The Climatic Effects of a Blue Ocean Event

[Archimid]

The following video posted by Jim Hunt at the Stupid Questions thread made it clear to me that the best way to determine how a BOE will affect the climate would be by looking at how the climate changed during Dansgaard–Oeschger Events (DOE) and try to extrapolate those changes to a modern day climate. 

Video: https://forum.arctic-sea-ice.net/index.php/topic,143.msg227842.html#msg227842


I have found what looks like a wonderful collection of links from samples of different types of proxies collected all over the planet at the bottom of the following page:

https://www.ncdc.noaa.gov/abrupt-climate-change/Heinrich%20and%20Dansgaard%E2%80%93Oeschger%20Events

 

I think DOEs are a great analogues for BOEs but with key differences:

1. DOEs happened during the last ice age when the world was a much colder place. Max DOE temperatures didn't even reach holocene levels of warming, except perhaps the last one.

2. The arctic was meters thick and covered a larger portions of the North Atlantic, particularly along the the east coast of Greenland. A "sudden" loss of ice in that region could have reinforced whatever caused the loss of ice in the first place, creating DOE events.

3. Huge ice sheets covered the NH. It is these ice sheets what created the opposite of DOE, Heinrich events. Ice sheets also provided lower albedo and melt surface.

4. DOE events seem to be the result of astronomical events, local to the NH. The whole world was cold but the Arctic "warm", thus the world was helping restore the ice. The reason for today's BOE is the opposite, the world is getting warmer, pushing the Arctic into amplification mode.

5. There were few humans at the time. Any information about humans during that time would be welcomed, but I doubt it exists.

I'm randomly review some of the links above to see If I can learn more.

[Tom_Mazanec]

Paul Beckwith on effects of a BOE:

In my previous two videos I discussed how the reflectivity of the Arctic region reduced from 52% to 48% between 1979 and 2011, with global average warning 0.21 W/m2 (1/4 that of CO2). Now I explain the newest science from 2019 on how a Blue-Ocean State (zero Arctic sea ice) in summer would heat the overall planet 0.71 W/m2 with expected cloud invariance (or 2.24 W/m2 with clear skies, or 0.37 W/m2 if overcast). This equals 1 trillion tons of CO2 or 25 years of warming. i.e. global food shortage chaos.

In this video I continue to explain the latest cutting edge science from late 2019 on how a Blue-Ocean State (zero Arctic sea ice) in summer would heat the overall planet 0.71 W/m2 if cloud behaviour stays similar to now. If clouds behave differently, one extreme case would have heat forcing of 2.24 W/m2 with completely clear skies; the other extreme case would be 0.37 W/m2 if the Arctic skies were all overcast (over 95% cloud coverage; similar thickness (optical depth) to now. The middle case (most likely?!) with 0.71 W/m2 is equivalent to 1 trillion tons of CO2 or 25 years of warming. i.e. global food shortages.

In previous videos I explained how the latest cutting edge science from late 2019 expects that a Blue-Ocean State (zero Arctic sea ice) in summer would heat the overall planet the equivalence of 25 years of global warming or 1 Trillion tons of CO2. Putting this into context, as of 2016 an estimated 2.4 Trillion tons has been emitted since the preindustrial period; due to both fossil fuel combustion (1.54 Trillion tons) and land use changes (0.82 Trillion tons). It becomes glaringly obvious that we will blow through 1.5C and 2C Paris safety targets when this happens, not to mention methane and Greenland vulnerabilities.

He states a BOE is likely in five years, certain in ten.

[oren]

There is a big diferece between a traditional BOE (1 million km2) in mid-September, and his "zero Arctic sea ice in summer ". (Is that August? July? June?) While I expect the former in 10 years, the latter is still far off, surely not 5 or 10 years.

[The Walrus]

There is a big diferece between a traditional BOE (1 million km2) in mid-September, and his "zero Arctic sea ice in summer ". (Is that August? July? June?) While I expect the former in 10 years, the latter is still far off, surely not 5 or 10 years.

Not too many scientists take him seriously.  His discipline lies in laser research.  He has some good publications there, but not in the field of climate science.  Remember, he predicted the Arctic would be ice-free in 2013.

[Archimid]

Oren, what do you think of the definition of a BOE as the unit of time, during summer, when surface air temperature north of 80 shoots up beyond normal summer variability? I think that will be a climatically momentous occasion. There will be much less than 1 million km2 remaining when that happens, and it will likely happen in August.

I don't think < 1 million km2 by mid-September as a BOE. I call that a virtually ice-free arctic because I've read it that way somewhere. Hopefully, a virtually ice-free Arctic happens before a BOE, but even if it does, it will happen towards the end of a continuum that already started. The effect of the event over mankind is proportional to the length of the continuum.  The longer the continuum, the better for us. The faster it happens the worse.  A virtually ice-free arctic is the last step before a BOE.

If both a BOE and a VIFA (Virtually Ice Free Arctic, because wth) happen in the same year, Mc Pherson was right. But after this year's freezing season, I find it more likely that a VIFA will happen without a BOE before the year of the first BOE in human history.

[El Cid]

1. Beckwith is not a climate scientist, his guesses are as good as mine at the minimum. Actually, he is worse, as he's been known to make extraordinary claims that proved to be completely false. I would be very careful about anything he says.
2. The research he quotes above is valid though, written by actual climate scientists. I read the paper.
3. Ice albedo feedback is a very important but not very well quantified mechanism, there are still a lot of questions about it (mostly cloud-effects). Still, it is unquestionable that the warming of the planet (especially the oceans) leads to less arctic ice, which leads to more heating of the arctic sea, that leads to less arctic ice. Eventually a BOE will happen and it will seriously effect the climate of the whole planet.
4. I would argue that as the Arctic becomes icefree, there will be more moisture and more clouds, that lessen this effect, but as all real climate scientists know, future cloud-effects are the greatest uncertainity in modelling climate.
5. Most of the extra "heating" would come from spring and summer insolation. An ice-free Arctic in September or even August would not change much as per the paper.
6. Their calculation of 25 years of extra Co2 would probably imply 0,5-0,9 C of global warming. If there are more clouds as I expect, it is probably around or below 0,5 C. All this will happen only with an ice-free arctic during summer and spring! That is basically a year-around free arctic. No real scientists see that happening within 50 years.
7. So for the next decade the extra warming even from an Arctic that becomes mostly ice-free in August/September (this will probably happen in the 2020s I think), is at most +0,1 C globally.
8: It is quite obvious though that +1,5 C or +2 C globally is not achievable. +3 C is the best that mankind can hope for by 2100. I think that is achievable. Mind you, that would probably imply +6 C on NH midlatitude land! (cca +4 C vs current temps)

[oren]

Oren, what do you think of the definition of a BOE as the unit of time, during summer, when surface air temperature north of 80 shoots up beyond normal summer variability? I think that will be a climatically momentous occasion. There will be much less than 1 million km2 remaining when that happens, and it will likely happen in August. 

Yes, that is when the climatic shit his the fan IMHO. But when? Hard to guess.

[Tom_Mazanec]

I’m not so sure that a million square kilometers is enough to prevent such a sudden jump in temperature.

[Archimid]

Hard to guess indeed, but as we get nearer to the date clues are starting to emerge.

The current behavior of Chukchi ASI  may offer new clues.

As I see it, ice didn't really start growing until November. Then as it got surrounded by ice and by mid-December it was almost fully closed. Surface air temperatures anomalies were very high while the ocean was open and then dropped to relatively cold levels after the oceans closed and the heat dissipated.


If we used DMI N80, the 1 million km2 would have to be right in the center to avoid shooting the temperatures up.

[Tom_Mazanec]

What was special about, IIRC, 2012? When we had record low September ice (and that big storm in NYC that may have resulted from it)? Why was the ice so low that year? Could it happen agin?

[nanning]

It can happen again and will happen again until it's annual. It is a temporary phase the arctic ocean will go through on its way to atlantification, losing the thermohalocline. The forcing of evil GHG is just too great and is still growing.
It was special because it was a freak outlier.

[Tom_Mazanec]

Yes, but what caused that freak outlier? Why was it a lower minimum than the one seven years later with all that extra warming? Was there a storm or something?

[The Walrus]

Yes, but what caused that freak outlier? Why was it a lower minimum than the one seven years later with all that extra warming? Was there a storm or something?

Tom, yes.  There was a major Arctic cyclone that began in early August and latest nearly two weeks.  The storm churned up significant warm water and the wave action broke up large sections of ice.  Nothing similar has occurred since.  When using statistics to calculate sea ice trends, it is best to ignore that year, lest the data becomes skewed.  An example would be those claims of sea ice growth over the past decade.

[nanning]

It was a butterfly.

[dnem]

When using statistics to calculate sea ice trends, it is best to ignore that year, lest the data becomes skewed. 

No! An outlier can be excluded when there is a reason to question the validity of the data point. 2012's low minimum happened and will likely be exceeded before long. Obviously CHERRY PICKING 2012 in some way, like looking at a trend from 2013 so 2019 is wrong, but no long term analysis of arctic sea ice trends can just "ignore" 2012!

[Archimid]

It was a butterfly.

That's the scary part. A butterfly flaps her wings with the force of Godzilla to produce record low ASI extent and volume. The "logical" response, ignore it as an outlier.

[The Walrus]

When using statistics to calculate sea ice trends, it is best to ignore that year, lest the data becomes skewed. 

No! An outlier can be excluded when there is a reason to question the validity of the data point. 2012's low minimum happened and will likely be exceeded before long. Obviously CHERRY PICKING 2012 in some way, like looking at a trend from 2013 so 2019 is wrong, but no long term analysis of arctic sea ice trends can just "ignore" 2012!

I was not referring to long term trends wee one datapoint makes little difference.  Rather, I was referring to recent trends.  Much has been made of the recent slowdown in Arctic melt.  When calculating 10-year trend (or similar) the inclusion of 2012 can result in a skewed (increasing minimum),  trend due to endpoint problems.  Starting from 2013 will generate a decreasing trend, but has a much higher uncertainty, due to the shortage of data points since.  It is obvious from the data, that the ice has undergone two different transitions, resulting in three different trends; namely the slow decrease from 1979-1998, the large decrease over the next decade, and the slow decline since.  Hence, a linear 40-year trend does not due justice to the data. 

[Bruce Steele]

Walrus, For this forum it is always a good idea to include sources. When you say the “ the storm stirred up significant warm water “ maybe you could show me some statistics or published papers that can show me what those increased temperatures where and when they occurred ? We had ITP buoys running for the 2012 GAC and I was watching them but I didn’t see the warm water penetrate the surface fresh water . I have heard the warm water theory before, it makes sense , but I never saw the published data on it’s whereabouts. 

[The Walrus]

Walrus, For this forum it is always a good idea to include sources. When you say the “ the storm stirred up significant warm water “ maybe you could show me some statistics or published papers that can show me what those increased temperatures where and when they occurred ? We had ITP buoys running for the 2012 GAC and I was watching them but I didn’t see the warm water penetrate the surface fresh water . I have heard the warm water theory before, it makes sense , but I never saw the published data on it’s whereabouts.

My apologies.  I thought this was general knowledge.

https://earthobservatory.nasa.gov/images/78812/2012-arctic-cyclone

[gerontocrat]

It was a butterfly.

That's the scary part. A butterfly flaps her wings with the force of Godzilla to produce record low ASI extent and volume. The "logical" response, ignore it as an outlier.

In an analysis I did sometime ago I treated 2007 and 2012 as outliers to demonstrate that there was not a leveling off in the rate of decline in Arctic Sea Ice Extent (and volume).

My justification was that the records showed that the climatic conditions in those years were close to ideal for a maximum melt.

What I unsuccessfully argued was that those 2 years showed the maximum variation from the average trend that can be reasonably expected in any one year given those ideal conditions.

For NSIDC Extent, the value is around 1.4 million km2. On trend, by 2030 on trend the September average extent would be around 3.5 million km2. If in that year, conditions were ideal for melting, that suggests a September average extent of just over 2 million km2. i.e. Not ice-free.

Applying the same methodology to VOLUME produces a contrasting story. There are several years when the variation from trend in September Average Volume is well over 2,000 km3.

This suggests that by about 2024, there is an ever-increasing possibility of a BOE.

Obviously, the methodology assumes that Extent and volume continue to decline more or less at trend. The next post has a graph that suggests that the contrast between the rate of decline in volume and extent must break down sometime in this decade.

[gerontocrat]

The graph attached suggests that sometime this decade, if volume continues to decline at trend, sea ice extent and area decline must accelerate to well above the current rate which is much lower than the current rate of volume loss.

This would cause a steep rise in the Arctic's Albedo Warming Potential from its record high in 2019, greatly enhancing the existing climate change from increasing AWP (and open water vs ice-cover).

[Hefaistos]

---
This would cause a steep rise in the Arctic's Albedo Warming Potential from its record high in 2019, greatly enhancing the existing climate change from increasing AWP (and open water vs ice-cover).

The sea ice minimum is in mid September or so, thus the first BOE would also happen in September, most likely. Assuming that the first instances of the BOE will be 'light'.
But what about insolation in September? Already very low, thus not so much effect on Albedo.
Thus, I believe 'small' BOE's wll not have that big an effect on climate change as you postulate.

[nanning]

Thank you gerontocrat for all your well argumented and very smart analyses. And your hard work, graphs, coherent databases and your interesting views.

[gerontocrat]

---
This would cause a steep rise in the Arctic's Albedo Warming Potential from its record high in 2019, greatly enhancing the existing climate change from increasing AWP (and open water vs ice-cover).

The sea ice minimum is in mid September or so, thus the first BOE would also happen in September, most likely. Assuming that the first instances of the BOE will be 'light'.
But what about insolation in September? Already very low, thus not so much effect on Albedo.
Thus, I believe 'small' BOE's wll not have that big an effect on climate change as you postulate.

To get to a BOE in September implies accelerated early melting which is, as you say, the key to accelerated increases in AWP. E.g. in 2019 the early melt of the Bering Beaufort & Chukchi Seas made a major contribution to the record AWP

There are climatic effects in Autumn / early Winter from seas with increased open water and less ice cover. Maritime vs icy desert climate.

https://cryospherecomputing.tk/NRTawp.html

[Hefaistos]

Thanks for those graphs, Geron.
I think your first graph with the albedo warming potential of the different seas in the Arctic region pretty much proves my point, that there will be no dramatic effects of a BOE.

If you take the 3 seas with the greatest AWP, they are Bering, Chukchi and Beaufort. But those 3 seas are already having a local summer 'BOE' in each sea, each summer. So no additional AWP from them if we get an overall BOE in the Arctic.

As for non-summer BOE, we have very little AWP due to the lack of insolation.

I find it hard to see that we will be, as you claim "greatly enhancing the existing climate change from increasing AWP".

[pietkuip]

I think your first graph with the albedo warming potential of the different seas in the Arctic region pretty much proves my point, that there will be no dramatic effects of a BOE.

We may already be seeing the effects of more open water on the weather patterns in the Northern Hemisphere. There are some conference talks on YouTube by Jennifer Francis. More open water would mean that the surface temperature won't go down after the Arctic sunset. There would also be much more evaporation. I am afraid that this might throw weather out of whack even more.

[gerontocrat]

Thanks for those graphs, Geron.
I think your first graph with the albedo warming potential of the different seas in the Arctic region pretty much proves my point, that there will be no dramatic effects of a BOE.

If you take the 3 seas with the greatest AWP, they are Bering, Chukchi and Beaufort. But those 3 seas are already having a local summer 'BOE' in each sea, each summer. So no additional AWP from them if we get an overall BOE in the Arctic.

As for non-summer BOE, we have very little AWP due to the lack of insolation.

I find it hard to see that we will be, as you claim "greatly enhancing the existing climate change from increasing AWP".

Tealight's (aka Nico Sun) graph on potential max AWP vs Actual attached. Significant additional AWP certainly possible likely in the years to come.

I haven't got a spare super-computer(s) (or the science) available to evaluate the climatic impact.

[El Cid]

We've discussed it upthread and the conclusions from scientific research are quite obvious: no significant global insolation change effect from an August or September BOE, not even July! Picture attached

[Hefaistos]

Tealight's (aka Nico Sun) graph on potential max AWP vs Actual attached. Significant additional AWP certainly possible likely in the years to come.

I haven't got a spare super-computer(s) (or the science) available to evaluate the climatic impact.

Sure, you can calculate a AWPotential but if there is no sun anyway, it seems a bit theoretical, doesn't it?

[Hefaistos]

I think your first graph with the albedo warming potential of the different seas in the Arctic region pretty much proves my point, that there will be no dramatic effects of a BOE.

We may already be seeing the effects of more open water on the weather patterns in the Northern Hemisphere. There are some conference talks on YouTube by Jennifer Francis. More open water would mean that the surface temperature won't go down after the Arctic sunset. There would also be much more evaporation. I am afraid that this might throw weather out of whack even more.

I live on 60 N in Sweden, and we certainly see this effect each winter. The real winter weather  starts later, and generally speaking, winters are much milder nowadays. It's not so dramatic, just boring
As the Atlantic Ocean is warmer, it does evaporate more during the early winter period. Evaporation means that the warm ocean water cools down as it is brought north by the Amoc, and the dominating SW winds.
Only when the ocean water is cool enough, we get a persistent change in the jet stream that favours a stable winter weather.

[gerontocrat]

We've discussed it upthread and the conclusions from scientific research are quite obvious: no significant global insolation change effect from an August or September BOE, not even July! Picture attached

I think your graph shows the daily insolation over the melting season. Of course the effect of increased sea ice loss is minimal when daylight hours and the sun's altitude tend to zero.

Tealight's graph shows the CUMULATIVE AWP.

Some scientists think sea ice loss and the effect on AWP are already significant -see below.

and that's all I am going to say about that.
_______________________________________________________
https://www.theverge.com/2018/5/10/17339046/arctic-sea-ice-decline-albedo-effect-climate-change-global-warming
The albedo effect due to vanishing sea ice is already responsible for about 25 percent of global warming, according to Jennifer Francis, a research professor at Rutgers University’s School of Environment and Biological Sciences.

https://www.researchgate.net/profile/Dana_Veron/publication/229038576_Winter_Northern_Hemisphere_weather_patterns_remember_summer_Arctic_sea-ice_extent/links/0fcfd50eef354ac3d7000000.pdf
Winter Northern Hemisphere weather patterns remember summer
Arctic sea-ice extent

The dramatic decline in Arctic summer sea-ice cover is a compelling indicator of change in the global climate system and has been attributed to a combination of natural and anthropogenic effects.

Through its role in regulating the exchange of energy between the ocean and atmosphere, ice
loss is anticipated to influence atmospheric circulation and weather patterns. By combining satellite measurements of sea-ice extent and conventional atmospheric observations,
we find that varying summer ice conditions are associated with large-scale atmospheric features during the following autumn and winter well beyond the Arctic’s boundary. Mechanisms by which the atmosphere ‘‘remembers’’ a reduction in summer ice cover include warming and destabilization of the lower troposphere, increased cloudiness, and slackening of the poleward thickness gradient that weakens the polar jet stream.

This ice atmosphere relationship suggests a potential long-range outlook for weather patterns in the northern hemisphere.

1. Introduction
Sea ice is the primary arbiter of energy exchange between the Arctic atmosphere and ocean. Its high albedo regulates the amount of insolation entering the surface, its seasonal phase changes modulate ocean characteristics and control summer temperatures, its insulating properties retard heat exchange, and its rheology inhibits kinetic energy transfer. The large interannual variability and dramatic loss of ice coverage, therefore, is expected to have substantial effects on the climate system.

https://link.springer.com/article/10.1007/s10712-014-9284-0
Effects of Arctic Sea Ice Decline on Weather and Climate: A Review

As the heat capacity of a unit volume of ocean water is about 3,600 times larger than that of the air, it is expected that temperature changes are much more detectable in the atmosphere, particularly in winter when the heat flux from the ocean is large. In addition, the reduced surface albedo results in heating of the ocean in summer, compensating for the increased heat loss, which occurs in other seasons.

[TerryM]

The abrupt halt of phase change when there is no ice to melt in a particular basin,(or the entire Arctic Ocean) after a BOE may need to be accounted for.


Energy that had previously been absorbed without raising temperatures because of ice melt will subsequently be raising the temperature of the top layer of the open water. The increased evaporation of the heated water will increase the local atmospheric GH effect, even though clouds and mist may effectively block most of the available Sept. insolation.


Dr. Francis wrote of the uniquely heavy fog and mist she encountered in (late Oct.)? as they steamed toward the Pole near the ESAS in (2012)? in Polarstern. (Sorry, it's been a while)


The heat from waters warmed during summer solstice, then captured under thick clouds is the reason usually given for the large forests and semi-tropical fossils found on Baffin Island.


Once the ice available for phase change has been melted in Sept (BOE), the cloud cover will slow the onset of freeze-over, lowering the volume (and extent)? of ice in subsequent years. This in turn leads to earlier, and more extensive BOEs until we again find camels & turtles living in the Arctic.


The initial BOE, with both the albedo change & the loss of ice to sop up energy at ~0⁰C will signal the beginning of the end of "Ice-Age Earth", and the beginning of "Greenhouse Earth". Some here will live to witness it.
Terry

[Archimid]

A hot BOE can't happen in September because there isn't enough sunlight in September. In September we can only have an ice-free arctic. A BOE must happen in August, so there is time for the higher latitudes oceans to absorb solar energy.`

After the first BOE, the march towards no ice in July and June begins.


See the Chukchi for early characteristics of a BOE.

Late refreeze, very high Air surface temperatures followed by a fast freeze in November-Dec, then thin ice until the beginning of the melting season.

[gerontocrat]

A hot BOE can't happen in September because there isn't enough sunlight in September. In September we can only have an ice-free arctic. A BOE must happen in August, so there is time for the higher latitudes oceans to absorb solar energy.`

After the first BOE, the march towards no ice in July and June begins.

See the Chukchi for early characteristics of a BOE.

Late refreeze, very high Air surface temperatures followed by a fast freeze in November-Dec, then thin ice until the beginning of the melting season.

The point I keep on trying to make is that to have a BOE requires early melting in the peripheral seas and the seas surrounding the CAB, and it is that early melting that is already having the greatest impact on increasing the Cumulative Albedo Warming Potential.

ps: The Bering Sea used to be known as "The Smoky Sea" by the sailors who used to go seal hunting / poaching in the 19th and early 20th Century, due the prevalence of fog and mist during the summer (hunting) months.

I guess one climatic effect of more open water in the Arctic Ocean itself will be an increase in foggy days.

[Archimid]

The point I keep on trying to make is that to have a BOE requires early melting in the peripheral seas and the seas surrounding the CAB

What you mention seems to be a requirement. Indeed, it is the natural progression that will eventually take us to a BOE. It is what will likely happen if nothing new emerges.

The new thing that I think will emerge before a BOE happens is poofing. By poofing I mean extraordinary events characterized very large losses of contiguous, non-edge, ASI surface area.
Poofing will likely require a combination of very low ASI thickness and strong WAA.

Poofing might allow summer sunlight to get into N80 waters a lot sooner than just the decay of peripheral ASI.

[Tony Mcleod]

A hot BOE can't happen in September because there isn't enough sunlight in September. In September we can only have an ice-free arctic. A BOE must happen in August, so there is time for the higher latitudes oceans to absorb solar energy.`

After the first BOE, the march towards no ice in July and June begins.

See the Chukchi for early characteristics of a BOE.

Late refreeze, very high Air surface temperatures followed by a fast freeze in November-Dec, then thin ice until the beginning of the melting season.

The point I keep on trying to make is that to have a BOE requires early melting in the peripheral seas and the seas surrounding the CAB, and it is that early melting that is already having the greatest impact on increasing the Cumulative Albedo Warming Potential.

Indeed. The first BOE will probably be brief and in September. But it is not just that week or two that's the problem. In the lead up, there obviously need to be weeks and months of large, open areas of dark ocean; weeks and months of insolation, weeks and months of surface mixing through increased wave action and weeks and months of surplus energy warming water instead of melting ice. It will be the beginning of an era of 'first year' only ice. It's the Laptev bite making it to the pole by early July!
I think how brief or how late in the season the first BOE is will be irrelevant, it will mark a clear tipping point when each subsequent year is so much more likely also to go poof. There may be a cooler year or two down the track that buck the trend but that would be matter of luck. Other than glaciation or centuries of natural CO2 drawdown, there really is no going back from a BOE.

[The Walrus]

A hot BOE can't happen in September because there isn't enough sunlight in September. In September we can only have an ice-free arctic. A BOE must happen in August, so there is time for the higher latitudes oceans to absorb solar energy.`

After the first BOE, the march towards no ice in July and June begins.

See the Chukchi for early characteristics of a BOE.

Late refreeze, very high Air surface temperatures followed by a fast freeze in November-Dec, then thin ice until the beginning of the melting season.

The point I keep on trying to make is that to have a BOE requires early melting in the peripheral seas and the seas surrounding the CAB, and it is that early melting that is already having the greatest impact on increasing the Cumulative Albedo Warming Potential.

Indeed. The first BOE will probably be brief and in September. But it is not just that week or two that's the problem. In the lead up, there obviously need to be weeks and months of large, open areas of dark ocean; weeks and months of insolation, weeks and months of surface mixing through increased wave action and weeks and months of surplus energy warming water instead of melting ice. It will be the beginning of an era of 'first year' only ice. It's the Laptev bite making it to the pole by early July!
I think how brief or how late in the season the first BOE is will be irrelevant, it will mark a clear tipping point when each subsequent year is so much more likely also to go poof. There may be a cooler year or two down the track that buck the trend but that would be matter of luck. Other than glaciation or centuries of natural CO2 drawdown, there really is no going back from a BOE.

On the contrary, a BOE is not necessarily permanent.  It will be, if temperatures continue to climb.  However cooling, even slightly, would cause increased ice formation.  This is a physical process, which is completely reversible.

[Tom_Mazanec]

On the contrary, a BOE is not necessarily permanent.  It will be, if temperatures continue to climb.  However cooling, even slightly, would cause increased ice formation.  This is a physical process, which is completely reversible.

Walrus, sans massive geoengineering we are not going to see cooling this century, and likely not this millennium.

[The Walrus]

On the contrary, a BOE is not necessarily permanent.  It will be, if temperatures continue to climb.  However cooling, even slightly, would cause increased ice formation.  This is a physical process, which is completely reversible.

Walrus, sans massive geoengineering we are not going to see cooling this century, and likely not this millennium.

While that may be true, we are just 20% into this century, and a mere 2% into the millennium.  You must have quite the crystal ball to make such forecasts.  It all depends on how many years it takes to reach a BOE.  If a BOE is not reached until much later into the warming curve, then the likelihood of cooling is much greater. 

[blumenkraft]

There is absolutely no indication that the world climate is cooling. Not this year, not this decade, not this century.

I recomment dropping this argument here and now!

[The Walrus]

There is absolutely no indication that the world climate is cooling. Not this year, not this decade, not this century.

I recomment dropping this argument here and now!

No one is claiming that the world is cooling.  However, any prediction near the end of this century or subsequent ones cannot rule out this possibility.  However, since this is purely academic, I will honor your request and drop it.

[kassy]

Indeed. The first BOE will probably be brief and in September. But it is not just that week or two that's the problem. In the lead up, there obviously need to be weeks and months of large, open areas of dark ocean; weeks and months of insolation, weeks and months of surface mixing through increased wave action and weeks and months of surplus energy warming water instead of melting ice.

I wonder if that ´brief and in September´will pan out.

We are used to look at the normal cycle and yes that is when it hits is lowest point in the current state. However into the thirties all the ice is much more south so that leaves so much open water which can also bring other things into play like increased atlantification of the siberian side and a lot of early open water over the beaufort which could be bad if waters start mixing.

Also we have seen the development of the Greenland Crack and that will probably get worse so while it is likely that the remaining ice will pile up near Greenland in winter it is not obvious it is going to stay there all summer and where it floats.

The relevant graphic:

.

There was also some point about the actual thread title. What could it be? 



 

[gerontocrat]

A bit of a rambling rant...

To have a BOE requires the peripheral seas and the seas bordering the Arctic Ocean - except perhaps or perhaps not, North of Greenland, to melt out earlier, and they are. So the climatic effects of a BOE are already with us, as that is the direction of travel. Even the winter maximum has reduced - the JAXA March monthly average from 16 million km2 to 14 million km2 - i.e. on average 45,000 km2 less ice every year. And the September monthly average has reduced from 7.5 million km2 to 3.5 million km2 (current guess)- i.e. on average 95,000 km2 less ice every year.

So there are parts of the Arctic where the icy desert has become open water permanently, and in much of the rest of the Arctic Seas for an ever increasing part of the year..

It seems to me that a BOE will just be a bit more of the same. We just need to look at what is happening now - greening of the Tundra, heatwaves burning the Tundra, movement of ocean life north, and surely the climate scientists can tell us what the Arctic climate might be like, say in 2030, with half a million km2 less ice in winter and a million km2 less ice in summer in an average year.

Who needs tipping points & drama when disaster is already baked in, even if the baking time is long? But of course if Arctic Amplification becomes amplification of a general acceleration in world temperatures (say from collapsing carbon sinks), then the BOE would largely be an effect of global heating rather than a major  cause of regional and world climate changes.

But what a vast subject - feedbacks with Greenland Ice Sheet Mass Loss and / or Gain springs to mind. No, too hard a nut to even attempt to crack.

[interstitial]

a tipping point requires a feedback mechanism it is not just an arbitrary milestone along the way. A good example is grounding line retreat underneath a glacier. If water temperatures cools the grounding line could move towards the ocean. If water temperature increase the grounding line moves away from the ocean. If their is an underwater ridge on the seafloor when the grounding line moves over the ridge away from the ocean that is a tipping point. Its not because its a reference point in the glaciers retreat. A retro grade slope is known to increase the speed of grounding line retreat. That is what makes it a tipping point. The decreased resistance to grounding line retreat makes it harder/less likely that cooling waters would cause the grounding line to move towards the ocean. Waters are not cooling that is not the point. Calling it a tipping point implies a large enough change that a reversal in conditions is unlikely to restore things to their previous state. If you could somehow cool the earth 1.5 C without affecting anything else and a tipping point is passed you would not go back to original conditions. A blue ocean event (BOE) is a milestone along the way but is it a tipping point? People seem to disagree on this point but it seems to me more of a disagreement on what a tipping point is. Though I am not certain of this. Without a tipping point a BOE is a non event.


If I may I would like to rephrase the title "Is a blue Ocean event a tipping point?" Does warming accelerate because of a BOE or does it as Gerontocrat says "be a bit more of the same"?


Personally I do not think/have not heard of what would cause a tipping point near a BOE. A significant milestone on the way to doom? Absolutely. What mechanism changes near a BOE? I say near a blue ocean event because their is little point in arguing the exact definition. If someone comes up with a tipping point near a BOE that would provide a compelling case to change the definition to that tipping point. A BOE may be radically different than the past what changes it from before a near BOE to after a near BOE

[El Cid]

I agree with interstitial. I see no tipping point during /casue by the BOE. It is one further step on the road but not a trigger. I do not see the mechanism by which it would change the speed or trajectory

[zufall]

Technically, the term "positive feedback loop" refers to a process while the term "tipping point" refers to a specific state. But it seems to me that (especially in public discourse) the terms are sometimes used interchangeably, i.e. mixed up.

[Avalonian]

I've always looked at it as being not a sudden switch at a BOE, but rather a change in regime that applies the longer the BOE is active - and that regime change is latent heat. High Arctic temperature is kept near 0 because the heat input goes into melting ice. Latent heat of fusion is  approx. 80 times the SHC of water, so once there is no more ice to melt, the temperature starts to rise very rapidly. I've heard that one way of defining a BOE is when the DMI80 temps leave zero behind, and I agree this captures the critical point.

Once that happens, I'm not qualified to say how the feedbacks precipitate, but there would be much higher heat levels stored in the Arctic Ocean come the refreeze season... and I can't imagine that would have no effect.

<caveat: I'm a rank amateur in this, so feel free to shoot me down... but everything I know, I learned from your folks!  >

[Archimid]

DO events were not BOE's, but large changes in sea ice cover had large effects on these events.

Impact of abrupt sea ice loss on Greenland water isotopes during the last glacial period

https://www.pnas.org/content/116/10/4099

In the north of Greenland, there is an extraordinary simulated range of DO event behaviors. This can be seen in the NEEM δ18O changes and the δ18O–temperature relationships at NEEM and partly, NGRIP (Fig. 2 and Table 1): NEEM shows the largest range of δ18O–temperature coefficients (Fig. 2C), compared with any of the other ice cores sites. The amount of variance in δ18O for the largest simulated DO events directly explained by temperature (sea ice changes) is less than 29% (39%) at NEEM. However, at the other end of Greenland, the record of δ18O change at DYE3 for the largest events is nearly entirely 95% explained by sea ice changes (Fig. 2 C and D, r values converted to explained variances).

This is how I think it went:

1. Orbits, ocean currents and GHG's align
2. Large chunks of sea ice are lost.
3. The sun hits ocean areas previously frozen, increasing the surface temperature, changing the behavior of oceans flows, salinity and increasing the temperature of the ocean/atmosphere interface
4. NH quickly warms, changing weather patterns all over the world but more so over the NH.
5. Because DO events happenned during an ice age the result of the warming is glacier melt.
6. Glacier melts proceeds to cool the oceans.
7. Over millenia sea ice recovers.


DO events are the closest analogues to BOEs with some key differences:

1. DO events happpened during an ice age. BOE happens during a time with no glaciers except greenland. What we have now is permafrost.

2. The changes in sea ice during the DO events likely did not included a BOE, only peripheral melt, mostly in the Atlantic side.

[Archimid]

3. The sun hits ocean areas previously frozen, increasing the surface temperature, changing the behavior of oceans flows, salinity and increasing the temperature of the ocean/atmosphere interface

Albedo changes and ocean absorbtion of solar energy alone are probably not enough to account for the total atmospheric warming observed during DO events.

 However, the chain of climatic interactions that preceded and followed the loss of sea ice likely included their own positive and negative feedback loops that accumulatively resulted on a positive feedback loop large enough to cause the DO events.

In the case of DO events, the sum of loops were not enough to counteract the mountains of ice that melted to absorb the new heat. The warmth probably didn't last enough for natural GHG's to create a self sustaining reaction. Large chunks of GHG's were safely stored below the mountains of ice anyway.

A BOE happens in a different world. There are no glaciers in the NH except for Greenland, only exposed permafrost, ready to activate with life, well fed with high atmospheric CO2, not starved like  during the wimpy DO event.

Nah. A BOE will be the end of the world as we know it.  It might be unknowable if or when it will happen. But we shouldn't go and find out. We are very much on our way to finding out.

[dnem]

A key question is how much hysteresis the arctic will exhibit. Is there an amount of melt, early enough in a given season, past which the system cannot recover? Can enough ice melt, exposing enough open water to insolation, and giving the opportunity for mixing to bring heat up, such that the next freeze season simply can't repair the damage?

If a BOE is a fleeting phenomenon for a few days in September, and the following freeze season can essentially reset the system, then a BOE is just a point on a continuum of damage. (The slow transition theory postulates that so much heat would be lost to space during the arctic night after a big melt season that the system can robustly reset after a big melt). If a BOE for a few days represents a hole out of which arctic ice cannot climb, then it is a tipping point.