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Antarctica 2018

Re: Antarctica 2018

Unread postby onlooker » Fri 15 Jun 2018, 11:51:04

So Rockdoc, you are saying that "IMBIE is an international collaboration of polar scientists, providing improved estimates of the ice sheet contribution to sea level rise." and using satellite data and statistical analysis including regression analysis are clueless? And also, NASA and the European Space Agency? The language used is non technical and quite clear and unambiguous. Is your data challenging this assertion of a tripling of ice loss/melting impact? If it is, then its a matter of who you believe
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Re: Antarctica 2018

Unread postby Plantagenet » Fri 15 Jun 2018, 11:58:51

rockdoc123 wrote:....onwards to 2100 you are looking at a total sea level equivalent contribution of 137 mm (13 cm) or 5 inches. If you are worried about this then you need a better hobby IMO.


Your problem is you can't do math.

The latest direct measurements of global sea rise show it going up by more than 3.5 mm/yr...and that rate is like to increase. However, even if we assume that the current rate of sea level rise doesn't increase, 82 years at 3.5 mm/yr yields 287 mm by the year 2100, i.e. more than twice the phony number you came up with.

Which brings us back to this new paper in NATURE on Antarctica's contribution to sea level rise. Denialists like you used to argue that no ice loss was occurring from Antarctica. But this latest paper confirms a long series of prior research papers that show Antarctica is indeed losing ice mass, and, whats more, the rate of ice loss is increasing in Antartica.

Increasing rates of ice loss from Antarctica, Greenland, etc. are consistent with the increasing global warming we are seeing.....and that means that as the planet continues to warm, the rate of ice loss will increase and the rate of sea level rise is also likely to continue to increase and the actual amount of sea level rise by 2100 will be commensurately greater as well.

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Re: Antarctica 2018

Unread postby rockdoc123 » Fri 15 Jun 2018, 13:36:18

Your problem is you can't do math.

The latest direct measurements of global sea rise show it going up by more than 3.5 mm/yr...and that rate is like to increase. However, even if we assume that the current rate of sea level rise doesn't increase, 82 years at 3.5 mm/yr yields 287 mm by the year 2100, i.e. more than twice the phony number you came up with.


your problem is you can't read. I was referring to the contribution from Antarctica which when you use the acceleration suggested as continuing (which the data is already showing it isn't) then you get 137 mm of sea level rise total over the period from now to 2100 attributed to Antarctica. Antarctica contributes somewhere between 13 and 17% of total current sea level rise. Do the numbers yourself. And if current sea level rise continues as you suggest then the total amount of sea level rise by 2100 is about 30 cm, less than predicted at the most likely case in AR5. The argument isn't about what is going on elsewhere it is about Antartica and it's contribution. Clean your reading glasses.

So Rockdoc, you are saying that "IMBIE is an international collaboration of polar scientists, providing improved estimates of the ice sheet contribution to sea level rise." and using satellite data and statistical analysis including regression analysis are clueless? And also, NASA and the European Space Agency? The language used is non technical and quite clear and unambiguous. Is your data challenging this assertion of a tripling of ice loss/melting impact? If it is, then its a matter of who you believe


As I said...read the damned paper. "the language used is non-technical" simply because it isn't in the publication. The statistics they use in the paper are simply to outline the 1 sigma range of outcomes from all the inputs. What they did not do is run a T-test in order to understand the significance of their results. When you are asserting there is a difference between two means with attendant standard deviations it is not good enough to just compare the means (which is what the Imbie team and the press release have done) you have to compare the entire range of standard deviation about those means between the two populations. The fact the two ranges overlap substantially is your first clue there is a problem but the only way to calculate whether they are statistically different populations is to run a T-test which I did. They aren't. Do it yourself, it is a pretty easy calculation. And as I said the main reason why there is such a huge uncertainty about the means calculated is due to all the error associated with GIA calculations. This is a well known and well published observation.

Denialists like you used to argue that no ice loss was occurring from Antarctica. But this latest paper confirms a long series of prior research papers that show Antarctica is indeed losing ice mass, and, whats more, the rate of ice loss is increasing in Antartica.


You are an ass, complete mischaracterization of anything I have ever said. What I have said in the past is completely congruent with the results of this paper and several others published in the last few years. This is the first paper published to add in years 2015 and 2016. What I have said is that there are losses in Western Antarctica and the Peninsula currently and that there are minor gains in East Antarctica and overall that is the true picture. I can show you the plots to prove that. Also what I have said is that AR5 points to the fact Antarctica will actually have a negative contribution to sea level in the not too distant future under modeled scenarios simply because a warmer world results in more snow accumulation and rising SMB. That is also backed up by a number of publications in the past few years (both models and observations) which I have pointed to previously. And what I am saying here is the rate of increase in Antarctic mass loss is going to be relatively inconsequential in terms of sea level rise unless you believe 13 cm of sea level rise is earth shaking. :roll:

Increasing rates of ice loss from Antarctica, Greenland, etc. are consistent with the increasing global warming we are seeing.....and that means that as the planet continues to warm, the rate of ice loss will increase and the rate of sea level rise is also likely to continue to increase and the actual amount of sea level rise by 2100 will be commensurately greater as well.


First off some false idea of a global temperature has frig all to do with melt in Antarctica, what should be important is atmospheric temperatures over the Antarctic continent and SST in the Southern Ocean. Neither has been rising (based on satellite, AWS surface date, and Argo), in fact, some argue that overall they both have been decreasing slightly for some time. And AR5 addresses modeled responses to projected forcings. Their worst possible case (which makes no sense emission wise if you believe in Peak Oil and/or replacement of ICE with EVs) results in a metre of rise, their most likely case is in the tens of cm range.
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Re: Antarctica 2018

Unread postby jedrider » Fri 15 Jun 2018, 14:06:45

I didn't read the article. Seemed too long and/or not appealing.

rockdoc123 wrote:First off some false idea of a global temperature has frig all to do with melt in Antarctica, what should be important is atmospheric temperatures over the Antarctic continent and SST in the Southern Ocean. Neither has been rising (based on satellite, AWS surface date, and Argo), in fact, some argue that overall they both have been decreasing slightly for some time. And AR5 addresses modeled responses to projected forcings. Their worst possible case (which makes no sense emission wise if you believe in Peak Oil and/or replacement of ICE with EVs) results in a metre of rise, their most likely case is in the tens of cm range.


I think it is clear the Antarctica is melting and caving continually at far greater rates than probably our worst estimates. So, if temperatures are still cold and relatively stable from surface temperature measurements, I am wondering about the effect of the AMOC slowdown. Is that the reason that Antarctica is caving? If it is, well, what an amazing interconnected climate machine our earth is! Too bad we're wrecking it.
Last edited by Tanada on Fri 15 Jun 2018, 14:10:51, edited 1 time in total.
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Re: Antarctica 2018

Unread postby rockdoc123 » Fri 15 Jun 2018, 14:35:30

I think it is clear the Antarctica is melting and caving continually at far greater rates than probably our worst estimates. So, if temperatures are still cold and relatively stable from surface temperature measurements, I am wondering about the effect of the AMOC slowdown. Is that the reason that Antarctica is caving? If it is, well, what an amazing interconnected climate machine our earth is! Too bad we're wrecking it.


as I said above the main issue regionally in Antarctica is WAIS. The Pennisula has actually seen a reduced rate in loss of SMB over the past few years and it's overall contribution pales in comparison to WAIS. And as I pointed out perhaps it is just a coincidence but the highest areas for heat flux at the land/ice interface is in WAIS west of the suture zone.
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Re: Antarctica 2018

Unread postby Plantagenet » Fri 15 Jun 2018, 16:00:50

rockdoc123 wrote:your problem is you can't read.


You're the one making silly math mistakes and posting wildly inaccurate numbers on the rate of global sea level rise, not me.

rockdoc123 wrote: if current sea level rise continues .....then the total amount of sea level rise by 2100 is about 30 cm


As I said, you can't do math, and as a result you make dumb mistakes post wildly inaccurate numbers. In this case you are so wrong it is absurd. The annual rate of sea level rise is now about 3.5 mm per year. That means there will be 30 cm of sea level rise in just 9 years----not the 82 years you postulate. So now your math is wrong by a factor of 10. I'm afraid you are hopeless when it comes to math.

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Re: Antarctica 2018

Unread postby rockdoc123 » Fri 15 Jun 2018, 16:50:17

You're the one making silly math mistakes and posting wildly inaccurate numbers on the rate of global sea level rise, not me.

As I said, you can't do math, and as a result you make dumb mistakes post wildly inaccurate numbers. In this case you are so wrong it is absurd. The annual rate of sea level rise is now about 3.5 mm per year. That means there will be 30 cm of sea level rise in just 9 years----not the 82 years you postulate. So now your math is wrong by a factor of 10. I'm afraid you are hopeless when it comes to math.


And where did you learn your math? You purport to be a geophysicist and do not know how to convert mm to cm?
here is what you said up thread

However, even if we assume that the current rate of sea level rise doesn't increase, 82 years at 3.5 mm/yr yields 287 mm by the year 2100

287 mm = 28.7 cm which is somewhat close to the 30 cm I mentioned

And lets also look at your recent statement

The annual rate of sea level rise is now about 3.5 mm per year. That means there will be 30 cm of sea level rise in just 9 years----not the 82 years you postulate.


OK class who here can show that 3.5 mm times 9 is 31.5mm and not 30 cm? :roll:

But go ahead, keep making a fool of yourself.
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Re: Antarctica 2018

Unread postby dissident » Fri 15 Jun 2018, 17:53:50

Oh my, math mistakes are the only thing to care about.

It is clear from the data that 3.5 mm is not going to stay fixed between now and 2100. The data clearly indicates an acceleration of the sea level rise every year. This is consistent with the physics of the land ice. The less of it there is, the faster it melts. One factor is the progressive change in the albedo of the ice surface due to melt. Light-absorbing aerosol deposited via precipitation over the millions of years of ice accumulation from snow, begins to concentrate on the surface of the ice. You can see this effect clearly in the case of the Greenland ice sheet. Antarctica is experiencing the same thing. And as posted before, winter snow accumulation does not counteract summer melt.

The exponential doubling time for Antarctica is 5 years, which is faster than the over 10 year doubling time from Greenland. But it cannot be assumed that the doubling time will remain constant until 2100. Both the Greenland and the Antarctic ice sheets will undergo cataclysmic collapse after some point. It does not help that both Greenland and Antarctica are actually mostly under water due to isostatic compression from the 3 to 4 km of ice sitting on them. After sufficient melt, there will be warm water intrusion deep into the interior far from the coasts.

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Re: Antarctica 2018

Unread postby rockdoc123 » Fri 15 Jun 2018, 19:56:08

The exponential doubling time for Antarctica is 5 years, which is faster than the over 10 year doubling time from Greenland. But it cannot be assumed that the doubling time will remain constant until 2100. Both the Greenland and the Antarctic ice sheets will undergo cataclysmic collapse after some point. It does not help that both Greenland and Antarctica are actually mostly under water due to isostatic compression from the 3 to 4 km of ice sitting on them. After sufficient melt, there will be warm water intrusion deep into the interior far from the coasts.


This has all been discussed at length previously on these threads. You can imagine any possibility in the future you want but the current information from Antarctica does not support your views and neither do the models (unless there is a new one I haven't seen). As I said above since 2015 SMB for all of Antarctica has been decreasing at a slower rate (as evidenced from the data in this paper) which does not support an ever-increasing rate. As an example in 2014 the rate of change was -22 GT/yr but in early 2015 it was back to -17 GT/yr (a number not seen since 2 yr previous) and by mid 2015 it was down to -11 GT/yr (a rate of change not seen since 2009). Scientists are a long way from understanding all the complexities of Antarctic SMB as pretty much every paper published on the subject suggests.
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Re: Antarctica 2018

Unread postby Plantagenet » Sat 16 Jun 2018, 17:44:17

One of the most dramatic changes in Antarctica has been the recent collapse of multiple ice shelves

antarctic ice shelf loss will lead to accelerating sea level rise

A new scientific paper describes how climatic warming is causing the ice shelves to collapse, and predicts that more ice shelves will collapse in the future, leading to accelerating sea level rise.

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Warmer Temps are causing Antarctic ice shelves to collapse, resulting in increased ice flux into the sea with concomitant increases in sea level.

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Re: Antarctica 2018

Unread postby onlooker » Sat 16 Jun 2018, 18:13:17

I think Rockdoc, is failing to acknowledge, that the climate has systemic tipping points and accelerated exponential momentum so that it will abruptly lurch into a new state. That it will do this when pushed sufficiently is a scientific certainty
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Re: Antarctica 2018

Unread postby rockdoc123 » Sat 16 Jun 2018, 18:21:01

with reference to new work in Antarctica and the Shepherd et al paper:

http://dailycaller.com/2018/06/15/antarctica-ice-sheets

Is Antarctica melting or is it gaining ice? A recent paper claims Antarctica’s net ice loss has dramatically increased in recent years, but forthcoming research will challenge that claim.
NASA glaciologist Jay Zwally first challenged the “consensus” on Antarctica in 2015 when he published a paper showing ice sheet growth in eastern Antarctica outweighed the losses in the western ice sheet.
Zwally will again challenge the prevailing narrative of how global warming is affecting the South Pole. Zwally said his new study will show, once again, the eastern Antarctic ice sheet is gaining enough ice to offset losses in the west.
Much like in 2015, Zwally’s upcoming study will run up against the so-called “consensus,” including a paper published by a team of 80 scientists in the journal Nature on Wednesday. The paper estimates that Antarctic is losing, on net, more than 200 gigatons of ice a year, adding 0.02 inches to annual sea level rise.
“Basically, we agree about West Antarctica,” Zwally told The Daily Caller News Foundation. “East Antarctica is still gaining mass. That’s where we disagree.”
Reported ice melt mostly driven by instability in the western Antarctic ice sheet, which is being eaten away from below by warm ocean water. Scientists tend to agree ice loss has increased in western Antarctica and the Antarctic Peninsula has increased.
Measurements of the eastern ice sheet, however, are subject to high levels of uncertainty. That’s where disagreements are.


“In our study East Antarctic remains the least certain part of Antarctica for sure,” Andrew Shepherd, the study’s lead author and professor at the University of Leeds, told TheDCNF.
“Although there is relatively large variability over shorter periods, we don’t detect any significant long-term trend over 25 years,” Shepherd said.
However, Zwally’s working on a paper that will show the eastern ice sheet is expanding at a rate that’s enough to at least offset increased losses the west.
The ice sheets are “very close to balance right now,” Zwally said
. He added that balance could change to net melting in the future with more warming.
So, why is there such a big difference between Zwally’s research and what 80 scientists recently published in the journal Nature?
There are several reasons for the disagreement, but the biggest is how researchers make what’s called a glacial isostatic adjustment (GIA), which takes into account the movement of the Earth under ice sheets.


As I said previously the big uncertainty is in GIA models and the resultant calculations. Zwally's original paper of a couple of years ago had EAIS increasing steadily in SMB. This latest work apparently confirms his former analysis. It will be an interesting read when it comes out.

I think Rockdoc, is failing to acknowledge, that the climate has systemic tipping points and accelerated exponential momentum so that it will abruptly lurch into a new state. That it will do this when pushed sufficiently is a scientific certainty


Yeah right, what a complete load of bollicks. When confronted with facts that do not support your theory you fall back to the ominous and never proven "tipping points". Like the bogey man they are hiding out there just waiting to get us. Jesus wept. Get over it, the Shepherd paper for all the press it got fails to prove anything dire and now Zwally is pointing out that it doesn't take much adjustment in GIA to completely wipe out all the losses.
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Re: Antarctica 2018

Unread postby onlooker » Sat 16 Jun 2018, 18:26:28

Rockdoc, I think Dissident will confirm what I just stated. In the meantime :

https://newatlas.com/climate-change-tip ... co2/50199/
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Re: Antarctica 2018

Unread postby Plantagenet » Sat 16 Jun 2018, 19:27:05

rockdoc123 wrote:if current sea level rise continues .....then the total amount of sea level rise by 2100 is about 30 cm


Image

You're just making a complete fool out of yourself on this one.

Your claim it will take 82 years to generate 30 cm of sea level rise in the year 2100 is moronic. Right now sea level is going up something like 3.3 to 3.5 mm per year. Do the math----it will only take about 9 years to get ca. 30 cm of sea level rise.

Do you get it now? If so, then please man up and acknowledge your error. :lol: :lol: :lol: :lol: :lol:

-----------------------------------------

AND here's an even neater bit of math. Since the rate of sea level rise is slowly and progressively increasing its possible to fit a curve to the trend of increasing rate of sea level rise. A recent study in the Proceedings of the National Academy of Sciences did just that, and if the current trend continues they predict about 650 cm of sea level rise by 2100. Here's a news report discussing that result.

sea-level-rise-accelerating

The prediction of ca. 650 cm of sea level rise by 2100 in the study published by the PNAS is actually more than 20 times larger then the 30 cm by 2100 you incorrectly calculated. Again, this would be a reasonable time for you to admit you made an unfortunate mistake, and then go on with the discussion. :lol: :lol: :lol: :lol:

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Re: Antarctica 2018

Unread postby dohboi » Sat 16 Jun 2018, 19:38:18

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Re: Antarctica 2018

Unread postby rockdoc123 » Sat 16 Jun 2018, 23:05:21

Your claim it will take 82 years to generate 30 cm of sea level rise in the year 2100 is moronic. Right now sea level is going up something like 3.3 to 3.5 mm per year. Do the math----it will only take about 9 years to get ca. 30 cm of sea level rise.


OK....once again read what you wrote. 3.5 mm per year time over 9 years does not give you 30 cm it gives you 30 mm or 3 cm.
Honestly, you claim to be a geophysicist and you can't convert mm to cm? I laid this out pretty simply before. Do you actually think mm and cm are the same thing?

So once again....3.5 mm/yr over 82 years is 287 mm or 28.7 cm if you can't understand simple math like this you have a problem. The projections into the future are model based on various representative concentration pathways....they are not a continuation of current trends.
Unfortunately, it doesn't seem to stop you from coming back and repeating your nonsense....but I guess making a fool of yourself isn't a problem for you. :roll:

AND here's an even neater bit of math. Since the rate of sea level rise is slowly and progressively increasing its possible to fit a curve to the trend of increasing rate of sea level rise. A recent study in the Proceedings of the National Academy of Sciences did just that, and if the current trend continues they predict about 650 cm of sea level rise by 2100. Here's a news report discussing that result.


well I doubt anyone will be going to you for math lessons anytime soon....that being said the thread is about Antarctica, my post was about the Shepherd et al paper and not the rest of contributions to sea level rise and I included the increasing rates of melt that Shepherd claim they found ignoring the fact that their time periods show no statistical difference. That is how I came up with the potential contribution from Antarctica by 2100 of 113 mm and that assumes acceleration continued when in fact since 2015 it has been going the other way (lower amounts of decreased SMB each year).

If you want to discuss sea level, in general, there is a thread for that. If you want to discuss the Shepherd paper then it would make sense to read it first.
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Re: Antarctica 2018

Unread postby onlooker » Sun 17 Jun 2018, 12:09:09

Precisely what has been referred to on this thread
"The study, by an international team of polar scientists led by Canada Research Chair Christine Dow of Waterloo’s Faculty of Environment, discovered that the process of warmer ocean water destabilizing ice shelves from below is also cracking them apart from above, increasing the chance they’ll break off."

https://uwaterloo.ca/news/news/climate- ... sea-levels
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Re: Antarctica 2018

Unread postby dissident » Sun 17 Jun 2018, 14:43:57

onlooker wrote:Rockdoc, I think Dissident will confirm what I just stated. In the meantime :

https://newatlas.com/climate-change-tip ... co2/50199/


Indeed, the global atmosphere ocean system is nonlinear and exhibits meta-stability in terms of its trajectory progression through phase space. Tipping points are jumps in phase space that linear systems cannot experience. In the case of humanity, we are not merely perturbing the system, but actually imposing a substantial forcing.

Global warming deniers do not have any understanding of dynamical systems theory (BTW, theory means proven construct and not the slang, layman notion of unproven hypothesis) and use their linear gut feelings to make all sorts of stupid claims and attempts to fob off the facts. These morons run around claiming that variability is some sort of dominant process that renders human "perturbations" irrelevant. Only morons would do this since we are talking about deterministic nonlinearity and not pure stochasticity (think quantum mechanics at the small scale). Variability is the result of actual processes. It does not dominate these processes since it is not a process itself. Pumping greenhouse gases into the atmosphere will trigger tipping points and destructive climate change. This is beyond question.
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Re: Antarctica 2018

Unread postby dohboi » Tue 19 Jun 2018, 07:50:59

Cook in East Antarctica is more unstable than previously known:

doi: 10.5194/tc-2018-107

"We have shown that despite little change over the past decade, there have been dynamic
changes in the velocity of both the Cook East and West glaciers during periods over the past
~45 years.

For Cook East we provide one of the few observations linking a short-lived increase
in velocity to a subglacial flood event, in addition to a longer-term velocity increase of 19%
between 1989 and 2001. For Cook West we link a doubling of its velocity to the near-complete loss of its floating ice shelf between 1973 and 1989..."
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Re: Antarctica 2018

Unread postby rockdoc123 » Tue 19 Jun 2018, 14:53:03

Cook in East Antarctica is more unstable than previously known:


the paper doesn't say that at all. What it points to are periods of increased velocity and advance and periods where there was retreat. West Cook retreated and hasn't re-advanced but East Cook retreated and has now re-advanced past its former margin. They have no explanation for current patterns of velocity other than suggestions which can't be substantiated because there is almost no bathymetric or ocean temperature data in the immediate area. The paper points out that the area is in balance (meaning accumulation matches losses) and that is born out by other papers which point to marginal gains in SMB in this area.
Note that the periods of increased velocity were 1 to 2 decades ago and the authors wonder if the climate might have been more variable back then.

they conclude with:

In the case of Cook West, the changes in velocity we observe in response to the loss of its floating ice shelf are some of the largest recorded in the 370 satellite era in Antarctica. However, in terms of observations of subsurface ocean temperatures, bathymetry and bed topography, it is one of the least studied. This needs to be addressed in order to fully understand the processes driving changes in the recent past and improve our understanding on how it will respond to future changes in climate.
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