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.
I gave you a reference that indeed shows that the flow rate of glaciers increased when when the Larsen B ice shelf collapsed.
Reality does not care what you believe to be preposterous.
Steve:
“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 ever.
It seems that topography, elevation, the triple point of water, and precipitation at higher altitudes must all have a measurable effect on a glacier’s flow rate. But calving at the terminus? Not so much.
Out of the planet’s ≈160,000 glaciers, many of them enter the ocean as an ice shelf, and do not immediately calve. What then? Does the flow stop? I’m not a glacier expert, but it seems that of all the factors influencing glacier flow, surely the very least important — if it affects the speed at all — is calving into icebergs at sea level.
Also, regarding the question of mass conservation, it seems that since a glacier can expand and contract at various points [since it isn’t flowing through a pipe], calving would have even less effect at the source. If there is any measurable effect at all, which I still question — particularly as it applies to Chris Noble’s assumption regarding the primary influence of calving on a glacier’s flow speed.
Chris Noble
Their map shows an area of ice loss at high elevation more than 700km from the coast.
Smokey, obviously you are not a glacier expert. You don’t understand that glaciers are constantly flowing. And they can speed up or slow down depending on a number of factors. There are many Antarctic studies in recent years (and in Greenland) looking at the various factors contributing to enhanced glacier flow at some of the outlet glaciers. In Greenland one of the major mechanisms under evaluation is the percolation of melt water on the surface to lubricate the bedrock and speed glacier flow. In Antarctica as we know it’s too cold to melt (except on the Antarctic Peninsula), and so a lot of studies are looking at changes in acceleration of glaciers that happens when say sea ice is removed, or an ice shelf collapses. This is because that ice acts like a dam holding back the glacier. When the dam breaks, the glacier speeds up. In Antarctica calving is the major form of ice loss (not surface melt).
I still haven’t gotten an answer to my question, so I’ll ask it again in a different way.
The GRACE data shows changes in the mass well away from the Antarctic shore. Now, a lump of floating ice displaces an amount of water that is equal to its mass. So whether there is ice or not, there is no change in the amount of mass at that spot.
So how come GRACE is finding a change in the mass way out in the ocean???
w.
Chris Noble says:
July 1, 2010 at 4:21 pm
“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.
—…—…
Gee. That’s funny.
See, Hansen’s entire premis is that the entire Antarctic ice shield (interior and coastal) ice MUST melt (OK – sublime) in only a few years in order to “raise sea levels” by the amount he needs to create enough fear to pass Obama’s 1.3 trillion dollar tax proposal.
But here you claim that onl;y a few (short range/small distance) glaciers near the caost are what is being studied. Are what are calving at the edges. Are what are losing mass. Gee.
Now, Tell me exactly how a local coastal calving affects a 1200 km long mid-continent glacier mass that is NOT resting precariously on hidden lakes of water just waiting to slip out from underneath. Hansen is claiming that the entire ice mass will “melt” (OK – sublime) and will cause catastrophic sea level rises. His math fails. Your assumptions of ice movement fail.
The satellite is said to show interior ice loss, is claimed to correct for land rebound, is claimed to correct for geode effects, is claimed to correct for continental drift, is claimed to correct for satellite drift … but -like Mann-made tree ring data that proved that the LIA and MWP didn’t exist – why should we believe this study?
Show me that math that an “assumed” effect (loss of 5 million kg of ice at a glacier’s edge supposedly caused by a 1/2 of one degree change in air temperature in 25 years!) physically will “move” back through real-world ice to affect glacier ice thickness 1200 km inland. Pick your fastest glacier – what: 50 km/year? A sudden increase in snow fall inland (an increase of 100 meters of snowfall over a 50 year interval) won’t affect the edge flow at the sea exit for hundreds of years.
I just followed the very interesting discussion here. I just picked out two comments with the following statements.
Jeff Brown says:
Kadaka says:
We also wonder how possibly ice can flow “upwards”, how ice can melt at such low and at times even declining temperatures.
Now, given that Grace found a decline in altitude of some areas in the West Antarctic Ice Shield and given the above-mentioned subglacial topography, I see ONE possibility what could actually happen is bottom melting owing to Ocean water seeping in through the weakening underbelly of ice shelves.
I just went to http://bobtisdale.blogspot.com/ where this graph shows the change in ocean heat content in the southern ocean. While other ocean basins are losing heat, the southern ocean was still gaining heat which peaked around 2005-2007 and since 2009.
Could it be that it could not escape because of the lid of increasing sea ice?
Heat trapped deep down there could have melted that ridge under the Pine Island Glacier and other ice streams and allowing sea water to flow far inland under the ice sheet. With much melting going on, the sea will eventually cool down and the melting (and sea level rise) will stop. What do you think?
Interesting thought, climatepatrol. Over 3 million undersea volcanoes have already been discovered — many more than on a comparable land area. More evidence that the planet warms and cools naturally, and one more nail in the coffin of the CO2=CAGW conjecture.
Oh, and jeff brown, I agree, as I said I am not a glacier expert. In fact, as I stated before your post.
Interesting thing about your post, though: you don’t admit to not being a glacier expert either. So, can we assume that you are? Or not? Which is it? Personally, I assume that you know no more about the subject than anyone else here; certainly less than the author of this article. [If you disagree, please write your own article. That would be fun!]
For example, your analogy of a “dam” holding back a glacier is simply wrong. When a glacier flows into the ocean there is no ‘dam’ effect; the ice river simply keeps flowing past the shore. Where is the ‘dam’? Can you show us?
My original post was only to point out that giving priority to the minor effect of calving [compared with precipitation at higher altitudes, etc.], while ignoring more important factors, was wrong, or at least deliberately incomplete.
If you would like to correctly prioritize the effects of various forces on glacier flow rates, maybe we will be in agreement. But singling out only one minor effect as the primary cause affecting glacier flow rates, while ignoring topography, precipitation, and other much more significant causes is somewhat duplicitous, no?
Smokey says:
July 1, 2010 at 6:33 pm
Steve:
Also, regarding the question of mass conservation, it seems that since a glacier can expand and contract at various points [since it isn’t flowing through a pipe], calving would have even less effect at the source. If there is any measurable effect at all, which I still question — particularly as it applies to Chris Noble’s assumption regarding the primary influence of calving on a glacier’s flow speed.
It’s termed ‘continuity’ in fluid mechanics, if the end of a glacier flow increases the flow of ice nearer the source must also increase or the glacier will break.
Willis Eschenbach says:
July 1, 2010 at 7:05 pm
I still haven’t gotten an answer to my question, so I’ll ask it again in a different way.
The GRACE data shows changes in the mass well away from the Antarctic shore. Now, a lump of floating ice displaces an amount of water that is equal to its mass. So whether there is ice or not, there is no change in the amount of mass at that spot.
So how come GRACE is finding a change in the mass way out in the ocean???
Collapse of the forbulge in response to the isostatic rebound.
It isn’t. This is just spatial leakage of the signal from the glaciers at the coast.
The satellite is at an altitude of about 460 km and this limits the spatial resolution to a few hundred kilometers. In addition a 300 km Gaussian filter is applied to the data.
Two main sources of error are discussed in the paper. Spatial leakage and errors in the Post Glacial rebound model. The authors do not discuss this area in detail but write “There are other inland signals above the estimated noise level which we have not included in the model. An example is the region of negative rates between Points D and C [the area you refer to]. Excluding this and similar inland regions will not strongly affect estimates of either continental total or East Antarctic rates.”
The authors are not claiming that this signal is due to acceleration of glacial flow.
Read the paper. Criticize the points made in the paper rather than straw men.
Bob from the Uk …
Don Easterbrook has posted a comment largely supporting Steve’s post.
I would be interested in hearing your opinion on his knowledge on the subject of glaciology?
Easterbrook’s comment did support “Steve’s” post, in that Easterbrook too focused on the unlikelihood of melting because Antarctic air is so cold:
Last winter, temperature at the South Pole hit -106 degrees and the last time I looked, the average annual temperature in Antarctica was -58 degrees. That means in order to melt any ice, the temperature must rise 58 + 32 degrees = 90 degrees just to get to the melting point of ice. I don’t think the Antarctic ice sheet, which is well over 10,000′ thick, is going to melt at these temperatures.
West Antarctica is surrounded by ocean water, which has warmed during the 1977-1998 warm period, and has caused minor melting, but that’s a totally different story than the main continental ice sheet which lies well to the east and shows no signs of melting.
But, as many posters have noted, neither the Chen et al. article that was the target of “Steve’s” polemic, nor the many other recent studies cited by Robert and others above, had claimed that Antarctic mass loss had much to do with surface melting. So Easterbrook’s comment raises the question of whether he, like “Steve,” had not actually read the research being criticized.
Easterbrook’s recent Heartland Institute talk stirred controversy when people looked skeptically at his graphs. For example,
http://scienceblogs.com/deltoid/2010/05/don_easterbrook_hides_the_incl.php
Phil.
It appears that you are acknowledging that the authors are confusing isostasy with ice loss. Isn’t that what this article is about?
The straw men are out in force today.
Read the paper.
http://www.nasa.gov/pdf/121653main_ScambosetalGRLPeninsulaAccel.pdf
and
I’ll let you guys fight that one out … but it does seem to reflect our lack of knowledge.
Nick Davis says:
July 1, 2010 at 1:38 pm
Anna, have you read the paper?
For the second time I repeat that I will be happy to read the full paper if somebody provides a link that is not behind a pay wall.
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.
The crux here is everything that is available .
This is the fifth time I am asking for a link of the availability of the underlying gravitational field changes due to tectonic and magma motions, as seen the the one snapshot of changes given by GRACE that I linked to above.
Lacking that real extra measurement, everything is a model output of the guess of the combination of contributions entering with an extra unknown, the intrinsic change in the gravitational field.
Indeed, and anomalies include things like atmospheric pressure variations, not just geologic processes like rebound and convective currents.
And intrinsic gravitational changes that we know are of a similar order of magnitude. which people bent on interpreting changes as ice keep ignoring.
“if all of this ice melted, it would raise global sea level by about 60 meter (197 feet).“
And if the sun quits shining tomorrow, NASA won’t have anymore play time… er, any time…
Or you could …… read the paper!
Accelerated Antarctic ice loss from satellite gravity measurements
Chris Noble
You think that statements from NASA’s top climatologist about Antarctica are off topic for an article questioning NASA’s handling of Antarctic climate information?
stevengoddard says:
July 1, 2010 at 9:07 pm
Phil.
It appears that you are acknowledging that the authors are confusing isostasy with ice loss. Isn’t that what this article is about?
No I was answering this question:
“So how come GRACE is finding a change in the mass way out in the ocean???”
Collapse of a forbulge will cause that, not the only reason of course.
BA
No matter how hard you try to ignore it, this GRACE data has been used over and over again as evidence of widespread Antarctic melting. Like this article in the Washington Post from four years ago.
http://www.washingtonpost.com/wp-dyn/content/article/2006/03/02/AR2006030201712.html
This is what Kerry and Waxman said about GRACE. I’m surprised all the GRACE apologists here didn’t rush to Washington to straighten them out.
Read the paper and supplementary material.
http://www.nature.com/ngeo/journal/v2/n12/abs/ngeo694.html
They discuss at length the sources and likely magnitudes of errors in the calculations.
Is it really too much to ask for you to read the paper and address points made in the paper rather than a series of straw men?