Arctic sea ice could completely melt away by the summer of 2015

[Vergent]

http://www.telegraph...lt-by-2015.html

http://www.arctic.no...ice-npole.shtml

melt pond formation:

2002 8/18

2003 7/4

2004 7/15

2005 ?

2006 7/5

2007 ?

2008 6/30

2009 7/14

2010 6/27

2011 7/1

I think the key to the volume/thickness losses is the date when melt ponds form at the poll. the earlier it happens the greater the loss. the extra days at high insolation and low albedo count for a lot.

[skierinvermont]

I will stick with 2030-2050 as is supported by the mainstream literature.

Summary of this thread: "The hurricane appears likely to hit Seattle in 5 days"

[Vergent]

I will stick with 2030-2050 as is supported by the mainstream literature.

Summary of this thread: "The hurricane appears likely to hit Seattle in 5 days"

Mass balance trends are long term stable. on the thousand year level.

The global terrestrial mass balance losses are accelerating.

In order for the Arctic sea ice to hang on for twenty to forty years, the mass balance losses would have to decelerate dramatically. What does your literature say is the forcing that slows the loss by a factor of 5 to 10?

[TerryM]

http://www.flickr.com/photos/scleroplex/6258403755/

Seems that the IPPC was wrong.

[Vergent]

http://www.flickr.co...lex/6258403755/

Seems that the IPPC was wrong.

Nice. I found a site where you can copy the graph,

That is why I took the under rather than the over.

[skierinvermont]

I see absolutely no reason to believe that losses will be linear or accelerate. That is entirely an assumption. Models say that the volume losses will slow.

Moreover you are assuming that PIOMAS is 100% accurate, which it probably isn't.

[Vergent]

I see absolutely no reason to believe that losses will be linear or accelerate. That is entirely an assumption. Models say that the volume losses will slow.

Moreover you are assuming that PIOMAS is 100% accurate, which it probably isn't.

Are your models the same ones that say we had a 7.0Mkm^2 minimum extent this year?

Piomas2.0 has error bars, the heading for zero trend is slope is narrowly defined.

[The_Global_Warmer]

I will stick with 2030-2050 as is supported by the mainstream literature.

Summary of this thread: "The hurricane appears likely to hit Seattle in 5 days"

I am not sure if you are making a joke about extrapolating the current trends showing the possible melt off by 2015 or if your saying it is just absurd for it to happen.

I struggle with accepting this possibility but the only preventive measure I can conjure up is that the current rate of melt can not feedback much further without a substantial increase in GHGs.

Or that is wrong and the ice will simply melt out earilier and earlier and be thinner and thinner allowing for more and more solar insolation over a larger area.

However going by volume the ice is toast in a couple years if it has anymore large drops...

[dabize]

I see absolutely no reason to believe that losses will be linear or accelerate. That is entirely an assumption. Models say that the volume losses will slow.

Moreover you are assuming that PIOMAS is 100% accurate, which it probably isn't.

Isn't there likely to be a "boundary effect" as we get toward an ice-free situation?

I suppose it could act to stabilize the summer ice and prevent it's total loss, but the most obvious feedback mechanisms (most particularly reduced summertime albedo) would seem to suggest the opposite.

[skierinvermont]

Isn't there likely to be a "boundary effect" as we get toward an ice-free situation?

I suppose it could act to stabilize the summer ice and prevent it's total loss, but the most obvious feedback mechanisms (most particularly reduced summertime albedo) would seem to suggest the opposite.

Well there are numerous negative feedbacks as well which become more powerful as the ice extent decreases.

1. Less extent in fall leads to more heat loss from the ocean and a more rapid freeze up. There is still a lot of ocean covered with ice in the fall. If even half of this was ice-free in October, it would be a massive ice-volume generating machine. Vergent would have you believe it's 'all about the volume.' But it's not. The minimum extent remains near 5 million sq km which means a lot of surface area is not being used for heat release and ice production in the fall and if you reduce that by just 1 or 2 million sq km, it means much more ice generation in the fall.

2. We've already lost nearly all the multi-year ice over the last 5-10 years, so we can't lose any more. We might even gain some with a few good winters.

3. The remaining ice is more geographically protected from the winds and currents which blow the ice into the atlantic.

4.The remaining ice is more geographically protected from the ice periphery where most of the melting occurs. The ice melts from the ice edge along Siberia and Alaska starting in June. The ice near the Canadian archipelago and Greenland is still many hundreds of miles away from this melting process. The melt process will have to speed up dramatically to make it from Siberia to Greenland in one summer.

[dabize]

Well there are numerous negative feedbacks as well which become more powerful as the ice extent decreases.

1. Less extent in fall leads to more heat loss from the ocean and a more rapid freeze up. There is still a lot of ocean covered with ice in the fall. If even half of this was ice-free in October, it would be a massive ice-volume generating machine. Vergent would have you believe it's 'all about the volume.' But it's not. The minimum extent remains near 5 million sq km which means a lot of surface area is not being used for heat release and ice production in the fall and if you reduce that by just 1 or 2 million sq km, it means much more ice generation in the fall.

2. We've already lost nearly all the multi-year ice over the last 5-10 years, so we can't lose any more. We might even gain some with a few good winters.

3. The remaining ice is more geographically protected from the winds and currents which blow the ice into the atlantic.

4.The remaining ice is more geographically protected from the ice periphery where most of the melting occurs. The ice melts from the ice edge along Siberia and Alaska starting in June. The ice near the Canadian archipelago and Greenland is still many hundreds of miles away from this melting process. The melt process will have to speed up dramatically to make it from Siberia to Greenland in one summer.

Thanks for the detailed reply - I can see why watching both the melt and refreeze dynamics here can be attractive

I suppose the time to worry will be when the M'Clure Strait/NW passage opens early enough (late July?) so that melt/low albedo conditions can work on the remaining ice when there is still significant sun angle at 75-80 degrees north......

That would mean several weeks earlier than the record low so far, no?

[skierinvermont]

Thanks for the detailed reply - I can see why watching both the melt and refreeze dynamics here can be attractive

I suppose the time to worry will be when the M'Clure Strait/NW passage opens early enough (late July?) so that melt/low albedo conditions can work on the remaining ice when there is still significant sun angle at 75-80 degrees north......

That would mean several weeks earlier than the record low so far, no?

This year was the record and I think it was some time in early or mid August but I'm not sure.

The thing is even if M'Clure strait opens earlier, there is still very thick ice pressed up against Greenland, Ellesmere, and the smaller islands west of Ellesmere. So any melting would have to occur from the Alaska-Siberian side.

I suppose it might be possible that the ice pack could become dislodged and blown away from Canada and Greenland, but I think the prevailing winds prevent that.

[dabize]

This year was the record and I think it was some time in early or mid August but I'm not sure.

The thing is even if M'Clure strait opens earlier, there is still very thick ice pressed up against Greenland, Ellesmere, and the smaller islands west of Ellesmere. So any melting would have to occur from the Alaska-Siberian side.

I suppose it might be possible that the ice pack could become dislodged and blown away from Canada and Greenland, but I think the prevailing winds prevent that.

Isn't that where the reduced ice volume comes into play?

While melting would have to occur at very high latitude from only the seaward side, IIRC there is now very little of that "very thick ice" left.......

It has the feel to me of a climatological "nowcast" event (an oxymoron, I know).

[Alpha5]

wasnt sea ice supposed to be gone in 2012......

[skierinvermont]

Isn't that where the reduced ice volume comes into play?

While melting would have to occur at very high latitude from only the seaward side, IIRC there is now very little of that "very thick ice" left.......

It has the feel to me of a climatological "nowcast" event (an oxymoron, I know).

Well the ice near the archipelago and greenland is certainly much thinner than it used to be but is still quite thick. All I'm saying is I don't think we will see melting occur from that side - the melting will have to encroach from the Siberian and Alaskan sides.

There was a study that came out this year which showed that even if the ice were artificially reduced to zero, the minimums would recover to near 5 million sq km within a few years. The primary mechanism for this is that all the open water releases a lot of heat and produces a lot if ice in the fall and winter (even once it freezes it continues to thicken rapidly until it reaches 1-1.5m). The thermodynamics of the arctic continue to support ice.

It's probably hard to overestimate how much more ice would be produced in the fall and winter if the minimum extent were reduced by 1 or 2 or 3 million sq km.

[dabize]

wasnt sea ice supposed to be gone in 2012......

Supposed by whom?

Not anyone here. This 2015 extrapolation estimate is by far the earliest I've ever heard

Maybe you are thinking of something some wingnut said while waiting to be raptured.....

[skierinvermont]

Supposed by whom?

Not anyone here. This 2015 extrapolation estimate is by far the earliest I've ever heard

Maybe you are thinking of something some wingnut said while waiting to be raptured.....

I think Al gore said 2012

edit: he said 2013

[skierinvermont]

and I believe he based that statement off of a study by Weislaw Maslowski which said ice would be gone be 2013 or sooner.

Maslowski has since revised this prediction to 2015 if I recall correctly.

I fully expect that every few years he will have to continue to revise the prediction later and later. That is what happens when you base your predictions off of extrapolation of a trend rather than physics.

[dabize]

Well the ice near the archipelago and greenland is certainly much thinner than it used to be but is still quite thick. All I'm saying is I don't think we will see melting occur from that side - the melting will have to encroach from the Siberian and Alaskan sides.

There was a study that came out this year which showed that even if the ice were artificially reduced to zero, the minimums would recover to near 5 million sq km within a few years. The primary mechanism for this is that all the open water releases a lot of heat and produces a lot if ice in the fall and winter (even once it freezes it continues to thicken rapidly until it reaches 1-1.5m). The thermodynamics of the arctic continue to support ice.

It's probably hard to overestimate how much more ice would be produced in the fall and winter if the minimum extent were reduced by 1 or 2 or 3 million sq km.

I saw that study.

I thought the point of it was that there isn't as much "inertia" caused by the presence/absence of existing ice as one might suppose.....that the baseline conditions other than ice volume/extent are sufficiently dominant that the initiation conditions aren't very important.

To me, that says that ice extent/volume is more important as a marker of underlying conditions that we can't measure directly - making the unforecasted and precipitous fall in ice volume measured by PIOMASS rather unsettling.

[dabize]

and I believe he based that statement off of a study by Weislaw Maslowski which said ice would be gone be 2013 or sooner.

Maslowski has since revised this prediction to 2015 if I recall correctly.

I fully expect that every few years he will have to continue to revise the prediction later and later. That is what happens when you base your predictions off of extrapolation of a trend rather than physics.

My bad - I didn't know that. Sneer retracted.

But I am still a bit concerned (like Vergent) that we don't know enough about the arctic heat budget to model ice volume loss accurately.

[skierinvermont]

I saw that study.

I thought the point of it was that there isn't as much "inertia" caused by the presence/absence of existing ice as one might suppose.....that the baseline conditions other than ice volume/extent are sufficiently dominant that the initiation conditions aren't very important.

To me, that says that ice extent/volume is more important as a marker of underlying conditions that we can't measure directly - making the unforecasted and precipitous fall in ice volume measured by PIOMASS rather unsettling.

Yes that was one point of the study.. but the study is also very clear that declining extent represents a strong negative feedback to further extent loss because the increased open water in fall means much greater heat loss and ice production.

The reason the ice reverts to the base condition you say is that it is full of negative feedbacks. And these feedbacks are primarily controlled by the extent, not the volume. Less extent means greater ice production. And we've got 5 million sq km of extent left.

[dabize]

Yes that was one point of the study.. but the study is also very clear that declining extent represents a strong negative feedback to further extent loss because the increased open water in fall means much greater heat loss and ice production.

The reason the ice reverts to the base condition you say is that it is full of negative feedbacks. And these feedbacks are primarily controlled by the extent, not the volume. Less extent means greater ice production. And we've got 5 million sq km of extent left.

I once spent half an hour explaining to a Jehovah's Witness why God was the Second Law of Thermodynamics - just to get rid of him.

Guess its time to put my faith to the test - I hope you're right.

[skierinvermont]

I once spent half an hour explaining to a Jehovah's Witness why God was the Second Law of Thermodynamics - just to get rid of him.

Guess its time to put my faith to the test - I hope you're right.

Well the good thing is we should know within 2 or 3 years. Thus far the min extent has shown itself to be pretty stable near the 5 million mark. We will have to start seeing some radical shifts and instability if we are to make it to 1 million in 4 years. Even a 1 year recovery would in my opinion toss what little possibility exists of an ice free arctic by 2015 out the window.

[The_Global_Warmer]

There is the study that just came out about the cold air inversions trapping heat in the arctic in the fall and winter as the ice expands outward but that wouldn't prevent the ice from expanding since that kind of heat would still be well below zero. But it would help keep some heat trapped under the thinner ice.

I think that how fast the ice can melt out completely will also depend on thickness and snow cover...it is a huge help to have massive snow cover anomalies in April and May to allow warmer air and water on the periphery of the arctic in time for the melt season.

I am not as confident as skier about this. Looking at buoy data it looks like a big shift under the water took place after 2007 when so much heat was left in the water. This could be playing a major role in the current major bottom melts. But there is an increasing highway of warmer water under the top 25-50 meters in the Beaufort and Eastern Arctic basin( by the Atlantic/Barents). So its over deep waters not just the shallow ones.

the water off the N coast of Greenland is mostly cold with no such layer.

[Vergent]

People seem very fixated at edge melt. This is 88N, a thousand k from the edge. The melt ponds did not form until July, 1. In 2002 melt ponds did not form at all up here. in 2010 they formed June, 27. a few years ago they were forming in mid July.

What will happen when the melt ponds form in mid June? 550 watts / sq. meter 24/7 for two weeks. This will melt an additional metric ton of ice per square meter of melt pond or a sq meter of 1.1 meter thick ice for each sq meter of melt pond. This is assuming a .5 albedo for the melt ponds. The ice up there was .9 M thick. What happens to the extent when the thickness goes to zero?

[TerryM]

Well there are numerous negative feedbacks as well which become more powerful as the ice extent decreases.

1. Less extent in fall leads to more heat loss from the ocean and a more rapid freeze up. There is still a lot of ocean covered with ice in the fall. If even half of this was ice-free in October, it would be a massive ice-volume generating machine. Vergent would have you believe it's 'all about the volume.' But it's not. The minimum extent remains near 5 million sq km which means a lot of surface area is not being used for heat release and ice production in the fall and if you reduce that by just 1 or 2 million sq km, it means much more ice generation in the fall.

2. We've already lost nearly all the multi-year ice over the last 5-10 years, so we can't lose any more. We might even gain some with a few good winters.

3. The remaining ice is more geographically protected from the winds and currents which blow the ice into the atlantic.

4.The remaining ice is more geographically protected from the ice periphery where most of the melting occurs. The ice melts from the ice edge along Siberia and Alaska starting in June. The ice near the Canadian archipelago and Greenland is still many hundreds of miles away from this melting process. The melt process will have to speed up dramatically to make it from Siberia to Greenland in one summer.

Why would this effect kick in at 5 million when it didn't at 6 or 7 million? - what makes 5 million sq km unique

[TerryM]

Well there are numerous negative feedbacks as well which become more powerful as the ice extent decreases.

1. Less extent in fall leads to more heat loss from the ocean and a more rapid freeze up. There is still a lot of ocean covered with ice in the fall. If even half of this was ice-free in October, it would be a massive ice-volume generating machine. Vergent would have you believe it's 'all about the volume.' But it's not. The minimum extent remains near 5 million sq km which means a lot of surface area is not being used for heat release and ice production in the fall and if you reduce that by just 1 or 2 million sq km, it means much more ice generation in the fall.

2. We've already lost nearly all the multi-year ice over the last 5-10 years, so we can't lose any more. We might even gain some with a few good winters.

3. The remaining ice is more geographically protected from the winds and currents which blow the ice into the atlantic.

4.The remaining ice is more geographically protected from the ice periphery where most of the melting occurs. The ice melts from the ice edge along Siberia and Alaska starting in June. The ice near the Canadian archipelago and Greenland is still many hundreds of miles away from this melting process. The melt process will have to speed up dramatically to make it from Siberia to Greenland in one summer.

MYI has indeed become a small percentage of the ice and melting MYI soaked up large amounts of solar energy, without it much more FYI will be melted.

[TerryM]

Well there are numerous negative feedbacks as well which become more powerful as the ice extent decreases.

1. Less extent in fall leads to more heat loss from the ocean and a more rapid freeze up. There is still a lot of ocean covered with ice in the fall. If even half of this was ice-free in October, it would be a massive ice-volume generating machine. Vergent would have you believe it's 'all about the volume.' But it's not. The minimum extent remains near 5 million sq km which means a lot of surface area is not being used for heat release and ice production in the fall and if you reduce that by just 1 or 2 million sq km, it means much more ice generation in the fall.

2. We've already lost nearly all the multi-year ice over the last 5-10 years, so we can't lose any more. We might even gain some with a few good winters.

3. The remaining ice is more geographically protected from the winds and currents which blow the ice into the atlantic.

4.The remaining ice is more geographically protected from the ice periphery where most of the melting occurs. The ice melts from the ice edge along Siberia and Alaska starting in June. The ice near the Canadian archipelago and Greenland is still many hundreds of miles away from this melting process. The melt process will have to speed up dramatically to make it from Siberia to Greenland in one summer.

[TerryM]

Well there are numerous negative feedbacks as well which become more powerful as the ice extent decreases.

1. Less extent in fall leads to more heat loss from the ocean and a more rapid freeze up. There is still a lot of ocean covered with ice in the fall. If even half of this was ice-free in October, it would be a massive ice-volume generating machine. Vergent would have you believe it's 'all about the volume.' But it's not. The minimum extent remains near 5 million sq km which means a lot of surface area is not being used for heat release and ice production in the fall and if you reduce that by just 1 or 2 million sq km, it means much more ice generation in the fall.

2. We've already lost nearly all the multi-year ice over the last 5-10 years, so we can't lose any more. We might even gain some with a few good winters.

3. The remaining ice is more geographically protected from the winds and currents which blow the ice into the atlantic.

4.The remaining ice is more geographically protected from the ice periphery where most of the melting occurs. The ice melts from the ice edge along Siberia and Alaska starting in June. The ice near the Canadian archipelago and Greenland is still many hundreds of miles away from this melting process. The melt process will have to speed up dramatically to make it from Siberia to Greenland in one summer.

Last year very little ice was advected through Nares or Fram - the bulk of if melted in situ - unlike 2007

[TerryM]

Well there are numerous negative feedbacks as well which become more powerful as the ice extent decreases.

1. Less extent in fall leads to more heat loss from the ocean and a more rapid freeze up. There is still a lot of ocean covered with ice in the fall. If even half of this was ice-free in October, it would be a massive ice-volume generating machine. Vergent would have you believe it's 'all about the volume.' But it's not. The minimum extent remains near 5 million sq km which means a lot of surface area is not being used for heat release and ice production in the fall and if you reduce that by just 1 or 2 million sq km, it means much more ice generation in the fall.

2. We've already lost nearly all the multi-year ice over the last 5-10 years, so we can't lose any more. We might even gain some with a few good winters.

3. The remaining ice is more geographically protected from the winds and currents which blow the ice into the atlantic.

4.The remaining ice is more geographically protected from the ice periphery where most of the melting occurs. The ice melts from the ice edge along Siberia and Alaska starting in June. The ice near the Canadian archipelago and Greenland is still many hundreds of miles away from this melting process. The melt process will have to speed up dramatically to make it from Siberia to Greenland in one summer.

Last summer ice melted from Alaska to Ellesmere on two occasions, in the latter melt all of Ellesmere as well as Northern Greenland's coast were ice free - Melt didn't move from Siberia to Greenland, but in fact occurred from both hemispheres.

BTW I hope you are right.