[Note: this post (and a few others) was lost in WordPress, and I had no notification of its existence. While a bit dated, it is still valid – note to guest authors with WUWT WordPress privileges – when you submit something, be sure to notify me via email too – Anthony]
Guest post by David Middleton
From Live Science…
Records Melt Away on Greenland Ice Sheet
By Brett Israel, OurAmazingPlanet Staff Writer posted: 21 January 2011
The disappearing Greenland Ice Sheet set several records during an unusually long melt last year, according to a new study.
Running from April to mid-September, the melt season of 2010 was about a month longer than usual, said study team member Jason Box, a geographer and climatologist at Ohio State University.
[…]
“The disappearing Greenland Ice Sheet”… Where in the heck did the author get the idea that the Greenland Ice Sheet was disappearing?
A recent publication by a team from TU Delft & JPL found that the Greenland ice sheet was melting at half the rate previously thought. They estimate that the Greenland ice sheet is losing ~230 gigatonnes (Gt) of ice per year. One Gt of water has a volume of 1 cubic km (km^3). 1 Gt of ice has a larger volume than 1 Gt of water… But, for the purpose of this exercise, we’ll assume 1 Gt of ice has a volume of 1 km^3.
If 1 Gt of ice has a volume of 1 km^3 and the current volume of the Greenland ice sheet is ~5 million km^3 and Greenland continues to melt at a rate of 230 km^3/yr over the next 90 years… The Greenland ice sheet will lose a bit more than 0.4% of its ice volume.~230 gigatonnes (Gt) of ice per year equates to about 0.005% of ice mass loss per year. At the current rate, it would take 1,000 years for the Greenland Ice Sheet to lose 5% of its volume.
The Earth’s climate was at least 2°C warmer during the Holocene Climatic Optimum and the Greenland Ice Sheet did not melt, disappear or destabilize…
The Earth’s climate was at least 2°C warmer and the Arctic was about 5°C warmer than it currently is during the Sangamonian (Eemian) interglacial. and the Greenland Ice Sheet did not melt, disappear or destabilize.
Greenland’s glaciation began during the Miocene, when the Earth’s climate was at least 5°C warmer than it currently is. It advanced rapidly after the Mid-Pliocene Warm Period.
Earth’s climate would have to warm back up to where it was in the mid-Miocene (~15 MYA) in order to destabilize the Greenland ice sheet…
There is no scientific evidence to back up the assertion of a “disappearing Grrenland Ice Sheet. For a detailed explanation as to why the Greenland ice sheet cannot collapse under any AGW scenario, see Ollier & Pain, 2009.
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Cwoop, Sie habten lande gefunden; finde lande, found land, new found land. There were sites there excavated in the 1960’s that showed viking habitation in old National Geographics. Southern europe must think finde is vines for grapes but the vikings finded lande, found land.
There’s some very interesting commentary here – it’s defo got me scratching my head!
Also, it’s great to see KR being soundly PWNED with a solid argument.
Nice work, Crispin In Jo’Burg – I reckon matey’s suckin his teeth and huggin his knees.
As well he should.
}:o(
KR says…
and…
Lets consider at 36.3 GT/year/year acceleration. That means at the end of the 18 year period there were 653 GT/year more melting than at the beginning of the 18 year period. (18 years X 36.3 GT/year/year).
So, the portion of the sea level rise rate due to addition water (as opposed to steric effects) at the end of that 18 year period should have been 1.8 mm/year greater than at the beginning of that period (653 GT/year X 2.78e-3 mm/GT).
Can you see that 1.8 mm/year increase here…
http://sealevel.colorado.edu/files/2012_rel1/sl_ns_global.png
or in some other global mean sea level data? I can’t.
Also, please consider viewing movie of PSMSL sea level data here…
http://climatesanity.wordpress.com/
Correction…
Please consider viewing teh movie of PSMSL sea level data here…
http://climatesanity.wordpress.com/2012/03/11/updated-psmsl-sea-level-video/
KR;
New Orleans: inland hole in the ground protected by dykes. Will flood again if they break.
Bangladesh: river delta that grows and shrinks with silt deposit variations. Warming will increase them. Currently gaining area. In no danger of vanishing.
Errata… The Holocene Climatic Optimum was ~2C warmer than the mid 1800’s. When I originally wrote this, I forgot that Alley cut off before 1900.
@KR,
Neither SST nor MSL have been rising, much less accelerating in their rise, over the last few years. Therefore, ice melt can’t be accelerating.
Our “little” planet is huge !!!
Numbers like this boggle my mind and should really but things into perspective for everyone:
“If 1 Gt of ice has a volume of 1 km^3 and the current volume of the Greenland ice sheet is ~5 million km^3 and Greenland continues to melt at a rate of 230 km^3/yr over the next 90 years… The Greenland ice sheet will lose a bit more than 0.4% of its ice volume.~230 gigatonnes (Gt) of ice per year equates to about 0.005% of ice mass loss per year. At the current rate, it would take 1,000 years for the Greenland Ice Sheet to lose 5% of its volume.”
Excellent post Mr. Middleton !!
David Middleton – “Neither SST nor MSL have been rising, much less accelerating in their rise, over the last few years. Therefore, ice melt can’t be accelerating.”
Over the last few years? If you’re only looking at short term data, yes. But if you look at longer terms for sea level rise, long enough for statistically significant trends, as in Church 2006 (http://naturescapebroward.com/NaturalResources/ClimateChange/Documents/GRL_Church_White_2006_024826.pdf – Fig. 2, also shown at http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch5s5-5-2.html), there is a considerable acceleration in sea level rise – the best fit for the last 140 years is quadratic upwards. Looking at only “the last few years” for sea level rise rates is looking at only noise.
As to ice melt rates, see http://www.ccrc.unsw.edu.au/Copenhagen/Copenhagen_Diagnosis_LOW.pdf – Figure 8 for Greenland, Figure 10 for Antarctica, showing multiple studies of mass balance, using different methods, and the accelerating trends seen.
Quite frankly, the general approach of the comments here, arguing that melt isn’t going to be that bad, is in my opinion just wishful thinking.
Eventually, as the Pleistocene Era ends some 12 – 14+ million years from now, Greenland will likely have segued southwest to more temperate zones. End of glaciers, not due to shifts in atmospheric or oceanic currents –most certainly not to any doofus CO2 effect– but solely to plate tectonics re-positioning landmasses over time.
Not climatology but geophysics is the discipline applicable here. For all its seeming rigor, which in fact is no more “scientific” than Blondlot’s N-rays, CAGW is on par with Aristotle’s “impetus” and Ptolemaic epicycles. Faugh.
KR- The study by Houston and Dean did not find an acceleration in sea level rise per this link: http://www.jcronline.org/doi/pdf/10.2112/JCOASTRES-D-10-00157.1
Birdieshooter,
Interesting paper, thanks for linking. From the Conclusions:
In addition to the ~5,000,000 Giga-tonnes of ice on Greenland there is another 30,000,000 Giga-tonnes in Antarctica. At the present global average rate of melting (<280 Giga-tonnes/year) it is going to take 100,000 years to melt it all.
http://diggingintheclay.wordpress.com/2012/03/24/more-unwelcome-light/
R. de Haan says:
April 5, 2012 at 12:11 pm
“There is no scientific evidence to back up the assertion of a “disappearing Grrenland Ice Sheet.”
And the same goes for all the other scare based propaganda that we’re recycling at this blog.
There is no scientific evidence, Period
______________________________
Pssst. keep that under your hat…
the solvency of our “sacred” institutions of higher learning is at stake!
Houston and Dean 2011 is a notable study – notable for the use of a subset of tide gauge data, a subset of the time span, and results that are not supported (http://tinyurl.com/5sxbskd) by the full data.
Their claims of deceleration are inconsistent with the any review of the full set of data available – sea level rise rates have accelerated over the last 140 years. If you look at all the data, their paper is really an exercise in disinformation.
@KR,
The ice melt has supposedly accelerated since 2003 (Velicogna, 2009). The rate of sea level rise decelerated since 2003.
GRACE (Gravity Recovery And Climate Experiment) consists of two satellites, launched in 2002, that measure subtle variations in Earth’s gravitational field. GRACE is the ideal tool for measuring changes in Earth’s polar ice caps.
One of the most prolific authors on GRACE has been Dr. Isabella Velicogna, UC Irvine. Back in 2009 Dr. Velicogna published this paper in GRL:
Increasing rates of ice mass loss from the Greenland and Antarctic ice sheets revealed by GRACE
Dr. Velicogna concluded that the ice mass-loss was “accelerating with time.” She found that “in Antarctica the mass loss increased from 104 Gt/yr in 2002–2006 to 246 Gt/yr in 2006–2009.”
Since the launch of GRACE, Dr. Velicogna has participated in several papers on GRACE and ice mass loss estimates for Antarctic and Greenland. Each paper has presented a more dire situation than the previous one, yet GRACE has not actually measured a significant ice mass loss in Antarctica. The actual GRACE measurements indicate a net mass gain (44 ±20 Gt/yr) from October 2003 through February 2007.
Riva2007.png
Furthermore, the GIA-adjusted Total Mass Differences (TMD) from the TU Delft publication are significantly lower than those of Velicogna 2009.
GIA is the abbreviation for “glacial isostatic adjustment,” sometimes referred to as post-glacial rebound (PGR). The areas of the Earth’s crust that were covered by thick ice sheets during the last glacial maximum were depressed by the ice mass. As the ice sheets have retreated over the last 15-20,000 years, the crust has rebounded (risen) in those areas. So, the GRACE measurements have to be adjusted for GIA. The problem is that no one really knows what the GIA rate actually is. This is particularly true for Antarctica.
Riva et al., 2007 concluded that the ice mass-loss rate in Antarctica from 2002-2007 could have been anywhere from zero-point-zero Gt/yr up to 120 Gt/yr. Dr. Riva recently co-authored a paper in GRL (Thomas et al., 2011) which concluded that GPS observations suggest “that modeled or empirical GIA uplift signals are often over-estimated” and that “the spatial pattern of secular ice mass change derived from Gravity Recovery and Climate Experiment (GRACE) data and GIA models may be unreliable, and that several recent secular Antarctic ice mass loss estimates are systematically biased, mainly too high.” (I don’t have access to the full text of Thomas et al., 2011, just the abstract).
So, there’s no evidence that the Antarctic ice sheets have experienced any significant ice mass-loss since GRACE has been flying. The GIA has generally been as large or larger than the asserted ice mass-loss.
Now, regarding a quadratic function for sea level rise, yes it did follow a quadratic function as it accelerated from the Little Ice Age hiatus to its modern rate.
A projection of the measured sea level rise from 1700 to 2009 gives us about 300 mm of sea level rise from 2007-2100. That’s 11.8 inches. Less than 1 foot.
See…
David Middleton – You are aware, I hope, of the fact that ENSO effects the rate of sea level rise? That La Nina events increase precipitation, resulting in movement of water from the oceans onto the land? These variations add noise to the sea level rise rates, making it very important to look at longer terms to extract trends. Short term trend estimates are not statistically significant, and are in fact cherry-picking – in the presence of noise I could take an insignificantly short period and extract almost any rate I liked; but that would be meaningless.
See http://sealevel.colorado.edu/content/nasa-satellites-detect-pothole-road-higher-seas and http://adsabs.harvard.edu/abs/2007AGUFM.G33B1247H for some details on ENSO effects.
Regarding Antarctic ice mass, http://www.nasa.gov/home/hqnews/2006/mar/HQ_06085_arctic_ice.html has data through 2005, and your own Velicogna 2009 reference (http://ess.uci.edu/researchgrp/velicogna/files/increasing_rates_of_ice_mass_loss_from_the_greenland__and_antarctic_ice_sheets_revealed_by_grace.pdf) indicates increasing rates of Antarctic mass loss. As I pointed to in a previous post (http://wattsupwiththat.com/2012/04/05/more-glacial-junk-science-journalism/#comment-946634) multiple studies using different methods all agree on increasing Antarctic mass loss rates.
You have not supported your points.
KR says @April 5, 2012 at 7:30 pm [ … ].
Linking to Tamina’s Closed Mind exposes your alarmist belief system. This unrefuted peer reviewed paper debunks the T-bagger.
After this, please stick to credible sources. Thanx.
Smokey – Dismissing clearly explained statistical analysis for cherry-picked start dates and subsets of tide gauge data exposes your confirmation bias.
As to “”unrefuted”, I suggest looking at Rahmstorf 2011 (http://www.jcronline.org/doi/pdf/10.2112/JCOASTRES-D-11-00082.1), published as a reply in the same journal. Houston and Dean 2011 is a horrible paper.
>>>kim2ooo says:
April 5, 2012 at 2:42 pm
Dubbed “Glacier Girl” after being recovered
My question is / was doesn’t this mean during the 1940′s there was a lot less ice on Greenland?
——————————
Kim2ooo – in a book I read about the recovery of Glacier Girl. One of the pictures showed a tractor that was left on the ice in 1990. The picture was taken in 1992, and the tractor was in a 15-20 ft hole. About 15 ft of new glacier has formed over the tractor in two years. I guess it’s melting from the bottom. About 200 ft of ice had accumulated on Glacier Girl since it crashed in about 1944.
“The Earth’s climate was at least 2°C warmer during the Holocene Climatic Optimum and the Greenland Ice Sheet did not melt, disappear or destabilize…”
Yes, but the lies sound so much more dramatic when they say it will.
KR,
Anyone who believes Rahmsdorf is anything but a grant-trolling climate alarmist is engaging in psychological projection when talking about confirmation bias. Rahmsdorf would be a certified nobody if it were not for his having both front feet in the taxpayer trough. Rahmsdorf is as incredible as Mann. Find someone credible, then I’ll listen.
regarding the recovery of “Glacier Girl” as proof that the ice is melting:
the ice melted to get her out all right… they had to melt down through 268′ of ice to reach her, and first located the wreck with ground penetrating radar… all of which tends to disprove your claim that global warming had anything to do with getting the plane back.
nice try though!
details here: http://p38assn.org/glacier-girl-recovery.htm
@KR,
The hysterical predictions of >1 meter sea level rise by the end of this century are based on accelerating ice melt. A realistic estimation of GIA does not support accelerating ice mass loss. The sea level and SST data over the period of supposed accelerating ice melt also do not support accelerating ice mass loss. The short term data (during the GRACE era of ice mass measurement) do not support accelerating sea level rise.
The long term sea level trend (Jerejeva et al) smoothly ties into the recent satellite data and indicates insufficient acceleration to raise sea level by more than 1 foot by the end of this century. The long term data do not support accelerating sea level rise.
Neither the short term nor the long term data support accelerating sea level rise. Is there some sort of Goldilocks term data set?
Matt said: “… potholer had graced this issue with a video, saying that it isn’t so much the melt rate, but rather the lubricating effect of melt water underneath, which makes it basically slide a lot faster…”
Slide up hill? I understood that the weight of Greenland’s ice sheet has depressed the center of that large Island in some places to below sea level. Which, if true, then the rise in the sea level due to the melting of all of its ice would be offset by the rebound of Greenland’s land mass.
Crispin in Johannesburg, not Waterloo at the moment says:
April 5, 2012 at 2:16 pm
It is simple facts like this which the public is not told about: 1,560,000,000,000 tons of CO2 would be absorbed by the water just from a melted Greenland ice sheet. That is equal to the total emissions from burning 410,000,000,000 tons of carbon or roughly 500 billion tons of good quality dry coal.
Impressive use of large numbers! Let me try.
2010 global coal comsumption, 7.237 billion tons. (Hard and Brown coal)
<a href=http://www.worldcoal.org/resources/frequently-asked-questions/<World Coal Association
Without including the increase in coal use ( as we keep hearing china is putting online 1 coal plant per week) thats 723.7 billion tons in 100 years. According to your figures, thats almost 45% more than will be absorbed by the melt water or 702,000,000,000 tons of CO2 still going into the atmosphere. As brown coal produces more CO2, this figure would be higher.
Have we got enough coal? You betcha!
from the same link above
The reserves to production (R/P) ratio provides an indicator of how long proved coal reserves will last at the current rate of extraction. BP calculated this to be 118 years for coal at the end of 2010.
So to wrap up it IF the Greenland ice sheet melted (your thoughts not mine), it would only absorb 70 years of coal use at 2010 consumption rates.
No, Crispin, Your Welcome!