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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: 65

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

Author Topic: When will the Arctic Go Ice Free?  (Read 34377 times)

be cause

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Re: When will the Arctic Go Ice Free?
« Reply #350 on: May 15, 2019, 02:13:11 AM »
when the ice goes I may still be 59 ! .. b.c.
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Klondike Kat

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Re: When will the Arctic Go Ice Free?
« Reply #351 on: May 15, 2019, 02:36:17 AM »
Saying the arctic will go ice free before 2030 is just as valid as saying it won’t

That is because at this point, it has not happened.  So neither is right or wrong, and the no one can accurately calculate the odds.

b_lumenkraft

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Re: When will the Arctic Go Ice Free?
« Reply #352 on: May 15, 2019, 06:42:15 AM »
Schrödinger's sea ice!

wdmn

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Re: When will the Arctic Go Ice Free?
« Reply #353 on: May 15, 2019, 06:58:21 AM »
This is generally a fact about probability:

Propositions expressing probabilities have a grammar that sets the criteria
for their verification or falsification on past events. Such a proposition says
something about the current state of affairs by connecting it to past events, based
on induction. This holds whether the sentence is given as:

The weather looks like it will rain tomorrow. Or,
There’s a 70% chance of showers tomorrow.

Neither proposition says anything about the future weather (in the sense that they
can be falsified or verified by what actually happens). We are only inclined to think
they do because of the ‘surface’ grammar. The second example may be based on
specific measurements about how often rain follows a certain weather pattern,
whereas the first sentence is a more general empirical proposition.

In other words, you can be correct to say, "there's a 99% chance of rain tomorrow" even if it doesn't end up raining. The truth of your statement is based on past events (patterns) and not on what actually comes to pass.

This is what makes the IPCC, and for that matter, all model pathways, of limited value. Since our knowledge is extremely limited on these matters. It can be correct to consider something improbable even if it ends up happening. That is why ASLR is always talking about "fat tailed risk" and the precautionary principle.

crandles

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Re: When will the Arctic Go Ice Free?
« Reply #354 on: May 15, 2019, 09:53:52 AM »

In other words, you can be correct to say, "there's a 99% chance of rain tomorrow" even if it doesn't end up raining. The truth of your statement is based on past events (patterns) and not on what actually comes to pass.

This is what makes the IPCC, and for that matter, all model pathways, of limited value. Since our knowledge is extremely limited on these matters. It can be correct to consider something improbable even if it ends up happening. That is why ASLR is always talking about "fat tailed risk" and the precautionary principle.

'Correct to say' is an odd term to use in this situation when it cannot be falsified and moreover someone else might have a better model that predicts a different percentage.

A single probability percentage prediction is unfalsifyable but I used term 'better model'. This relies on testing a lot of random situations which might not be indicative of skill at the current situation so is still somewhat problematic but it might be a reasonable indication. In this sense, one model may appear better than another model. 'Correct' is likely to be unobtainable because it is always possible that someone could find some other factors to use in some currently unknown way to improve the skill of your model.

'Makes the IPCC of limited value'
Think I disagree here too, at least to some extent. There is a danger that what you said conflates chaotic weather and fairly stable climate. With chaotic weather, a better model than a random guess might be practically impossible, whereas with fairly stable boundary issue problem, progress may well be possible and using best models may well yield more reliable results. Then using the most expert models is sensible.

There is also the one prediction unfalsifyable but can test a large number of predictions to get a sense of which model is better.

Also, It is only possible to talk about 'fat tail risk' in a situation where you can compare models.


So, I am getting impression that you are implying too much from a single prediction being unfalsifyable but maybe that is me inferring too much from what you said.

wdmn

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Re: When will the Arctic Go Ice Free?
« Reply #355 on: May 15, 2019, 01:12:13 PM »
"'Correct to say' is an odd term to use in this situation when it cannot be falsified and moreover someone else might have a better model that predicts a different percentage."

Yes there is a difference. In the case of the predictions being made here, when comparing them, we are better of saying "it's more or less defensible to say."

"A single probability percentage prediction is unfalsifyable..."

That is not true. If you have a good statistical probability for an event, then your proposition is verified or falsified by those statistics. The proposition is about your reading of those statistics, and the truth or falsity of it depends on whether or not you've read them correctly.

When the predictions are based off of model projections, the best we can do is defend one or another projection, and the propositions to be assessed will be the propositions we make in defense.

We can also, of course, make statements that are verifiable or falsifiable within any given projection (or aggregate of them). Such as, "according to this (or these) model(s), the probability of such and such an event is 60%." We could also be less specific, and say something like, "according to these models the likelihood of this happening is very high." All of these propositions can be verified or falsified.

When it can be shown that our projections have left out many relevant factors, then the value of our projections goes down.

When the risks involved are very high, and the timeframes are relatively short, then using the probability distribution of one of these models, or an aggregate of these models (as is very often done when discussing pathways, say to 1.5 or 2C warming), is extremely risky.

So we have AR5 give a median ECS of 3C (you can verify this proposition), and CMIP6 (so far) give a median ECS of 4.3C. This difference is enough to suggest that most of the projected pathways to 1.5 or 2C of warming are worse than useless, since they may have resulted in us under appreciating the risks involved...

I should be clear that it was these pathways that I had in mind, though I didn't make that entirely clear.

There is greater value to lots of the other projections made by models, including those incorporated into IPCC reports.

Of course, it is also possible to say, even without any models, that the risks of rapidly altering the concentration of co2 (and other GHGs) in the atmosphere are great. And we could defend this claim well enough that it would be called "true."
« Last Edit: May 15, 2019, 10:22:50 PM by wdmn »

Klondike Kat

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Re: When will the Arctic Go Ice Free?
« Reply #356 on: May 15, 2019, 01:46:19 PM »
"Correct to say" is a fine term, and probabilities based on mathematics is accurate.  If you flip a coin 10 times, there is a 99% probability that it will comes up heads at least once.  However, there is a finite possibility that it will not.  The outcome, in no way chances the odds, nor does it falsify them.

When talking about the weather or climate, the probabilities are a bit more nebulous.  When a forecaster gives a percentage chance of rain, it is not based on strict mathematics, but on past data.  The less data available (or factors omitted), the less reliable are the projections.  Additionally, there are unknowns that may influence the system, before the time arrives, changing the potential outcome. 

Tom_Mazanec

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Re: When will the Arctic Go Ice Free?
« Reply #357 on: May 15, 2019, 02:01:20 PM »
Human Habitat Index:
Thanks! Bookmarked article.
« Last Edit: May 15, 2019, 03:56:07 PM by Tom_Mazanec »
SHARKS (CROSSED OUT) MONGEESE (SIC) WITH FRICKIN LASER BEAMS ATTACHED TO THEIR HEADS

Dharma Rupa

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Re: When will the Arctic Go Ice Free?
« Reply #358 on: May 16, 2019, 10:34:06 PM »
...There is a danger that what you said conflates chaotic weather and fairly stable climate...

Climate is just as chaotic as weather but on a (slightly) longer timescale.

gerontocrat

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Re: When will the Arctic Go Ice Free?
« Reply #359 on: May 18, 2019, 08:03:36 PM »
NSIDC Data

A couple of graphs looking at the Arctic Central Seas only, about what melt is required for a BOE of < 1 million km2 extent. The peripheral seas are ignored as they always melt out completely to the extent as makes no difference.

Currently a BOE requires an extent loss from now of circa 7.5 million km2 compared with an average of circa 4.5 million, i.e. circa 65% above average. The most that happened was in 2012, when extent loss from now was circa 20% above average.

So a BOE currently requires a series of circumstances (tipping points?) completely outside and beyond previous experience.

____________________________________________________________
Area data gives similar results. Note that at minimum area is usually about 65% of extent. So a BOE of 1 million km2 extent might be about 0.65 million km2 area.
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Sam

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Re: When will the Arctic Go Ice Free?
« Reply #360 on: May 18, 2019, 09:03:40 PM »
"Correct to say" is a fine term, and probabilities based on mathematics is accurate.  If you flip a coin 10 times, there is a 99% probability that it will comes up heads at least once.  However, there is a finite possibility that it will not.  The outcome, in no way chances the odds, nor does it falsify them.

When talking about the weather or climate, the probabilities are a bit more nebulous.  When a forecaster gives a percentage chance of rain, it is not based on strict mathematics, but on past data.  The less data available (or factors omitted), the less reliable are the projections.  Additionally, there are unknowns that may influence the system, before the time arrives, changing the potential outcome.

With a truly random system and truly even random odds, you need only flip the coin 7 times to have a >99% chance that at least one of those times would come up heads. On average in a long series of trials 1 time in about 128 the coin will come up heads only once, with all of the rest being tails.

With 10 coin flips the odds are ~ 99.93%

However - and this is a huge however - it is unfortunately common for odds to not apply at all in studies, or for the situation to not be balanced, fully known and free of external influences.

Quite often systems may behave similarly to random processes, yet not be such at all. In those cases, statistical tests and bounds may be useful, but also be wrong. They can mislead us greatly.

Chaotic systems may for a time exhibit quasi random statistical like behavior within certain bounds. Deviate slightly and the statistics may suddenly not work at all.

Some systems exhibit what appears to be statistical noise and random behavior only to exhibit wildly non-random behavior that far exceeds the statistical bounds. So-called "stiff" equations in chemical engineering behave this way. They appear stable for long periods before some small input accumulates in effects and drives wild changes in the results.

Systems with unrecognized, hidden, or ignored state changes may also exhibit either true or apparent random behavior about a mean, but with changes in the underlying conditions, or slight changes in the mean can walk across a system boundary and suddenly completely change behaviors completely outside any statistical analysis of the previous behavior to that point. These are actually quite common. Traffic jams are one such example. With minor changes in the traffic volume, a sudden state change can occur. The traffic that previous flowed in ways that could be modeled like a gas, now behaves like a liquid, or even a highly viscous liquid, or a true solid.

Many of the parameters that we routinely use also have strange behaviors in conditions away from the usual. It is common in modeling to treat collections of discrete objects as a uniform flow field of a quasi-fluid. Tensor analysis often falls victim to this flaw. The usual examples are far from the common world, but are informative.

For example, though gases behave like a quasi-fluid flow field and are easily modeled as such, and even though they exhibit properties like temperature (the kinetic energy of the particles in the fluid); when the flow conditions change to rarified conditions, the energy transfer between the discrete particles breaks down. When that happens, simple ideas like temperature are revealed not to be static values, nor vectors, nor even tensor gradients. The temperature of gases under near vacuum conditions are one such example. They become highly directional, often with little or no correlation at large angles to the main flow direction.

The assumptions and presumptions that go into building an assessment or model are critically important for understanding the limitations of the results. Far too often in my experience researchers leave these unstated, and often unknown.

These ideas are often forgotten, neglected, ignored or dismissed in examining real world systems. And that error can be at our great peril.

To quote Monty Python, "Nobody expects the Spanish Inquisition!".

With the ice loss in the Arctic, there are a large number of unknown factors and variables. The changes from year to year exhibit quasi-random behavior around a moving mean. But that is a fiction. The reality is that it is a mostly deterministic system with random variation in many parameters, and chaotic inputs of many types. These all interact to exhibit the behavior we see and that we interpret as randomness. And that is useful, even though it is wrong.

We can over short timespans extrapolate from past behavior to anticipate future likely behavior. However, it is not a truly random variation, and these variations only act and appear random. We must always bear that in mind.

Additionally, our choice of definitions play large roles in what we see. We have arbitrarily decided to define what portion of ice cover in a given area constitutes being ice covered - essentially treated as 100% ice. Our usual rule for that is that if the area in question is 15% ice covered, then we treat it as 100% ice covered.

This then leads to strange results. If we take the same large segment of ice and shatter it, moving the shattered parts away from each other, the ice area remains the same, while the extent can increase dramatically.

Here near the end of the ice, as the ice thins, we see this playing out over large areas. The extent artificially remains much higher than it would have as a comparison to ice area in decades gone by.

While it made sense to have such a rule when the only place it applied was around the edges of the ice sheet, the rule now serves to mislead us when the whole of the ice sheet is disintegrating. That misleading statistic then can lead us to erroneously project that the ice will last longer that other metrics like ice volume and thickness imply.

Sam

Tor Bejnar

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Re: When will the Arctic Go Ice Free?
« Reply #361 on: May 18, 2019, 09:38:17 PM »
Sam,
Thanks for the statistics tutorial.

Concerning the use of "extent", remote sensing can still not discern the difference between a melt pond and sea water, so even as extent gets progressively more inaccurate, there is not a lot of alternative.  At some point in time, detection of the several centimeters difference in height may become possible...
Arctic ice is healthy for children and other living things.

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Re: When will the Arctic Go Ice Free?
« Reply #362 on: May 18, 2019, 09:46:33 PM »
Sam,
Thanks for the statistics tutorial.

Concerning the use of "extent", remote sensing can still not discern the difference between a melt pond and sea water, so even as extent gets progressively more inaccurate, there is not a lot of alternative.  At some point in time, detection of the several centimeters difference in height may become possible...
I thought IceSat2 was getting pretty close to that.

I still say, no matter what measure one uses, the chances of a BOE this year are vanishingly small.
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magnamentis

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Re: When will the Arctic Go Ice Free?
« Reply #363 on: May 18, 2019, 10:12:47 PM »
Sam,
Thanks for the statistics tutorial.

Concerning the use of "extent", remote sensing can still not discern the difference between a melt pond and sea water, so even as extent gets progressively more inaccurate, there is not a lot of alternative.  At some point in time, detection of the several centimeters difference in height may become possible...
I thought IceSat2 was getting pretty close to that.

I still say, no matter what measure one uses, the chances of a BOE this year are vanishingly small.

calculating the excess energy needed to melt the estimated reminder of sea-ice, that would be around 3 million km2 +/-1 million km2 it's not that bold to say it's "IMPOSSIBLE"

after all there remain the laws of physics and as long as we exclude extraordinary events like impacting asteroids and/or (non-existent) POLAR undersea-volcanoes we can conclude the impossibility of it.
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be cause

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Re: When will the Arctic Go Ice Free?
« Reply #364 on: May 18, 2019, 10:43:13 PM »
  ' vanishingly small ' and ' IMPOSSIBLE '  ?   we shall see .. b.c.
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HapHazard

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Re: When will the Arctic Go Ice Free?
« Reply #365 on: May 19, 2019, 01:18:22 AM »
RE: statistics:

I always viewed statistics in a very simplistic yet accurate way:

Statistics are like bikinis: what they reveal is interesting, but what they hide is crucial.

Rich

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Re: When will the Arctic Go Ice Free?
« Reply #366 on: May 19, 2019, 01:26:30 AM »
My hunch is that there is plenty of energy available to melt the ice, but there is a barrier between the ice and the energy beneath.

If that energy can find it's way to the surface......

magnamentis

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Re: When will the Arctic Go Ice Free?
« Reply #367 on: May 19, 2019, 01:40:31 AM »
My hunch is that there is plenty of energy available to melt the ice, but there is a barrier between the ice and the energy beneath.

If that energy can find it's way to the surface......

of course there is enough energy, one could assume the earth gets a bit closer to the sun and "bingo" only that it won't happen.

it does not make sense to state the obvious that is not going to happen. there has always been enough energy on planet earth to melt all the ice, only that it did not cross the various barriers.

same now, we can assume that the oceans won't turn upside down within the next 4 months.

BTW those barriers as well are subject to the laws of physics.

it's somehow interesting how some people like to stick out by gambling on the least probable scenario and try to make it sound realistic or make all others look stupid. I think we're all aware that there is enough heat/energy in the system, be it air, water, earth core, solar system and/or the universe. the point was whether it will happen this year and the answer is no to such a high degree that i suggest that those who like to gamble play poker or black jack.

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oren

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Re: When will the Arctic Go Ice Free?
« Reply #368 on: May 19, 2019, 02:11:33 AM »
Vanishingly small? Not, IMHO.
First, I dislike the use of NSIDC data for fine distinctions, when we have the much more accurate and hi-res AMSR2, especially the UH 3.125km version, and especially with Wipneus' "home brew" algorithm that gets rid of various data problems.
Second, I think extent is a poor metric for September, as 2016 showed well.
I'll define my own version of "BOE" as <1M km2 of actual sea ice, namely Wipneus' AMSR2 area. This is not ice-free in any way, but is an important milestone.
For this BOE, I estimate a probability of 5-10% per year, with the odds rising slightly with time.
The variability in the system is high. 2012 showed that beyond a doubt, going from nearly last to first in about a month. 2016 showed that GACs are not so rare. The ice state is worse than it's ever been, looking at the MYI percentages and at the grinding and breakage in the Lincoln Sea refuge.
Take any year with low starting conditions, add sunny weather in May-June-July, especially weather that increases export towards the Atlantic, and add an August GAC. The BOE could easily follow.
I am not a weather expert, but a high pressure dome could do this from what I have read here. Both export and sunny skies. And I've also read here that high pressure is coming. Will it stay? I sure don't know. Can this year reach a BOE? Not totally impossible.
I will be highly surprised if a first BOE does not happen by 2030.

Archimid

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Re: When will the Arctic Go Ice Free?
« Reply #369 on: May 19, 2019, 04:00:03 AM »
Thanks for the graphs Gerontocrat.

First thing I notice is how the distance between each decadal minimum increases.

The second thing I notice is how far below the 2010 decadal average is the decadal minimum.

Then in my head I imagine where the 2020s decade average will be using the increasing gaps of the first observation.

And then I imagine the decadal minimum for the 2020s to be as far down from the average as the 2010s. If I'm not mistaken there is a very likely BOE there.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

kiwichick16

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Re: When will the Arctic Go Ice Free?
« Reply #370 on: May 19, 2019, 06:55:01 AM »
IF   .....the 2020 average drops to 2million sq kms  .....and we have an  extreme loss  .....similar to 2012 ...then we could be close to 1 million  sq kms  at the minimum.

The 2020's are only 7 months away.

wdmn

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Re: When will the Arctic Go Ice Free?
« Reply #371 on: May 19, 2019, 07:13:34 AM »
Quite often systems may behave similarly to random processes, yet not be such at all. In those cases, statistical tests and bounds may be useful, but also be wrong. They can mislead us greatly.

Chaotic systems may for a time exhibit quasi random statistical like behavior within certain bounds. Deviate slightly and the statistics may suddenly not work at all.

Some systems exhibit what appears to be statistical noise and random behavior only to exhibit wildly non-random behavior that far exceeds the statistical bounds. So-called "stiff" equations in chemical engineering behave this way. They appear stable for long periods before some small input accumulates in effects and drives wild changes in the results.

Systems with unrecognized, hidden, or ignored state changes may also exhibit either true or apparent random behavior about a mean, but with changes in the underlying conditions, or slight changes in the mean can walk across a system boundary and suddenly completely change behaviors completely outside any statistical analysis of the previous behavior to that point.

Thank you Sam for giving a detailed, expert explanation of what I could only generally describe.

My point -- which KK was in part responding to -- was that any probability, whether of coin flips or of "chaotic systems," can only legitimately be based on observed frequencies. That means that they can only be verified or refuted by reference to past observations (and the assumptions/presumptions that go with them).

But what does this mean for "chaotic systems?" It means that assigning numerical probabilities is dangerous and imprudent, precisely because it gives the appearance that we know more than we do. So, as I stated previously, I think that many of the pathways laid out for limiting warming are less than useless. They would be useless if they were so shrouded in uncertainty as to not give much direction in determining what to expect. They are worse than useless when this holds, and there is an extreme amount of risk should we end up being wrong, which the assigned probabilities cause us to not properly appreciate. It is even worse when we use models which give us the appearance of a statistical record, but are not actually based on observations, and so are not observed frequencies at all, but merely the figure of our assumptions being traced over and over again.

To me, this is the meaning of the precautionary principle. When we really don't know how things will play out, when we know that we have an incomplete picture about something with significant consequences, but we choose to assign a numerical probability that masks this uncertainty, we expose ourselves unnecessarily.

Without bashing any climate scientists too much, it is clear that the really capable ones appreciate this. James Hansen, for example, has been warning for a long time that are better to act sooner rather than later, because we don't properly understand all of the feedbacks (positive and negative), or ECS very well. Moreover, there's enough observational data (from the paleoclimate records) to suggest that what we have been doing with our emissions is potentially very dangerous. Early results from CMIP6 runs are now telling us that what we thought were pathways to 2C of warming over preindustrial, are likely insufficient.

I quote a recent study to support this:

“The massive analysis shows that meeting the 2C target is exceptionally difficult in all but the most optimistic climate scenarios. One pathway is to immediately and aggressively pursue carbon-neutral energy production by 2030 and hope that the atmosphere’s sensitivity to carbon emissions is relatively low, according to the study. If climate sensitivity is not low, the window to a tolerable future narrows and in some scenarios, may already be closed.

... If the climate sensitivity is greater than 3 Kelvin (median of assumed distribution), the pathway to a tolerable future is likely already closed.”

Source: https://phys.org/news/2019-03-pathways-climate-future-action.html

Given that the median value from the early results of CMIP6 runs is 4.3C we could be in a lot of trouble.

Forgive me where I am wrong. I've studied probability from a philosophical perspective, but am definitely not a statistician or even very good at maths.

Aluminium

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Re: When will the Arctic Go Ice Free?
« Reply #372 on: May 19, 2019, 07:49:35 AM »
after all there remain the laws of physics and as long as we exclude extraordinary events like impacting asteroids
How big should an asteroid be?

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Re: When will the Arctic Go Ice Free?
« Reply #373 on: May 19, 2019, 02:14:56 PM »
Can this year reach a BOE? Not totally impossible.
I will be highly surprised if a first BOE does not happen by 2030.

And even if we do not reach a true BOE before 2030, there will be little difference between a minimum of 1.8 M km2 vs. < 1.0 M km2 when we consider the impact it will have on climate.
« Last Edit: May 19, 2019, 02:41:59 PM by Shared Humanity »

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Re: When will the Arctic Go Ice Free?
« Reply #374 on: May 19, 2019, 02:20:25 PM »
+1 SH
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

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Re: When will the Arctic Go Ice Free?
« Reply #375 on: May 19, 2019, 06:38:26 PM »
+2 SH  ;)

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Re: When will the Arctic Go Ice Free?
« Reply #376 on: May 19, 2019, 06:48:24 PM »
Can this year reach a BOE? Not totally impossible.
I will be highly surprised if a first BOE does not happen by 2030.

And even if we do not reach a true BOE before 2030, there will be little difference between a minimum of 1.8 M km2 vs. < 1.0 M km2 when we consider the impact it will have on climate.

good point and has to be mentioned from time to time to bring talks back to what really matters.
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Rich

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Re: When will the Arctic Go Ice Free?
« Reply #377 on: May 19, 2019, 06:54:46 PM »
Are people underappreciating the consequences of a BOE?

My understanding is that it takes 70-80x as much energy to convert a g of water from me ice to liquid as it does to raise the temp of water 1C.  When the ice is melted, we lose a buffer for more rapid heating. We also lose albedo. These are two important positive feedback effects associated with declining ice, no?

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Re: When will the Arctic Go Ice Free?
« Reply #378 on: May 19, 2019, 07:09:42 PM »
Are people underappreciating the consequences of a BOE?

Yes. The mainstream does. This is why we are in this mess. If people would understand what's happening there, we'd have a carbon tax for 30 years.

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Re: When will the Arctic Go Ice Free?
« Reply #379 on: May 19, 2019, 07:17:34 PM »
Wdmn,

I believe you have it exactly correct.

The IPCC has begun hedging all of its analyses by using probabilities of success, and accepting lower probabilities precisely to avoid the most draconian actions required to avoid calamity. In doing so they forget or neglect several things, including:

1) how much we do not know
2) the time lags in the system
3) how humans react to directly sensed impacts and very poorly to delayed impacts
4) the chaotic nature of the systems
5) the severe consequences of step changes in physical behavior, points of no return, ...
6) how horrible people are at understanding probability and consequences, and reacting to those
7) just how hard it is to take large actions, how slow they are to start, and how slow they are to cause meaningful change
8 ) how resistant people are to sacrifice (no one wants to give up their toys)
9) how dependent society is on growth (even brief periods of stagnation, let alone negative growth, lead to problems, and negative growth of any significance leads to societal collapse)
10) the practical impossibility of achieving and sustaining the negative growth rates required to meet targets of less than 4 degrees C increase in temperature
11) people’s unwillingness to shrink population size, and in fact the in built bias reinforced in all societies and religions to expand population to out populate the “others” thereby winning by head count, and having the bodies needed to do war on the “others” to win in the battles of belief.
11) etc...

Number 10 is particularly troubling. If we consider what flat or negative growth has done to previous societies and civilizations, and use that as a guide to what we can do, it is hard to escape the conclusion that we have already lost the war in its entirety.

It is certainly possible to use renewables to do this. The Netherlands is a case example of success.  That is a slow process. And it has serious limits and problems that must be overcome. Many of these problems require societal changes to succeed, e.g. distributed power, high energetic efficiency in design, low waste, working near home, minimal travel, growing our food near where we each live, undoing much of the industrial revolution, ...  These are things people are highly resistant to surrendering.

Much of our population has little to no grasp on the importance of the wild world in maintaining the stability of the earths systems. They view population growth as an inherent good, and the wilds as just something to consume. Until we stand shoulder to shoulder unable to move, they cannot see a problem.

And all of these combined take us to an ice free earth in short order, with an ice free arctic being the first and most immediate hallmark.

The denial built into our societal and belief structures, our desire for a better life in the near term, with little or no understanding of the long term consequences, and almost no willingness to fight against the short sighted myopic financial interests that drive us to ruin in the near term, let alone the long term, lead us inexorably to a hothouse earth and to a very early ice free arctic.

Sam

Archimid

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Re: When will the Arctic Go Ice Free?
« Reply #380 on: May 19, 2019, 07:19:12 PM »
Quote
These are two important positive feedback effects associated with declining ice, no?

Just think about it for a bit. The consequences are scary as hell. Unbelievable. If you speak of the consequences of such an event you will be called a madman. It is better to pretend that is not going to happen.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

Aluminium

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Re: When will the Arctic Go Ice Free?
« Reply #381 on: May 19, 2019, 07:47:59 PM »
About albedo effect of BOE.
3.0 M km2, 102 W/m2, 107 s (~4 months of sunshine in year). This is enough to melt 9000 Gt per year. Currently, the volume loss is only about 400 km3 (~400 Gt) per year.

magnamentis

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Re: When will the Arctic Go Ice Free?
« Reply #382 on: May 19, 2019, 07:57:09 PM »
Wdmn,

I believe you have it exactly correct.

The IPCC has begun hedging all of its analyses by using probabilities of success, and accepting lower probabilities precisely to avoid the most draconian actions required to avoid calamity. In doing so they forget or neglect several things, including:

1) how much we do not know
2) the time lags in the system
3) how humans react to directly sensed impacts and very poorly to delayed impacts
4) the chaotic nature of the systems
5) the severe consequences of step changes in physical behavior, points of no return, ...
6) how horrible people are at understanding probability and consequences, and reacting to those
7) just how hard it is to take large actions, how slow they are to start, and how slow they are to cause meaningful change
8 ) how resistant people are to sacrifice (no one wants to give up their toys)
9) how dependent society is on growth (even brief periods of stagnation, let alone negative growth, lead to problems, and negative growth of any significance leads to societal collapse)
10) the practical impossibility of achieving and sustaining the negative growth rates required to meet targets of less than 4 degrees C increase in temperature
11) people’s unwillingness to shrink population size, and in fact the in built bias reinforced in all societies and religions to expand population to out populate the “others” thereby winning by head count, and having the bodies needed to do war on the “others” to win in the battles of belief.
11) etc...

Number 10 is particularly troubling. If we consider what flat or negative growth has done to previous societies and civilizations, and use that as a guide to what we can do, it is hard to escape the conclusion that we have already lost the war in its entirety.

It is certainly possible to use renewables to do this. The Netherlands is a case example of success.  That is a slow process. And it has serious limits and problems that must be overcome. Many of these problems require societal changes to succeed, e.g. distributed power, high energetic efficiency in design, low waste, working near home, minimal travel, growing our food near where we each live, undoing much of the industrial revolution, ...  These are things people are highly resistant to surrendering.

Much of our population has little to no grasp on the importance of the wild world in maintaining the stability of the earths systems. They view population growth as an inherent good, and the wilds as just something to consume. Until we stand shoulder to shoulder unable to move, they cannot see a problem.

And all of these combined take us to an ice free earth in short order, with an ice free arctic being the first and most immediate hallmark.

The denial built into our societal and belief structures, our desire for a better life in the near term, with little or no understanding of the long term consequences, and almost no willingness to fight against the short sighted myopic financial interests that drive us to ruin in the near term, let alone the long term, lead us inexorably to a hothouse earth and to a very early ice free arctic.

Sam

your list tell the entire story and makes it obvious where we are heading without a feasible way out.

also whoever is talking about human extinction, it won't be temps, storms or any of the natural impacts but it will be the consequences of forces measures as of paragraph 10 that have the potential to cause extinction of humanity.

in fact i prefer the term "drastic decimation" over extinction because i'm quite sure that there are places like those medium high and medium latitudes as well as surrounded by mountains that will allow a few to survive even most of the worst case scenarious.

before getting to much OT and distracted here just wanted to submit my kudos for the
list where one can find > 90% of what this is all about.
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Ktb

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Re: When will the Arctic Go Ice Free?
« Reply #383 on: May 20, 2019, 07:45:38 AM »
NSIDC Data

A couple of graphs looking at the Arctic Central Seas only, about what melt is required for a BOE of < 1 million km2 extent. The peripheral seas are ignored as they always melt out completely to the extent as makes no difference.

Currently a BOE requires an extent loss from now of circa 7.5 million km2 compared with an average of circa 4.5 million, i.e. circa 65% above average. The most that happened was in 2012, when extent loss from now was circa 20% above average.

So a BOE currently requires a series of circumstances (tipping points?) completely outside and beyond previous experience.

____________________________________________________________
Area data gives similar results. Note that at minimum area is usually about 65% of extent. So a BOE of 1 million km2 extent might be about 0.65 million km2 area.



And this is why I began maintaining a BOE spreadsheet. I just don't think people realize how amazing a BOE year will have to be.
If we started doing daily drops to actually be on pace (averaging 88,232 km^2 per day), we would have the 2nd strongest may melt, the strongest June melt, an average July, the strongest August, and the strongest September to minimum.

2012 didn't even have the strongest July melt, averaging -91,753 km^2 per day, making it 5th place in the years 2007-2018.

That being said, I still voted for 2020-2025. We can't dodge cannonballs forever, and one year everything is going to line up just perfectly.
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dnem

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Re: When will the Arctic Go Ice Free?
« Reply #384 on: May 20, 2019, 02:26:18 PM »
Are people underappreciating the consequences of a BOE?

My understanding is that it takes 70-80x as much energy to convert a g of water from me ice to liquid as it does to raise the temp of water 1C.  When the ice is melted, we lose a buffer for more rapid heating. We also lose albedo. These are two important positive feedback effects associated with declining ice, no?

Certainly true Rich, but when we first get to a BOE it will be at the very end of the melt season.  Some of that summer's energy will still have gone into overcoming the heat of fusion of melting the ice, and the albedo loss will be cumulative over the season and only reaching its maximum at the end.  And then the arctic night will come and there will be refreezing.  So it isn't quite right to think that once we get there, we'll be in a system with no ice to melt and no cover to reflect sunlight.

Klondike Kat

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Re: When will the Arctic Go Ice Free?
« Reply #385 on: May 20, 2019, 02:55:31 PM »
I would like to comment on the precautionary principle, because it has been used quite often when discussing climate changes.  While this pathway is based on sound reasoning, it may not be the best approach.  This principle would actually prevent more action, than it would encourage.  While many view this as a positive step (preventing negative outcomes), it can also be viewed negatively (preventing positive outcomes).  The precautionary principle would block risky ventures, because they are not proven to be safe.  This contrasts normal human behavior, which tends to encourage behavior, until proven unsafe.  This is precisely how the EPA, OSHA, and other regulatory agencies operate.  Most inventors, explorers, and scientists in general, operate opposite to the precautionary principle.  Would  clinical trials ever exist, if medical practitioners followed this principle?  Would man have ever set foot on the moon, if NASA had followed this principle? 

As Sam said, "Many of the parameters that we routinely use also have strange behaviors in conditions away from the usual."  The only way to know for sure, is to test them.  This is where scientists tend to deviate from the average person.  The average person like to remain in their safe "known" environment, whereas the scientists is pushing the boundaries to new areas.  Sometimes they succeed, sometimes they fail.  Some make great discoveries (Marie Curie) only to succumb to the perils of their discovery.  Civilization would not be where it is today, if people of the past followed the precautionary principle.  Some view this as the best, others the worst.  Consider this:  when combating climate change, should we implement new technologies, before they are proven safe, or should we try them in the hopes of making grand changes? 

Research is a way of taking calculated risks to bring about incalculable consequences.
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SteveMDFP

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Re: When will the Arctic Go Ice Free?
« Reply #386 on: May 20, 2019, 03:14:23 PM »
I would like to comment on the precautionary principle, because it has been used quite often when discussing climate changes.  While this pathway is based on sound reasoning, it may not be the best approach.  This principle would actually prevent more action, than it would encourage.  While many view this as a positive step (preventing negative outcomes), it can also be viewed negatively (preventing positive outcomes).  The precautionary principle would block risky ventures, because they are not proven to be safe...

A thoughtful post, for which I'd offer a moderately contrasting perspective.
There may be some benefit in presenting a definition and discussion of what the Precautionary Principle entails:

The precautionary principle in environmental science.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1240435/

" The precautionary principle, proposed as a new guideline in environmental decision making, has four central components: taking preventive action in the face of uncertainty; shifting the burden of proof to the proponents of an activity; exploring a wide range of alternatives to possibly harmful actions; and increasing public participation in decision making..."
_____________________________________________

The difficulty may be less in the Precautionary Principle than how to apply it to societal decision-making.  I'd emphasize "taking preventive action in the face of uncertainty."  That is, if continuing BAU carries even a small risk of catastrophic consequences, such preventive action is necessary.  This wouldn't imply avoiding actions that might be beneficial, rather the opposite.

There's also the matter of what constitutes "action" or "activity."  Continuing the status quo must be considered an action.  The proposal to, say, burn another gigaton of fossil fuels should be weighed against whether to build a megawatt of solar power.  The solar power array shouldn't be viewed as the only "action" or "activity" in this choice.

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Re: When will the Arctic Go Ice Free?
« Reply #387 on: May 20, 2019, 03:28:41 PM »
dnem makes an extremely important point.

The first BOE very likely happens in September. At that point, the power of the Sun over the Arctic is minimal. Let's start there.

Let's imagine a situation where the last few million square kilometers of ice poof out of existence creating the first BOE. Let's suppose that the thermodynamic balance of the arctic switches from Melt to Freeze at the instant the BOE happens. No heat accumulated in the atmosphere or the oceans. No enthalphy considerations. The freezing season begins.

What happens next?  The maximum volume of ice that the Arctic has created in a Freezing season is 19.66 (1000 km3). If the year after the first BOE the Arctic creates the maximum volume on record, then max volume in April will be 19.66 of thin, one year ice. The average Melt from 2006 to 2018 was 17.89, but included thick ice. The maximum let on record was 19.69, more than the Maximum gain.

 If everything stayed the same, it is very likely that the year following the first BOE is followed by another  BOE that happens earlier. Then you start the freezing season with negative ice, ending the following the freezing season with even less ice setting up the Arctic for another even earlier BOE.

This cycle will not go on for long before sea ice is gone by June and the northern hemisphere is a different world.
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SteveMDFP

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Re: When will the Arctic Go Ice Free?
« Reply #388 on: May 20, 2019, 03:40:34 PM »
dnem makes an extremely important point.

The first BOE very likely happens in September. At that point, the power of the Sun over the Arctic is minimal. Let's start there.
...
If the year after the first BOE the Arctic creates the maximum volume on record, then max volume in April will be 19.66 of thin, one year ice. The average Melt from 2006 to 2018 was 17.89, but included thick ice. The maximum let on record was 19.69, more than the Maximum gain.

 If everything stayed the same, it is very likely that the year following the first BOE is followed by another 

A reasonable interpretation.  However, we shouldn't ignore a major negative feedback (against all the worrisome positive feedbacks).  A BOE leaves the arctic with vast open expanses of bare water going into the arctic night.  Open ocean radiates far more heat out into space during the night than ocean covered with ice and snow as an insulator.  I really would expect above-record refreezing after a BOE.  Enough to preclude a subsequent repeat BOE?  I don't know.   

Klondike Kat

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Re: When will the Arctic Go Ice Free?
« Reply #389 on: May 20, 2019, 05:20:12 PM »
I would like to comment on the precautionary principle, because it has been used quite often when discussing climate changes.  While this pathway is based on sound reasoning, it may not be the best approach.  This principle would actually prevent more action, than it would encourage.  While many view this as a positive step (preventing negative outcomes), it can also be viewed negatively (preventing positive outcomes).  The precautionary principle would block risky ventures, because they are not proven to be safe...

A thoughtful post, for which I'd offer a moderately contrasting perspective.
There may be some benefit in presenting a definition and discussion of what the Precautionary Principle entails:

The precautionary principle in environmental science.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1240435/

" The precautionary principle, proposed as a new guideline in environmental decision making, has four central components: taking preventive action in the face of uncertainty; shifting the burden of proof to the proponents of an activity; exploring a wide range of alternatives to possibly harmful actions; and increasing public participation in decision making..."
_____________________________________________

The difficulty may be less in the Precautionary Principle than how to apply it to societal decision-making.  I'd emphasize "taking preventive action in the face of uncertainty."  That is, if continuing BAU carries even a small risk of catastrophic consequences, such preventive action is necessary.  This wouldn't imply avoiding actions that might be beneficial, rather the opposite.

There's also the matter of what constitutes "action" or "activity."  Continuing the status quo must be considered an action.  The proposal to, say, burn another gigaton of fossil fuels should be weighed against whether to build a megawatt of solar power.  The solar power array shouldn't be viewed as the only "action" or "activity" in this choice.

That is true.  Perhaps I should have said something along the lines of new or novel activity.  Continuing the status quo is, of course, an action.  However, I would consider it more of a known action, even if the future has some unknowns attached.  That is why I mention that many people prefer to stay in their safe, known environments, rather than venture into something new.  Hence, I view maintaining the status quo of more an inaction, as nothing really changes.

GoSouthYoungins

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Re: When will the Arctic Go Ice Free?
« Reply #390 on: May 20, 2019, 06:11:50 PM »
A BOE leaves the arctic with vast open expanses of bare water going into the arctic night.  Open ocean radiates far more heat out into space during the night than ocean covered with ice and snow as an insulator.  I really would expect above-record refreezing after a BOE.  Enough to preclude a subsequent repeat BOE?  I don't know.

I think you are getting your wires crossed a bit here.  Heat can only get spaced into the black night if there is no ice. So once there is a thin layer of ice, the insulation begins. Thus it is impossible to get more ice from having less ice. (If you are only talking about extent increase from the minimum, I agree.)

The rate of refreeze would be epic. In a few weeks almost the entire arctic basin would be covered with ice. There would be parts of the Chukchi Sea that may not refreeze, and refreeze in the Bering would likely be minimal. Meanwhile, the Bering Strait will almost certainly freeze due to its proximity to very cold land.

The real problems start the year after a BOE. The thin ice will melt out in much of the arctic by the solstice. July and August would see incredible amounts of heat sunk into the ocean. That fall refreeze would be many weeks delayed, and the ice layer that forms would be substantially inferior to typical first year ice. The next summer much of the basin is ice free by June causing refreeze to be many more weeks delayed.

Archimid is correct: once a BOE occurs, the rate of change increases. And before long there is only winter and spring ice. What ice forms in the arctic night a decade or two after the first BOE is way to complicated to really even hypothesis at currently.
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Re: When will the Arctic Go Ice Free?
« Reply #391 on: May 20, 2019, 07:01:36 PM »
Was there a BOE in the Eemian? Maybe that will give us a clue as to what the consequences will be.
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