Arctic sea-ice not a "tipping point"

[Ken Caldeira]

Tietsche, S., D. Notz, J. H. Jungclaus, and J. Marotzke (2011), Recovery mechanisms of Arctic summer sea ice, Geophys. Res. Lett., 38, L02707, doi:10.1029/2010GL045698.

Abstract.

 We examine the recovery of Arctic sea ice from
prescribed ice‐free summer conditions in simulations of 21st
century climate in an atmosphere–ocean general circulation
model. We find that ice extent recovers typically within two
years. The excess oceanic heat that had built up during the
ice‐free summer is rapidly returned to the atmosphere during
the following autumn and winter, and then leaves the Arctic
partly through increased longwave emission at the top of the
atmosphere and partly through reduced atmospheric heat
advection from lower latitudes. Oceanic heat transport does
not contribute significantly to the loss of the excess heat. Our
results suggest that anomalous loss of Arctic sea ice during
a single summer is reversible, as the ice–albedo feedback
is alleviated by large‐scale recovery mechanisms. Hence,
hysteretic threshold behavior (or a “tipping point”) is
unlikely to occur during the decline of Arctic summer seaice
cover in the 21st century.

see also:

Holland, M. M., Bitz, C. M., Tremblay, L.-B. & Bailey, D. A. Am. Geophys. Union Geophys. Monogr. Ser. 180, 133–150 (2008).

http://www.cgd.ucar.edu/oce/mholland/papers/holland_AGU_DeWeaver_Ch10.pdf

___________________________________________________
Ken Caldeira

Carnegie Institution Dept of Global Ecology
260 Panama Street, Stanford, CA 94305 USA
+1 650 704 7212 kcal...@carnegie.stanford.edu
http://dge.stanford.edu/labs/caldeiralab  @kencaldeira

[John Nissen]

Hi Ken,

I think this paper gives an extremely misleading view of the situation in the Arctic, with the unprecendented retreat of the Arctic sea ice, and steady decline in volume since 2007.  I asked Professor Peter Wadhams, a leading expert on Arctic sea ice, what he made of the paper, and this was his response:

---

The problem with the Tietsche et al. paper is that the authors misinterpret their own results. The model experiment that they carry out is to artificially remove all the sea ice from the Arctic and see whether (in the model simulation) it comes back again. They find that it does in 2-3 years, to an area that is characteristic of the current state of the climate. They re-do the experiment for various future states of the ice cover (they acknowledge that its area is diminishing year on year), and in each case they get a recovery, but only to an area characteristic of the climate of the time. What does this demonstrate? They say that it indicates that if we were to stop stressing the sea ice cover by adding CO2 to the atmosphere, it would recover in 2-3 years and there is therefore no tipping point that determines an irrevocable end to the ice cover. Such an interpretation is false for the following reasons. 1. Reduction or even cessation of CO2 emissions does not cause the instant cessation of warming, since the warming of the earth lags behind the radiative forcing of the CO2-enriched atmosphere; at the moment only about 55% of the potential warming for our current CO2 state has been realised. So even if we stop emissions entirely we will keep warming up for several decades, with a consequent continued reduction in sea ice cover, possibly ending in its complete removal. They don't simulate this. In fact they ignore it. 2. Artificial removal of the sea ice cover is just that - artificial. Of course no natural fluctuation of the sea ice cover could ever be that big, so naturally in a model study the ice will come back again after such an unnatural imposed change. This is telling us absolutely nothing about the real world. It is like saying that if you hit someone over the head and they recover consciousness, this proves that you can slowly starve them without them ultimately dying of malnutrition.

---

It is strange how, as the situation deteriorates, people write papers to suggest all is well and we can relax for a few decades.  There was that paper about polar bears surviving the Arctic warming, provided we reduce our emissions [1].  Peter said it was so full of holes it should never have been published.  He is considering a formal complaint to the editors of Nature.  BTW, I'm glad to find that this paper has been rebuffed [2] - but how many people read the paper without knowing, especially journalists?  Here a quote from the rebuttal:

[quote]

If you missed Nature, you probably saw the headlines:

• Arctic icecap safe from runaway melting: study (AFP)
• Polar Bears: On Thin Ice? Extinction Can Be Averted, Scientists Say (NSF press release)
  

I really wish any of that were realistic, not so much because the polar bear is a critical linchpin species, but because the loss of Arctic ice in the summer may well trigger even more rapid warming (see “Tundra 4: Permafrost loss linked to Arctic sea ice loss“ and below).  But in fact a much more reasonable AFP headline would be “Arctic ice cap on verge of runaway melting:  study.”  The NSF release should read, “Polar bear extinction now likely.”

I understand that journalists typically don’t read studies closely, but Nature ought to know better.    Perhaps, as we will see, it is just a matter of climate scientists of being utterly divorced from the reality of our energy and political systems.   Still, in reading the study and its supplementary information, I am puzzled why Nature published the article as written and especially why it chose to sensationalize it on the cover.

[end quote]

Cheers,

John

[1] http://www.nature.com/nature/journal/v468/n7326/full/nature09653.html

[2] http://climateprogress.org/2010/12/20/polar-bear-arctic-sea-ice-all-but-doomed-misleading-nature-cover-story/

---

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[Andrew Lockley]

John

Your email contains a significant mistake

If we stop emissions, co2e levels won't be constant. They will fall rapidly due to sinks, e.g. ocean , and simultaneously be pulled up due to sources such as rainforest ecosystem collapse and tundra excursions

Further, you fail to challenge the central premise of the paper, that sea ice is not of itself a tipping point.

A

> If you missed *Nature*, you probably saw the headlines:
>
> - Arctic icecap safe from runaway melting:
> study<http://green.yahoo.com/news/afp/20101215/sc_afp/environmentclimatewarmingarcticicespeciesbear.html>(AFP)
> - Polar Bears: On Thin Ice? Extinction Can Be Averted, Scientists
> Say<http://www.nsf.gov/news/news_summ.jsp?cntn_id=118224>(NSF press

> release)
>
> I really wish any of that were realistic, not so much because the polar bear
> is a critical linchpin species, but because the loss of Arctic ice in the
> summer may well trigger even more rapid warming (see “Tundra 4: Permafrost
> loss linked to Arctic sea ice

> loss<http://climateprogress.org/2008/06/12/breaking-news-tundra-4-permafrost-loss-linked-to-arctic-sea-ice-loss/>“

> and below). But in fact a much more reasonable AFP headline would be
> “Arctic ice cap on verge of runaway melting: study.” The NSF release
> should read, “Polar bear extinction now likely.”
>

> I understand that journalists typically don’t read studies closely, but *
> Nature* ought to know better. Perhaps, as we will see, it is just a

> matter of climate scientists of being utterly divorced from the reality of
> our energy and political systems. Still, in reading the study and its

> supplementary information, I am puzzled why *Nature* published the article

[David Keith]

John

 

Maybe it would help if you said what ‘tipping point’ means to you.

 

It might also be important to remember that the disagreement here is not about urgency of action or about how much the arctic matters. I, for one, do see rapid CO2-driven climate change in the arctic as an important reason for action. And, having spent a lot of time up there traveling and watching bears I certainly care about that landscape.

 

What I do not see is a scientific basis for your continued claims that arctic sea ice is the Big Climate Tipping point and that it’s about to tip. The basic physics, the observations and the results of many papers seem to argue against this point of view.

 

Yours,

David

[Eugene I. Gordon]

The lifetime of CO2 in the atmosphere has components ranging from several hundred years to over 1000. I have Antarctic ice data that shows changes in concentration take over 1000 years.

 

 

From: climatein...@googlegroups.com [mailto:climatein...@googlegroups.com] On Behalf Of Andrew Lockley
Sent: Monday, March 07, 2011 8:36 AM
To: johnnis...@gmail.com
Cc: John Nissen; Climate Intervention
Subject: Re: [clim] Arctic sea-ice not a "tipping point"

 

John

[Andrew Lockley]

Yes, but in response to short spikes much of the carbon is quickly drawn back down into sinks.  Only when these sinks equilibriate would carbon longevity increase markedly.

The opposite effect of runaway climate change also may dominate, as shown by the recent tundra carbon excursion study. Heads we live, tails we die.  What do you call?

A

>>> climateinterven...@googlegroups.com <mailto:climateintervention%2Bunsu...@googlegroups.com> .

>>> For more options, visit this group at
>>> http://groups.google.com/group/climateintervention?hl=en.
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>>
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[Mike MacCracken]

Even if it is correct that there is no hysteresis in the Arctic sea ice cover [and my limited understanding is that, from ice cover history before the warming really got started, that low ice years tended to be followed by a return to the average or even above, suggesting that there might not be a point of no return—which is what I think is meant by tipping point], the warm conditions in the Arctic could reach a point where the permafrost starts giving off substantial methane (or even CO2) and so overall global warming is amplified and we would not for many decades get back to the sea ice cover that existed before. And so that level of warmth might of the region, which involves some combination of GHG level and sea ice retreat, might be called a tipping point.

Now, it would be a bit strange if there were no hysteresis given the role of sea ice thickness, but this hysteresis might be quite modest, something less than a decade. It seems that it really was this that was mainly tested in the paper—not the full blown regional and global implications of there being enough warming to have pushed the ice cover down to zero that, one would suspect, might trigger permafrost thawing, etc.

So, indeed, as David says, we do need to be very careful and precise in what is being suggested as a tipping point.

Mike MacCracken

On 3/7/11 8:42 AM, "David Keith" <ke...@ucalgary.ca> wrote:

John
 
Maybe it would help if you said what ‘tipping point’ means to you.
 
It might also be important to remember that the disagreement here is not about urgency of action or about how much the arctic matters. I, for one, do see rapid CO2-driven climate change in the arctic as an important reason for action. And, having spent a lot of time up there traveling and watching bears I certainly care about that landscape.
 
What I do not see is a scientific basis for your continued claims that arctic sea ice is the Big Climate Tipping point and that it’s about to tip. The basic physics, the observations and the results of many papers seem to argue against this point of view.
 
Yours,
David
 
 
From: climatein...@googlegroups.com [mailto:climatein...@googlegroups.com] On Behalf Of John Nissen
Sent: Monday, March 07, 2011 6:27 AM
To: kcal...@gmail.com
Cc: Ken Caldeira; Climate Intervention; John Nissen; P. Wadhams
Subject: Re: [clim] Arctic sea-ice not a "tipping point"


Hi Ken,

I think this paper gives an extremely misleading view of the situation in the Arctic, with the unprecendented retreat of the Arctic sea ice, and steady decline in volume since 2007.  I asked Professor Peter Wadhams, a leading expert on Arctic sea ice, what he made of the paper, and this was his response:

---

The problem with the Tietsche et al. paper is that the authors misinterpret their own results. The model experiment that they carry out is to artificially remove all the sea ice from the Arctic and see whether (in the model simulation) it comes back again. They find that it does in 2-3 years, to an area that is characteristic of the current state of the climate. They re-do the experiment for various future states of the ice cover (they acknowledge that its area is diminishing year on year), and in each case they get a recovery, but only to an area characteristic of the climate of the time. What does this demonstrate? They say that it indicates that if we were to stop stressing the sea ice cover by adding CO2 to the atmosphere, it would recover in 2-3 years and there is therefore no tipping point that determines an irrevocable end to the ice cover. Such an interpretation is false for the following reasons. 1. Reduction or even cessation of CO2 emissions does not cause the instant cessation of warming, since the warming of the earth lags behind the radiative forcing of the CO2-enriched atmosphere; at the moment only about 55% of the potential warming for our current CO2 state has been realised. So even if we stop emissions entirely we will keep warming up for several decades, with a consequent continued reduction in sea ice cover, possibly ending in its complete removal. They don't simulate this. In fact they ignore it. 2. Artificial removal of the sea ice cover is just that - artificial. Of course no natural fluctuation of the sea ice cover could ever be that big, so naturally in a model study the ice will come back again after such an unnatural imposed change. This is telling us absolutely nothing about the real world. It is like saying that if you hit someone over the head and they recover consciousness, this proves that you can slowly starve them without them ultimately dying of malnutrition.

---

It is strange how, as the situation deteriorates, people write papers to suggest all is well and we can relax for a few decades.  There was that paper about polar bears surviving the Arctic warming, provided we reduce our emissions [1].  Peter said it was so full of holes it should never have been published.  He is considering a formal complaint to the editors of Nature.  BTW, I'm glad to find that this paper has been rebuffed [2] - but how many people read the paper without knowing, especially journalists?  Here a quote from the rebuttal:

[quote]
If you missed Nature, you probably saw the headlines:

• Arctic icecap safe from runaway melting: study <http://green.yahoo.com/news/afp/20101215/sc_afp/environmentclimatewarmingarcticicespeciesbear.html> (AFP)
• Polar Bears: On Thin Ice? Extinction Can Be Averted, Scientists Say <http://www.nsf.gov/news/news_summ.jsp?cntn_id=118224> (NSF press release)
  

I really wish any of that were realistic, not so much because the polar bear is a critical linchpin species, but because the loss of Arctic ice in the summer may well trigger even more rapid warming (see “Tundra 4: Permafrost loss linked to Arctic sea ice loss <http://climateprogress.org/2008/06/12/breaking-news-tundra-4-permafrost-loss-linked-to-arctic-sea-ice-loss/> “ and below).  But in fact a much more reasonable AFP headline would be “Arctic ice cap on verge of runaway melting:  study.”  The NSF release should read, “Polar bear extinction now likely.”

I understand that journalists typically don’t read studies closely, but Nature ought to know better.    Perhaps, as we will see, it is just a matter of climate scientists of being utterly divorced from the reality of our energy and political systems.   Still, in reading the study and its supplementary information, I am puzzled why Nature published the article as written and especially why it chose to sensationalize it on the cover.

[end quote]

Cheers,

John

[1] http://www.nature.com/nature/journal/v468/n7326/full/nature09653.html

[2] http://climateprogress.org/2010/12/20/polar-bear-arctic-sea-ice-all-but-doomed-misleading-nature-cover-story/

---

On Wed, Mar 2, 2011 at 11:54 PM, Ken Caldeira <kcal...@carnegie.stanford.edu> wrote:
Tietsche, S., D. Notz, J. H. Jungclaus, and J. Marotzke (2011), Recovery mechanisms of Arctic summer sea ice, Geophys. Res. Lett., 38, L02707, doi:10.1029/2010GL045698.

Abstract.

 We examine the recovery of Arctic sea ice from

prescribed ice-free summer conditions in simulations of 21st

century climate in an atmosphere–ocean general circulation
model. We find that ice extent recovers typically within two
years. The excess oceanic heat that had built up during the

ice-free summer is rapidly returned to the atmosphere during

the following autumn and winter, and then leaves the Arctic
partly through increased longwave emission at the top of the
atmosphere and partly through reduced atmospheric heat
advection from lower latitudes. Oceanic heat transport does
not contribute significantly to the loss of the excess heat. Our
results suggest that anomalous loss of Arctic sea ice during
a single summer is reversible, as the ice–albedo feedback

is alleviated by large-scale recovery mechanisms. Hence,

hysteretic threshold behavior (or a “tipping point”) is
unlikely to occur during the decline of Arctic summer seaice
cover in the 21st century.

see also:

Holland, M. M., Bitz, C. M., Tremblay, L.-B. & Bailey, D. A. Am. Geophys. Union Geophys. Monogr. Ser. 180, 133–150 (2008).

http://www.cgd.ucar.edu/oce/mholland/papers/holland_AGU_DeWeaver_Ch10.pdf

___________________________________________________
Ken Caldeira

Carnegie Institution Dept of Global Ecology
260 Panama Street, Stanford, CA 94305 USA

+1 650 704 7212 <tel:%2B1%20650%20704%207212>  kcal...@carnegie.stanford.edu
http://dge.stanford.edu/labs/caldeiralab  @kencaldeira

[William Fulkerson]

Dear All:
An important issue is the impact of loss of summer sea ice on the ecology of the Arctic.  If iconic species are impacted by loss of sea ice, including perhaps significant loss of biodiverstiy, the biodiversity people may want to moderate their stance against climate engineering.  It may be the only strategy that can reverse the situation in time.  My ignorant impression is that we don’t know enough about the biodiversity of the Arctic.  Surely that’s one area where the
climate engineering and biodiversity research people can come together.
With best regards,
Bill Fulkerson
Bill Fulkerson, Senior Fellow and LERDWG Chair
Institute for a Secure and Sustainable Environment
University of Tennessee
311 Conference Center Bldg.
Knoxville, TN 37996-4138
wf...@utk.edu
865-974-9221, -1838 FAX
Home
865-988-8084; 865-680-0937 CELL
2781 Wheat Road, Lenoir City, TN 37771

[John Nissen]

Hi Bill,

I have been taking "tipping point" on Tim Lenton's definition from a paper by him [1]:

Such non-linear transitions where “a small change can make a big difference” have been described as ‘tipping points’ – a term popularised in a sociological context by Malcolm Gladwell in his book ‘The Tipping Point’. For clarity, we have recently introduced the term ‘tipping element’ to describe the components of the Earth system that can be switched – under particular conditions – into a qualitatively different state by small perturbations (Lenton et al, submitted). The term ‘tipping point’ is then used to refer to the critical point (in forcing and a feature of the system) at which such a transition is triggered.

and further down:

A case can be made that climate warming may have caused the Arctic sea-ice to pass a tipping point. Certainly the area coverage of both summer and winter Arctic sea-ice are declining at present, summer sea-ice more markedly with a record minimum in 2007, and the ice has thinned significantly over a large area. Elegant analysis has shown that positive ice-albedo feedback (the warming due to changing from reflective ice to dark ocean surface) dominates over external forcing (the global warming signal) in causing the thinning and shrinkage since around 1988. This suggests the system may already be undergoing a non-linear transition toward a different state with less Arctic sea-ice (perhaps none in summer).

This is what I have been arguing - a non-linear transition toward a different state with perhaps no sea ice in summer.

The non-linearity and timescale is important.  Scientists have tended to do linear extrapolations from a pair of points, which can suggest (depending on choice of points) that the sea ice will last till 2100, 2060, 2040, 2030 or even 2020.  But if you allow for non-linearity due to the positive feedback, then the sea ice could disappear before 2020. If you then add in the uncertainty due to weather and winds, the sea ice could practically disappear any summer from this year onwards - perhaps 'very unlikely' in 2011 or 2012, but just 'unlikely' in 2013 or 2014.  You get a lognormal (skewed towards present) distribution rather than a normal (symetric Bell shaped) distribution.

It's also more important to look at the ice volume, which has been decreasing steadily since 2007, rather than the ice extent.

Thus the polar bears have had it, unless we apply SRM to cool the Arctic.  You don't have to be a biodiversity specialist, but you do have to appreciate the science of the situation.

BTW, the current behaviour of sea ice suggests we could be in for a record retreat this year.

Cheers,

John

[1] http://researchpages.net/esmg/people/tim-lenton/tipping-points/

---

[Veli Albert Kallio]

Even in case of total sea ice loss, the sea ice will start to reform along the coasts as the autumn darkeness and cold sets in. But from summer 2007 to winter-spring-summer 2008 we could see that sea ice struggled greatly to recover and never returned to 2006 level.
 
Last summer 2010 the sea ice area was 3,072,000 km2, when in 2007 it was 2,992,000 km2 with Cryosphere Today measures. Again we saw this winter how the sea ice has been struggling to reform, remains thin.
 
My view is that in all likelihood ice free ocean under current athmospheric forcing would melt open the following summer as well. The spring melting moves earlier, and the autumn freezes get increasingly postponed leading to ever shrinking ice cover and ice volume.
 
Initially the melting is near arrival of autumn darkeness, but moves earlier which increases the amount of sunlight captured. First ice free summer is not the disaster for permafrost, but as albedo fights against with help of climatic forcing, longer summers become the norm.
 

---

From: eugg...@comcast.net
To: andrew....@gmail.com; johnnis...@gmail.com
CC: j...@cloudworld.co.uk; climatein...@googlegroups.com
Subject: RE: [clim] Arctic sea-ice not a "tipping point"
Date: Mon, 7 Mar 2011 09:25:26 -0500

> summer may well trigger even more rapid warming (see 锟斤拷Tundra 4: Permafrost

> loss linked to Arctic sea ice

> loss<http://climateprogress.org/2008/06/12/breaking-news-tundra-4-permafrost-loss-linked-to-arctic-sea-ice-loss/>锟斤拷

> and below). But in fact a much more reasonable AFP headline would be

> 锟斤拷Arctic ice cap on verge of runaway melting: study.锟斤拷 The NSF release
> should read, 锟斤拷Polar bear extinction now likely.锟斤拷
>
> I understand that journalists typically don锟斤拷t read studies closely, but *

> Nature* ought to know better. Perhaps, as we will see, it is just a
> matter of climate scientists of being utterly divorced from the reality of
> our energy and political systems. Still, in reading the study and its
> supplementary information, I am puzzled why *Nature* published the article
> as written and especially why it chose to sensationalize it on the cover.
> [end quote]
>
> Cheers,
>
> John
>
> [1] http://www.nature.com/nature/journal/v468/n7326/full/nature09653.html
>
> [2]
> http://climateprogress.org/2010/12/20/polar-bear-arctic-sea-ice-all-but-doomed-misleading-nature-cover-story/
>
> ---
>
> On Wed, Mar 2, 2011 at 11:54 PM, Ken Caldeira <
> kcal...@carnegie.stanford.edu> wrote:
>
>> Tietsche, S., D. Notz, J. H. Jungclaus, and J. Marotzke (2011), Recovery
>> mechanisms of Arctic summer sea ice, Geophys. Res. Lett., 38, L02707,
>> doi:10.1029/2010GL045698.
>>
>> Abstract.
>>
>> We examine the recovery of Arctic sea ice from

>> prescribed ice锟絓free summer conditions in simulations of 21st
>> century climate in an atmosphere锟紺ocean general circulation

>> model. We find that ice extent recovers typically within two
>> years. The excess oceanic heat that had built up during the

>> ice锟絓free summer is rapidly returned to the atmosphere during

>> the following autumn and winter, and then leaves the Arctic
>> partly through increased longwave emission at the top of the
>> atmosphere and partly through reduced atmospheric heat
>> advection from lower latitudes. Oceanic heat transport does
>> not contribute significantly to the loss of the excess heat. Our
>> results suggest that anomalous loss of Arctic sea ice during

>> a single summer is reversible, as the ice锟紺albedo feedback
>> is alleviated by large锟絓scale recovery mechanisms. Hence,
>> hysteretic threshold behavior (or a 锟斤拷tipping point锟斤拷) is

>> unlikely to occur during the decline of Arctic summer seaice
>> cover in the 21st century.
>>
>> see also:
>>
>> Holland, M. M., Bitz, C. M., Tremblay, L.-B. & Bailey, D. A. Am. Geophys.

>> Union Geophys. Monogr. Ser. 180, 133锟紺150 (2008).

[John Nissen]

Hi Albert,

I think what you are arguing is that, once the sea ice gets below a certain level (about 3,000,000 km2) at the end of summer, it is liable to stay around or below that level in subsequent summers.  This is like a ratchet effect.  It means that the sea ice is indeed past the tipping point.  Tim Lenton made a certain case for this here [1] and a stronger case with others here [2].  The latter is referenced (as [5]) in [3]:

A 'tipping' process could potentially commence as the Arctic region warms, if there is positive feedback with sufficient gain. Professor Tim Lenton suggests that the retreat of sea ice is such a process, and the tipping may have started already^[5]. Geoengineering has been proposed for preventing or reversing tipping point events in the Arctic, in particular to halt the retreat of the sea ice.

My argument for the sea ice being past its tipping point may appear slightly different from yours, Albert - it is that there is powerful positive feedback from the albedo flip effect (as ice replaced by water), and this has caused an accelerating decline in Arctic sea ice from summer to summer.  (IPCC models show a linear trend line whereas, since the 80s, observed sea ice extent has followed a non-linear trend line, curving downwards [4]).

Earlier in this thread, Andrew Lockley accused me of a gross error.  He wrote:

If we stop emissions, co2e levels won't be constant. They will fall rapidly due to sinks, e.g. ocean , and simultaneously be pulled up due to sources such as rainforest ecosystem collapse and tundra excursions

Actually they won't fall rapidly due to any sinks, because near equilibrium (between atmosphere and sink) is reached in a few years as emissions rise.  A proportion of the excess CO2 (i.e. above pre-industrial level) will effectively stay in the atmosphere for thousands of years [6].  This is known as a "long tail" in the distribution curve for lifetime.   Thus, other things being equal, global warming would continue for over a century if we could by some magic reduce our emissions to zero overnight.

Thus, not only are we past the tipping point for the sea ice, but we are past the point of no return, unless we apply geoengineering.  This means that, without geoengineering the Arctic will continue to warm and inevitably all the permafrost will melt, releasing ever increasing quantities of methane as a positive feedback on the global temperature builds up.  This is like a nuclear reactor going into meltdown, when there is not enough moderator to control positive feedback - and the average neutron released from nuclear decay reacts to create heat plus more than one neutron.  Geoengineering is needed as a 'moderator' of positive feedback in the Arctic - to allow the whole Arctic to cool down and prevent explosive growth of atmospheric methane with global warming spiralling out of control.

As with a nuclear reactor overheating, it is vital to cool the Arctic as quickly as possible, to try to prevent the ultimate disaster which could come from methane: an extinction event of such magnitude as to wipe out Homo Sapiens.

Best wishes,

John

[1] http://researchpages.net/esmg/people/tim-lenton/tipping-points/

[2] http://www.pnas.org/content/105/6/1786.long
Reference [5] in [3] below.

[3] http://en.wikipedia.org/wiki/Arctic_geoengineering

[4] http://www.ccrc.unsw.edu.au/Copenhagen/Copenhagen_Diagnosis_LOW.pdf
See figure 13, page 30.

[6] http://www.pik-potsdam.de/~victor/archer.subm.clim.change.pdf

---

> summer may well trigger even more rapid warming (see “Tundra 4: Permafrost

> loss linked to Arctic sea ice

> loss<http://climateprogress.org/2008/06/12/breaking-news-tundra-4-permafrost-loss-linked-to-arctic-sea-ice-loss/>“

> and below). But in fact a much more reasonable AFP headline would be

> “Arctic ice cap on verge of runaway melting: study.” The NSF release
> should read, “Polar bear extinction now likely.”
>

> I understand that journalists typically don’t read studies closely, but *

> Nature* ought to know better. Perhaps, as we will see, it is just a
> matter of climate scientists of being utterly divorced from the reality of
> our energy and political systems. Still, in reading the study and its
> supplementary information, I am puzzled why *Nature* published the article
> as written and especially why it chose to sensationalize it on the cover.
> [end quote]
>
> Cheers,
>
> John
>
> [1] http://www.nature.com/nature/journal/v468/n7326/full/nature09653.html
>
> [2]
> http://climateprogress.org/2010/12/20/polar-bear-arctic-sea-ice-all-but-doomed-misleading-nature-cover-story/
>
> ---
>
> On Wed, Mar 2, 2011 at 11:54 PM, Ken Caldeira <
> kcal...@carnegie.stanford.edu> wrote:
>
>> Tietsche, S., D. Notz, J. H. Jungclaus, and J. Marotzke (2011), Recovery
>> mechanisms of Arctic summer sea ice, Geophys. Res. Lett., 38, L02707,
>> doi:10.1029/2010GL045698.
>>
>> Abstract.
>>
>> We examine the recovery of Arctic sea ice from

>> prescribed ice‐free summer conditions in simulations of 21st
>> century climate in an atmosphere–ocean general circulation

>> model. We find that ice extent recovers typically within two
>> years. The excess oceanic heat that had built up during the

>> ice‐free summer is rapidly returned to the atmosphere during

>> the following autumn and winter, and then leaves the Arctic
>> partly through increased longwave emission at the top of the
>> atmosphere and partly through reduced atmospheric heat
>> advection from lower latitudes. Oceanic heat transport does
>> not contribute significantly to the loss of the excess heat. Our
>> results suggest that anomalous loss of Arctic sea ice during

>> a single summer is reversible, as the ice–albedo feedback

>> is alleviated by large‐scale recovery mechanisms. Hence,
>> hysteretic threshold behavior (or a “tipping point”) is

>> unlikely to occur during the decline of Arctic summer seaice
>> cover in the 21st century.
>>
>> see also:
>>
>> Holland, M. M., Bitz, C. M., Tremblay, L.-B. & Bailey, D. A. Am. Geophys.

>> Union Geophys. Monogr. Ser. 180, 133–150 (2008).

[Veli Albert Kallio]

Hi John,
 
We don't know. I am only stating that the ocean dynamic responses are unknown as we have not seen the open ocean there before.
 
The only things I can say are:
 
- the changing ratio of ice covered and open sea allows more sea ice movement, the ice congestion reduced, the sea ice becomes more fluid, it travels within the Arctic Ocean more, and the ice floes are not grid locked as easily between the archipelagoes, so more ice also escapes to the Atlantic Ocean
 
- the longer stretches of open ocean generate far more winds and waves, as ice is thinner and seasonal containing little more salt, it breaks easily when facing the newly emerging waves
 
- the albedo gradient between ice covered and open ocean creates wind patterns, the stronger winds facing the pack ice ridges, islands, and when pushing ice floes around cause vertical upturning of the ocean on localised scale, this rises warm water from beneath, increasing the extraction of heat from the ocean. Indeed, the ice floes travel by ploughing the ocean, wind presses the edge of ice and also keeps higher water column on winward side, as water is water it keeps sinking while pushing water more against ice.
 
These are all in addition to the increased temperatures and sunlight absorbtion that IPCC and the Arctic Council based their position that the sea ice would most likely to disappear in summers around year 2150. I had to make a phantom presentation for World Water Week, Stockholm in 2006 as I knew that the stuff the IPCC and the Arctic Council was simplistic. (Sweden's experts were in the Arctic Council.)
 
 
This is similar to the elastic response, (elastic thrust of the Pacific plate) as more water accummulates on the top and it has started to behave like baker's dough under the massage of the extra water in the ocean. This also applies to the Indian Ocean and other oceans. The "promoted earthquakes" as the Pacific Rim mountain chains has their glaciers melting away makes the continenal plates more buoyant especially where the Pacific plate naturally thrusts under the continental plate. Chile and Alaska are seeing increases in these promoted earthquakes, whereas Greenland has ice quakes from rebounding ground as its glaciers are melting away.  

 

---

Date: Wed, 16 Mar 2011 22:52:30 +0000

Subject: Re: [clim] Arctic sea-ice not a "tipping point"

From: johnnis...@gmail.com
To: albert...@hotmail.com
CC: eugg...@comcast.net; andrew....@gmail.com; j...@cloudworld.co.uk; climatein...@googlegroups.com

> summer may well trigger even more rapid warming (see 锟斤拷Tundra 4: Permafrost

> loss linked to Arctic sea ice

> loss<http://climateprogress.org/2008/06/12/breaking-news-tundra-4-permafrost-loss-linked-to-arctic-sea-ice-loss/>锟斤拷

> and below). But in fact a much more reasonable AFP headline would be

> 锟斤拷Arctic ice cap on verge of runaway melting: study.锟斤拷 The NSF release
> should read, 锟斤拷Polar bear extinction now likely.锟斤拷
>

> I understand that journalists typically don锟斤拷t read studies closely, but *

> Nature* ought to know better. Perhaps, as we will see, it is just a
> matter of climate scientists of being utterly divorced from the reality of
> our energy and political systems. Still, in reading the study and its
> supplementary information, I am puzzled why *Nature* published the article
> as written and especially why it chose to sensationalize it on the cover.
> [end quote]
>
> Cheers,
>
> John
>
> [1] http://www.nature.com/nature/journal/v468/n7326/full/nature09653.html
>
> [2]
> http://climateprogress.org/2010/12/20/polar-bear-arctic-sea-ice-all-but-doomed-misleading-nature-cover-story/
>
> ---
>
> On Wed, Mar 2, 2011 at 11:54 PM, Ken Caldeira <
> kcal...@carnegie.stanford.edu> wrote:
>
>> Tietsche, S., D. Notz, J. H. Jungclaus, and J. Marotzke (2011), Recovery
>> mechanisms of Arctic summer sea ice, Geophys. Res. Lett., 38, L02707,
>> doi:10.1029/2010GL045698.
>>
>> Abstract.
>>
>> We examine the recovery of Arctic sea ice from

>> prescribed ice锟絓free summer conditions in simulations of 21st
>> century climate in an atmosphere锟紺ocean general circulation

>> model. We find that ice extent recovers typically within two
>> years. The excess oceanic heat that had built up during the

>> ice锟絓free summer is rapidly returned to the atmosphere during

>> the following autumn and winter, and then leaves the Arctic
>> partly through increased longwave emission at the top of the
>> atmosphere and partly through reduced atmospheric heat
>> advection from lower latitudes. Oceanic heat transport does
>> not contribute significantly to the loss of the excess heat. Our
>> results suggest that anomalous loss of Arctic sea ice during

>> a single summer is reversible, as the ice锟紺albedo feedback

>> is alleviated by large锟絓scale recovery mechanisms. Hence,
>> hysteretic threshold behavior (or a 锟斤拷tipping point锟斤拷) is

>> unlikely to occur during the decline of Arctic summer seaice
>> cover in the 21st century.
>>
>> see also:
>>
>> Holland, M. M., Bitz, C. M., Tremblay, L.-B. & Bailey, D. A. Am. Geophys.

>> Union Geophys. Monogr. Ser. 180, 133锟紺150 (2008).

[Veli Albert Kallio]

I somehow missed out two items:
 
- In the autumn time Arctic darkness the temperature gradient between the (increasingly lately open) Arctic Ocean and Siberia becomes more pronounced, the steepening temperature gradients stir up winds than tend to further increase the upturning of the ocean. As the ocean ice forms later, and breaks often even in mid winter, the ice remains thin and this translates to early arrival of spring.
 
- The wintertime's open ocean piles up snow on land more than before. As snow is insulator and the grounds are warmer than before, the preservation of heat in the soils is larger under the snow cover. Now microbial activities can carry out decomposing activities under the thickened snow blanket and warmed winters. Once spring arrives, the snow that rests on a warmed land masses in Siberia quickly melts back into the ocean causing amplified spring floods that come early and have more water. As the water is goes back earlier, and in larger quantities, and the ground albedo kicks early spring, the coastal regions see far increased heat import and earlier then before.
 
All these make it hard to believe the ice can stay in place when the heavy melting starts under the strong springtime summer. Today, the sea ice area is readily 1,152,000 km2 below normal. We grasp the possibility of little, or no, sea ice remaining at the end of this summer.
 
Rgs, Albert
 

---

From: albert...@hotmail.com
To: johnnis...@gmail.com

CC: eugg...@comcast.net; andrew....@gmail.com; j...@cloudworld.co.uk; climatein...@googlegroups.com

Subject: RE: [clim] Arctic sea-ice not a "tipping point"

Date: Thu, 17 Mar 2011 10:07:44 +0000

[John Nissen]

Oops.  I had assumed, from my distant memory of university physics, that a "moderator" was in the control rods.  Andrew Lockley has pointed out that a "moderator" in a nuclear reactor actually enhances the chain reaction, by slowing the neutrons emitted in fission so that they are better able to cause further fission.  The control rods contain what is called "poison" which actually absorbs neutrons.  If a reactor starts overheating, and causes a "power excursion" or "criticality", then control rods have to be inserted otherwise meltdown will occur.  Meltdown can also occur if there is a coolant circulation failure and fuel rods are exposed.

In the Fukushima active reactors 1-3, the control rods were inserted, but meltdown is liable (and has probably happened at one or two of the reactors) because of the coolant level has fallen, exposing the top of the fuel rods which can then melt.  In reactor 4, the spent fuel was simply cooled by water, and the water level has fallen exposing the end of the rods.  Our chief scientific adviser, Dr Beddington, is very concerned by exposure of fuel rods, as they emit fierce radiation making it impossible for people to work in the vicinity.  (The possibility of criticality and explosion has not been ruled out - putting the disaster close to the Chernobyl class!)

In the case of the Arctic , there are several positive feedbacks at play. 

1.  There is the albedo flip of the Arctic sea ice.  As the Arctic warms and sea ice melts, there is more open water to absorb solar radiation, feeding back into Arctic warming.  The warming of the water acts to melt permafrost below the sea-bed, releasing methane from methane hydrates. 

2.  There is the albedo flip over ground.  As the Arctic warms, the snow melts exposing darker rocks and vegetation underneath which absorb more solar radiation, feeding back into Arctic warming.  The warming of the ground acts to melt permafrost to release CO2, methane and N2O.

3.  As the isotherms move northwards, and snowline recedes, shrubs can grow that have an even lower albedo than exposed earth, grass and rocks, feeding back into Arctic warming.

4.  As forested areas warm, they are more liable to fire, which deposits black carbon onto snow and ice, reducing their albedo and feeding back to Arctic warming.

Once methane excursion becomes significant, we also have these positive feedbacks:

5.  The decomposition of organic matter, unfrozen from permafrost, generates heat.  In particular, if methane is converted to CO2, significant heat is generated, which will feedback to melting the permafrost and release of more gas.  (Note to Andrew - this is another positive feedback for your list!)

6.  The greenhouse gases from permafrost disperse quickly and add to general global warming from the excess of greenhouse gases already in the atmosphere.  This additional warming feeds back to melting of more permafrost and release of more gas.

So I could modify the analogy with a nuclear reactor:


Thus, not only are we past the tipping point for the sea ice, but we are past the point of no return, unless we apply geoengineering.  This means that, without geoengineering, the Arctic will continue to warm and inevitably all the permafrost will melt, releasing ever increasing quantities of methane as a positive feedback on the global temperature builds up.  This is like a nuclear reactor going critical with uncontrolled positive feedback - where the average neutron released from nuclear decay causes more than one further nuclear decay in a chain reaction.  Geoengineering is needed to dampen positive feedback in the Arctic - to allow the whole Arctic to cool down and prevent explosive growth of atmospheric methane with global warming spiralling out of control.


Cheers,

John

---