Guest Post by Willis Eschenbach
This topic is a particular peeve of mine, so I hope I will be forgiven if I wax wroth.
There is a most marvelous piece of technology called the GRACE satellites, which stands for the Gravity Recovery and Climate Experiment. It is composed of two satellites flying in formation. Measuring the distance between the two satellites to the nearest micron (a hundredth of the width of a hair) allows us to calculate the weight of things on the earth very accurately.
One of the things that the GRACE satellites have allowed us to calculate is the ice loss from the Greenland Ice Cap. There is a new article about the Greenland results called Weighing Greenland.
Figure 1. The two GRACE satellites flying in tandem, and constantly measuring the distance between them.
So, what’s not to like about the article?
Well, the article opens by saying:
Scott Luthcke weighs Greenland — every 10 days. And the island has been losing weight, an average of 183 gigatons (or 200 cubic kilometers) — in ice — annually during the past six years. That’s one third the volume of water in Lake Erie every year. Greenland’s shrinking ice sheet offers some of the most powerful evidence of global warming.
Now, that sounds pretty scary, it’s losing a third of the volume of Lake Erie every year. Can’t have that.
But what does that volume, a third of Lake Erie, really mean? We could also say that it’s 80 million Olympic swimming pools, or 400 times the volume of Sydney Harbor, or about the same volume as the known world oil reserves. Or we could say the ice loss is 550 times the weight of all humans on the Earth, or the weight of 31,000 Great Pyramids … but we’re getting no closer to understanding what that ice loss means.
To understand what it means, there is only one thing to which we should compare the ice loss, and that is the ice volume of the Greenland Ice Cap itself. So how many cubic kilometres of ice are sitting up there on Greenland?
My favorite reference for these kinds of questions is the Physics Factbook, because rather than give just one number, they give a variety of answers from different authors. In this case I went to the page on Polar Ice Caps. It gives the following answers:
Spaulding & Markowitz, Heath Earth Science. Heath, 1994: 195. says less than 5.1 million cubic kilometres (often written as “km^3”).
“Greenland.” World Book Encyclopedia. Chicago: World Book, 1999: 325 says 2.8 million km^3.
Satellite Image Atlas of Glaciers of the World. US Geological Survey (USGS) says 2.6 million km^3.
Schultz, Gwen. Ice Age Lost. 1974. 232, 75. also says 2.6 million km^3.
Denmark/Greenland. Greenland Tourism. Danish Tourist Board says less than 5.5 million km^3.
Which of these should we choose? Well, the two larger figures both say “less than”, so they are upper limits. The Physics Factbook says “From my research, I have found different values for the volume of the polar ice caps. … For Greenland, it is approximately 3,000,000 km^3.” Of course, we would have to say that there is an error in that figure, likely on the order of ± 0.4 million km^3 or so.
So now we have something to which we can compare our one-third of Lake Erie or 400 Sidney Harbors or 550 times the weight of the global population. And when we do so, we find that the annual loss is around 200 km^3 lost annually out of some 3,000,000 km^3 total. This means that Greenland is losing about 0.007% of its total mass every year … seven thousandths of one percent lost annually, be still, my beating heart …
And if that terrifying rate of loss continues unabated, of course, it will all be gone in a mere 15,000 years.
That’s my pet peeve, that numbers are being presented in the most frightening way possible. The loss of 200 km^3 of ice per year is not “some of the most powerful evidence of global warming”, that’s hyperbole. It is a trivial change in a huge block of ice.
And what about the errors in the measurements? We know that the error in the Greenland Ice Cap is on the order of 0.4 million km^3. How about the error in the GRACE measurements? This reference indicates that there is about a ± 10% error in the GRACE Greenland estimates. How does that affect our numbers?
Well, if we take the small estimate of ice cap volume, and the large estimate of loss, we get 220 km^3 lost annually / 2,600,000 km^3 total. This is an annual loss of 0.008%, and a time to total loss of 12,000 years.
Going the other way, we get 180 km^3 lost annually / 3,400,000 km^3 total. This is an annual loss of 0.005%, and a time to total loss of 19,000 years.
It is always important to include the errors in the calculation, to see if they make a significant difference in the result. In this case they happen to not make much difference, but each case is different.
That’s what angrifies my blood mightily, meaningless numbers with no errors presented for maximum shock value. Looking at the real measure, we find that Greenland is losing around 0.005% — 0.008% of its ice annually, and if that rate continues, since this is May 23rd, 2010, the Greenland Ice Cap will disappear entirely somewhere between the year 14010 and the year 21010 … on May 23rd …
So the next time you read something that breathlessly says …
“If this activity in northwest Greenland continues and really accelerates some of the major glaciers in the area — like the Humboldt Glacier and the Peterman Glacier — Greenland’s total ice loss could easily be increased by an additional 50 to 100 cubic kilometers (12 to 24 cubic miles) within a few years”
… you can say “Well, if it does increase by the larger estimate of 100 cubic km per year, and that’s a big if since the scientists are just guessing, that would increase the loss from 0.007% per year to around 0.010% per year, meaning that the Greenland Ice Cap would only last until May 23rd, 12010.”
Finally, the original article that got my blood boiling finishes as follows:
The good news for Luthcke is that a separate team using an entirely different method has come up with measurements of Greenland’s melting ice that, he says, are almost identical to his GRACE data. The bad news, of course, is that both sets of measurements make it all the more certain that Greenland’s ice is melting faster than anyone expected.
Oh, please, spare me. As the article points out, we’ve only been measuring Greenland ice using the GRACE satellites for six years now. How could anyone have “expected” anything? What, were they expecting a loss of 0.003% or something? And how is a Greenland ice loss of seven thousandths of one percent per year “bad news”? Grrrr …
I’ll stop here, as I can feel my blood pressure rising again. And as this is a family blog, I don’t want to revert to being the un-reformed cowboy I was in my youth, because if I did I’d start needlessly but imaginatively and loudly speculating on the ancestry, personal habits, and sexual malpractices of the author of said article … instead, I’m going to go drink a Corona beer and reflect on the strange vagaries of human beings, who always seem to want to read “bad news”.
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” Ed MacAulay says:
May 23, 2010 at 4:41 am
The logical next step is to consider if the land is rising, what is dropping? If the ocean floor is subsiding then are we in danger of lower sea levels?”
Let’s see:
“Now, scientists at the University of Miami say Greenland’s ice is melting so quickly that the land underneath is rising at an accelerated pace.
Some coastal areas are going up by nearly 1 inch per year, the scientists announced today. If current trends continue, that could accelerate to as much as 2 inches per year by 2025, said Tim Dixon, professor of geophysics at the University of Miami Rosenstiel School of Marine and Atmospheric Science (RSMAS) and principal investigator of the study. ”
1 inch, rising to 2 inches in 2025? Say we have a 0.07 inch rise in on the base rise of 1 inch per day, starting at 2010 with 1 inch, then ending at 2011 with 2 inches. That’s 23.8 inches (57cm) in all.
Willis, could you run the figures for our entertainment please?
Maybe the planet’s core is just a giant marshmallow which will expand to eventually turn the place into a proper flat earth, if only given enough time and research grants… ;-D
Willis:
Gets us right back to the “Medieval Warm Period” again! Take a look at this :
http://www.archaeology.org/online/features/greenland/
Great write up on the Viking settlements. We have to ask: What trends were in the ice cap +/- 200 years of their arrival and their leaving?
Perhaps somewhat unrelated but in the long run appropriate – NASA’s World Wind 1.4 currently shows a Northern Hemisphere which has about 50% of the winter peak snow coverage still in place. It’s a rather stunning graphic presentation of the best sattellite views, I recommend it highly.
Frank K. says: “– remember the cardinal rule of Climate “Science” research:
“Bad News” for the climate = Good News for my research budget!”
And remember the cardinal rule for tabloid science – all news is bad news:
Getting warmer: BAD
Getting colder: BAD
More rain: BAD
Less rain: BAD
More wind: BAD
Less wind: BAD
Species spread: BAD
Species contract: BAD
Earlier spring: BAD
Later spring: BAD
Mild winter: BAD
Cold winter: BAD
And it is all caused by Man-made Global Warming. If only things would go back to the way they used to be when there were no storms anywhere, no droughts anywhere, no floods and no gales etc etc.
Greenland icecap melting at this rate yields sea level rise of about .59mm / year or just over 2″ by the turn of the century. I believe that’s the way to look at it, not how long it will take to disappear. Is my math right?
toby says:
May 23, 2010 at 1:39 am
“Of course it is only six years of evidence, but taken with all the other peices of evidence, it IS bad news. Like this:”
The oceans stopped warming in 2006. There was a big jump when the Argo floats were first installed then nothing since. There has been a lot of discussion of how much of the jump that occurred when the Argo floats were installed was ‘calibration’ and how much was ‘actual heat’. The article you linked to tries to resolve that question.
It does not address the question as to ‘why haven’t the oceans warmed since 2006’.
Even if I ignore the ‘oceans stopped warming’ problem, the .64 watts/m^2 warming in the oceans isn’t put into perspective. It doesn’t provide any evidence that things are worse then we thought. It does provide evidence that things are a lot better then worst case scenario’s.
Driven by nonsense … forced by the sun.
It’s like the a degree or two of temperature change, related to what, or the 20 foot sea rise, related to what, engineers would see this in the scheme of things as noting more than relative error factor. For instance the seas go up and down 400 feet each way, so 20 feet, or is it more generally accepted now to be measured in centimeters, or millimeters, this is nothing more than rounding error.
After all, how does one actually measure sea level world wide. or for that matter, temperature world wide with any accuracy, say 1000 years ago. The best I can do is when grapes grow once more in England, it would be about as warm as it were when the Vikings were farming Greenland.
All at best — A good guess.
Great post on the truth behind the numbers. The more the careful reader runs into this style of exaggeration the more skeptical one becomes of the thesis that proponents wish so desperately to be true.
To Willis Eschenbach : I have translated this article into French and published it here : http://www.contrepoints.org/C-est-grand-comment.html
with a view to spreading the word.
If you don’t agree with this, please let me know and I’ll take it off line.
Feel free, of course, to use this translation for whatever purpose you see fit.
First error: It’s LIME not lemon!
Next point: 6 years of data is one small section of a noise spike compared to the 12,000 year stretch of the melting of Greenland.
Third: If you went back in time 12,000 years, was there twice as much ice as there is now? If yes, then “move along, nothing to see here”, all is normal.
When I read in Sky&Telescope magazine, a few years back , that the GRACE satellites have detected “accelerating ice loss in Geenland” I asked them (besides the data) if that had anything to do with the accelerating expansion of the universe. They never answer. I since stoped my decades long subscription.
Let’s get US Representative Hank Johnson (4th Congressional District, GA) on the horn and have him issue a press release saying the loss of weight on Greenland is a good thing. Hank had this to say about Guam:
I was afraid if Greenland’s ice kept getting bigger the whole island would capsize! So this is great news.
It’s also a bit silly to take a six-year period andthink that it says anything about longer-term trends. The amount of ice is a function of temperature, precipitation, cloud cover, windspeed and no doubt other factors. Those factors vary in non-linear ways. A six-year slice, whether it is a loss or accumulation, says nothing about where things wil be a 100 or 1,000 years from now.
It’s equivalent to thinking that a linear extrapolation of six days of stock price activity says anything about the price of that stock a year from now.
>> Willis Eschenbach says:
May 23, 2010 at 3:35 am
The corresponding rule for climate papers is “Any study with the word “Robust” in the title of the study … isn’t”. <<
Willis, you are wrong about this. In climate science the word 'robust' is a polite synonym for 'bull****', and the authors were just being honest about their work.
Catastrophic AGW (CAGW) is a social movement, not a science based movement.
CAGW reflects the biases and social needs of its believers. Any similarity between it and the science of climate is accidental.
Thanks Willis. I will spread this far and wide among my overly concerned friends.
I just thought of another good thing. If Greenland was getting heavier it would be putting more pressure on the liquid mantle underneath it. This in turn would put a greater pressure on the magma underlying nearby Iceland. Connect the dots, folks! Less ice on Greenland means less active volcanism in Iceland. Hurray!!!!!!
How come the so-called scientists never think these things through?
One of the more interesting facts I have found is the rags to riches stories behind some of the big players in “Global Warming” If you have done even the most minor internet searches on Maurice Strong you will find. Strong ”grew up in a poor family in a small town in Manitoba during the Great Depression.” You will also find Strong’s various brushes with litigation due to unethical behavior. Now of course he is a multi-billionaire. I mentioned San Greenberg in the above comment . Again we see a rags to riches story. One wonders if our beloved Mike Mann, Gavin Schmidt, Phi Jones and the other core players also have “rags to riches” stories as well as well padded swiss bank accounts. Or are they just foot soldiers – useful idiots. Another commenter recently mentioned Mann was having problems with his PhD thesis until he switched thesis advisors and was suddenly fast tracked. His thesis was on oceans not trees by the by.
Here is more on Stan Greenburg & Friends
Weathiest Members Of Congress
“John Kerry (D) $900 Million
Herb Kohl (D) $315 Million
Jay Rockefeller (D) $275 Million
Nancey Pelosi (D) $268 Million
Moving up fast……
The Clintons amassed nearly $169 million in the past 10 years of “public service”.
But the entry that really sent my Democratic strategist friend ballistic was the one for Rep. Rosa DeLauro, the Connecticut Democrat. La Rosa–tied for #48 on the Richest list–gets the lion’s share of her wealth from her husband–Clintonista pollster and campaign strategist Stan Greenberg. Says Roll Call, “DeLauro’s primary asset is a 67-percent stake in Greenberg Quinlan Rosner Research Inc., a Washington-based firm run by her husband, Democratic pollster Stan Greenberg. Her share in the company nets the Representative $5 million to $25 million. She has a partial stake in two other polling/consulting firms. The first is Greenberg Research, of which she and her husband own 100 percent, and Sun Surveys, in which she owns a 60 percent stake. Neither of these is as lucrative as Greenberg Quinlan Rosner, however.”
My bud the political warhorse snorted, “Hell, when she first ran for Congress she didn’t have a dime–I was one of her biggest contributors. And Stan Greenberg, who worked for me back when he was starting out, used to have holes in his socks!” Noting that Congressional wealth is usually closer to the higher than to the lower estimates on the disclosure forms, my dour Democrat gasped, “That means they’re making around $50 million! These people shouldn’t be running Democratic campaigns!”
So, if you want to know why the national Democrats seem, in this campaign, to have a tin ear where touching the hearts and minds of the working stiffs is concerned, think about this: the three partners in the Democracy Corps–Greenberg, James Carville, and Kerry’s chief message-shaper Bob Shrum–are all multimillionaires. And yet their counsel–proferred in an endless series of free Democracy Corps memos distributed to the party elite well before and during the presidential primaries, whose content (or lack of it) they helped shape–is taken as gospel by Democratic liberals feverish for victory. Well, as the old Texas populist Maury Maverick Jr. used to say, “a liberal is a power junkie without the power.”
I wonder where those millions amassed “during public service” came from, don’t you???
Wiillis, as long as you are getting outraged, read the article on “Polar Meltdown” on page 45 of the new issue of “Scientific American” . You would think some people would be ashamed of what they write, but there’s no evidence of that.
Thanks for the analysis. Please keep it up.
Are there any estimates of the amount of ice that normally melts in a year at the edges versus the amount of new snow added in a year at the interior? I wonder how that figure compares with the “third of Lake Erie” number. By the way, let’s also not forget that whoever chose Lake Erie, chose the shallowest of the great lakes
http://mff.dsisd.net/mff/Images/GreatLakeProfiles2.jpg
LA fishermen contemplate suicide, wow.
http://www.neworleans.com/index.php?option=com_content&view=article&id=399556&Itemid=2603
More prime fishing grounds closed:
http://www.nola.com/news/gulf-oil-spill/index.ssf/2010/05/state_closes_southern_portion.html
Russians recommend a nuclear bomb to stop the spill:
http://www.csmonitor.com/Science/2010/0513/Why-don-t-we-just-drop-a-nuclear-bomb-on-the-Gulf-oil-spill
And we don’t know jack about what is going on under the surface:
http://www.nytimes.com/2010/05/20/science/earth/20noaa.html
Any ideas on whether a hurricane will help or hurt?
@hunter
re; CAGW is social movement
I agree. The individual CAGW pundit is a pusillanimous pussyfooter. Collectively they become a nattering nabobery of negativism.
RIP Bill Safire. You’re gone but not forgotten.
As I’ve said before, this type of alarmism by “scientists” is tantamount to waking up one morning, discover it’s raining, see that it rains for two more hours, and concluding that the world will be flooded within weeks.
Willis Eschenbach says: May 23, 2010 at 2:43 am
“It is measuring the weight of the ice. As such, the isostatic rebound doesn’t affect the answer, because although the underlying rock moves vertically, the weight of it doesn’t change.”
Not quite.
They actually measure the change in acceleration between the two satellites and use that to infer a change in gravitational pull in the area under the leading satellites (after the trailing satellite has seen the same change, the affect becomes the common frame of reference).
If the height of the mass (the ice and mountains) ice was to remain constant; and the density of rock is greater than ice; and if gravity has an inverse square relationship of the force affect between the source and the observer; then the isostatic rebound would actually hide a small amount of ice loss.
So event this ‘simple’ measurement contain more error factors then indicated. Without knowing the actual contour of the underlying rock and the geology of the islands shelf and the rebound rate relative to the observers the measurements are not much better then a guess.
The satellites were designed to measure underground aquifers; water contained in porous rock; in large stable land masses (central USA and California) and re-purposing them to measure a dynamic system in uplift is like using the bulb of a mercury thermometer as a carpenter’s level. Close but not right.
With all this accelerated ice-sheet melting and all this accelerated land rebound from the loss of ice as measured by the Grace satellites, …
… pretty soon, there will be an acceleration in sea level rise.
http://www.aviso.oceanobs.com/fileadmin/images/news/indic/msl/MSL_Serie_MERGED_Global_IB_RWT_NoGIA_NoAdjust.gif
If loss of such an insignificant proportion of the Greenland ice sheet is some of the “most powerful evidence of global warming”, then even though we thought it was bad, the hyperbole “is worse than we thought”.
The biggest long term issue this throws up is that global warming may not be enough to prevent the onset of the next ice age.