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petm

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Laurentide II
« on: August 13, 2019, 07:40:47 PM »
Starting this thread in response to the following post and a few others below it on the melting thread:

https://forum.arctic-sea-ice.net/index.php/topic,2591.msg221748.html#msg221748

petm

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Re: Laurentide II
« Reply #1 on: August 13, 2019, 07:44:43 PM »
Personally, I think it's absurd to claim that we're entering a new glacial period when all of the ice on the planet is melting, rapidly. Sure, there may be more snowfall in some areas, maybe even overall -- just as there is more precipitation of all types, as expected with more evaporation. But it takes more than just snowfall to make an ice sheet...
« Last Edit: August 13, 2019, 07:51:39 PM by petm »

binntho

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Re: Laurentide II
« Reply #2 on: August 13, 2019, 07:48:01 PM »
It's been a pet theory of bbr for quite some time, although it may be some months since he last mentioned it.

RoxTheGeologist

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Re: Laurentide II
« Reply #3 on: August 13, 2019, 07:56:44 PM »

I posted a question on stupid questions noting that early and heavy snowfall is probably a good way to heat up the planet as it does a very good job of insulating against heat loss that would otherwise have been going on.

El Cid

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Re: Laurentide II
« Reply #4 on: August 13, 2019, 07:58:48 PM »
On a longer timeframe-comparison there is no cooling in the Hudson region although there is some in the short term, see chart:

Sebastian Jones

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Re: Laurentide II
« Reply #5 on: August 13, 2019, 08:04:28 PM »
It does seem counterintuitive that while Greenland is experiencing massive negative SMB that the mainland further south would find a way to go in the opposite direction.
Weird things do happen....Bbr is a pretty smart cookie, so I cannot discount him out of hand.

philopek

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Re: Laurentide II
« Reply #6 on: August 13, 2019, 09:41:17 PM »
They are both wrong.


You see, I asked to end it and with such a side note you make it impossible.

Before making such remarks after a lengthy discourse you should read first, it's so easy and if you read my text and the linked text you might start to understand that the scientific and true definition of "Ice-Age" is as long as any ice exists on planet earth. Everything else are stages of the same:

https://en.wikipedia.org/wiki/Ice_age

Users with your good reputation should be extra careful because your content weighs heavy.

Since this is a scientific place and it's mentioned so often, the scientific definition of "Ice-Age"
should be what counts.

BTW all  my previous content was copied text from various papers by scientists with doctorates and professorship on the topic.

EDIT: The Laurentides were stages of the current ice-age and they are used in street language as "the ice-age" which is not correct.

Everyone who has another OPINION can have it of course but everyone who wants to be serious and has another opinion should now start reading and diversify between official, scientific terms and common street language mostly used by those not educated or educated with a narrow focus.

A medical doctor for example won't go through as stupid or not smart but in fact, if he knows little else than what it takes for his field  of expertise and if he learned all that with thousands of hours of learning through the nights, he can indeed be neither specially smart nor well educated. For example he would probably not know what the definition of ice-age is.

One can stand in front of thousand people with 10 topics to lecture and once one would proof the the first group of hundred that they know little and are wrong, 900 others would acclaim and scream hurray, but only until it's their term to be ousted as narrow minded or narrow educated and what remains at the end of the day is one lynched man, the one who proved them all wrong a mob of thousand who killed the guy because they were hurt in their egos.

This sound unpopular, it is unpopular and the reason why it's so unpopular is because it's the sad truth.

One can go to a place with 1000 people with the same goal and a similar motivation and a similar opinion and at the end they will go to war with each other over a tiny difference in interpretation.

One of the best examples are Muslims and Christians, they have the same god, the same the same the same and still they kill each other for thousands of years because their leaders seek power and want to install and maintain their power though claiming that they know the only truth, i.e which of their joint prophets is the main prophet, they not even deny the other prophet's existence, such a joke, and the same happens here and everywhere.

BTW someone said that deleting an account is horrible and such. As long as a forum admin can BAN users, users of course can BAN the forum by deleting their account. Another one of those examples where the same is not the same.

And as long as such is mankind and feels fit to change the worlds nothing can change at all. All has been, is and will be lost in disputes over hurt egos and insisting to apply power over others, small or big.

Last but not least the discussion that lead to this thread was whether we are in an ice-age or not, i said yes and bbr said no. So this thread title should be: Are we in an ice age or not ?

Many will not be interested because they don't know what "Laurentides 1 + 2 were and will continue to believe that the ice-ages were defined by ice being where their house is now. Totally self-centered views as always.


« Last Edit: August 13, 2019, 10:25:46 PM by philopek »

bbr2314

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Re: Laurentide II
« Reply #7 on: August 13, 2019, 10:42:29 PM »
The implicit takeaway from Hansen et al 2016 is that ice sheets will soon begin to form once again. I don't see how you get temps up to -21C vs. 2000 in wide swathes of the NATL without this happening.

Just because someone's pea brain can't process the fact that the IPCC is complete garbage and that the outcome of climate change will be catastrophic WARMTH and catastrophic COLD simultaneously does not mean it will not occur.

https://www.atmos-chem-phys.net/16/3761/2016/acp-16-3761-2016.pdf

bbr2314

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Re: Laurentide II
« Reply #8 on: August 13, 2019, 10:46:41 PM »
Oh, and real world data shows that the situation is even worse than projected by Hansen. April-May 2018 and 2019 posted below.

Of course philopek will reply with "bla bla bla," so this will go over his head, and the simulations from corrupt / deluded / stupid IPCC scientists will be given preference over real-world data confirming that a scenario even worse than that projected by Hansen is now unfolding.

I would say the problem with Hansen's research is it does not provide assumptions for ice-sheet regrowth as temperatures drop below X threshold in Y regions, which will skew the actuality substantially from modeled projections -- I would think this results in some temperance of the cold in Northern Europe, and a severe worsening of the cold in much of North America.

FWIW: D-J-F temps are irrelevant as to ice sheet regrowth, in fact, warmth in this timeframe will only allow for MORE snow over most polar regions. The critical months are April, May, June, and July. 2018 saw winter extend into June and July for parts of North America, but 2019 broke this mold. I think 2020 will match or exceed 2018 due to the heat now accumulating at the Pole combining with the impacts of meltwater released from Greenland etc this summer, a feature which 2018 lacked as it saw a net mass GAIN in Greenland in spite of global temps being blah blah blah past baseline and CO2 also soaring XX% since the last mass gain year of 1972.

DrTskoul

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Re: Laurentide II
« Reply #9 on: August 14, 2019, 12:50:30 AM »
The implicit takeaway from Hansen et al 2016 is that ice sheets will soon begin to form once again. I don't see how you get temps up to -21C vs. 2000 in wide swathes of the NATL without this happening.

Just because someone's pea brain can't process the fact that the IPCC is complete garbage and that the outcome of climate change will be catastrophic WARMTH and catastrophic COLD simultaneously does not mean it will not occur.

https://www.atmos-chem-phys.net/16/3761/2016/acp-16-3761-2016.pdf

Spare us with the brain size comparisons.... maybe you have the pea brain that cannot explain it well enough for others to get...it can work both ways you see....

petm

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Re: Laurentide II
« Reply #10 on: August 14, 2019, 12:58:00 AM »
The implicit takeaway from Hansen et al 2016 is that ice sheets will soon begin to form once again.

I highly doubt that such a dramatic result would be implicit. If their models suggested it, that would be the focus or at least a focus of the paper, or indeed a separate cover-story Science paper. Nevertheless, I'm curious about what you mean. Would you mind saying what figure that is that you attached? That's a rather long PDF...

Reduced air temps (and SSTs) adjacent to rapidly melting ice caps shouldn't surprise anyone here and I don't see how it could lead to the formation of new ice sheets.

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Just because someone's pea brain can't process

These silly attacks are annoying and counterproductive to fruitful discourse. I wish everyone would cease and desist.

bbr2314

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Re: Laurentide II
« Reply #11 on: August 14, 2019, 01:05:26 AM »
The implicit takeaway from Hansen et al 2016 is that ice sheets will soon begin to form once again.

I highly doubt that such a dramatic result would be implicit. If their models suggested it, that would be the focus or at least a focus of the paper, or indeed a separate cover-story Science paper. Nevertheless, I'm curious about what you mean. Would you mind saying what figure that is that you attached? That's a rather long PDF...

Quote
Just because someone's pea brain can't process

These silly attacks are annoying and counterproductive to fruitful discourse. I wish everyone would cease and desist.

What I mean is that there is no way the NATL and adjacent landmasses could drop 10-21C and NOT end up fully covered in ice for the entirety of each year. That would put all high-elevation areas of Scandinavia and the UK *firmly* or *significantly* below 0c for their annual average temperatures and at that point there is going to be snow accumulating almost all year long.

Oh, and the same goes for the NATL under the deepest purples. The implicit output of Hansen's work would include sea ice stretching from Greenland to Iceland to the UK to Norway, with glaciation happening across all areas covered in purple.

I do not see how an average annual temperature drop of 20 degrees Celsius (even 10C) could result in anything else, in these areas that generally feature average annual temps of +5-10C.


KiwiGriff

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Re: Laurentide II
« Reply #12 on: August 14, 2019, 01:11:19 AM »
Hansen et al 2016 proposes that ocean surface temperatures will be cooled by pulses of fresh water  from retreating ice sheets.
Maintaining this will lead to a glaciation goes against the entire premise of the paper.
I would never suggest Hansen is wrong. I will strongly suggest that one paper a theory does not make.

bbr2314

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Re: Laurentide II
« Reply #13 on: August 14, 2019, 01:18:32 AM »
Hansen et al 2016 proposes that ocean surface temperatures will be cooled by pulses of fresh water  from retreating ice sheets.
Maintaining this will lead to a glaciation goes against the entire premise of the paper.
I would never suggest Hansen is wrong. I will strongly suggest that one paper a theory does not make.
It does not go against the entire premise of the paper. If the ocean and adjacent landmasses see temperature departures of the magnitude suggested by Hansen, it WOULD lead to glaciation, implicitly... this does not mean that GIS mass loss halts entirely, it means that at a certain threshold of mass loss, the surrounding land bodies, and the NATL itself, will ice over, until heat builds up again sufficient to resume the melt-glaciation seesaw.

petm

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Re: Laurentide II
« Reply #14 on: August 14, 2019, 01:29:57 AM »
I do not see how an average annual temperature drop of 20 degrees Celsius (even 10C) could result in anything else, in these areas that generally feature average annual temps of +5-10C.

So if I understand correctly, you're suggesting that the ice would shift southward? But if that started to happen, wouldn't there be a negative feedback on the melting? Where would the heat to melt the ice come from?

Edit: Ah I see you mention a teeter-totter above. Interesting thought. Seems this would require repeated, cyclic changes to global ocean circulation patterns. I guess under such a scenario, increased ice-albedo feedback would dampen global temperature rise while the GIS slowly spiraled down. I wonder how high we could pump up the atmospheric CO2 then before being forced to deal with it.  :D
« Last Edit: August 14, 2019, 01:36:50 AM by petm »

bbr2314

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Re: Laurentide II
« Reply #15 on: August 14, 2019, 01:40:51 AM »
I do not see how an average annual temperature drop of 20 degrees Celsius (even 10C) could result in anything else, in these areas that generally feature average annual temps of +5-10C.

So if I understand correctly, you're suggesting that the ice would shift southward? But if that started to happen, wouldn't there be a negative feedback on the melting? Where would the heat to melt the ice come from?

Edit: Ah I see you mention a teeter-totter above. Interesting thought. Seems this would require repeated, cyclic changes to global ocean circulation patterns. I guess under such a scenario, increased ice-albedo feedback would dampen global temperature rise while the GIS slowly spiraled down. I wonder how high we could pump up the atmospheric CO2 then before being forced to deal with it.  :D
Yes, this is what I believe will happen. I think that the ice loss / temp changes since 2012 show that we have severely underestimated the impact of GIS wasting + OHC accumulation, as there has been a very dramatic shift in temperatures since that year.

DrTskoul

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Re: Laurentide II
« Reply #16 on: August 14, 2019, 01:56:37 AM »
Why the injection of water in the Hansen paper happens at -15oC ??

Quote
Ice sheet discharge (icebergs plus meltwater) is mixed as freshwater with mean temperature −15◦C into the top three ocean layers (Fig. S6).

I would think fresh melt water is 0oC and melted sea ice is -1.8oC...

KiwiGriff

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Re: Laurentide II
« Reply #17 on: August 14, 2019, 01:57:00 AM »
Look carefully at your image from the paper above @.10:42:29 PM
It is suggesting ocean surface temperatures will fall.
The paper does not propose land surface temperatures falling much below the present.
However.
 A Cold  ocean surface will result in less Precipitation building the ice sheets above along with the sustained ice sheet retreat from the warmer bottom water.
There is no support from the paper for significant  glaciation being initiated from the cooling effects of ice melt. 
 

petm

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Re: Laurentide II
« Reply #18 on: August 14, 2019, 02:01:50 AM »
I think that the ice loss / temp changes since 2012 show that we have severely underestimated the impact of GIS wasting + OHC accumulation

Even without new ice sheet formation, increased increased snowfall could at least offset some of the ice-albedo loss due to sea ice and GIS loss. That would be a negative feedback that would expire once the GIS is gone. I wonder if such a feedback has been incorporated into models? Presumably, as apparently they are capturing the cooling and increased snowfall.

But I guess the time-frame of near-complete GIS loss is well beyond the scope of any planning. What is that timeframe anyways?

bbr2314

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Re: Laurentide II
« Reply #19 on: August 14, 2019, 03:22:15 AM »
Look carefully at your image from the paper above @.10:42:29 PM
It is suggesting ocean surface temperatures will fall.
The paper does not propose land surface temperatures falling much below the present.
However.
 A Cold  ocean surface will result in less Precipitation building the ice sheets above along with the sustained ice sheet retreat from the warmer bottom water.
There is no support from the paper for significant  glaciation being initiated from the cooling effects of ice melt.
You are incorrect. The map shows proposed land and ocean surface temperatures. The areas that see substantial falls include all land masses adjacent to the North Atlantic -- Quebec, Newfoundland, Iceland, the UK, Scandinavia, and much of Europe. Please look closely!

binntho

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Re: Laurentide II
« Reply #20 on: August 14, 2019, 07:33:53 AM »
Not that I can be bothered to read every word of the above argumentations, but I did go and look at "Hansen et al 2016" which I found here https://www.atmos-chem-phys.net/16/3761/2016/acp-16-3761-2016.pdf

But before commenting on that paper (which is bloody long and detailed) I'd like to point out that this summer, with the mega-melt ongoing in Greenland, the cold blob south of Greenland HAS DISAPPEARED.

So the theory was that the cold blob was a result of Greenland melting, and that this was slowing the AMOC down or what have you. Well, I guess it's back to the drawing board for a lot of people now!

binntho

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Re: Laurentide II
« Reply #21 on: August 14, 2019, 07:44:25 AM »
The map that bbr posted here https://forum.arctic-sea-ice.net/index.php/topic,2875.msg221842.html#msg221842 seems very counterintuitive to me. If the AMOC stops as seems indicated by the massive cold area in the North Atlantic, then presumably Greenland ice melt will slow down very rapidly, thus making the entire problem go away?

binntho

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Re: Laurentide II
« Reply #22 on: August 14, 2019, 11:00:46 AM »
Been thinking a bit more about the supposed effects that Hansen et al see from melting ice: As the Greenland ice sheet melts, it releases enough cold water quickly enough to cause localized ice age in the North Atlantic..

But Greenland ice melts mostly by contact with warm sea water, secondly by high temperatures, and thirdly by insolation.

So if the oceans around Greenland get colder with increased melt, and the air get colder as well, doesn't the melt stop?

So really this is a process that can never take off ...

bbr2314

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Re: Laurentide II
« Reply #23 on: August 14, 2019, 11:09:32 AM »
Been thinking a bit more about the supposed effects that Hansen et al see from melting ice: As the Greenland ice sheet melts, it releases enough cold water quickly enough to cause localized ice age in the North Atlantic..

But Greenland ice melts mostly by contact with warm sea water, secondly by high temperatures, and thirdly by insolation.

So if the oceans around Greenland get colder with increased melt, and the air get colder as well, doesn't the melt stop?

So really this is a process that can never take off ...

This is completely incorrect... barely any Greenland ice melts due to contact with warm sea water, high temperatures derived from +OHC are the main cause, and insolation is only effective when combined with high temps.

You are ignoring the decline in Arctic sea ice as well; as the Arctic goes increasingly ice-free, it is going to build up enormous amounts of +OHC (as it is already doing). Greenland melt ends up in the NATL, not in the Arctic, leaving the Arctic as a residual source of Greenland melt even when the NATL ices over due to mass wasting.

binntho

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Re: Laurentide II
« Reply #24 on: August 14, 2019, 11:33:17 AM »
Been thinking a bit more about the supposed effects that Hansen et al see from melting ice: As the Greenland ice sheet melts, it releases enough cold water quickly enough to cause localized ice age in the North Atlantic..

But Greenland ice melts mostly by contact with warm sea water, secondly by high temperatures, and thirdly by insolation.

So if the oceans around Greenland get colder with increased melt, and the air get colder as well, doesn't the melt stop?

So really this is a process that can never take off ...

This is completely incorrect... barely any Greenland ice melts due to contact with warm sea water, high temperatures derived from +OHC are the main cause, and insolation is only effective when combined with high temps.

How do you know that warm sea water has no effect - do you have any figures or data to back this up? I did a quick search myself and found e.g. this article http://sciencenordic.com/warm-sea-currents-caused-melting-greenland%E2%80%99s-ice and https://www.igsoc.org/annals/53/60/a60A136.pdf both of which seem to support the generally accepted (at leas in my mind) theory that warm ocean waters are a major factor in Greenland ice melt.

And I did put high temps higher than insolation, but according to Hansen, temperatures are going to collapse totally.

Quote
You are ignoring the decline in Arctic sea ice as well; as the Arctic goes increasingly ice-free, it is going to build up enormous amounts of +OHC (as it is already doing). Greenland melt ends up in the NATL, not in the Arctic, leaving the Arctic as a residual source of Greenland melt even when the NATL ices over due to mass wasting.
This sounds like a load of bull. Besides, what do you mean by +OHC ... it's not in the glossary?

peterlvmeng

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Re: Laurentide II
« Reply #25 on: August 14, 2019, 11:46:27 AM »
The map that bbr posted here https://forum.arctic-sea-ice.net/index.php/topic,2875.msg221842.html#msg221842 seems very counterintuitive to me. If the AMOC stops as seems indicated by the massive cold area in the North Atlantic, then presumably Greenland ice melt will slow down very rapidly, thus making the entire problem go away?

I am not sure if they have considered greenhouse effect. Barely melting water no matter from sea ice or ice cap however other factors remain unchange, I do not think it is a good simulation.

Normally we think melting ice slow down the north atlantic current and the earth will become cold. But the reality is more melting water, more heat wave in Europe in summer. The SST of north atlantic seems not greatly drop down. So it is just a balance to figure out the main factor the greenhouse effect or weak AMOC.

El Cid

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Re: Laurentide II
« Reply #26 on: August 14, 2019, 02:28:22 PM »
If I understood the paper correctly, they simply prescribed a certain amount of freshwater-pulse, and not considered any feedbacks (from the freshwater, namely that it leads to more arctic ice and colder temps in greenland), so binntho's argument seems valid to me.

bbr2314

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Re: Laurentide II
« Reply #27 on: August 14, 2019, 02:53:19 PM »
I literally do not know how to respond to the last sequence of posts because the implicit takeaway is that, by Binntho's logic, Greenland will not melt and we have nothing to worry about. ????? It is non sequitur after non sequitur I'm sorry if you cannot properly read Hansen's paper.

binntho

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Re: Laurentide II
« Reply #28 on: August 14, 2019, 03:15:09 PM »
I literally do not know how to respond to the last sequence of posts because the implicit takeaway is that, by Binntho's logic, Greenland will not melt and we have nothing to worry about.

No, not at all! I wonder if this is what Killian would call a straw man - I guess it is. I did not say that Greenland would not melt. I did imply that if Greenland melt causes cooling, then that would be a strong negative feedback to Greenland melt, causing it to slow down.

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????? It is non sequitur after non sequitur I'm sorry if you cannot properly read Hansen's paper.

Well it's a really very very long paper with one huge colored image that seems to invalidate any point you want to make from it, by ignoring the very strong negative feedback caused by any melt-water pulses.

Besides you forgot to explain what you mean by +OHC.

dnem

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Re: Laurentide II
« Reply #29 on: August 14, 2019, 04:01:50 PM »
OHC=Ocean Heat Content?

oren

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Re: Laurentide II
« Reply #30 on: August 14, 2019, 04:18:49 PM »
This is completely incorrect... barely any Greenland ice melts due to contact with warm sea water, high temperatures derived from +OHC are the main cause
So warm sea water has barely any effect on Greenland marine glaciers. (I disagree, never mind).
High temperatures derived from Ocean Heat Content are the main cause. (If you say so).
Aren't OHC and warm sea water synonyms, or at least highly correlated?

BTW, what happened to the other glaciation theory, the one with extra winter snow causing an albedo-driven cooling?

El Cid

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Re: Laurentide II
« Reply #31 on: August 14, 2019, 04:34:57 PM »
I went thru the paper again. They specifically state that the prescribe a certain amount of freswater pulse, while not considering that the cold Arctic/Greenland caused by the freswater pulse, would simply stop the freswater pulse:

"Freshwater  injection  is  360 Gt year−1(1 mm  sea  level)  in2003–2015, then grows with 5-, 10- or 20-year doubling time(Fig. 5) and terminates when global sea level reaches 1 or 5 m."

However they state:

"When freshwater injection in the Southern Ocean is halted,global  temperature  jumps  back  within  two  decades to the value it would have has without the freshwater injections"

The model is simple: regardless of everything, it pours fresh water into the ocean.



gerontocrat

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Re: Laurentide II
« Reply #32 on: August 14, 2019, 05:06:52 PM »
This is completely incorrect... barely any Greenland ice melts due to contact with warm sea water, high temperatures derived from +OHC are the main cause
So warm sea water has barely any effect on Greenland marine glaciers. (I disagree, never mind).
High temperatures derived from Ocean Heat Content are the main cause. (If you say so).
Aren't OHC and warm sea water synonyms, or at least highly correlated?

BTW, what happened to the other glaciation theory, the one with extra winter snow causing an albedo-driven cooling?
Some basic data about Greenland's mass changes.

Greenland loses more ice from calving and contact of marine-terminating glaciers with the ocean than from surface melting.

From DMI (see postings in Greenland thread)

On average, accumulated snowfall in the 9 months September to May adds around just under 600GT to Greenland's SMB.
Average surface melting in the 3 months June to August is about 200GT,
leaving a net SMB yearly gain on average of just under 400 GT.

GRACE- + GRACE FO data (still waiting for latest data from Potsdam)
On average 2009-2019, Annual Greenland mass loss has been around 250 million GT p.a.

Arithmetic tells you that Mass loss from calving and sea-water melt is therefore around 600GT to 700GT annually.

How much is calving and how much is sea-water melt I do not know. I wonder if anyone does.

One thing is for is for sure, ice mass loss from calving and sea-water melt continues for 12 months of the year, even if reduced in winter.
Calving is partly a function of gravity (though warming glaciers lose strength and surface melting (moulins etc) lubricate the base?) They tell me gravity is a 24/7 effect.
Surface sea ice around Greenland will not stop seawater melting of glaciers terminating at the ocean at depth. AbruptSLR has posted much on how movement of warmer water southwards at great depth is a major and increasing factor in Antarctic melt.

Data? Shock? Horror?

And that is all I am going to say about that on this thread
« Last Edit: August 14, 2019, 07:10:04 PM by gerontocrat »
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DrTskoul

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Re: Laurentide II
« Reply #33 on: August 14, 2019, 07:03:25 PM »
I went thru the paper again. They specifically state that the prescribe a certain amount of freswater pulse, while not considering that the cold Arctic/Greenland caused by the freswater pulse, would simply stop the freswater pulse:

"Freshwater  injection  is  360 Gt year−1(1 mm  sea  level)  in2003–2015, then grows with 5-, 10- or 20-year doubling time(Fig. 5) and terminates when global sea level reaches 1 or 5 m."

However they state:

"When freshwater injection in the Southern Ocean is halted,global  temperature  jumps  back  within  two  decades to the value it would have has without the freshwater injections"

The model is simple: regardless of everything, it pours fresh water into the ocean.

They also prescribe the temperature of the freshwater addition as -15oC... why ?

El Cid

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Re: Laurentide II
« Reply #34 on: August 14, 2019, 08:25:37 PM »
I went thru the paper again. They specifically state that the prescribe a certain amount of freswater pulse, while not considering that the cold Arctic/Greenland caused by the freswater pulse, would simply stop the freswater pulse:

"Freshwater  injection  is  360 Gt year−1(1 mm  sea  level)  in2003–2015, then grows with 5-, 10- or 20-year doubling time(Fig. 5) and terminates when global sea level reaches 1 or 5 m."

However they state:

"When freshwater injection in the Southern Ocean is halted,global  temperature  jumps  back  within  two  decades to the value it would have has without the freshwater injections"

The model is simple: regardless of everything, it pours fresh water into the ocean.

They also prescribe the temperature of the freshwater addition as -15oC... why ?

I was also surprised by that. Don't know the reason

MyACIsDying

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Re: Laurentide II
« Reply #35 on: August 14, 2019, 09:12:07 PM »
I went thru the paper again. They specifically state that the prescribe a certain amount of freswater pulse, while not considering that the cold Arctic/Greenland caused by the freswater pulse, would simply stop the freswater pulse:

"Freshwater  injection  is  360 Gt year−1(1 mm  sea  level)  in2003–2015, then grows with 5-, 10- or 20-year doubling time(Fig. 5) and terminates when global sea level reaches 1 or 5 m."

However they state:

"When freshwater injection in the Southern Ocean is halted,global  temperature  jumps  back  within  two  decades to the value it would have has without the freshwater injections"

The model is simple: regardless of everything, it pours fresh water into the ocean.

They also prescribe the temperature of the freshwater addition as -15oC... why ?

I was also surprised by that. Don't know the reason

From the article: Ice sheet discharge (icebergs plus meltwater) is mixed as freshwater with mean temperature −15 ◦C into the top three ocean layers

At this point they're describing massive greenland losses to the tune of melting the entire icesheet out (7m sea level rise). That would involve a lot of icebergs dropping into the Atlantic at core temps of -15 to -20 oC.  *Ref1

I find it fascinating tbh, the SST anomaly map at https://climatereanalyzer.org/clim/sst/ shows a decent impact on the region south of Greenland (4 degree cooling?) as sea levels have risen 4-6cm during that time.

Ref1: https://www.sciencedirect.com/science/article/pii/0165232X84900089


Klon

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Re: Laurentide II
« Reply #36 on: August 14, 2019, 09:20:50 PM »
I'm sorry to say, but people who talk like bbr are zealots and bullies, and impossible to have a rational discussion with.

DrTskoul

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Re: Laurentide II
« Reply #37 on: August 14, 2019, 09:49:15 PM »
I went thru the paper again. They specifically state that the prescribe a certain amount of freswater pulse, while not considering that the cold Arctic/Greenland caused by the freswater pulse, would simply stop the freswater pulse:

"Freshwater  injection  is  360 Gt year−1(1 mm  sea  level)  in2003–2015, then grows with 5-, 10- or 20-year doubling time(Fig. 5) and terminates when global sea level reaches 1 or 5 m."

However they state:

"When freshwater injection in the Southern Ocean is halted,global  temperature  jumps  back  within  two  decades to the value it would have has without the freshwater injections"

The model is simple: regardless of everything, it pours fresh water into the ocean.

They also prescribe the temperature of the freshwater addition as -15oC... why ?

I was also surprised by that. Don't know the reason

From the article: Ice sheet discharge (icebergs plus meltwater) is mixed as freshwater with mean temperature −15 ◦C into the top three ocean layers

At this point they're describing massive greenland losses to the tune of melting the entire icesheet out (7m sea level rise). That would involve a lot of icebergs dropping into the Atlantic at core temps of -15 to -20 oC.  *Ref1

I find it fascinating tbh, the SST anomaly map at https://climatereanalyzer.org/clim/sst/ shows a decent impact on the region south of Greenland (4 degree cooling?) as sea levels have risen 4-6cm during that time.

Ref1: https://www.sciencedirect.com/science/article/pii/0165232X84900089


yeah but the surface of the iceberg is 0oC.  And freshwater mixes much more readily with the ocean layers. The iceberg just floats 10% of it exposed to air 90% below water. Barely at the skin of the ocean that can exchange heat with the air and be heated by the sun readily. The third layer in their model ...not so... so I suspect they are a cooling the two layers of the ocean below the first much more than they would otherwise.

MyACIsDying

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Re: Laurentide II
« Reply #38 on: August 14, 2019, 10:17:25 PM »
Can mixing of freshwater at -15oC into the sea mean that the freshwater (icebergs) stay in ice form. If bottom melt is lower then mass gain from influx and precipitation, a new ice sheet forms below Greenland? As the article mentions, it would be very regional while the rest of the world heats up and attacks it form all sides.

If it forms it may get a nice spin to it, looking at the pressure systems commonly seen in the area, possibly to be used as natural cross Atlantic hop-on hop-off ferry? :)

TerryM

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Re: Laurentide II
« Reply #39 on: August 14, 2019, 10:49:23 PM »
Liquid water a -15C ain't going to happen at oceanic salinities. It's a typo or a misinterpretation.
Terry ;)

petm

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Re: Laurentide II
« Reply #40 on: August 14, 2019, 10:56:36 PM »
Quote
Ice sheet discharge (icebergs plus meltwater) is mixed as freshwater with mean temperature −15 ◦C into the top three ocean layers (Fig. S6).

They're talking about the mean temp of icebergs plus meltwater => A lot of icebergs.

bbr2314

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Re: Laurentide II
« Reply #41 on: August 15, 2019, 12:10:46 AM »
Liquid water a -15C ain't going to happen at oceanic salinities. It's a typo or a misinterpretation.
Terry ;)
Misinterpretation as is most else in this thread; the anomalies are just that, ANOMALIES versus current temperatures, and that is further proof it will be quite frozen since -15C or whatever versus today (anything -10C or lower in that region) would be ice-covered, probably year-round.

I'm sorry to say, but people who talk like bbr are zealots and bullies, and impossible to have a rational discussion with.

Who r u ok bye

binntho

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Re: Laurentide II
« Reply #42 on: August 15, 2019, 07:43:27 AM »
<snip>
I find it fascinating tbh, the SST anomaly map at https://climatereanalyzer.org/clim/sst/ shows a decent impact on the region south of Greenland (4 degree cooling?) as sea levels have risen 4-6cm during that time.
</snip>

Well as I've been trying to pout out, this region south of Greenland is no longer cold.

The persistent "cold blob" that you are referring here (I assume) disappeared last month, first time in several years, and now that same area is excessively warm.

At the same time, Greenland is melting like never before. If that "cold blob" doesn't reassert itself, all theories about a connection between Greenland melt and N-Atlantic sea temps are out of the window (including bbr's).

binntho

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Re: Laurentide II
« Reply #43 on: August 15, 2019, 07:45:32 AM »
Liquid water a -15C ain't going to happen at oceanic salinities. It's a typo or a misinterpretation.
Terry ;)
Misinterpretation as is most else in this thread; the anomalies are just that, ANOMALIES versus current temperatures, and that is further proof it will be quite frozen since -15C or whatever versus today (anything -10C or lower in that region) would be ice-covered, probably year-round.

Strangely dissonant argumentation. When somebody points out the totally irrealistically low temperatures assumed in the paper, you double down and say that they are even lower!

Have you given up on trying to argue your own theories?

bbr2314

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Re: Laurentide II
« Reply #44 on: August 15, 2019, 08:00:34 AM »
<snip>
I find it fascinating tbh, the SST anomaly map at https://climatereanalyzer.org/clim/sst/ shows a decent impact on the region south of Greenland (4 degree cooling?) as sea levels have risen 4-6cm during that time.
</snip>

Well as I've been trying to pout out, this region south of Greenland is no longer cold.

The persistent "cold blob" that you are referring here (I assume) disappeared last month, first time in several years, and now that same area is excessively warm.

At the same time, Greenland is melting like never before. If that "cold blob" doesn't reassert itself, all theories about a connection between Greenland melt and N-Atlantic sea temps are out of the window (including bbr's).
It hasn't disappeared, there is a huge remnant cold blob stretching across the NATL from Newfoundland on East, a relic of this spring's melt.

Greenland melts every year in recent record, even if it saw gain in 2018, meaning there is always flux in the NATL and it isn't necessarily abnormal. The cold pool usually weakens in summer and becomes much more prominent in winter to spring. This has been a recurring theme the past few years, the main source of the anomaly in my opinion is now the +SWE balance in North America, worsening each year, and melting out later and later.


binntho

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Re: Laurentide II
« Reply #45 on: August 15, 2019, 08:22:41 AM »
<snip>
I find it fascinating tbh, the SST anomaly map at https://climatereanalyzer.org/clim/sst/ shows a decent impact on the region south of Greenland (4 degree cooling?) as sea levels have risen 4-6cm during that time.
</snip>

Well as I've been trying to pout out, this region south of Greenland is no longer cold.

The persistent "cold blob" that you are referring here (I assume) disappeared last month, first time in several years, and now that same area is excessively warm.

At the same time, Greenland is melting like never before. If that "cold blob" doesn't reassert itself, all theories about a connection between Greenland melt and N-Atlantic sea temps are out of the window (including bbr's).
It hasn't disappeared, there is a huge remnant cold blob stretching across the NATL from Newfoundland on East, a relic of this spring's melt.

Now there is an unsubstantiated claim if there ever was. On what basis whatsoever can you state that the cold anomalies in mid latitude Atlantic is a "relic of this spring's melt".

Quote

Greenland melts every year in recent record, even if it saw gain in 2018, meaning there is always flux in the NATL and it isn't necessarily abnormal. The cold pool usually weakens in summer and becomes much more prominent in winter to spring.
<snip>
Has it? Well, I do like it if people support their claims with evidence. Those that can't be bothered don't really believe in what they are saying. So let's have a look at mid-august for the last 10 years (gif, further down). Rather inconclusive, to my mind, although the "cold blob" seems to have been very prominent 2015, 2017 and 2018, but missing 2019. Rather inconclusive, if you ask me. But I'll admit that 2016 didn't have a cold blob in mid august.

binntho

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Re: Laurentide II
« Reply #46 on: August 15, 2019, 08:46:17 AM »
<snip>
This has been a recurring theme the past few years, the main source of the anomaly in my opinion is now the +SWE balance in North America, worsening each year, and melting out later and later.

Are you saying that the main source of the "cold blob" anomaly is the +SWE balance in North America? How would that work?

I am assuming  that by SWE you mean "Snow Water Equivalent". So let's see if there are any obvious changes in snow cover (and snow amount) over the last years.

First is a graph from https://climate.rutgers.edu/snowcover/chart_anom.php?ui_set=0&ui_region=nhland&ui_month=7 showing snow extent. Not really any obvious upwards trends, seems to be mostly downward.

But I know that you are talking about SWE, not snow cover. It's surprisingly difficult to find data to compare between years, perhaps you have something you could show us? The best I could do was the second image, from https://globalcryospherewatch.org/assessments/snow/2018/

The top year is 2018, followed by 1999 in second, 2000 in third, 2008 in fourth. No real +SWE trend here, except for 2018 all the recent years are in the middle of the pack.

oren

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Re: Laurentide II
« Reply #47 on: August 15, 2019, 08:47:47 AM »
The cold pool usually weakens in summer and becomes much more prominent in winter to spring. This has been a recurring theme the past few years, the main source of the anomaly in my opinion is now the +SWE balance in North America, worsening each year, and melting out later and later.
This has indeed been a recurring theme on the forum the past few years, but is not true (or requires much better proof than just handwaving). The meltwater anomaly actually flowing into the North Atlantic is not as high as you think it is, even when Snow Water Equivalent is much higher than normal.

Where will all the snowmelt go?


Besides flowing in multiple directions and not just into the "NATL", there's also sublimation, evaporation, and soil infiltration.

To prove actual effect on the NATL, one must show differences in the spring discharge of relevant rivers. The best practice is also to compare it to the normal discharge, the size of the relevant ocean area, direct rain and snow freshening of the ocean itself, and Greenland meltwater discharge (which is time-shifted by some months compared to NA snowmelt). It would also be useful to check river water temperature to verify how cold the water actually is.

KiwiGriff

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Re: Laurentide II
« Reply #48 on: August 15, 2019, 09:00:21 AM »

North America Snow cover is declining in both spring and summer.
https://www.epa.gov/climate-indicators/climate-change-indicators-snow-cover

gerontocrat

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Re: Laurentide II
« Reply #49 on: August 15, 2019, 10:07:14 AM »
Most of the models say snow will increase at high latitudes - warmer air with more water in it.
They also say that at lower latitudes the snow line is moving North and will continue to move North and to higher altitudes.

It snowed an awful lot in North America  Feb / March 2019, and melted out in double quick time. Hudson Bay melted out quicker than in 2018, and Baffin Bay SSTs are very high.

"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
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