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When will the Arctic Extent dip below 1,000,000 Km^2

2018-2019
12 (17.9%)
2020-2025
21 (31.3%)
2026-2030
13 (19.4%)
2031-2040
15 (22.4%)
2041-2060
2 (3%)
2061-2080
0 (0%)
2081-2099
1 (1.5%)
2100-beyond
3 (4.5%)

Total Members Voted: 64

Voting closed: July 27, 2018, 07:46:32 AM

Author Topic: When will the Arctic Go Ice Free?  (Read 71975 times)

kassy

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Re: When will the Arctic Go Ice Free?
« Reply #500 on: July 11, 2019, 07:47:01 PM »
I think the BOE timing is also important.

If we hit BOE on the last day of the season we will have a gloomy party but things go on as they go.

If we get a lot of open sea early in those central arctic seas and huge storms there this could mix up lots of heat from the deep. And mix waters. Not sure how much you need to wreck the halocline but the less salty water is from rivers or ice so that might make interesting refreeze patterns in the middle?

Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #501 on: July 11, 2019, 07:51:36 PM »
I know it is OT (sry) but I attach this chart for gerontocrat regarding drowning in the Mediterranean and the number of migrants.

Truth is migrants arrive mostly (exception: Syrian war refugees) looking for a job and once they are not welcome anymore, they get the message and don't come anymore
The OT continues.

So we create Fortress Europe - just like Trump in the USA.
How civilised.

Does this stop climate / political / economic refugees increasing?
No. They get trapped in appalling conditions in Libya etc etc.
Out of sight, out of mind.
How civilised.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

aslan

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Re: When will the Arctic Go Ice Free?
« Reply #502 on: July 11, 2019, 08:01:08 PM »
Sorry to quote myself but the end of the thinking woul have been too much off topic I think :

To add to the discussion about the begining of the end, June 2019 was the warmest month of June regarding SST in Bering sea and Bering strait according to reanalysis.
Aans as an illustration, Kotzebue is near or above record Tn and Td since 4 days : http://ogimet.com/cgi-bin/gsynres?ind=70133&ano=2019&mes=7&day=11&hora=12&min=0&ndays=30

The transport is strong this year trough the strait, and so the SST are more asymetric than usual, but despite this all the Bering sea and Chuckchi sea are at or above record level, and strong currents are burring this heat to great depth. The chart from the DMI is now saturated with red, after reaching a "low" the 4th. An incredible amount of heat is building into Arctic Ocean, and is now wanting to ease.

In 2009 Eisenman published a paper : https://www.pnas.org/content/106/1/28.short which was later criticized : https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011GL048739 or https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-14-00654.1 but not fully rejected : https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011JD015653

In the same time, with lower sea ice cover, there is an increase in cloud cover in Autumn and Winter, acting as a positive feedback insulating the open ocean below.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2010JD013900

I think we are nearer and nearer to the point where open ocean, increase poleward oceanic heat flux, and increase SST, will make the system unstable. As a warm, sunny, open Arctic in Spring and Summer will build up a lot of energy. In Autumn and Winter, warm ocean, help by poleward heat transport, will moisten the atmospheric column, with an increase in low clouds, insulating the Ocean and allowing the heat build up in Summer to be lost slowly. As the next Summer comes, even though the weather is the friend of ice, as there is no more ice, heat can build up again in the system -and it is quite unlikely to see low cloud cover increased in Summer as in Winter- and bringing the all Arctic to a state change.

Glen Koehler

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Re: When will the Arctic Go Ice Free?
« Reply #503 on: July 11, 2019, 08:18:52 PM »
BOE-year: "aaaah, blue ocean" "oh, nothing happens, it just refreezes"
BOE-year+1: "oh, again blue ocean" and we will have some weird weather, but those are just 'incidents'
BOE-year+2: "that's weird, 3rd BOE in a row and too early" and weather patterns become unpredictable in northern hemisphere with lots of extreme weather and reality finally sinks in

 :) Yup, human adaptability is huge with both good and bad consequences.

    Wipneus monthly volume chart ...
 https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/piomas/grf/piomas-trnd2.png?attachauth=ANoY7crjDWOoXxuYh--3XZJMMEyECWySrgq9Q6TOUN13dC9ljMI_ZkqhIWoNNcgTFYxBjLxvMe3STZLbt3k6bd0GwBpqzGkzohemPAA3GvfzG6SssxfZyFH-g31mVYUi2ry5mVuUDXgqskqLyP-DxntNev3GJXMUYPhCqQkciQp6wMWdg2ZwozcLhLTUP5cobWGW4oqexYFgcc5c_0LIY1S59DGxmZW-Fjn61fUNUVGaZPJ2bmTzGpCSJLsnGmLbSmB9feyuhBT_&attredirects=0

    ... shows that August (and October) only trail September by about 2 years.  Since September is pretty flat on the volume curve, it doesn't seem like it would take too many years for a BOE day in September to lead to a full month September BOE.  Then, with the usual annual variations adding a few years of noise, we might have a BOE for much of August.  And that would create some serious albedo change and create a new "melting momentum" that might not be polite enough to stop by the time we notice. 

     In recent interview Peter Wadhams threw out a concept I hadn't heard before.  With continued loss of ASI there could be a tipping point where polar jet stream doesn't just weaken and wobble, but just goes away completely.  I don't know if that is at all realistic, but if it did happen it would seem to be like Jennifer Francis thesis on steroids, with potential drastic changes in weather patterns, or just weather chaos until new patterns emerged.  I guess there's always a pattern, but if there was a complete loss of polar jet stream steering of weather systems that just seems like crazy town.
« Last Edit: July 11, 2019, 08:28:31 PM by Glen Koehler »

pietkuip

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Re: When will the Arctic Go Ice Free?
« Reply #504 on: July 11, 2019, 09:16:56 PM »
In recent interview Peter Wadhams threw out a concept I hadn't heard before.  With continued loss of ASI there could be a tipping point where polar jet stream doesn't just weaken and wobble, but just goes away completely.
I suppose that would be the single large Hadley cell extending from equator to pole? As in hothouse paleoclimates.

HapHazard

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Re: When will the Arctic Go Ice Free?
« Reply #505 on: July 11, 2019, 09:21:07 PM »
Yep, it's the atmospheric effects that concern me most, going forward. (jet streams, hadley cell)

jdallen

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Re: When will the Arctic Go Ice Free?
« Reply #506 on: July 11, 2019, 09:35:52 PM »
Find me a paper that describes what happens after the first BOE...
That seems to be very uncertain. The IPCC states "with high confidence" that there will be no hysteresis ...
<snippage>
I think we're already seeing hysteresis with changes in feedback and increased uptake of heat, not to mention the extermination of ice more than 4 years old.  It would take generations of pre-1980's weather to restore the pack to the state it was in before 2010, much less earlier.
This space for Rent.

Tom_Mazanec

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Re: When will the Arctic Go Ice Free?
« Reply #507 on: July 12, 2019, 02:29:31 AM »
 A BOE will most certainly not cause the end of all life on earth, not by a long shot. Only the end of modern civilization and, overtime, a huge chunk of the human population. Most of nature will be just fine after a few hundred years of climate stability. A scientist 50k years from now will


Archimid, your prediction cut off in mid-sentence. What was it?
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Archimid

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Re: When will the Arctic Go Ice Free?
« Reply #508 on: July 12, 2019, 03:45:15 AM »

The research like Tietsche et al and Schroeder and Connolley
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007GL030253

I asked for a resource with a BOE before 2070 for a good reason. If the model that you use says the arctic will have ice in the summer 50 years from now, that model is missing something huge, a BOE will happen much sooner than that. Thus a model that has the ice going by 2070 is very likely to assume the ice will return, because it is already underestimating the changes happening in the Arctic.

The paper you posted uses HadCM3. From a quick search HadCM3 predicts ice free during summer somewhere around 2080. That ain't happening. Please try a newer source, with a model that makes a prediction for the first BOE that more closely matches the observations.

Quote
suggests that the lack of ice from BOE means little snow can be supported by ice during time when there are reasonable amounts of snow. The ice gets thicker than usual (not thinner) during the freeze season due to lack of insulating snow.

I don't understand. Can you explain to me how can there be conditions for sea ice formation but no condition for snow? It seems the opposite will happen. There will be more snow than ever before. By your own argument that should result in warming. The data clearly indicates that snow fall during fall is increasing.

Quote
  After two years it gets back to pretty near normal. This research is covering situation where unusual weather causes a BOE when the climate is not really ready for a BOE yet.

Actually, this research is covering an imaginary situation where the first BOE happens close to 2080.

Quote
I think arguing that one BOE causes next year to have longer BOE is like arguing that a record low ice volume means the next year will definitely beat that record.

All things being equal, a record low volume increases the chances of a lower volume next year for the mere fact of having a lower starting point. But the argument of  why the first BOE highly increases the chances of a BOE the year after is much more nuanced than that and with better fundamentals.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

Archimid

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Re: When will the Arctic Go Ice Free?
« Reply #509 on: July 12, 2019, 04:09:06 AM »
The impacts of a BOE is simply a continuum of what we are already seeing. The very low SIE and SIA we are reaching now are already impacting the weather across the NH. While we define a BOE as less than 1 million square kilometers, NH weather will see no real diffirence between 1.4 and 0.8 million square kilometers.

I agree that it is a continuum. It has already started. From now on things only get worse as more open Arctic is warmed and the atmospheric currents start running amok. Things get progressively worse as ASI shrinks during summer and the Arctic winter keeps its meteoric temperature increase. By the time a BOE is here ( excluding sudden BOE) we'll be in enough trouble. But a BOE makes things worse, much worse. The year after the first BOE, by definition there will only be first year ice.  It will lead to another BOE , but earlier, and with more heat to dissipate before freezing begins. This will warm the Arctic faster than it is warming now, with global consequences to match.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

Archimid

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Re: When will the Arctic Go Ice Free?
« Reply #510 on: July 12, 2019, 04:16:56 AM »
A BOE will most certainly not cause the end of all life on earth, not by a long shot. Only the end of modern civilization and, overtime, a huge chunk of the human population. Most of nature will be just fine after a few hundred years of climate stability. A scientist 50k years from now will


Archimid, your prediction cut off in mid-sentence. What was it?

My apologies, I thought I deleted that. I was trying to make a point that a scientist long into the future will not know about our abrupt climate change problem because they will be surrounded by green, just like we are today. They might assume that because it is green and there is life around them humanity's climate change problem never happened.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

nanning

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Re: When will the Arctic Go Ice Free?
« Reply #511 on: July 12, 2019, 05:53:21 AM »
<snippage>
     In recent interview Peter Wadhams threw out a concept I hadn't heard before.  With continued loss of ASI there could be a tipping point where polar jet stream doesn't just weaken and wobble, but just goes away completely.  I don't know if that is at all realistic, but if it did happen it would seem to be like Jennifer Francis thesis on steroids, with potential drastic changes in weather patterns, or just weather chaos until new patterns emerged.  I guess there's always a pattern, but if there was a complete loss of polar jet stream steering of weather systems that just seems like crazy town.
Hi Glen, I'd like to read/listen to this interview. Do you perhaps have a link?
"It is preoccupation with possessions, more than anything else, that prevents us from living freely and nobly" - Bertrand Russel

crandles

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Re: When will the Arctic Go Ice Free?
« Reply #512 on: July 12, 2019, 12:43:46 PM »


I asked for a resource with a BOE before 2070 for a good reason. If the model that you use says the arctic will have ice in the summer 50 years from now, that model is missing something huge, a BOE will happen much sooner than that. Thus a model that has the ice going by 2070 is very likely to assume the ice will return, because it is already underestimating the changes happening in the Arctic.

The paper you posted uses HadCM3. From a quick search HadCM3 predicts ice free during summer somewhere around 2080. That ain't happening. Please try a newer source, with a model that makes a prediction for the first BOE that more closely matches the observations.

You might want a newer source and better model, but basically tough: If it doesn't exist, then you are not going to get it. If there are two papers saying the same thing, then another paper is unlikely to be published unless it is saying something markedly different.

Quote
Quote
suggests that the lack of ice from BOE means little snow can be supported by ice during time when there are reasonable amounts of snow. The ice gets thicker than usual (not thinner) during the freeze season due to lack of insulating snow.

I don't understand. Can you explain to me how can there be conditions for sea ice formation but no condition for snow? It seems the opposite will happen. There will be more snow than ever before. By your own argument that should result in warming. The data clearly indicates that snow fall during fall is increasing.

I agree there will be more snow fall, but if this falls on open water because the ice hasn't formed yet then the snow is not supported by ice and melts in ocean rather than persisting. I do find the conclusion slightly odd in that I expect the snow season to be extended until surrounding area is mostly ice covered. So perhaps the effect is that the minimum of the season becomes broad and flatish but with the freeze over happening later then it happens faster. This leaves a shorter period when the ice is able to support snow and there is reasonable amounts of snow falling.

Not sure of my mechanism described above, but the models seem to predict it and they are much more likely to include lots of things we are unlikely to be able to accurately describe.


Quote
Quote
  After two years it gets back to pretty near normal. This research is covering situation where unusual weather causes a BOE when the climate is not really ready for a BOE yet.

Actually, this research is covering an imaginary situation where the first BOE happens close to 2080.

The models are far from perfect and 2080 does seem late. But they are better than nothing, you have to work with the tools you have got not the ones you would like, and the models show the same thing for 2020 2040 and 2060. If you think it is happening faster, why is there anything much wrong with treating 2060 as if it is just an incorrect label and that is more representative of maybe 2025?

Quote
Quote
I think arguing that one BOE causes next year to have longer BOE is like arguing that a record low ice volume means the next year will definitely beat that record.

All things being equal, a record low volume increases the chances of a lower volume next year for the mere fact of having a lower starting point. But the argument of  why the first BOE highly increases the chances of a BOE the year after is much more nuanced than that and with better fundamentals.

We didn't get new record in year following 2012, 2007, ... Better fundamentals, yes in direction I am arguing IMO, but you just choose to question/dismiss.

Archimid

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Re: When will the Arctic Go Ice Free?
« Reply #513 on: July 12, 2019, 01:00:29 PM »
Quote
But they are better than nothing, you have to work with the tools you have got not the ones you would like, and the models show the same thing for 2020 2040 and 2060.

Let me be very clear about this. In the model that predicts a BOE by 2080, if you instantly remove the ice in 2020, 2040, or 2060 the ice immediately comes back. Well of course it does. The model is underestimating melt and/or overestimating freeze.

A wrong model is worse than nothing, if you make decisions according to the wrong model.

However, as the arctic keeps changing and showing scientist new secrets, I'm sure that better models will emerge.

Quote
You might want a newer source and better model, but basically tough: If it doesn't exist, then you are not going to get it. If there are two papers saying the same thing, then another paper is unlikely to be published unless it is saying something markedly different.

You don't think missing the first BOE by 4 decades (possibly more) is something markedly different?
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

crandles

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Re: When will the Arctic Go Ice Free?
« Reply #514 on: July 12, 2019, 01:44:13 PM »
Just because a model is wrong or very poor on one topic doesn't mean the model is useless at everything.

The models are all over the place on when we get a BOE. So you would be crazy to trust them on that.

OTOH if several models are showing at several different attempts that there is no hyteresis and reliably show they are more likely to bounce back the following period after an unusual disturbance, what then should you conclude?

Should you cautiously trust them on such matters or throw the baby out with the bathwater leaving yourself nothing to rely on?

If you choose the latter, there doesn't seem much more to say.

We don't trust long term weather forecasts but climate models are useful. This is nothing more than working out when and when not to trust such models.

Quote
You don't think missing the first BOE by 4 decades (possibly more) is something markedly different?

If the paper is on the topic of when the first BOE will be, the models are all over the place so one new model saying something different doesn't seem particularly new or important.

If the paper is on the topic of what happens after instantaneous removal of sea ice then what happens after instantaneous removal has to be markedly different to make it markedly different.





Klondike Kat

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Re: When will the Arctic Go Ice Free?
« Reply #515 on: July 12, 2019, 01:55:51 PM »
The abrupt changes in planetary climate that a BOE will bring are not magic. They are simple physics. The Earth has had a planetary refrigerator for likely millions of years. After a BOE that refrigerator fails and the NH will know true climate change. There won't be any denying because we'll be busy surviving.

I'm not arguing against logic here. It is frustrating to see how intelligent people who are aware of the role of arctic sea ice on atmospheric and oceanic patterns can't see the destruction that will ensue as the arctic disappears. The destruction has already started and the Arctic has barely begun to change.

But I may be wrong, so let's get to the science. Find me a paper that describes what happens after the first BOE, that doesn't ignore the ASI teleconections to the rest of the world and predicts a BOE much sooner than 2070.

Good luck with it.

The impacts of a BOE is simply a continuum of what we are already seeing. The very low SIE and SIA we are reaching now are already impacting the weather across the NH. While we define a BOE as less than 1 million square kilometers, NH weather will see no real diffirence between 1.4 and 0.8 million square kilometers.

I found this analysis of a BOE event to be rather informative.

https://climatetippingpoints.info/2019/04/02/fact-check-will-an-ice-free-arctic-trigger-a-climate-catastrophe/

crandles

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Re: When will the Arctic Go Ice Free?
« Reply #516 on: July 12, 2019, 05:57:13 PM »
I found this analysis of a BOE event to be rather informative.

https://climatetippingpoints.info/2019/04/02/fact-check-will-an-ice-free-arctic-trigger-a-climate-catastrophe/

Nice but surprisingly little about negative winter ice thickness/insulation negative feedback.

crandles

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Re: When will the Arctic Go Ice Free?
« Reply #517 on: July 12, 2019, 06:17:09 PM »
Global warming of 1.5C IPCC draft report, sorry if this has been quoted and discussed before. Probably not supposed to quote it yet but at this level and if it is available....

Quote
11 3.3.8 Sea ice
12
13 Summer sea ice in the Arctic has been retreating rapidly in recent decades. During the period 1997 to 2014
14 for example, the monthly mean sea-ice extent during September decreased on average by 130,000 km² per
15 year (Serreze and Stroeve, 2015). This is about four times as fast as the September sea-ice loss during the
16 period 1979 to 1996. Also sea-ice thickness has decreased substantially, with an estimated decrease in ice
17 thickness of more than 50% in the central Arctic (Lindsay and Schweiger, 2015). Sea-ice coverage and
18 thickness also decrease in CMIP5-model simulations of the recent past, and are projected to decrease in the
19 future (Collins et al., 2013). However, the modeled sea-ice loss in most CMIP5 models is much weaker
20 than observed. Compared to observations, the simulations are weak in terms of their sensitivity to both
21 global mean temperature rise (Rosenblum and Eisenman, 2017) and to anthropogenic CO2 emissions (Notz
22 and Stroeve, 2016). This mismatch between the observed and modeled sensitivity of Arctic sea ice implies
23 that the multi-model-mean response of future sea-ice evolution probably underestimates the sea-ice loss for
24 a given amount of global warming. To address this issue, studies estimating the future evolution of Arctic
25 sea ice tend to bias correct the model simulations based on the observed evolution of Arctic sea ice in
26 response to global warming. Often based on such bias correction, pre-AR5 and post-AR5 studies agree that
27 for 1.5 °C global warming relative to pre-industrial levels, the Arctic Ocean will maintain a sea-ice cover
28 throughout summer for most years (Collins et al., 2013; Notz and Stroeve, 2016; Screen and Williamson,
29 2017; Jahn, 2018; Niederdrenk and Notz, 2018; Sigmond et al., 2018). For 2°C global warming relative to
30 pre-industrial levels, chances of an ice-free Arctic during summer are substantially higher (Screen and
31 Williamson, 2017; Jahn, 2018; Niederdrenk and Notz, 2018; Screen et al., 2018; Sigmond et al., 2018). The
32 Arctic is very likely to have experienced at least one ice-free Arctic summer after about 10 years of
33 stabilized warming at 2°C compared to after about 100 years of stabilized warming at 1.5°C (Jahn, 2018;
34 Screen et al., 2018; Sigmond et al., 2018). For a specific given year under stabilized warming of 2°C,
35 studies based on large ensembles of simulations with a single model estimate the likelihood for ice-free
36 conditions as 35% without a bias correction of the underlying model (Sanderson et al., 2017; Jahn, 2018);
37 as between 10% and >99% depending on the observational record used to correct the sensitivity of sea ice
38 decline to global warming in the underlying model (Niederdrenk and Notz, 2018); and as 19% based on a
39 procedure to correct for biases in the climatological sea ice coverage in the underlying model (Sigmond et
40 al., 2018). The uncertainty of the first year of the occurrence of an ice-free Arctic Ocean arising from
41 internal variability is estimated to be about 20 years (Notz, 2015; Jahn et al., 2016).
42
43 The more recent estimates of the warming necessary to achieve an ice-free Arctic Ocean during summer are
44 lower than the ones given in AR5 (about 2.6C-3.1C relative to preindustrial or 1.6C-2.1C global
45 warming relative to the present day), which was similar to the estimate of 3C relative to preindustrial
46 levels (or 2C global warming relative to the present day) by Mahlstein and Knutti (2012) based on bias47 corrected CMIP3 models. Rosenblum and Eisenman (2016) explain why the sensitivity estimated by


1 Mahlstein and Knutti (2012) might be too low, estimating instead that September sea ice in the Arctic
2 disappears for 2°C relative to preindustrial (or about 1°C global warming relative to the present day), in line
3 with the other recent estimates. Notz and Stroeve (2016) use the observed correlation between September
4 sea-ice extent and cumulative CO2 emissions to estimate that the Arctic Ocean would become nearly sea5 ice-free during September with a further 1000 Gt of emissions, which also implies a sea-ice loss at about
6 2°C global warming. Some of the uncertainty in these numbers derives from the possible impact of aerosols
7 (Gagne et al., 2017) and of volcanic forcing (Rosenblum and Eisenman, 2016). During winter, little Arctic
8 sea ice is projected to be lost for either 1.5°C or 2ºC global warming (Niederdrenk and Notz, 2018).
9
10 Regarding the behavior of Arctic sea ice under decreasing temperatures following a possible overshoot of a
11 long-term temperature target, a substantial number of pre-AR5 studies have found that there is no indication
12 of hysteresis behavior of Arctic sea ice (Holland et al., 2006; Schroeder and Connolley, 2007; Armour et
13 al., 2011; Sedláček et al., 2011; Tietsche et al., 2011; Boucher et al., 2012; Ridley et al., 2012). In
14 particular, the relationship between Arctic sea-ice coverage and GMST is found to be indistinguishable
15 between a warming scenario and a cooling scenario. These results have been confirmed by post-AR5
16 studies (Li et al., 2013; Jahn, 2018), which implies high confidence that an intermediate temperature
17 overshoot has no long-term consequences for Arctic sea-ice coverage.

While more on the consequences of loss of sea ice, the discussion is as follows:

Quote
33 Loss of sea ice
34 Sea ice has been a persistent feature of the planet’s polar regions (Polyak et al., 2010) and is central to
35 marine ecosystems, people (e.g. food, culture and livelihoods) and industries (e.g. fishing, tourism, oil and
36 gas, and shipping). Summer sea ice in these regions (e.g. Arctic, Antarctic and Southern Ocean), however,
37 has been retreating rapidly in recent decades (Section 3.3.8) with an assessment of the literature revealing
38 that a fundamental transformation is occurring in polar organisms and ecosystems driven by climate change
39 (high agreement, robust evidence) (Larsen et al., 2014). These changes are strongly affecting people in the
40 Arctic who have close relationships with sea ice and associated ecosystems, and are facing major adaptation
41 challenges as a result of sea level rise, coastal erosion, the accelerated thawing of permafrost, changing
42 ecosystems and resources, and many other issues (Ford, 2012; Ford et al., 2015).
43
44 There is considerable and compelling evidence that a further increase of 0.5°C from today in average global
45 surface temperature will lead to multiple levels of impact on a variety of organisms - from phytoplankton to
46 marine mammals some of the most dramatic changes occurring in the Arctic Ocean and Western Antarctic
47 Peninsula (Turner et al., 2014, 2017b; Steinberg et al., 2015; Piñones and Fedorov, 2016).

1
2 The impacts of climate change on sea ice is part of the focus of the IPCC Special Report on the Ocean and
3 Cryosphere in a Changing Climate (SROCC), due to be released in 2019. Therefore, without intending to be
4 comprehensive, there are a range of responses to the loss of sea ice that are occurring and are likely to
5 increase at 1.5°C and 2°C of global warming. Photosynthetic communities such macroalgae, phytoplankton,
6 and microalgae dwelling on the underside of floating sea ice are changing due to increased temperatures,
7 light, and nutrient levels. As sea ice retreats, mixing of the water column increases, and phototrophs have
8 increased access to seasonally high levels of solar radiation (Dalpadado et al., 2014; W.N. Meier et al., 2014)
9 (medium agreement, medium evidence). These changes are very likely to stimulate fisheries productivity in
10 high latitude regions by mid-century (Cheung et al., 2009, 2010, 2016b; Lam et al., 2014), with evidence of
11 this is already happening for several fisheries species in high latitude regions in the northern hemisphere
12 such as the Bering Sea, although these ‘positive’ impacts may be relatively short-lived (Hollowed and
13 Sundby, 2014; Sundby et al., 2016). In addition to the impact of climate change on fisheries via impacts on
14 NPP, there are also direct effects of temperature on fish, which may have a range of impacts (Pörtner et al.,
15 2014). Sea ice in Antarctica is undergoing changes that exceed those seen in the Arctic (Maksym et al.,
16 2011; Reid et al., 2015) with increases in sea ice coverage in the western Ross Sea being accompanied by
17 strong decreases in the Bellingshausen and Amundsen seas (Hobbs et al., 2016). While Antarctica is not
18 permanently populated, the ramifications of changes to the productivity of vaste regions such as the Southern
19 Ocean has substantial implications as far as ocean foodwebs and fisheries are concerned.

gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #518 on: July 12, 2019, 06:30:08 PM »
Global warming of 1.5C IPCC draft report, sorry if this has been quoted and discussed before. Probably not supposed to quote it yet but at this level and if it is available....

Quote
In particular, the relationship between Arctic sea-ice coverage and GMST is found to be indistinguishable  between a warming scenario and a cooling scenario. These results have been confirmed by post-AR5 studies (Li et al., 2013; Jahn, 2018), which implies high confidence that an intermediate temperature overshoot has no long-term consequences for Arctic sea-ice coverage.
In other words, it seems likely that IPCC will accept that a temperature overshoot will occur, but no matter, "We have the technology, we can rebuild the climate". A bit of BECCS here, a bit of Direct Carbon Capture there, and everything will be fixed.

Oh well, one can dream.



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pietkuip

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Re: When will the Arctic Go Ice Free?
« Reply #519 on: July 12, 2019, 07:48:18 PM »
Global warming of 1.5C IPCC draft report, sorry if this has been quoted and discussed before. Probably not supposed to quote it yet but at this level and if it is available....
Quote
Often based on such bias correction, pre-AR5 and post-AR5 studies agree that for 1.5 °C global warming relative to pre-industrial levels, the Arctic Ocean will maintain a sea-ice cover throughout summer for most years.
And we are not at global 1.5 °C global warming now.  Is it truthful to say that the Arctic Ocean is "maintaining a sea ice cover"?

crandles

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Re: When will the Arctic Go Ice Free?
« Reply #520 on: July 12, 2019, 11:37:02 PM »
And we are not at global 1.5 °C global warming now.  Is it truthful to say that the Arctic Ocean is "maintaining a sea ice cover"?

Hmm. I am thinking you have a point and the language needs to be tightened up: Does Arctic Ocean include the surrounding seas?

Also is "will maintain a sea-ice cover throughout summer for most years" being used as just the opposite of "an ice-free Arctic during summer" and hence former includes partial coverage during summer or is partial coverage a separate category that isn't discussed and hence excluded from 'maintaining cover throughout summer for most years' category?

If a 3 category interpretation, then what is written seems wrong, or if seas are excluded, highly likely to be wrong before 1.5C is reached.

Pragma

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Re: When will the Arctic Go Ice Free?
« Reply #521 on: July 13, 2019, 12:27:06 AM »
Hmm. I am thinking you have a point and the language needs to be tightened up: Does Arctic Ocean include the surrounding seas?

Also is "will maintain a sea-ice cover throughout summer for most years" being used as just the opposite of "an ice-free Arctic during summer" and hence former includes partial coverage during summer or is partial coverage a separate category that isn't discussed and hence excluded from 'maintaining cover throughout summer for most years' category?

If a 3 category interpretation, then what is written seems wrong, or if seas are excluded, highly likely to be wrong before 1.5C is reached.

Just like caveats about the limitations of various measurement methods, we need to remind ourselves of the fact that IPPC documents are essentially political statements.

After the scientists have had their say, the politicians, bureaucrats and diplomats take over and nothing gets put into the final report unless there is consensus.

When you couple this with the fact that most reports are at least five years old, they are out of touch with reality, and I would say for some, intentionally so.

The result is an anodyne word salad that should be taken with a large grain of salt.

It will be, however, a good document for whatever generations come after us, about how we said a great deal and accomplished little.

Ardeus

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Re: When will the Arctic Go Ice Free?
« Reply #522 on: July 13, 2019, 01:54:58 AM »
<snippage>
     In recent interview Peter Wadhams threw out a concept I hadn't heard before.  With continued loss of ASI there could be a tipping point where polar jet stream doesn't just weaken and wobble, but just goes away completely.  I don't know if that is at all realistic, but if it did happen it would seem to be like Jennifer Francis thesis on steroids, with potential drastic changes in weather patterns, or just weather chaos until new patterns emerged.  I guess there's always a pattern, but if there was a complete loss of polar jet stream steering of weather systems that just seems like crazy town.
Hi Glen, I'd like to read/listen to this interview. Do you perhaps have a link?

I am not sure if Glen was referring to this interview I did, but he did consider the possibility of the jetstream going away. I used a few minutes of this interview in a doc about Lake Tanganyika.


nanning

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Re: When will the Arctic Go Ice Free?
« Reply #523 on: July 13, 2019, 07:07:24 AM »
Thanks Ardeus.
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Klondike Kat

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Re: When will the Arctic Go Ice Free?
« Reply #524 on: July 13, 2019, 02:45:13 PM »
Hmm. I am thinking you have a point and the language needs to be tightened up: Does Arctic Ocean include the surrounding seas?

Also is "will maintain a sea-ice cover throughout summer for most years" being used as just the opposite of "an ice-free Arctic during summer" and hence former includes partial coverage during summer or is partial coverage a separate category that isn't discussed and hence excluded from 'maintaining cover throughout summer for most years' category?

If a 3 category interpretation, then what is written seems wrong, or if seas are excluded, highly likely to be wrong before 1.5C is reached.

Just like caveats about the limitations of various measurement methods, we need to remind ourselves of the fact that IPPC documents are essentially political statements.

After the scientists have had their say, the politicians, bureaucrats and diplomats take over and nothing gets put into the final report unless there is consensus.

When you couple this with the fact that most reports are at least five years old, they are out of touch with reality, and I would say for some, intentionally so.

The result is an anodyne word salad that should be taken with a large grain of salt.

It will be, however, a good document for whatever generations come after us, about how we said a great deal and accomplished little.

Wow!  I thought I was the only one that felt that way.

Glen Koehler

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Re: When will the Arctic Go Ice Free?
« Reply #525 on: July 13, 2019, 03:54:47 PM »
Thanks Ardeus.  Yes that is the one.  The jet stream part starts aroud 12:00.
(And thanks for doing the interview.)

 "Just Have A Think" also did a 4-part interview with Wadhams.  In part 1 he briefly discusses jet stream impact (starting at about 8:30). 

Archimid

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Re: When will the Arctic Go Ice Free?
« Reply #526 on: July 14, 2019, 10:48:25 AM »
Thanks Crandles. My response, quotes edited for legibility.

Quote
However, the modeled sea-ice loss in most CMIP5 models is much weaker than observed. Compared to observations, the simulations are weak in terms of their sensitivity to both global mean temperature rise (Rosenblum and Eisenman, 2017) and to anthropogenic CO2 emissions (Notz and Stroeve, 2016).

That makes perfect sense. Arctic sea ice is decreasing faster than the models predict because influence from positive feedbacks like albedo warming, intrusions of hot air and winter cloudiness are overtaking both the global warming signature and the CO2 signature.

Quote
This mismatch between the observed and modeled sensitivity of Arctic sea ice implies that the multi-model-mean response of future sea-ice evolution probably underestimates the sea-ice loss for a given amount of global warming.

The first mistake is to associate Arctic Sea Ice with global temperatures. If Antarctica cooled 10C and the Arctic warmed 10C the Arctic would melt with zero degrees of global warming.

Quote
To address this issue, studies estimating the future evolution of Arctic Sea Ice tend to bias correct the model simulations based on the observed evolution of Arctic sea ice in response to global warming.

Bias correct... I honestly don't know exactly what that means, but that never stopped me from speculating before, so here we go.

I assume bias correction involves tinkering with parameters and functions until the model produces a better match for the observations. Then the future results are expected to produce better result. If that's the case, I understand the scientific validity and necessity of bias correction. It is a process of perpetual improvement.

Quote
Often based on such bias correction, pre-AR5 and post-AR5 studies agree that for 1.5 °C global warming relative to pre-industrial levels, the Arctic Ocean will maintain a sea-ice cover throughout summer for most years

Bias correcting a model that has the wrong shape (strait line vs exponential) will still produce the wrong result. How do we know if the model has the wrong shape?  We don't, unless a model with a different shape shows better skill.

But what if a different shape can only be resolved adding so many variable that the model can't be computed? Or what if assumptions taken as invariable because of hundreds of years of climate data are no longer valid when the climate changes? Unknown unknowns.

Quote
In particular, the relationship between Arctic sea-ice coverage and GMST is found to be indistinguishable between a warming scenario and a cooling scenario. These results have been confirmed by post-AR5 studies (Li et al., 2013; Jahn, 2018), which implies high confidence that an intermediate temperature overshoot has no long-term consequences for Arctic sea-ice coverage.

So I went looking for the confirmation studies and found what I believe to be Jahn, 2018. This is part of the abstract:

Quote
For warming above 2 °C, frequent ice-free conditions can be expected, potentially for several months per year. Although sea-ice loss is generally reversible for decreasing temperatures, sea ice will only recover to current conditions if atmospheric CO2 is reduced below present-day concentrations.

https://www.nature.com/articles/s41558-018-0127-8


This paper says that the ice will be gone 2 months during summer,  so from mid July to mid September, but there will be no hysteresis. That is quite simply unbelievable and it doesn't even pass a sanity check.

Even more unbelievable is "sea ice will only recover to current conditions if atmospheric CO2 is reduced below present-day concentrations."

The sea ice disappearance might have started because of CO2, but the acceleration of sea ice loss is not because of CO2, as the failure of the models prove. The loss of sea ice is now mostly do to albedo feedback, jetstream destabilization and local Arctic GHG, not CO2. Reducing CO2 back to historic levels will eventually restore the ice, but that will take decades or centuries.
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Archimid

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Re: When will the Arctic Go Ice Free?
« Reply #527 on: July 14, 2019, 11:13:41 AM »
On the consequences of a BOE according to Crandles post:

Quote
These changes are very likely to stimulate fisheries productivity in high latitude regions by mid-century

Absolute madness. I totally believe that fish population may increase in the arctic because of warmer water and better light. However that is almost an irrelevant fact, relative with the myriad of changes that are happening as the Arctic melts.

This mentions nothing about changes in atmospheric currents that are already beginning, nor oceanic currents, nor acceleration of Greenland melt, nor forest fires, nor methane release...

Really, this part of the document is a work of fiction. It mentions possible positive feedbacks but it ignores possible negative impacts. This document misleads the proper risk assessment of the Arctic.
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gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #528 on: July 14, 2019, 12:19:53 PM »
On the consequences of a BOE according to Crandles post:

Quote
These changes are very likely to stimulate fisheries productivity in high latitude regions by mid-century

Absolute madness. I totally believe that fish population may increase in the arctic because of warmer water and better light. However that is almost an irrelevant fact, relative with the myriad of changes that are happening as the Arctic melts.

This mentions nothing about changes in atmospheric currents that are already beginning, nor oceanic currents, nor acceleration of Greenland melt, nor forest fires, nor methane release...

Really, this part of the document is a work of fiction. It mentions possible positive feedbacks but it ignores possible negative impacts. This document misleads the proper risk assessment of the Arctic.
"I totally believe that fish population may increase in the arctic because of warmer water and better light."

I think even that is totally optimistic. Ice covered sea does not cover a life-free ocean.

Concerning the Antarctic:-
Quote
Krill are a key part of the delicate Antarctic food chain. They feed on marine algae and are a key source of food for whales, penguins and seals. ... ...the ice that is home to the algae and plankton on which krill feed is retreating

I guess the algae and plankton in the Arctic form the base of a food-web that will be severely impacted by retreat of ice. The guy who wrote this stuff for the IPCC probably has not even 1.01 knowledge of the Arctic food-web.

It is an unfortunate fact that some scientists who are justifiably renowned experts in a specialised field sometimes feel the need to make pronouncements on other fields in which their expertise is - zilch
_______________________________________________________________
one google hit later.... Thin ice promotes phytoplankton, then zero ice reduces phytoplankton ?

https://www.newscientist.com/article/dn21893-plankton-under-sea-ice-may-disrupt-arctic-food-chain/
Plankton under sea ice may disrupt Arctic food chain
EARTH 7 June 2012

Quote
The water beneath a snow-covered expanse of ice 1 metre thick hardly seems like a good home for light-loving creatures. But microscopic phytoplankton, which rely on the sun for their nutrients and form the base of Arctic food webs, have managed to thrive under ice sheets that are thinning as the poles become warmer.

The buried “bloom” of phytoplankton – the largest ever found underneath an ice shelf – was four times more concentrated than blooms found in the open ocean. Some say its discovery could mark the first major change in the Arctic ecosystem as a result of climate change.

“We had no clue [they existed],” says Kevin Arrigo of Stanford University in Stanford, California, although he says researchers had found hints of blooms under the ice in the past.

Remote sensing technology, which monitors ocean life from space, cannot detect blooms through the ice. Arrigo and other researchers came across the bloom by accident on a cruise in Alaska’s Chukchi Sea. Their icebreaker was cutting through ice that was only 1 metre thick – compared to the 3-metre thickness in the past – and was pockmarked with pools of melted ice, which allow light through.

What is most amazing, Arrigo says, is that the column of phytoplankton extended downwards for 70 metres and was extremely dense. “It was like pea soup,” he says, “and not a lot of light gets through pea soup.”

Although rarely seen, under-ice blooms such as this one are almost certainly widespread. Arrigo says that most of the Arctic has the right conditions of shallow waters and nutrients. But finding out just how prevalent they are and when they bloom may prove difficult. “A ship is a needle in the haystack,” says Jean-Éric Tremblay of Université Laval in Quebec, Canada. He suggests that researchers might need to use multiple methods, such as sampling buoys, to detect them in the future.

It’s important we try, though. Although no one knows for sure how often blooms occurred under ice sheets in the past, they will probably bloom earlier in the year as the ice sheet thins and completes its summer cycle earlier and earlier, Arrigo says.

This could throw off the timing of the entire Arctic food web. When the ice sheet melts in the spring, zooplankton move into areas of open water to feed on phytoplankton, and in turn become food for fish. If they follow the seasons rather than the phytoplankton blooms, they may arrive too late.

Larger animals that feed directly on phytoplankton might be even more affected. “A whale in Baja California has no way of knowing the bloom will happen a month earlier this year and can’t get there any faster,” says Arrigo.

“These blooms could perhaps be one of the first major responses we can see with climate change,” says C.J. Mundy of the University of Manitoba in Winnipeg, Canada.
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crandles

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Re: When will the Arctic Go Ice Free?
« Reply #529 on: July 14, 2019, 12:42:36 PM »

The first mistake is to associate Arctic Sea Ice with global temperatures. If Antarctica cooled 10C and the Arctic warmed 10C the Arctic would melt with zero degrees of global warming.

1. Yes, certainly true if there is a redistribution of temperatures, but is this likely?

2. Given the report is tasked with reporting on a 1.5C warmer world (and perhaps whether much different from a 2C warmer world), they didn't really have much choice.

3. Is it a mistake? If they think it is a long way off (which unlikely with less than 1.5C warming implies), is it better to link it to some measure of global change rather than some specific years? Not sure on this, there is not much scope for 1.5C to arrive at noticeably different years but perhaps there is scope for 2C to arrive at different years depending what happens with future emissions.

Perhaps the stronger argument against this linkage to global temperatures is: does it depend whether aerosols decline rapidly as coal mining ends or not.

Quote

Bias correct... I honestly don't know exactly what that means, but that never stopped me from speculating before, so here we go.

I assume bias correction involves tinkering with parameters and functions until the model produces a better match for the observations. Then the future results are expected to produce better result. If that's the case, I understand the scientific validity and necessity of bias correction. It is a process of perpetual improvement.

Perpetual improvement goes on but I don't think this is what is being referred to here. I don't think the models are rerun just the output adjusted.

more like taking these models


and adjusting the output to look more like shown below (not the completely flat bit at the end)

Quote


Bias correcting a model that has the wrong shape (strait line vs exponential) will still produce the wrong result. How do we know if the model has the wrong shape?  We don't, unless a model with a different shape shows better skill.

Fair point but what if essentially all the models show the same shape? Do you still think that is co-incidence or do you start to ponder if this shape is a reliable result from the models

Quote

This paper says that the ice will be gone 2 months during summer,  so from mid July to mid September, but there will be no hysteresis. That is quite simply unbelievable and it doesn't even pass a sanity check.

Even more unbelievable is "sea ice will only recover to current conditions if atmospheric CO2 is reduced below present-day concentrations."

The sea ice disappearance might have started because of CO2, but the acceleration of sea ice loss is not because of CO2, as the failure of the models prove. The loss of sea ice is now mostly do to albedo feedback, jetstream destabilization and local Arctic GHG, not CO2. Reducing CO2 back to historic levels will eventually restore the ice, but that will take decades or centuries.

What is this? Seems like you are trusting your gut instead of the result of modelling.

crandles

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Re: When will the Arctic Go Ice Free?
« Reply #530 on: July 14, 2019, 01:06:08 PM »
it ignores possible negative impacts.

Those positive benefits did seems to stand out. However

Quote
a fundamental transformation is occurring in polar organisms and ecosystems driven by climate change (high agreement, robust evidence) (Larsen et al., 2014). These changes are strongly affecting people in the Arctic who have close relationships with sea ice and associated ecosystems, and are facing major adaptation challenges as a result of sea level rise, coastal erosion, the accelerated thawing of permafrost, changing ecosystems and resources, and many other issues (Ford, 2012; Ford et al., 2015).

There is considerable and compelling evidence that a further increase ....

is hardly ignoring negative impacts. However, I would agree that it does seem rather limited in scope and I would have expected some mention of some possible effects on mid latitude weather patterns and therefore on people outside the arctic region. Maybe this is elsewhere in the document.

Archimid

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Re: When will the Arctic Go Ice Free?
« Reply #531 on: July 14, 2019, 01:32:05 PM »
Quote
1. Yes, certainly true if there is a redistribution of temperatures, but is this likely?

There IS a redistribution of temperatures and it is mostly caused by Arctic sea ice loss.

https://www.nature.com/articles/s41467-018-07954-9

Abstract:
Quote
Warming in the Arctic has been much faster than the rest of the world in both observations and model simulations, a phenomenon known as the Arctic amplification (AA) whose cause is still under debate. By analyzing data and model simulations, here we show that large AA occurs only from October to April and only over areas with significant sea-ice loss. AA largely disappears when Arctic sea ice is fixed or melts away. Periods with larger AA are associated with larger sea-ice loss, and models with bigger sea-ice loss produce larger AA. Increased outgoing longwave radiation and heat fluxes from the newly opened waters cause AA, whereas all other processes can only indirectly contribute to AA by melting sea-ice. We conclude that sea-ice loss is necessary for the existence of large AA and that models need to simulate Arctic sea ice realistically in order to correctly simulate Arctic warming under increasing CO2.

From the paper:

Quote
We found that large AA occurs only from October to April and only over areas with significant sea-ice loss in both observations and model simulations. AA largely disappears when Arctic sea ice melts away or is held fixed for calculating surface fluxes. Periods with large AA are associated with large sea-ice loss in model simulations, and models with bigger sea-ice loss produce larger AA. Increased LW radiation and latent and sensible heat fluxes from the newly exposed Arctic waters enhance surface and low-tropospheric warming and cause AA, whereas water vapor feedback, increased downward LW radiation, and other processes can only modulate the AA induced by sea-ice loss or indirectly contribute to AA by melting sea ice. Our results highlight the essential role of sea-ice loss in producing AA under GHG-induced global warming.


Quote
2. Given the report is tasked with reporting on a 1.5C warmer world (and perhaps whether much different from a 2C warmer world), they didn't really have much choice.

I know they didn't have much choice. If they use the proper language to describe what the science tells, they will be considered mad alarmists and their words never published.

Quote
3. Is it a mistake? If they think it is a long way off (which unlikely with less than 1.5C warming implies), is it better to link it to some measure of global change rather than some specific years? Not sure on this, there is not much scope for 1.5C to arrive at noticeably different years but perhaps there is scope for 2C to arrive at different years depending what happens with future emissions.

It is a huge mistake. A BOE will happen because of the natural feedback that already started, evident by Arctic Amplification, not because of CO2 or global temperatures.

Quote
Perpetual improvement goes on but I don't think this is what is being referred to here. I don't think the models are rerun just the output adjusted.

To think the leader of the world will be making decisions based on this is terrifying.


Quote
Fair point but what if essentially all the models show the same shape? Do you still think that is co-incidence or do you start to ponder if this shape is a reliable result from the models

Most models are the same shape because:

1. They are based on the same set of assumption, which is the climate of the 20th century for high resolution and the climate of the past with low resolution. As the climate changes, the models will fail and then improve.
2. The models don't have enough local scale resolution.
3. Results of exponential shape are scary.

Quote
What is this? Seems like you are trusting your gut instead of the result of modelling.

I'm trusting what my eyes see, and when I search the literature I get confirmation. See article linked above.
 
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gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #532 on: July 14, 2019, 01:39:48 PM »

Seems like you are trusting your gut instead of the result of modelling.
Should I put my trust in a projection based on a 4 parameter Gompertz equation?
Any more than I should put my trust in the attached?
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crandles

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Re: When will the Arctic Go Ice Free?
« Reply #533 on: July 14, 2019, 01:56:04 PM »
Quote
1. Yes, certainly true if there is a redistribution of temperatures, but is this likely?
There IS a redistribution of temperatures and it is mostly caused by Arctic sea ice loss.

Yes you are right there is redistribution of temperature.

I was reacting to
Quote
If Antarctica cooled 10C and the Arctic warmed 10C the Arctic would melt with zero degrees of global warming.
which is somewhat extreme and I fell into giving extreme response to this extreme.

Archimid

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Re: When will the Arctic Go Ice Free?
« Reply #534 on: July 14, 2019, 02:03:43 PM »
10 and -10 nicely average to 0 and 10C guarantees an arctic sea ice melt down. I thought they were useful numbers to illustrate my point.
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pietkuip

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Re: When will the Arctic Go Ice Free?
« Reply #535 on: July 14, 2019, 03:27:55 PM »
10 and -10 nicely average to 0 and 10C guarantees an arctic sea ice melt down. I thought they were useful numbers to illustrate my point.
Sure. But (if a serious reaction is allowed), the areas beyond to polar circle are much smaller than the rest of the world.

The extra energy in the Arctic comes from all directions, the South is everywhere.

Klondike Kat

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Re: When will the Arctic Go Ice Free?
« Reply #536 on: July 14, 2019, 03:43:14 PM »

Seems like you are trusting your gut instead of the result of modelling.
Should I put my trust in a projection based on a 4 parameter Gompertz equation?
Any more than I should put my trust in the attached?

Probably not.  However the Gompertz does a better job of fitting the observation data.  Is that just coincidence?  On the other hand, is there any reason to suspect a straight line decline?  In any case, the largest rate of decline occurred over a roughly 10-year period, from 1998 - 2007.  The decades both before and after have shown much less melt.  Perhaps we are trying to apply a mathematical fit, where none exists.  I think the ice will continue to decline, but in method between the two fits; less than the straight line, but more than the Gompertz.  However, I could be just as wrong as the many others before who tried to predict the Arctic sea ice.

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Re: When will the Arctic Go Ice Free?
« Reply #537 on: July 14, 2019, 03:50:04 PM »
The discussion above about thinner ice creates more bio-activity sounded positive, but the comment that a 'no ice' Arctic decreased bio-activity seems to be based on the recent evidence of migrating mammals (whales) dying of starvation after spending 'bulking up' time in the Arctic with, apparently, inadequate food, so no actual 'bulking up' (as reported in other threads on the ASIF).
Arctic ice is healthy for children and other living things.

gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #538 on: July 14, 2019, 04:01:25 PM »
Quote
1. Yes, certainly true if there is a redistribution of temperatures, but is this likely?

There IS a redistribution of temperatures
NASA seem to think so
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grixm

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Re: When will the Arctic Go Ice Free?
« Reply #539 on: July 14, 2019, 04:36:31 PM »

Seems like you are trusting your gut instead of the result of modelling.
Should I put my trust in a projection based on a 4 parameter Gompertz equation?
Any more than I should put my trust in the attached?

Probably not.  However the Gompertz does a better job of fitting the observation data.  Is that just coincidence?  On the other hand, is there any reason to suspect a straight line decline?  In any case, the largest rate of decline occurred over a roughly 10-year period, from 1998 - 2007.  The decades both before and after have shown much less melt.  Perhaps we are trying to apply a mathematical fit, where none exists.  I think the ice will continue to decline, but in method between the two fits; less than the straight line, but more than the Gompertz.  However, I could be just as wrong as the many others before who tried to predict the Arctic sea ice.

A 4 parameter gompertz is a far more complicated equation than the 2 parameter straight line. When allowed complexity rises the pool of possible functions that fit the observed data also rises, but the chance of such a fit being genuine and not a coincidence also falls, because of overfitting. Thus, when several equations fit the observed data reasonably, the least complex of them is more likely to be more correct, that's Occam's razor.

crandles

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Re: When will the Arctic Go Ice Free?
« Reply #540 on: July 14, 2019, 05:18:53 PM »

A 4 parameter gompertz is a far more complicated equation than the 2 parameter straight line. When allowed complexity rises the pool of possible functions that fit the observed data also rises, but the chance of such a fit being genuine and not a coincidence also falls, because of overfitting. Thus, when several equations fit the observed data reasonably, the least complex of them is more likely to be more correct, that's Occam's razor.

Yes, this is certainly a very reasonable criticism of 4 parameter gompertz. I don't agree with the completely flat extrapolation and 2 or 3 parameters would certainly be preferable to 4 but I don't know any curve equation that has some curves in the ways needed to fit the data. Could go down to 2 parameter straight line but as I suspect curve is flattening out (backed by both data and models) then the straight line predicts too soon and I want some way to show this then I need to use something. 3 parameter gompertz may well be better for some uses.

>more likely to be more correct
All models are wrong but some are useful. So I don't think 'correct' is the right word to use but I do agree with the sentiment if you change that word to 'more accurate for future projections' or useful or something like that.

crandles

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Re: When will the Arctic Go Ice Free?
« Reply #541 on: July 14, 2019, 05:34:39 PM »
I think the responses to the IPCC draft report is interesting.

Do some of the responses have the feel of:

I am convinced a BOE is going to be fairly catastophic, and I am sure I am right about this. Given this, how little the IPCC report says feels very weird.

But it is IPCC, so top experts used so can't easily attack expertise.
Clearly has reviewed and summarised lots of scientific papers so can't attack limited scope.

Which sort of leaves attacking scientists reticence & toning down language. This may not really make sense as adequate explanation for large divergence in views on severity of a BOE, but if it is all that is left, someone confident in their beliefs may end up believing it adequately explains the large divergence to protect their own world views.

Does this strike others as happening on the thread above?

Or maybe it is just me seeing this because I want to believe it as reinforcing my beliefs?

It isn't all that, of course. There is some genuine discussion of the report as well.

oren

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Re: When will the Arctic Go Ice Free?
« Reply #542 on: July 14, 2019, 05:59:35 PM »
To a certainty, the IPCC process is conservative, reticent and toned down by politics. Very understandable.
This doesn't mean that a BOE (1M km2 in mid September) will be a step-change catastrophic.

gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #543 on: July 14, 2019, 06:17:08 PM »
My difficulty with the IPCC report(s) comes from a different place. I cannot challenge the science and methodologies the scientists use. So on what basis can I criticise.

Simply put, because so far in each cycle they have been wrong, and each new IPCC cycle has built into it an unrealistic view of what the world is doing and will do.

Why,
- because the action taken by the world has not reduced CO2 emissions. They have increased.
- because the majority of new papers with new and improved data say things are worse.
- because the IPCC mandate is to look towards 2100.
- because ......

The proof is that the UN felt it necessary to issue the report to say to the world - you've got 12 years left or you/we are well are truly done for. And look at the reality, CO2 emissions are rising, carbon sinks are being degraded. We don't have 12 years. 2019 is not just a year wasted, it is a year that stole 2 years from that 12 years (if it exists at all).

So when will the Arctic go ice free? Sooner than when the IPCC says.
When will the Arctic return to its previous state? Probably never.

And that is all I am going to say about that.
Back to looking at data.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Pragma

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Re: When will the Arctic Go Ice Free?
« Reply #544 on: July 14, 2019, 06:22:15 PM »
With no disrespect intended toward any scientists involved, I think the IPCC is flawed and intentionally so. As I have said before, it is primarily a political document, constrained by consensus. I'm not sure we can exclude limited scope as a possibility. They continue to ignore reality, i.e. empiricism, because reality has yet to be peer reviewed.

Also, as I understand it, they specifically have not mentioned feedbacks in their reports. The rationale, such as it is, is that the feedbacks can not be adequately characterized, so they are eliminated. One can debate the merits of that approach, but a large gap exists, nonetheless.

This thread contains a wide variety of views, some scientific, some emotional, but deviating from the IPCC is far from blasphemy IMHO. 


Sam

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Re: When will the Arctic Go Ice Free?
« Reply #545 on: July 14, 2019, 08:05:25 PM »
The IPCC does one hugely good thing - confirm with an extraordinarily high consensus that climate disruption is real, that it is entirely caused by man and that it will devastate the environment, civilization, humanity and more.

The IPCC though also does a hugely bad thing. It repeatedly and systematically understates the severity of the problem, the severity of the consequences, the incredible speed at which the changes are occurring, the impossibly great difficulties that we will encounter in trying to keep the change to less than 2 degrees C, the incredibly great difficulty we will have in limiting the change to 3 C, the unimaginably horrible impacts a 3 C increase will have, and more. It is vital to note that the errors the IPCC makes in these regards are caused by politicians and financial interests aided by those who refuse to believe that man could possibly cause such impacts, or worse that the local personal impacts that change would have are more important than the devestation of the earth. It is also vital to note that these errors are intentional and that they all go in the same direction - understating both the severity of the problem, and the incredible speed at which the change is actually occurring.

All of that is shameful and disgusting. The iPCC’s failure as great as the failure of our leaders doom everyone and most species on the earth.

Before there can be any possibility of a meaningful response to climate disruption, we must first be honest about the effects. Only then can we be honest about what is needed to do anything about it, and to assess realistically how much we can do. But doing that means admitting massive failure and the future premature death and suffering of billions of people - and that is if we do succeed. That answer is too horrible for the leaders to even entertain. Failing to take those actions assures those harms and much worse. Somehow though they seem to wrongly believe that if they stick their heads in the ground like the proverbial ostrich, that either the problems won’t come to pass, or that they won’t personally be blamed.

And that leads to my last point. The scientists are particularly to blame for couching the outcome as risks. They seem not to understand or not to want to understand that the people they are reporting to utterly and completely fail to understand that these are certainties of massive destruction, and only uncertainties in how fast that will occur. Risks in this context are not gambles as to whether certain outcomes will occur, but rather how horribly severe they will be or how fast they will arrive.

The outcome is certain catastrophe on an unprecedented scale. And that will happen if we mobilize every capability we have, as fast as we physically can, AND destroy civilization as we know it in the process. Should we fail to do that the outcomes are vastly worse.

Sam

petm

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Re: When will the Arctic Go Ice Free?
« Reply #546 on: July 14, 2019, 08:15:18 PM »
The outcome is certain catastrophe on an unprecedented scale.

hear! hear!

Glen Koehler

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Re: When will the Arctic Go Ice Free?
« Reply #547 on: July 14, 2019, 11:18:11 PM »
    IPCC is made of humans.  From what I understand the scientists (mostly unpaid for the extra work) give their best effort at corralling and summarizing vast amounts of information, then the politicians get to edit the language used to communicate it.  The IPCC reports are essential and immensely useful, imagine if we did NOT have them.  But they are imperfect. 

     Short report well worth reading --
"What Lies Beneath: The scientific understatement of climate risks"
   excerpt: 
    "What were lower-probability, higher-impact events are now becoming more likely. This is a particular concern with potential climatic “tipping points” — passing critical thresholds which result in step changes in the system — such as the polar ice sheets (and hence sea levels), and permafrost and other carbon stores, where the impacts of global warming are non-linear and difficult to model at present. Under-reporting on these issues contributes to the “failure of imagination” that is occurring today in our understanding of, and response to, climate change. If climate policymaking is to be soundly based, a reframing of scientific research within an existential risk-management framework is now urgently required. "

https://www.researchgate.net/profile/David_Spratt3/publication/324528571_What_Lies_Beneath_The_scientific_understatement_of_climate_risks/links/5ad2e4120f7e9b2859343e58/What-Lies-Beneath-The-scientific-understatement-of-climate-risks.pdf

Archimid

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Re: When will the Arctic Go Ice Free?
« Reply #548 on: July 15, 2019, 12:10:13 PM »
Quote
Or maybe it is just me seeing this because I want to believe it as reinforcing my beliefs?

That is a brave question. So far it hasn't been answered. In fact it has been avoided. Too bad I can't answer it because I have the exact same question and I may be the one seeking to reinforce beliefs.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

crandles

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Re: When will the Arctic Go Ice Free?
« Reply #549 on: July 15, 2019, 02:28:32 PM »
My difficulty with the IPCC report(s) comes from a different place. I cannot challenge the science and methodologies the scientists use. So on what basis can I criticise.

Simply put, because so far in each cycle they have been wrong, and each new IPCC cycle has built into it an unrealistic view of what the world is doing and will do.

Why,
- because the action taken by the world has not reduced CO2 emissions. They have increased.
- because the majority of new papers with new and improved data say things are worse.
- because the IPCC mandate is to look towards 2100.
- because ......

The proof is that the UN felt it necessary to issue the report to say to the world - you've got 12 years left or you/we are well are truly done for. And look at the reality, CO2 emissions are rising, carbon sinks are being degraded. We don't have 12 years. 2019 is not just a year wasted, it is a year that stole 2 years from that 12 years (if it exists at all).

So when will the Arctic go ice free? Sooner than when the IPCC says.

It is certainly reasonable to have some divergence of views from what the IPCC reports: The IPCC only reports on what the science says. There can be quite considerable number of thinks that are suspected and reasonably feared but don't get into the science because both 1) the science isn't yet good enough to show these effects occur and 2) observations are not clear enough to demonstrate them.

In addition there are political considerations and scientific language toning things down.

So yes logical and sensible to believe the IPCC understates matters.

But how much of a gap?
On political interference, is it reasonable to think the scientists allow the politicians to completely rewrite to clearly distort fundamental meanings or is it just a little tinkering about the edges?

On the science, if the observations are not clear enough on an effect then there may still be an effect and it will almost certainly get worse with a +1.5C world rather than a +1C world. But if it is barely measurable is it really going to grow to be anywhere near of the order of civilisation collapsing effects?

.

'It is worse than we thought' headlines. Yes I believe this is true in many cases even if other times it is mere clickbait exaggeration. However, on the subject of arctic sea ice

https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/piomas/grf/piomas-trnd6-1.png?attachauth=ANoY7cqZn7MvUtOPSwAcG0HCDb0_QidUTkM1iUgm9Lmbvbi4Skbmj0H0SgbjaO5MYzgSYYwnDBpf6H10QTZgJHf8fpb7ljiaCjwNRSUj0mDjSqxr_wLTcXh1biD7cvh8acBIZHailxdtF6rBDslzGBqyf4SUOSZS6K8uIo06xXevpF5vocB192bUHAIa0EOqLPyKVVSG1_LBrMzPIIrHg2egUGSdaQeF4Rw_CS4cg9hNdhhIgtf946frtyhtCwabcZzi4UYSXsoF&attredirects=0

the conclusion seems to repeatedly be that it isn't as bad as we feared.