From the WOODS HOLE OCEANOGRAPHIC INSTITUTION and the “worse than we thought” department, comes this breathless press release that doesn’t even mention the name of the study somehow manages to spin model results into a future frenzy worse that if the ice shelves just collapsed.
New study projects that melting of Antarctic ice shelves will intensify
New research published on October 12th projects a doubling of surface melting of Antarctic ice shelves by 2050 and that by 2100 melting may surpass intensities associated with ice shelf collapse, if greenhouse gas emissions from fossil fuel consumption continue at the present rate.
Ice shelves are the floating extensions of the continent’s massive land-based ice sheets. While the melting or breakup of floating ice shelves does not directly raise sea level, ice shelves do have a “door stop” effect: They slow the flow of ice from glaciers and ice sheets into the ocean, where it melts and raises sea levels.
“Our results illustrate just how rapidly melting in Antarctica can intensify in a warming climate,” said Luke Trusel, lead author and postdoctoral scholar at Woods Hole Oceanographic Institution (WHOI). “This has already occurred in places like the Antarctic Peninsula where we’ve observed warming and abrupt ice shelf collapses in the last few decades. Our model projections show that similar levels of melt may occur across coastal Antarctica near the end of this century, raising concerns about future ice shelf stability.”
The study, published Oct. 12, 2015, in Nature Geoscience, was conducted by Trusel, Clark University Associate Professor of Geography Karen Frey, WHOI scientists Sarah Das and Kristopher Karnauskas, Peter Kuipers Munneke and Michiel R. van den Broeke of the Institute for Marine and Atmospheric Research Utrecht University, and Erik van Meijgaard of the Royal Netherlands Meteorological Institute.
To study how melting evolves over time and to predict future ice sheet melting along the entire Antarctic coastline, the scientists combined satellite observations of ice surface melting with climate model simulations under scenarios of intermediate and high levels of greenhouse gas emissions until the year 2100.
The results indicate a strong potential for the doubling of Antarctica-wide ice sheet surface melting by 2050, under either emissions scenario. However, between 2050 and 2100, the models reveal a significant divergence between the two scenarios. Under the high-emissions climate scenario, by 2100 ice sheet surface melting approaches or exceeds intensities associated with ice shelf collapse in the past. Under the reduced-emissions scenario, there is relatively little increase in ice sheet melting after the doubling in 2050.
“The data presented in this study clearly show that climate policy, and therefore the trajectory of greenhouse gas emissions over the coming century, have an enormous control over the future fate of surface melting of Antarctic ice shelves, which we must consider when assessing their long-term stability and potential indirect contributions to sea level rise,” said Frey.
###
Funding for the research was provided by NASA, the Doherty Postdoctoral Scholarship Program at WHOI, the Netherlands Earth System Science Centre, the Polar Program of the Netherlands Organization of Scientific Research, and the Dutch Ministry of Infrastructure and the Environment.
Since these bozos that wrote the press release didn’t provide a link to the study, I will.
http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2563.html
Divergent trajectories of Antarctic surface melt under two twenty-first-century climate scenarios
Ice shelves modulate Antarctic contributions to sea-level rise1 and thereby represent a critical, climate-sensitive interface between the Antarctic ice sheet and the global ocean. Following rapid atmospheric warming over the past decades2, 3, Antarctic Peninsula ice shelves have progressively retreated4, at times catastrophically5. This decay supports hypotheses of thermal limits of viability for ice shelves via surface melt forcing3, 5, 6. Here we use a polar-adapted regional climate model7 and satellite observations8 to quantify the nonlinear relationship between surface melting and summer air temperature. Combining observations and multimodel simulations, we examine melt evolution and intensification before observed ice shelf collapse on the Antarctic Peninsula. We then assess the twenty-first-century evolution of surface melt across Antarctica under intermediate and high emissions climate scenarios. Our projections reveal a scenario-independent doubling of Antarctic-wide melt by 2050. Between 2050 and 2100, however, significant divergence in melt occurs between the two climate scenarios. Under the high emissions pathway by 2100, melt on several ice shelves approaches or surpasses intensities that have historically been associated with ice shelf collapse, at least on the northeast Antarctic Peninsula.
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https://notalotofpeopleknowthat.wordpress.com/2014/05/24/antarctic-temperature-trends-2/
The facts which do not lend support to this study which is wishful thinking if you believe in AGW theory.
Why would one need a model to tell you that Antarctica melts around the edges and accumulates in the center? If it didn’t it would cover the earth with ice.
Antarctica didn’t melt away 10 thousand years ago when conditions were much warmer. Why would it melt away today?
Hey now…this be climate science.
Don’t be trying to get all logic-ey or nuthin’!
http://www.ospo.noaa.gov/data/sst/anomaly/2015/anomnight.10.12.2015.gif
More data which does not support AGW and what this article is predicting.
It is not happening nor will it happen. The trends in Antarctica have been toward cold not warmth and I expect this trend to continue moving forward.
There is some recent unusual very significant cooling around southern Greenland by to 5 c.
Does anybody have a recent assessment of the likelihood of the IPCC’s RCP8.5 scenario? Even these authors do not think that it is likely! On reading the article, I also wondered whether the GCM models they used have factored in the recent changes in sensitivity? My immediate reaction to the article is that the headline bears little relationship to the concluding paragraphs where all the caveats are listed.
Another source for past Antarctic temperatures
http://berkeleyearth.lbl.gov/auto/Regional/TAVG/Figures/antarctica-TAVG-Trend.png
How can any ice melt at minus 35ºC?
On the front page of the NY Times, ice can melt at any temperature you may desire – and the science on this is settled.
The satellite that cover far more area of Antarctic don’t agree with recent near 40 years and show no warming or cooling more recently.
No warming since 1979.
http://i772.photobucket.com/albums/yy8/SciMattG/UAH_AntarcticTemps1978_zpsd4yjaujj.png
Cooling from at least 1995.
http://i772.photobucket.com/albums/yy8/SciMattG/UAH_AntarcticTemps1995_zpsffvqdzf5.png
Hey, I just created a computer model that shows the Sun revolves around the Earth , thus, proving that the Sun has no effect on the Earth’s climate !!!! Wow, I could get Noble prize for this !!!! . . . What ???? No you can’t look at the data , you just want to prove me wrong !!!!!!
Just think of how many Mars missions we could have funded what for the useless exercise of Global Warmism!
We should feel lucky that the Warmists have seized upon CO2 as their excuse to foment their movement against modern life. They might have, or will next, decide that the reason that the North is warm while the South is getting colder is the mere presence of humans. Then they will no longer try to rid the world of fuel use, will decide that energy from any source is the culprit, and demand that the factor we need to change is to rid the planet of a few billion humans.
Oh wait – many are already advocating for this….
At the current rate (over the past 25 years) it may take 380’000 years for the Antarctic Ice sheet to be fully melted. This linear extrapolation is as silly as any other else.
(based on Surveys in Geophysics 201132:9137 DOI: 10.1007/s10712-011-9137-z
Ice Sheets and Sea Level: Thinking Outside the Box, Michiel R. Van den Broeke et al)
If the rate doubles, then we’ll have to be caught by surprise in 190’000 years.
How I wish I were around by year 2050 – ’cause then it will be possible to conduct a proper scientific study of the value of computer studies and computer projections of climate events. My guess is that all climate computers will be quietly retired as it will be abundantly clear that they are useles (worse that useless, in fact, as bias will be proveable).
AndyE
October 13, 2015 at 7:59 am
Not useless. They can be used as boat anchors or man made reefs after all the precious metals and hazardous materials are removed.
In the methods section of the study they state
“. The ability of CMIP5-based GCMs to accurately reproduce Antarctic mean summer (DJF) near-surface (2-m)air temperature (T2m) was examined to select the most ideal GCMs to simulate the
evolution of Antarctic air temperature and derive meltwater production. ”
My recollection of the results CMIP5-based GMCs noted on previous blogs on WUWT showed that their projections were consistently high when compared to observable data ( overstating the impact of CO2?).
They used a bad model to create an even worse model…..just in time for Paris !!!!
There is now ample model output to enable development of a model of models.
I might become a modeller of models. It would be fun making models of models. Then you would have a real fair dinkum model.
Apparently there was a memo that went around that stated hereafter and forthwith projections/forecasts/predictions/sheer speculation is hereby deemed as proven data input.
So in today’s world of science if I project the Sun will shine an average of 1 hour less a day, then I can use that as input to an algorithm that demonstrates the effect on agriculture, then use that as input to an algorithm that projects increasing famine. Global famine then becomes an issue we must address immediately.
Lets all meet in Paris and party.
Our projections reveal a scenario-independent doubling of Antarctic-wide melt by 2050.
If the rest of the earth were on fire I doubt whether there would be ‘Antarctic-wide melt’. The mean annual temperature of the interior of the continent is -57°C.
Do these people ever read the gibberish they publish and consider how foolish it appears.
The paper authors also said
“We considered two distinct future emissions trajectories under which to assess the evolution of
Antarctic surface melting, namely Representative Concentration
Pathways RCP4.5 and RCP8.5, representing intermediate and high
(∼4.5 and ∼8.5 W m−2) energy imbalances by the end of the twenty-first century.
By mid-century under RCP4.5, the total annual volume of surface
meltwater produced across Antarctica doubles from recent levels
(88± 26 Gt yr−1) to 177 ± 52 Gt yr−1, yet undergoes relatively little
increase afterwards (Fig. 3a). Under RCP8.5, the Antarctic melt volume increases similarly by 2050 (199± 60 Gt yr), but then exhibits significant divergence from the RCP4.5 simulations beyond mid-
century. Moreover, owing to the nonlinearity described above, by
2090–2100 the multimodel mean meltwater volume projected under
RCP8.5 accelerates to 613 ± 258 Gt yr”
So we have again business as usual option( intermediate ) with little change and a worst case( high) option . What we lack is information about what co2 impacts were included in the model to make the Antarctic temperatures rise dramatically during the Antarctic summers (DEC/JAN/FEB) after 2050 to cause such an increase in the melt rate for RCP 8.5. I suspect the impact of the co2 were overstated as they have noted in the past.
The probable answer is closer to the lower melt rate
“∼4.5 and ∼8.5 W m−2 energy imbalances by the end of the twenty-first century.”
These values are laughable and require at least one doubling of CO2 (888 ppm) or latter, two and half doublings of CO2. (1840 ppm)
∼4.5 W m-2 would result in around warming 1.22 c at most and ~8.5 W m-2 would result in around warming 2.3 c at most.
Can any really believe on a continent way below zero c in summer will melt at all with those modest temperature rises?
The answer is it won’t and surprising how awful this so called science publication is. (actually not surprising anymore)
The low melt rate wouldn’t even occur with the high energy imbalances by the end of the twenty-first century.
When I read nonsense like this I feel like I’m grading a Geology 101 paper—these authors may know about computer models, but they clearly don’t know much about glaciers and real data about Antarctic climate. There is so much unequivocally wrong with this paper that it would take a full length article (which I don’t have time for right now) to respond to all the misconceptions, but here are just a few examples.
“Ice shelves are the floating extensions of the continent’s massive land-based ice sheets. While the melting or breakup of floating ice shelves does not directly raise sea level, ice shelves do have a “door stop” effect: They slow the flow of ice from glaciers and ice sheets into the ocean, where it melts and raises sea levels.”
The idea that glaciers are controlled by ‘door stops’ at their terminus is paramount in all of the model studies of the Antarctic ice sheets and assumes that if you remove the ‘door stop,’ the glacier will slide into the sea. Every glacial geologist knows that this is total nonsense—glacier behavior is controlled by the relationship between snow accumulation and ablation (melting, calving, sublimation), regardless of whether or not there is an ice shelf at the terminus.
“Our results illustrate just how rapidly melting in Antarctica can intensify in a warming climate,”
‘Rapid melting’ in Antarctica? You’ve got to be kidding! The average annual temperature in Antarctica is about –58F, so to get any melting at all, you have to raise the temperature to the melting point (58 + 32=90F), then add several degrees more to get any significant melting.
“To study how melting evolves over time and to predict future ice sheet melting along the entire Antarctic coastline, the scientists combined satellite observations of ice surface melting with climate model simulations under scenarios of intermediate and high levels of greenhouse gas emissions until the year 2100.”
Basing ice sheet ‘melting’ on computer models of greenhouse gas emissions doesn’t work for a lot of reasons, including the fact that there has been only 0.008% change in the CO2 content of the atmosphere since recent warming began (1978-2000) and CO2 contributes only 3.6% of greenhouse gases. Aside from that, Antarctica is ‘protected’ from the rest of the world by constantly encircling winds that prevents interaction with climate elsewhere and to get ice sheet melting, you would have to raise the temperature 100F (58 + 32 + 10).
“The results indicate a strong potential for the doubling of Antarctica-wide ice sheet surface melting by 2050, under either emissions scenario.”
This is absurd! The East Antarctic Ice Sheet (which contains 90%+ of total Antarctic ice) is not melting! Temperature records from the South Pole and Vostock show no warming at all since 1957.
What this paper proves is that, like all computer models, garbage in, garbage out. And this is definitely garbage!
But Don…this paper was “peer reviewed”! You know, so that the lay public could be assured of its quality, thoroughness, and veracity. And I’m sure the reviewers and authors didn’t know each other at all…nope, never.
Don Easterbrook says “The idea that glaciers are controlled by ‘door stops’ at their terminus is paramount in all of the model studies of the Antarctic ice sheets and assumes that if you remove the ‘door stop,’ the glacier will slide into the sea. Every glacial geologist knows that this is total nonsense—glacier behavior is controlled by the relationship between snow accumulation and ablation (melting, calving, sublimation), regardless of whether or not there is an ice shelf at the terminus.”
I would have thought that the presence of ice shelf at the terminus of a glacier would slow down the flow. But I have been wrong before, and Don seems so sure. Apparently every glaciologist knows this to be the case. So I looked it up. From antarcticglaciers.org it says “However, ice shelves are important because they hold back the glaciers on land. When they abruptly collapse, as several have done around the Antarctic Peninsula, the glaciers flow faster and transmit more ice to the sea, resulting in sea level rise.”
There is even a name for this: ice shelf buttressing. There is section with several references “Glaciers that feed into ice shelves are held back by the ice shelf in front of them[14, 15]. Even small ice shelves play an important role in regulating flow from ice streams that feed into them[14]. This has been observed in several cases, most notably following the Larsen Ice Shelf [16-19] and Prince Gustav Ice Shelf collapses[20, 21].”
Refs 14 and 15 are
14. Dupont, T.K. and Alley, R.B., 2006. Role of small ice shelves in sea-level rise. Geophys. Res. Lett., 2006. 33(9): p. L09503.
15. Dupont, T.K. and Alley, R.B., 2005. Assessment of the importance of ice-shelf buttressing to ice-sheet flow. Geophys. Res. Lett., 2005. 32(4): p. L04503.
16. Scambos, T.A., Bohlander, J.A., Shuman, C.A., and Skvarca, P., 2004. Glacier acceleration and thinning after ice shelf collapse in the Larsen B embayment, Antarctica. Geophysical Research Letters, 2004. 31: p. L18402.
20. Glasser, N.F., Scambos, T.A., Bohlander, J., Truffer, M., Pettit, E., & Davies, B.J., 2011. From ice-shelf tributary to tidewater glacier: continued glacier recession, acceleration and thinning following the 1995 collapse of the Prince Gustav Ice Shelf on the Antarctic Peninsula. Journal of Glaciology 57, 397-406.
From that last one: “After the ice shelf collapsed, Röhss Glacier retreated rapidly, becoming a tidewater glacier in 2002 and receding a total of ~15 km between January 2001 and March 2009, losing >70% of its area. Topographic profiles of Röhss Glacier from ASTER-derived digital elevation models show a thinning of up to ~150 m, and surface speeds increased up to ninefold (0.1–0.9 m d–1) over the same period.”
It looks to me that Don has just got this totally wrong. The rate of glacier flow is affected by the ice shelf – even small ones – and removal of the shelf will result in faster galcier flow. Far from every glacial geologist knowing this is total nonsense, it seems to be a well recognised and uncontroversial part of glaciologists understanding of glacier flow.
This does not inspire confidence for the other claims he is making. Why say things that are so easily refuted as it weakens your case so much?
The West Antarctic sheet is losing 150 km3 of ice per year. http://geoid.colorado.edu/grace/docs/SC-VelicognaWahr-2006.pdf
But only after you apply “corrections” to the data. The East Antarctic ice cap is gaining ice; it is only the far small EAIS that is losing a little ice, and that in limited area on the magma-heated, very small Antarctic Peninsula.
The sea ice around Antarctica set new record high extents in 2014. An excess area larger than Greenland. And Antarctic sea ice has been steadily increasing since 1992. Of all areas of land-based Antarctica, only the WAIS is warming. A little bit.
Now, how many millions of innocents are YOU willing to kill by artificially raising energy prices so bankers, governments, and government-paid academics can get their hands on 31 trillion dollars a year in ENRON-invented carbon trading schemes?
If 25,000.00 paid one time buys an entire conservative “oil-funded” think tank forever, how many government-paid “scientists” can I buy for 92 billions in CAGW funding?
“Worse than we thought department?” Also from the “vary narrow perspective ignoring reality what if department” and the “if I squint between my thumb and forefinger held close enough to my eye, I’m crushing your head department.”
“Ice shelves are the floating extensions of the continent’s massive land-based ice sheets. While the melting or breakup of floating ice shelves does not directly raise sea level, ice shelves do have a “door stop” effect: They slow the flow of ice from glaciers and ice sheets into the ocean, where it melts and raises sea levels.”
Melting floating ice keeps ice sheets forming right up to South America and has always happened with this continent positioned here. Do we really expect this to not happen any century because it has never happened before, even during the depths of an ice age?
The door stop effect keeps occurring all the time because it is replaced immediately by ice pushing towards the ocean, that caused the collapses in the first place. It has nothing to do with melting ice on the continent just the ‘door stop’ effect and models are garbage years ahead and everyone to do with climate so far has proved this. While scientists (not always they fault) have the same mind set for securing grants the science will never advance.
Why hasn’t the collapses over recent decades increased the flow of ice from glaciers before?
That’s right the void has been filled again and made no difference.
The nonsense from this report is rather disgraceful and all about $$$$$$ and involves everything that I can’t stand in awful climate pseudoscience.
Exaggerating whole continent on a very small region not representative – check
No observations supporting scare – check
Blaming historic events that have no affect now – check
Alarming scare – check
Blaming collapses on melting when there is more than one cause – check
Blaming the ‘door stop’ effect that has always occurred – check
Hiding behind a model for alarm-ism – check
Why not show observations now that back up this concern?
Oh we can’t because there aren’t any, we won’t get a grant and temperatures have been declining with increasing sea ice over recent decades.
I don’t know if it’s all that unusual this time of year, but snow has covered massive areas of northern Canada/Alaska & Siberia:
http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow_asiaeurope.gif
And its only just begun .
Why not hold the next “World Conference” of “World Leaders” in Antarctica say next June 6 that way it would coincide with the celebration for the beginning of the liberation of Europe from totalitarian fascists! Send all the Mike Manns of the world too to deliver their latest papers on global warming. I suggest they hold a street dance to demonstrate to all us morons how stupid we are in a colorful multicultural display of unity that we could capture as though it was frozen in time.
ice shelves do have a “door stop” effect
===============
utter nonsense. ice shelves are the result of the flow. in effect the author is arguing that ice shelves slow the formation of ice shelves, and if the ice shelves melt, this will speed the formation of new ice shelves.
You should know by now alarmists love picking the effect for the cause.
The only ‘door stop’ effect ice shelves have is when ice advances towards it from advancing glaciers, due to increasing mass. This would happen whether or not the ice shelve was in water and makes no difference.
If magically raise temperatures 40 c and melt surrounding area’s near the ocean. No ice would be collapsing near the coast after a bit and melting in the ocean because instead it would had receded many miles away from the coast and collapsed there instead. Scientists involving ice are always spinning the warm side to collapses, not the too much mass cause forcing into warmer waters.
Below is a recycled comment I made from a post a week ago about ‘unstoppable sea level rise’:
The problem for the Antarctic scaremongers is that there hasn’t been a decent sized iceberg (>1,000 km²) break off the continent since 2002 (C-19 which broke off the Ross Ice Shelf). Two years before that, in 2000, the biggest recorded iceberg, B-15 (11,000 km²), also broke off the Ross Ice Shelf. The last one to break off the Filchner-Ronne Ice Shelf was A-38 in 1998. Before A-38 the only recorded big one was the Mertz Glacier tongue (B-9) which broke off in 1987. Recent icebergs from Antarctica (only two) have been tiny in comparison (310 & 660 km²).
It’s difficult to whip up alarmism when nothing of real note has happened in the way of big icebergs drifting off Antarctica for 13 years.
https://en.wikipedia.org/wiki/List_of_recorded_icebergs_by_area
I like data. My mother taught me “no news is good news” Cryosphere Today instead acts out ” good news is no news” Maybe if the ice all melts they will update their charts!
As a Dutchman by birth ( now Canadian) I am totally embarrassed by this junk and what is the “Ministry of Infrastructure and Environment? I sure hope they aren’t in charge of building dikes and de-watering projects ( I’d be moving to Eastern Holland if they were!).
New study projects that melting of Antarctic ice shelves will
intensifyeventually be measurable by some, as yet, unknown technology.Thar – fixed it.
They’re beyond bonkers.