface temperature may be), but at its melting temperature, as geothermal heat from below continuously melts ~1mm/yr of the base ice, lubricating the sheet and, where the topography permits, forming subglacial lakes.
Brad aka 1personofdifference says:
July 1, 2010 at 10:13 am
Chris Noble et al.
———
Well said! All these attacks and counterattacks are meaningless. What I, like most people who come onto WUWT, is loss of any ice in East or West Antarctica shown by evidence to be caused by man-made Co2 / greenhouse gases. I haven’t read any evidence on this thread or any other that provides that evidence.
AGWers like to point to increasing ice loss. So what? What does that show? Did man cause it? If you’re going to look at Antarctica then lets look at the big picture.
http://tinyurl.com/iceup43-nsidc
What caused the amount of 1980 sea ice extent and concentration? Why is it higher today? Why did it grow throughout the start and end of the warming period? The climate changes so let’s just get over it. The losses today can just as easily flip as the NSIDC link shows.
Which rat nibbled my jumbo pizza and is the nibbling accelerating? My mom occasionally sprinkles some cheese on top but the nibbling continues. How long before it’s all gone?
This is where this discussion is at!
Nick Davis says:
July 1, 2010 at 10:31 am
Brad, they are looking at mass changes over time. They are looking at, for example, gravity measurement at one location, and how those change over time. They aren’t just looking at a gravity map and saying, “look, there’s less gravity here so the ice is melting”, they are saying, “look, there is a negative trend in mass here, so there is likely some ice mass loss”.
Bold mine.
What is outlined in bold has a logical error. There is not only ice in Antarctica. There is underlying the corresponding mass of the planet that also has a changing gravitational field due to tectonics and magma and lithosphere sliding over whatever sphere. Antarctica is a continental shelf and this shelf is moving with velocities commensurate with the changes studied and attributed to ice reduction.
This is a change map of the geoid, from GRACE
http://earthobservatory.nasa.gov/Features/GRACE/page3.php
It us worth the trouble to look at it, the second plot.
It is the difference for the month of August 2002 from the average of all 2001. It is the type of difference used to make the claim that gravitational changes are ice depletion.
Note that the extremes of the scale for one month are in mms, and exist in the oceans and on the land masses, and not just in antarctica.
I think it is nonsense to be measuring gravitational anomalies and calling them ice changes when the underlying continental shelf is not concurrently mapped.
This is the fourth time I am saying this on this thread.
jeff brown,
To quote the late, great Ronald Reagan: There you go again.
When you say, “Smokey and Brad, no where in Steve’s post…” you are ignoring the fact that I commented specifically on your comment to Brad.
I happen to agree with Steve Goddard’s assessment. That is hardly ‘pulling the wool’ over my eyes, as you hopefully assert.
Much arm-waving is being done by the alarmist crowd over the completely natural fluctuations in the Arctic region. But if you believe that a harmless trace gas is the cause, then explain why the Antarctic is steadily gaining ice cover.
jeff brown
What I said is that ice is not melting in the interior of east Antarctica, which is exactly correct. Why are you repeatedly misquoting me?
http://www.nature.com/news/2005/050516/full/news050516-10.html
[off topic, c’mon Steven ~ctm]
Anna, have you read the paper?
Filtered signals in the study:
-Barotropic ocean signals
-Atmospheric pressure
-Estimated PGR, with large uncertainties included in their estimates of ice mass loss that account for the range of error associated with PGR
Their discussion of other papers identifying other sources of gravity changes, other than ice mass loss (ie, convective mantle currents), suggest that the authors took everything into account that is available.
Further, InSAR measurements of outflow and snow accumulation data were combined in Rignot, E. et al. 2008 to develop a mass balance model, which was used in combination with the remaining filtered data to estimate ice mass loss. In Arendt, A. A. et al., 2008, the authors found that laser altimetry validated other studies’ estimates of ice mass loss using filtered GRACE data. These are all referenced in the Nature paper.
My explanation to Brad was not meant to be an exhaustive description of their method, but merely to illustrate that the authors were looking at a time series of data.
“Note that the extremes of the scale for one month are in mms, and exist in the oceans and on the land masses, and not just in antarctica.”
Indeed, and anomalies include things like atmospheric pressure variations, not just geologic processes like rebound and convective currents.
Excerpt from: Nick Davis on July 1, 2010 at 10:31 am
Excerpt from: Nick Davis on July 1, 2010 at 9:10 am
KADAKA RESPONDS:
Perhaps some people could benefit from reading the Wikipedia article on ice, specifically the Phases section:
Simply put, given enough pressure ice can be forced to turn to water even though the temperature is still below freezing (0° C). That makes sense as water expands when it freezes, so if pressure tries to cram the frozen form into a smaller space the easy way to occupy less volume is transforming to the liquid phase.
Also ice is not just ice, there are many forms. Relevant info:
See this reference. -36°C may be where the Ice Eleven and Ice One-h transition takes place, but once it’s been XI if it “warms” and becomes Ih, it more easily transforms back to XI than ice that had never been XI before. Interesting stuff.
What does that tell you? Ice in Antarctica has been dang cold for a very long time. How deep does an Antarctic ice bore go to get 10,000 year old ice? How deep have they ever gone?
Now let’s look at the wonderful subglacial topography and bathymetry of Antarctica. Notice the rugged terrain, and how half of it (at least) is below sea level, some spots considerably below, most areas less than 2500 below sea level but some spots are up to 10,000 feet deep.
So, not only have certain people been arguing the ice just flows down a slope, because the temperatures at the bottom are high enough to melt the ice where it contacts the ground (but didn’t know enough to consider the incredible pressure from all that ice could result in liquid water without temperature-based melting), thus providing a liquid lubricant to let the ice just slide on out to the sea, but they are also arguing the ice will just slide uphill to do so, sliding upwards thousands of feet, with deformation of the ice not that important compared to the sliding.
Gee I wonder, if the ice is sliding away along the bottom and can move so quickly to the sea, where did that ancient ice they found in the ice cores come from? Wouldn’t all that old bottom ice have slid away ages ago?
Ice that flows uphill, as well as ice that’s ferroelectric thus also piezoelectric and pyroelectric. Yup, Antarctica sure sounds like a scientifically-interesting place.
PS: Re: Paul Birch on July 1, 2010 at 12:03 pm
I saw your comment after writing and when I checked the comments before posting. Well, Wikipedia thinks it could be related, so you can take that up with them. 😉
Well, we can see what effect the dogpile on Steven is having. The opposition is ganging up on him, since obviously one alone isn’t enough to take him down. Plus the diversionary tactics, trying to force him to fight meaningless side battles, indicates that even as a group they feel they can’t take him straight on.
He shows NASA temperature maps, the article they came from clearly says:
So they start a long fight where there is complaining he is making his argument with air temperatures.
So much effort to rattle and take down just one man, and they can’t even do that straight on!
This is getting to be like the mythical Wild West, when all the punks and bad guys converge on the town to take out the Sheriff, ’cause he’s just too good at taking them down. Then they take up positions and try to surround him, while seeing who gets to be first at shooting him in the back. While complaining how when he rode in for the fight he left his horse in a No Parking zone.
Guess that’s what happens when you are a living breathing Legend, here on the frontiers of Climate Truth.
Sorry Phil,
I have no tolerance for intellectual vandals, and there have been a number of them present for this article.
There are ~145 known lakes under all of that cold, frozen Antarctic ice. Hmmmm.
“What I said is that ice is not melting in the interior of east Antarctica, which is exactly correct. Why are you repeatedly misquoting me?”
If you actually read the study that you pretend to critique then you would find that the authors do not make this claim.
Why you constantly invoke this red herring is a question that you should answer.
You keep on misrepresenting the paper and the IPCC.
The paper in question provides evidence that in addition to ice loss in Western Antarctica there is also ice loss in a few coastal parts of Eastern Antarctica. The mechanism is the same, increased calving leads to accelerations in glacier flow rate which in turn leads to glacial thinning. This is completely uncontroversial and is backed up by multiple studies using a variety of satellite based measurements. All of the regions that they analyse are coastal and are not 700 km the coast.
The only thing that is clear in your article is that you don’t like these results. If you are going to critique a paper then at least read it and accurately describe the results and conclusions of the study. Your entire post is a massive red herring because you completely misrepresent the mechanism through which ice is lost in Antarctica. Nobody is claiming it is through melting. Nobody.
“I have no tolerance for intellectual vandals, and there have been a number of them present for this article.”
An intellectual vandal would describe the GRACE data as a melt map.
Your entire post is a calculated misrepresentation of a scientific study.
Chris Noble
The red herring is that climate experts like Hansen and others tell us that Antarctica is going to melt down. here is the latest piece of garbage.
http://www.vancouversun.com/technology/Magnitude+global+warming+uncertain+survey+finds/3212837/story.html
Chris Noble says:
“The mechanism is the same, increased calving leads to accelerations in glacier flow rate which in turn leads to glacial thinning.”
Why would calving lead to increased acceleration in glacier flow? How does that follow? Ice is viscous; it tends to stick together. Less glacier ice means less glacier weight, so the flow would tend to be slower, not faster. And glacier calving leads to thinner glaciers? Why would that be? What would make a glacier thinner just because pieces are breaking off where it enters the ocean? Does that mean glaciers get thicker if they don’t calve off icebergs? Who are you trying to kid?
I think you’d better re-read kadaka’s posts above. Especially the part where some folks seem to believe that glaciers can slide uphill and across rocky moraines, apparently friction-free. But most important, because he’s got your number.
Smokey, try reading actual scientific research.
http://www.nasa.gov/pdf/121653main_ScambosetalGRLPeninsulaAccel.pdf
Smokey, try reading some scientific papers rather than relying on the musings of “kakada”.
http://www.nasa.gov/pdf/121653main_ScambosetalGRLPeninsulaAccel.pdf
KADAKA
I understand that the melting temperature of ice is proportional to pressure. I also understand that there are different forms of ice.
Let’s look at the pressure under 3000m of ice (~10000ft). For the sake of keeping calculations simple but within an order of magnitude, let the density of the ice be 1000 Kg per cubic meter. The pressure under this ice is 2.94×10^7 Pa, or 29.4 MPa [3000m*1000(Kg/m^2)*9.8(m/s^2) / 1 m^2].
On the site you linked, there is a nice diagram of melting temperature versus pressure for ice: http://www1.lsbu.ac.uk/water/explan2.html#Pmelt
So, under the Antarctic ice, at its thickest, a pressure of ~30MPa yields a melting point of -3C. It clearly has to be close to the melting point at STP in order for liquid water to exist under the ice. Indeed, in the under-ice lake, Lake Vostok, the temperature is around -3C, warmer than the surface, and this is in fact due to geothermal heat flux and the insulating property of the ice sheet (http://en.wikipedia.org/wiki/Lake_Vostok I have no shame linking to Wikipedia for basic information).
KADAKA said:
“So, not only have certain people been arguing the ice just flows down a slope, because the temperatures at the bottom are high enough to melt the ice where it contacts the ground (but didn’t know enough to consider the incredible pressure from all that ice could result in liquid water without temperature-based melting),”
No, what has happened is that you have thrown out a concept without even using a back-of-the-envelope calculation to see if it is valid. I very well understand pressure melting – I just understand that it doesn’t appreciably affect the melting point under an ice sheet.
KADAKA said:
“but they are also arguing the ice will just slide uphill to do so, sliding upwards thousands of feet, with deformation of the ice not that important compared to the sliding.”
You can construct all sorts of arguments and attribute them to me, what you quoted was me discussing ice streams (http://en.wikipedia.org/wiki/Ice_stream#cite_note-BAS2009-2 for basic information). These do indeed slide on their bed, and slide faster on soft sediments near the coast. If you disagree, I suggest picking up a basic glaciology textbook, like Physics of Glaciers. Or, you can hike out to Antarctica, and see the ice streams supplying the ice shelves with ice. I mean, I’m not sure what you’re arguing: that the Antarctic ice sheet is static, and does not have streams of ice?
KADAKA said:
“Gee I wonder, if the ice is sliding away along the bottom and can move so quickly to the sea, where did that ancient ice they found in the ice cores come from? Wouldn’t all that old bottom ice have slid away ages ago?”
Exactly, which is one reason why ice cores used for paleoclimate reconstruction are drilled in regions with near-zero velocity ice, of which, there are numerous locations in Antarctica: http://upload.wikimedia.org/wikipedia/commons/thumb/d/d3/Bambervelocity.jpg/250px-Bambervelocity.jpg
Chris Noble,
Did they move the Antarctic Peninsula to East Antarctica?
Chris Noble says:
Your belief appears to be that the flow rate of a glacier, which may be hundreds of miles long, is a function of the calving of the glacier at its ocean terminus.
That is preposterous.
This may help …… http://lima.nasa.gov/img/rignot_basins.tif
Flow rates from zero to 1.5 km/year. Flow follows topography as expected but there is plenty of blue (zero).
Nick Davis Reur July 1, 2010 at 9:10 am
Please refer to this analysis of Jakobshavn glacier, and you should find that your statement is rather simplistic, and probably based on speculation and over assertion. Note that this famous glacier emerges from a large ice cap through an opening in mountains around the rim of the island. Furthermore, that the ground-line is predominantly uphill from the interior towards the coastal mountains. (the central regions are way-way below sea-level). If you look carefully, you can see striations in the ice surface that clearly show ice creeping around from the NNW and from the SE directions, because of the obstruction from the mountains. Notice too, that the retreat rate is puzzlingly erratic and is definitely NOT related to NH average temperature.
This image shows the striations more clearly.
Here is a larger version of the first image if necessary on your system.
Smokey
Due to the principle of conservation of mass, the average flow rate at the beginning of the glacier has to be equal to the average flow rate at the end (minus evaporation and melting.)
My objection is that a change in the rate of calving would not propagate upstream to the head of a 750km long glacier for a very long time.
“My objection is that a change in the rate of calving would not propagate upstream to the head of a 750km long glacier for a very long time.”
If you actually read the paper you pretend to critique then you would see that all of the areas that they argue are showing accelerated mass loss in the Antarctic are near the coast.
“Did they move the Antarctic Peninsula to East Antarctica?”
[SNIP]