Guest Post by Willis Eschenbach
I came across this beautiful example of chartsmanship today in a Chris Mooney post of raw, pure, visceral alarmism, it’s a gem. It’s from the Mother Jones website and comes with the lovely headline “Humans Have Already Set in Motion 69 Feet of Sea Level Rise”. I do love the claims that something is “set in motion”, it’s scientific cowardice to make that claim, it’s totally impossible to falsify. I could claim that Vladimir Putin has “already set in motion” the next financial meltdown … could you falsify my claim? In any case, Mooney’s post shows the terribly worrying loss of ice from Greenland, from a study by Jason Box
Figure 1. Cumulative loss of ice area in Greenland. As you can see, Greenland is toast … it’s losing well over a hundred square kilometres of ice per year, and the chart shows it heading to the cellar, looks like a total meltdown coming up.
So … what actually is happening with Greenland? To figure that out, we need another chart, the real chart—the chart of the post 2000 ice loss, and what might happen over say the next century if it continues losing over a hundred cubic kilometres of ice per year.
To do that, we have to start by finding out the area of the ice sheet that covers Greenland. As usual, there are various estimates. The Physics Hypertextbook is great for this kind of thing because it gives a variety of estimates from various authors. They range from a low end of 1.7 million square kilometres to a high of 2.2 million square km. I’ll take an average of 1.9 million square km.
So … here is the effect on the Greenland ice cap that a continued loss of -131.5 km2 per year every year until 2100 would have:
Figure 2. Effect of -131.5 km2/yr ice loss on the ≈ two million square kilometres of the Greenland ice cap.
Pretty scary, huh? By the year 2100, if it continues losing ice at the rate Jason Box claims above, -131.5 km2 per year, the total ice area of Greenland will have gone from 1.90 million square km all the way down to … well, to two decimals of accuracy, by the year 2100 the ice will be down to 1.90 million square kilometres …
Gotta love those charts … in any case, let us consider the headline, “Humans Have Already Set in Motion 69 Feet of Sea Level Rise”. I suppose it is true IF we are the cause and IF the decline continues, both of which seem doubtful. Assuming all that were true, at the current rate of -131.5 km2 of ice loss per year, Greenland will be ice-free fairly soon, in only … well … 1,900,000 km2 ice area / 131.5 km2 per year annual loss ≈ 14,500 years from now …
Rats … I guess it’s a bit early to be looking for a nice piece of land for my Greenland vineyard …
w.
[UPDATE] Well, it is inevitably true that what I think is clear actually isn’t … no surprise there. From the comments:
Kasuha says:
February 7, 2013 at 8:28 am
Um, you know… “Greenland marine-terminating glacier area changes” and “cumulative loss of ice area in Greenland” are two a bit different things. Or rather, very different things.
Maybe you should take one more look at what exactly are you doing here.
I completely agree with the conclusion that the alarmism is unsubstantiated in this case. But the way you used to get there is not valid.
I agree with you, Kasuha, that “Greenland marine-terminating glacier area changes” and “cumulative loss of ice area in Greenland” are two very different things. That’s the problem. Mooney is using a chart of the changes in the area of the discharge of the Greenland ice into the ocean as the screaming visual for a claim that we’ve set in motion a 69 foot sea level rise … and the two have absolutely nothing to do with each other.
I didn’t know how to best discuss that kind of lunacy, so I took the path of saying well, suppose Boxes’ results were correct and it actually made a difference regarding the ice area, what difference would it make? I was not attempting to model the entire ice loss of Greenland, as I’ve been through that question in some detail already …
Perhaps there are better ways to get the point across, as you point out … that’s the one I picked.
Thanks,
w.
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What about the Arctic sea ice..? Wasn’t that melting at ‘astonishing speed’ last September, according to the BBC’s Environment Correspondent, David Shukman…?
But wait – its re-frozen back right smack in the middle of the average for the last few years…
(Source: the same satellite-based graphs which identified the melting)…
Don’t you just hate it when someone switches the alarm off..??
Pretty complete story here in AirSpacemag … http://www.airspacemag.com/history-of-flight/FEATURE-glaciergirl-backstory.html?c=y&story=fullstory
Coupla interesting points:
Very interesting comment on the page by one Forrest Shafer explaining the nature of the glacier at that point.:
k scott denison says:
February 7, 2013 at 4:38 pm
—
Enough snow to create 268 feet of ice.
The weight of that snow pushed some of the ice in the basin out into the glacier, allowing the newer snow and ice to settle.
There is already a satirical response to chartmanship:
http://www.speld.nl/2013/01/31/februari-krimpt-significant-in-laatste-voorspelling/
peter laux says:
February 8, 2013 at 3:29 am
—
Your reference to layers is not relevant. As everybody has conceeded that it has snowed in Greenland since the planes landed there.
Nobody claimed that the planes “sunk” into the ice. The ice accumulated around the planes, then was pushed down by the weight of the accumulating snow/ice. The plane and the ice immediately around it were pushed down as the ice lower in the pack was squeezed out to form the glacier.
Pretty complete story here in AirSpacemag re Glacier Girl P38… http://www.airspacemag.com/history-of-flight/FEATURE-glaciergirl-backstory.html?c=y&story=fullstory
Coupla interesting points:
Very interesting comment on the page by one Forrest Shafer explaining the nature of the glacier at that point.:
mods .. sorry pls check for multiple postings ..they are vanishing into the ether………
To David:
Others have pointed out up-thread that the Arctic sea ice could melt entirely
with not effect at all on sea level, since the Arctic ice pack is floating. Ice
weighs less than the water it displaces, so melting the entire Arctic sea
ice pack would actually cause the worldwide sea level to go down very
slightly.
A more important concern is that the vanished ice would cause the albedo
of the Arctic to change, thus allowing more energy to be absorbed. Since
the Sun angle is never huge in the Arctic, this may turn out to be not a big
deal.
I do not even know how I ended up here, but I thought this post was great. I do not know who you are but definitely you’re going to a famous blogger if you are not already 😉 Cheers!|
Hallelujah — Willis — Thank you for using the word chartmanship. Thanks also for posting the first order chart.
I worked for a newspaper awhile back. I could use a computer and make spreadsheets work. We charted the circulation. I plotted the raw circulation number. My boss didn’t like the look of the chart. Circulation was dropping. We had another metric we tracked. The difference between this weeks circulation and last weeks circulation. We yet another metric that compared this years week-to-week difference to last years week-to-week difference. That number was getting smaller. It was still negative.
I protested, but I was overruled. We plotted that number. I sat at the front of the company and put the slides up on the overhead. “Look,” said the president,” things are getting better.”
I tried to explain that this was a 3rd order chart, but it fell on deaf ears.
Things were still getting worse, they were just getting worse a little more slowly.
2nd and 3rd order analysis IS worth doing. Anyone doing it though needs to keep the first order chart pasted in front of them. Anyone not keeping that 1st order chart in front of them is a bloody fool. Sadly, we have lots of people committing chartmanship fouls. They exist on both sides of this debate.
As Dr. Brignell (who might have coined the term chartmanship) points out, the greatest danger of chartmanship is fooling yourself. We are all susceptible to missing the effect of chartmanship.
Those who haven’t read about it should go http://www.numberwatch.co.uk/chartmanship.htm
Willis — you are guilty of a minor sin of chartmanship yourself. You put images behind your charts. You do it for decorative purposes. I understand. It is just one of the things that makes me put on my BS Boots….
hamblinart.com says:
February 8, 2013 at 12:08 pm
You are welcome. I prefer to start with an overview chart that starts at zero, I guess you call it a “first order chart”, it reveals things that detailed charts don’t show.
Actually, as usual, my motive are misunderstood. I have learned to my cost how hard it is to say why another man makes the choices he makes. Mostly I’ve given up trying. As an example of why, let me tell you how far from reality is your assumption that I put images behind my charts for “decorative purposes”.
First, I would say I do it for artistic purposes rather than decorative purposes. I am a graphic artist of some skill, and I see no reason why a scientific chart can’t also be lovely. I want to create enduring works of scientific art representing my best scientific knowledge at that instant, and I think I’ve been successful to some degree.
Second, I do it to provide a visual image of the subject matter to serve as an anchor for their ideation. If it were mere decoration I could use some random image, but I am trying to bring concreteness to intangible numbers. I pick the image to provide a framework for their conception. I want the person to see the ice core drilling machinery in the background as they contemplate the ice core CO2 records. It gives a physical solidity to an abstract “line on a page”.
Third, I make my charts in a distinctively consistent manner, because it lets people recognize the authorship of a chart of mine that they’ve never seen before … I might describe it as brand differentiation in a very crowded marketplace of scientific ideas. Now, that’s certainly not the way I conceptualized what I was doing when I started writing for the web. But I rapidly found out that in the incessant hubbub and boil of all the folks on the internet, I needed to make my own voice clearly recognizable. As a result, the style of my writings and the look of my graphics and the fact that I sign everything that I write with my mark of “w.” are deliberate choices, designed to ensure that I have a recognizable, distinguishable, and unique voice in the swirling maelstrom of ideas and memes and science and urban legend that is the internet …
And this is why guessing why another man has done something is is a mug’s game. As in this case, the reasons he puts images on his charts may not only be reasons you did not consider. Indeed, they may be way outside of anything you might have ever considered … I’m not saying this as implying that what you consider is faulty or limited, I don’t mean that. I mean that one man’s mind and his reasons are an eternal mystery to any other man, no matter how insightful.
My thanks,
w.
markx says:
Good posts! Thanks for the info.
MarkW, I find your explanation is still unsatisfactory. MarkX’s account by “Forrest Schafer” however makes better sense but is still totally unsatisfactory and to digress, with his opening mention of “global warming’ , makes me immediately askance.
In regard to his explanation , why would just the plane sink, with or without “overburden” ?
Why not the ice next to it, for after all the density of the plane, being hollow would have less density and be far lighter than the ice. (If it landed on water and was airtight it would happily float.)
Snow “overburden” would not discriminate between ice and plane, so why would it just “force” the plane down and not the ice?
In regard to this “temperate, watery glacier” that Forrest Schafer claims the P-38 sat on,this again makes little sense – if it were, the plane, if was singled out by “overburden snow” and forced downwards would have filled with this water and the excavators would have found the plane filled with ice – from the accounts i’ve read, they did not.
But my original point remains unchallenged and correct – “no need to worry about melting if Greenland keeps accumulating height in ice.”, as after inquiry you have found out. (It will also be depressing the land mass beneath.)
As has already been pointed out by MarkX, he area of Glacier Girl will also accumulate far more snow than Central Greenland because of its proximity to the coast.
peter laux says: February 8, 2013 at 8:38 pm
“…. account by “Forrest Schafer”..”
I agree there are a couple of troubling things about Schafer’s account:
1. As you pointed out his initial mention of his global warming viewpoint.
2. He is/was a “ground probing radar geologist”… which does not mean he is necessarily a “glacier expert”.
3. This point 2. leads perhaps to an apparent contradiction: ….A. “…In a temperate glacier the temperature is at the pressure melting point throughout the entire ice body except for the upper few meters of ice…”. B. …”.it’s a Warm-based Glaciers: Warm based glaciers are at the pressure melting point at their bed…”
From …. bw: February 7, 2013 at 8:52 pm
“…….map of Greenland showing position of crash site, southeast coast of Greenland. http://p38assn.org/glacier-girl.htm…”
Looks like it might be the Kangerlussuaq Gletscher (Glacier) … seen here in lovely detail (satellite photos …zoom in) … It is quite a complicated glacier accumulating snow/ice from all directions. http://mapcarta.com/19190872
It is quite conceivable to me that as ice flows from wide to narrow areas, what was on top in one place may go under in another.
However, we can speculate forever not knowing the exact position the planes were in, or the flow characteristics in that position.
It seems to me (and to most, I guess) that there has been one helluva lot (well known empirical unit) of precipitation in that area, but the only important detail is whether more ice is accumulating than is being lost. There are plenty of publications telling us there is at this time a nett loss from many, but not all the Greenland glaciers. How true that is I do not know.
It seems GRACE satellite was going to differentiate between the uplift (current opinion seems to be that Greenland is rising) of the mantle and the accumulation of ice, but given the paucity of publication on the topic and the few publication discussing “problems with GRACE” the answers may not be as clear as some ‘pessimists’ had expected.
Peter laux, as the account of Glacier Girl you refer to makes clear, the plane and its surrounding ice has slid 2 miles downslope since the landing.