(Featured image borrowed from http://www.clipartbest.com)
Naturally, the Real Clear Science headline actually read…
Greenland Lost 9 Trillion Tons of Ice in Century
Which sounds even more serious than the original headline…
Greenland has lost 9,000 billion tons of ice in a century
One would think that the fact that 99.7% of Greenland’s ice sheet survived the 20th Century might just be more scientifically relevant than a 0.3% loss… But I guess that doesn’t make for a very dramatic headline.
Here’s the math…
First I converted 9 trillion tons to metric tonnes.
9,000,000,000,000 tons = 8,164,662,660,000 tonnes
Then I converted tonnes to gigatonnes.
8,164,662,660,000 tonnes = 8,165 gigatonnes
Then I converted gigatonnes of ice to cubic kilometers, assuming 1 Gt = 1 km3.
8,165 Gt ~ 8,165 km3
Note: This conversion is inexact because ice is slightly less dense than water. But it is close enough for this exercise.
Now that I roughly knew the volume of ice loss during the 20th century, I needed to know how much ice volume was still in place. I chose to rely on the USGS and their figure of 2,600,000 km3.
So now I could calculate the percentage of ice volume which survived the 20th century…
The ice volume at the onset of the 20th century should be…
2,600,000 km3 + 8,165 km3 = 2,608,165 km3
Converting to percentage surviving the 20th century…
2,600,000 km3 / 2,608,165 km3 = 0.997 = 99.7%
To put the math into perspective, I’m going to actually rely on the SkepScibots…
So, throughout the 20th century, Greenland lost about 8,165 gigatonne ice cubes. 8,165 km3 equates to a 20 km x 20 km x 20 km cube of ice (3√ 8,165 = 20.136565). That would be one big@$$ cube of ice!
However, it’s not even a tiny nick when spread out over roughly 1.7 million square kilometers of ice surface. That works out a sheet of ice about 5 meters thick.
2,600,000 km3 / 1,700,000 km2 = 1.53 km
The average thickness of the Greenland ice sheet is approximately 1.5 km (1,500 meters). 5 meters is obviously 0.3% of 1,500 meters.
From a thickness perspective, 5 meters looks like this…
The red line along the top of the cross section is approximately 5 meters thick. Here is an enlarged view…
While my math may not be exact, estimates of the volume of the Greenland ice sheet vary from 2.6 to 5.5 × 106 km3. The difference between 2.6 and 5.5 million cubic kilometers of ice is quite a bit larger than 9,000 gigatonnes. For that matter, GRACE derived estimates of recent (2003-2011) ice mass balance vary widely as do the glacial isostatic adjustments…
For the analyzed period, the ice mass balance of Greenland and the corresponding GIA correction are, respectively, − 256 ± 21 Gt yr−1 and − 3 ± 12 Gt yr−1 (1%) for SM09, − 253 ± 23 Gt yr−1 and − 6 ± 5 Gt yr−1 (2%) for AW13, and − 189 ± 27 Gt yr−1 and − 69 ± 19 Gt yr−1(36%) for Wu10 (table 1). At the regional scale, the ice mass estimates are more dependent on the GIA correction, especially in NE Greenland where the Wu10-GIA correction is the largest portion of the signal measured by GRACE (table 1).
With ~±10% margins of error in modern satellite measurements of glacial mass balance and GIA accounting for up to 1/3 of the reported ice mass loss, it is truly amazing that a 0.3% reduction in the Greenland ice sheet during the 20th century can be identified with such robustness [/Sarc].
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Nice job, Dave! Even with doubling of the error bars, your 99.7% headline is far more impressive than the 9 trillion ton loss!!!
I wonder about error bars for these estimates – or are they measurements?
If the ice loss goes on in this way we can still do with Greenland ice for more than 30.000 years. So, no reason for big worry!!
0.3% loss is practically nothing compared with historic changes the last 1000 years. What is the accuracy of the satelite measurements for comparison?
Actually it is significant to the previous 1000 years for what we can surmise from the data the original study found.
WOW! That sure beats the 97% of the scientists that believe in global warming!
Steve,
Remember that Fat Boy Kim triumphed with 99.97% of the votes eligible to be cast.
I assume most of the others contracted lead poisoning at about 1800 feet/second.
Auto
He also played a game of golf once and scored 11 holes in one . What a man !
Yeah the 97% of the few people [they] wheel out each and every time they wanna capitalise on an alarming headline of their own creation.
Well, whenever politicians want to raise my taxes (when then aren’t changing the name to “user fee”) they gone about how its “only” a cup of coffee a week, or some such minor thing. After all, I get to keep 99.7% of my current income, right?
Nicely done.
In Ontario we are not taxed. We don’t pay “user fees”. We are “revenue tools”.
I stand corrected. Do they include our rising electricity rates as a “tool”? Might just be me, but I’m pretty sure I need most of the power I use.
Wynne’s revenue tools? That’s us
Mr. Middleton,
In my opinion, this is one of the best, humble, easy to understand and informative posts of the year!
Thank you and Happy New Year!!!!!!!!!
Mr. Doyle,
I agree with you. This post speaks clearly as to the duplicity of the alarmists and their willing accomplishes in the main stream media. As they say, figures* don’t lie but liars do figures.
* And they are not willing to just lie with arithmetic, they also cook the books like religious crazy people. Looking at you Gavin.
Nice work, unfortunately the 9 trillion tons of ice loss is based on Velaconga’s calculation of isostatic adjustment. It is complete BS, because he threw out the actual GPS measurements (which show ice loss within the margin of error) and replaced them with a computer model.
Yes, I think more attention needs to be spent on how that 9 trillion tons of ice loss was estimated.
sea levels have increased 8 inches in the past century.where do all you giants of knowledge figure that water came from?
[??? .mod]
Velingonga is a “she” and her research is fine… I am just putting it into perspective.
Please provide proof the GPS readings were bad, besides her rational that they gave the wrong answer.
Reblogged this on Public Secrets and commented:
So much for the hysterical claim that the Demon CO2 was melting the Greenland ice cap. Be sure to click through: I especially like the graphic of the “lost ice cube.”
There might be an easier calculation. The article from Clear Science says that the melt over the last 115 years, caused sea levels to rise 25mm. Previous calculations state that if the Greenland ice sheet completely melted, it would add 23 ft to the sea level. 23 ft = 7010.4 mm. 25mm of sea level rise would be .357% of the total. Sounds like your calculations were pretty spot on, but you did a lot more work than you needed. 🙂
I’m not sure that sea levels are rising.
Sea Level in Alaska is decreasing. I checked sea levels in Victoria BC and they are dead flat for a century (decreasing slightly within margin of uncertainty).
However sea levels in Halifax are increasing at 33cm / century. Weird.
When you cannot raise the bridge, lower the river. Water has the tendency to occupy lowest places quite evenly, and so any discrepancy can be explained in few simple ways. The Earth moves, continental plates exhibit vertical motions a lot. and they buckle too. Quite unevenly. Gravitational measurements around the globe are quite uneven too, many gravity ‘wells’ are known. So measuring ocean water levels is a tricky business, and so we apply some great statistical tools to come up with a nice number that totally obliterates the reality, as to what is really happening.
I’m sending a copy of this article to both Senators from Michigan, and after doing a slight bit of math I deduced that one would need a mircometer to measure the change in sea level due to that ice volume.
If Greenland actually lost ice then how did those WW2 airplanes that were forced to land on it end up buried under 250 feet of ice? https://www.youtube.com/watch?v=fNEmGaAplgI
net loss. The difference between a large loss and a large gain.
Leo Smith “net loss.” I.E. Higher global temperature affected everywhere on Greenland … except wherever there’s a downed WW2 airplane?
The loss of ice is not uniform across Greenland’s ice sheet. I believe there was a pretty good discussion of this question on this site within the past couple of weeks. My understanding is that most of the ice loss occurs around the coastal areas with massive sheets sloughing off into the ocean. The accumulation of snow and ice occurs inland and slowly flows out to the perimeter. That’s why those bombers are buried under 250′ of ice? I’m sure greater minds than mine on this site can provide a more definitive answer.
kelleydr
No. The coastal mountain ranges that encircle Greenland’s central very high ice cap prevent the central ice from “getting pushed” sideways. That central ice mass – now thousands of meters thick – is trapped between very high ranges to the east and west, north and south.
The short highly sloped EDGE ice masses can (and do!) move like classic mountain glaciers out and down to the seas. But those are “little” 50 and 75 kilometer glaciers “only” a few tens of meters thick. Now, multiply by many thousands kilometers around Greenland, and you do get a lot of ice that can move downhill and can (and sometimes does!) move out to the sea and calve off for dramatic photographs… But that central mass cannot get out to the sea.
Which is NOT a fact that these propagandists want you to know.
That’s close enough for credit.
@RACookPE1978 on December 30, 2015 at 4:25 pm
Ice moves from the “bowl” to the oceans via outflow glaciers. Also, the edges of the ice cap are seaward of the mountain ranges.
The bulk of the ice cap is secure in its topographic bowl. However, it does melt at the edges and it does push outflow glaciers to the sea, which it couldn’t do it it wasn’t accumulating ice in the interior.
Ice flows. Snow falls in the interior, gets compressed into ice, then flows out to the margins where it calves into the sea. The planes are getting carried along with the ice. In a few thousand years, had they not been dug out, they would have been dumped into the sea as well.
So, if my math is correct, at the rate of Greenland ice sheet loss for the past 100 years, almost the entire Greenland ice sheet will be gone in about 33,000 years? That is terrible, you know, except in about 33,000 years the earth should be well into the next major glaciation period… so that won’t be so bad, right?
Fortunately the loss of 0.3% was over 115 years, so that gives us another 5,000 years before it’s gone.
In the Eemian Greenland was ~5 degrees warmer. There were forests even with insects living at the lower altitudes but even with those conditions it never lost all of its ice. http://www.sciencedaily.com/releases/2007/07/070705153019.htm
FJS, your math is correct. And if you take the alarmist estimated ‘accelerated rate’ of 2000-2010 >200 GT/yr, rather than the previous low rate of 1990-2000 ~20GT/ yr, it still calculates out to ~16000 years. A footnote to essay Tipping Points.
Yes, but you have to understand, it is only a matter of seconds. Only half a trillion seconds until Greenland is ice-free.
What is the typical variation on an annualized basis over the last century; if known
‘known’ for 1990-2010. 1990-2000 ~20GT/yr. 2000-2010 ~200 GT/ yr. Error bars unknown.
How much ice has it lost since the medieval warm period?
Not enough to chill a highball.
Michael Mann killed the medieval warm period, may it rest in peace, with his Yamal Tree nonsense.
Sorry, Yamal wasn’t Mann, it was Briffa. Do pay attention.
Wow, that was an awesome job..really puts it in perspective !
From the original article: “According to Professor Jason Box from Geological Survey of Denmark and Greenland, the new data will make the predictions of climate change and sea level rise even more robust.”
The Danish Meteorological Institute (DMI…. arguably with skill from “ownership” of the island?) has modelled snowfall mass gain versus melting loss to find a nett annual gain of ~280 Gt/year when averaged over the 24 years from 1990 to 2013, yet with high variability as indicated by the range in grey shading in the graph below. With their newer model, for season 2014-15 alone they show a gain of ~220 Gt, and 2015-16 is on similar track, but for 2011-12 there was zero growth.
http://beta.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/
http://beta.dmi.dk/uploads/tx_dmidatastore/webservice/b/m/s/d/e/accumulatedsmb.png
DMI claims that separately modelled glacier calving (towards total mass balance) is about 200 Gt/year averaged over the last decade.
Thus, from these modelled data, it seems plausible that a nett of about 80 Gt/year average of liquid water was removed from the global water cycle over the last decade. That infers a nett potential Greenland-driven slight drop in sea level of ~0.2 mm/year. (~360 Gt = 1mm on sea level)
Jason Box has done some spectacular things starting in AR4 which in my opinion are far from robust
Every time I see that chart, it makes me wonder: what happened in 2012-2013 and 2013-2014? Why aren’t they on there but 2011-2012 is robustly prominent?
It might be something to do with revisions to their model in 2014/15 but a desire to throw-in the exceptionally scary season 2011/2?
the DMI uses the “record lowest” as a reference next to the mean and standard deviations imho a very good choice to compare current states with that exceptional year.
Reality: A 0.3% reduction in ice mass (+/- 2%).
That sums it up neatly. Thank you Scott.
Good work. When Greenpeace posted this ‘scary headline’ I responded (having done the same calculation) and, funnily enough, they didn’t reply. 9000 billion tonnes unrelated to the size of Greenland is designed to scare not inform. The alarmists have to lie because the truth is so innocuous.
“9000 billion tonnes unrelated to the size of Greenland is designed to scare not inform.”
PBDS (pale blue dot syndrome ; )
99.7% of Greenland’s ice sheet is retained after 100 years! Wow, that’s the new 97%!
The consensus among 99.7% of Greenland Ice Cubes is that “We Are Still Here!”
LOL!
Excellent comment. I’ll have ice with that.
A number is just a number.
Give it a unit of measure and you have a quantity.
Add another quantity and you can make a comparison.
Only after you make the comparison can you start reaching for Meaning.
Or the Scotch as the case may be…
Neat!
Curious that the media chooses to zoom in on the immenseness of the net shrinkage over a century rather than the triviality of its net impact.
At this rate it will melt completely away in only 33,000 years or so!
Back up and read “bobfj’s December 30, 2015 at 1:04 pm” comment again.
According to DMI, Greenland is gaining ice, not losing it. In 33,000 years there may be two Greenlands full of ice.
It helps if you’d use “approx.” instead of ~. Looks too much like a minus sign.
According to DMI, Greenland is losing ice.
And before you attack me, I just corrected what you said. According to DMI at their web page at,
http://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/
Greenland is losing mass at about 200Gt/yr. What the reality behind there really is – I can’t know. Satellites can be difficult to calibrate.
And even if it lost 97% it would be irrelevant to how it came about. Doesn’t prove anything. It’s just an interesting fact. like mentioning how many hot dogs were eaten in the past year. What’s the point?
like mentioning how many hot dogs were eaten in the past year. What’s the point?
Finding the missing heat.
So, they were chili dogs?
evanmjones: The strange thing is the search for the missing heat is an admission that the models have failed. If they hadn’t failed, no explanation would be needed as the observations would be as expected.
MarkW: if they were warm ones then they might get confused with sun dogs.
Plenty of photos of melting ice in the press, but almost no mention of Glacier Girl, the P38 buried under 268 feet of ice after an emergency landing 50 years before in 1942. I would like to remark as robustly as I can that no one knows what ice has done in Greenland in the 20th century – remembering that the North Pole was not reached until 1908 or 1909 by either Cook or Peary.
So what you’re saying is that while Greenland “lost” a total of 18 feet of total ice in the last 100 years, during that time it probably acquired more than 534 feet of ice in the same period placing the “total melt” of the last 100 years at 550ish feet of ice by 1.7 million kilometers. [math math math] resulting in a total 100 year estimated cycle of 26,675,951,219,512,194.6 liters of water based on the premise that the glacier has a uniform perimeter from top to bottom. Might as well round that up and tell Greenpeace to call it 27,000 trillion liters of freshwater lost from glacial melt in the last century!
The biggest and simplest argument I have ever used on warmists is “Are you so fucking stupid as to think the Earth’s existence is static and unchanging enough for ANY study of less than one ten thousandth of a percent of its lifespan is representative of its future with OR without mankind?” Perspective stops arguments, heals hate, saves children and will always make someone feel stupid.
How many Hiroshima bombs is that?
4.13 x 10^17 joules / KM^3. What does that number represent? That is the energy it takes to convert one cubic kilometer of continental ice from -30 °C to water at 4 °C – See
http://wattsupwiththat.com/2015/06/03/el-nino-strengthens-the-pause-lengthens/#comment-1953030
But you say ‘DD’ how does this compare to the well known ‘Hiroshima bomb’ measurement.
By today’s standards the two bombs dropped on a Japan were small — equivalent to 15,000 tons of TNT in the case of the Hiroshima bomb and 20,000 tons in the case of the Nagasaki bomb.
(Encyclopedia Americana. Danbury, CT: Grolier, 1995: 532.)
In international standard units (SI), one ton of TNT is equal to 4.184E+09 joule (J)
Hiroshima bomb TNT 15000 x TNT to Joules 4.18E+09 = Joules total 6.276E+13 =>
or 1 KM^3 of ice melt (4.1342E+17 / 6.276E+13) = # HiroBmb per Km^3 = 6,587
That is correct. Place one Hiroshima bomb in a grid every 54 meters apart to melt the ice.
So 8,165 km^3 x 6,587 HiroBmb/ km^3 = 53,782,855 HiroBmb
What I want to know is “Where are all the Icebergs?
D. Diemand, Coriolis, Shoreham, VT, USA Copyright ^ 2001 Academic Press doi:10.1006/rwos.2001.0002
Northern Regions
In general, the mean size of icebergs in Baffin Bay is about 60 m height, 100 m width and 100 m draft. Mean mass is about 5 to 10 Mt. The sizes of icebergs in this area are constrained by the water depth near the calving fronts, which is less than 200 m. Icebergs with a mass greater than 20 Mt are extremely rare, and for those found south of 60N, a mass greater than 10 Mt is seldom found.
http://curry.eas.gatech.edu/Courses/6140/ency/Chapter10/Ency_Oceans/Icebergs.pdf
1 gigaton = 1000 megaton so 200 Gt of total loss equals.
200,000 Mt total loss / 10 Mt high ave size = 20,000 icebergs created.
Anybody seen all of them?
Well since I live on the Southern US Coast, I am pretty concerned about the 25mm or 1 inch rise in global sea level over the past 115 years. Especially since there is a 9mm+- error which would amount to almost 1/3 of an inch. Ineed to be moving to higher ground pretty darn quickly!