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jai mitchell

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Re: Conservative Scientists & its Consequences
« Reply #450 on: January 28, 2015, 10:57:31 PM »
your paper on frozen soils was published after the cutoff date and was not included in the IPCC AR5

I was specifically referring to the IPCC that has so far no included frozen soil carbon feedbacks and only include carbon cycle feedbacks in the RCP 8.5 scenario.

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Quote
Arctic ice loss is in the ocean, frozen soils are on land.

When ice melts it maintains a constant temperature no matter how much energy you impart into the system.  once the ice is gone then the temperature can rise, and will.  Estimates for a sea ice free arctic show an increase in regional temperatures by between 8 and 14C, this will radically increase soil decomposition.  That is why it is a carbon cycle and frozen soil positive feedback as well as an albedo one.

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If part of the extra Arctic melt is caused by cold air leaving the Arctic for the continents then this mean that frozen soil loss will be slowed down, not sped up

This quote makes no sense, permafrost is maintained near or above the arctic circle, the decrease of regional temperatures in short pulses in the midlatitudes has absolutely no effect on this permafrost.  You appear to be making this up.

Quote
If the Arctic feedbacks are so important for total global temperature change then when whatever natural cycle is speeding up Arctic melt reverses then the extra warming for the extra Arctic melting will disappear and global warming will slow down.

you have absolutely no idea what you are talking about.

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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #451 on: January 29, 2015, 12:50:49 AM »
While I have mentioned it before, Schuur & Abbott (2011) have a good discussion of how much methane emissions from permafrost degradation, were left out of the AR5 projections:

Schuur, E.A.G. and Abbott, B., (2011), "High risk of permafrost thaw", Nature, 480, 32-33, Dec. 2011
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jai mitchell

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Re: Conservative Scientists & its Consequences
« Reply #452 on: January 29, 2015, 03:04:16 AM »
While I have mentioned it before. . .

ever get the feeling you are fighting zombies?
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #453 on: January 29, 2015, 03:21:27 AM »
While I have mentioned it before. . .

ever get the feeling you are fighting zombies?

:)
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Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #454 on: January 29, 2015, 07:04:40 AM »
your paper on frozen soils was published after the cutoff date and was not included in the IPCC AR5

That is the whole point of what I posted.  A study published after the IPCC AR5 which does include the carbon cycle feedbacks finds a warming amount only 0.2 greater than what IPCC AR5 finds.  And this amount is an overestimate as the models overestimate the amount of carbon feedbacks experienced to date.

When ice melts it maintains a constant temperature no matter how much energy you impart into the system.  once the ice is gone then the temperature can rise, and will.  Estimates for a sea ice free arctic show an increase in regional temperatures by between 8 and 14C, this will radically increase soil decomposition.  That is why it is a carbon cycle and frozen soil positive feedback as well as an albedo one.

Quote
If part of the extra Arctic melt is caused by cold air leaving the Arctic for the continents then this mean that frozen soil loss will be slowed down, not sped up

This quote makes no sense, permafrost is maintained near or above the arctic circle, the decrease of regional temperatures in short pulses in the midlatitudes has absolutely no effect on this permafrost.  You appear to be making this up.



Warm air in the Arctic ocean, cold air in the continents nearby.  Caused by winds blowing from Atlantic or Pacific into the Arctic ocean pushing the cold air out of the Arctic ocean where the ice lives into the continents where the permafrost lives.  Therefore ice melting faster than projected and permafrost (presumably) melting slower than projected.  This isn't happening all the time, (note chart is for Dec 10) but it is possibly part of the reason why ice is melting faster than projected.  Further discussion

Quote
If the Arctic feedbacks are so important for total global temperature change then when whatever natural cycle is speeding up Arctic melt reverses then the extra warming for the extra Arctic melting will disappear and global warming will slow down.

you have absolutely no idea what you are talking about.

Yes I do.  You left out the start that paraprapgh where I say 'If it is natural variation'.  I doubt anyone can prove that there is no natural cycle/variation etc that is currently speeding up the Arctic melt?
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jai mitchell

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Re: Conservative Scientists & its Consequences
« Reply #455 on: January 29, 2015, 08:39:26 AM »
so mike, what percentage of the cumulative global heat accumulation was used to reduce the maximum winter arctic ice volume from 32,000 cubic km in 1994 to 23,000 cubic km in 2014?  (hint, use ocean heat content accumulations from the NODC).

and tell me again how much this has reduced the earth's temperature?

And tell me again how the polar vortex moving down into Ohio and moving away from the arctic circle, where the permafrost is will somehow hinder permafrost decomposition?

If you only look at RCP 8.5 concentrations and you assume a reduced co2 response over a long-term then you will get significantly reduced warming.  If, however, you reach a tipping point where vast forests collapse and burn in the tropics and in the boreal regions, well then you suddenly have a much more rapid production of Land based CO2.  This is especially true if you reach it 40 years earlier, as we are observing.

Your paper brings nothing new to the discussion, it is a recycling of the IPCC values.  They model sea ice remaining through 2065, and negligible land-use responses while we are observing crushing droughts in the amazon, the south west and a massive increase in boreal forest fires, including boreal peat fires.  As I said before, and you still refuse to acknowledge, these events are being observed TODAY.



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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #456 on: January 29, 2015, 07:29:37 PM »
The linked articles describe how climate change can lead to abrupt changes in hypoxia in coastal fisheries (see the attached image and quote below):

http://www.nsf.gov/news/special_reports/deadzones/climatechange.pdf

http://www.theverge.com/2015/1/28/7930047/climate-change-could-mean-massive-ocean-dead-zones

Quote: "Though the exact mechanism driving dead zone expansion is unclear, studies show that it’s happening and will likely increase. One model predicts a 50 percent increase in low-oxygen water by the end of the century. As the zones spread, they reduce the number of habitats for many of the sea creatures we eat.
The disconcerting thing about Moffitt’s study is that it shows how quickly these changes can happen. Most policy discussions about climate change are conducted in terms of estimates and averages — 3 feet of sea level rise, 170 percent increase in ocean acidity — but what we’re dealing with are complex interlocking systems with tipping points and feedback loops we barely understand.
"It’s not just about temperature," says Moffitt. "It’s about disrupting fundamental earth processes that we as humans have understood to be very stable. They’re not stable. These systems have the capacity to be very unstable when you poke climate system with a sharp stick.""
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Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #457 on: January 29, 2015, 10:14:30 PM »
so mike, what percentage of the cumulative global heat accumulation was used to reduce the maximum winter arctic ice volume from 32,000 cubic km in 1994 to 23,000 cubic km in 2014?  (hint, use ocean heat content accumulations from the NODC).

and tell me again how much this has reduced the earth's temperature?

By next to nothing.  I see no relevance of this point to the current discussion.

And tell me again how the polar vortex moving down into Ohio and moving away from the arctic circle, where the permafrost is will somehow hinder permafrost decomposition?

Cold air does not use Star Trek style teleport beams.  It has to move across the land one inch at a time and so any cold air from the Arctic that makes it to Ohio will have cooled thousands of kilometres of permafrost along the way.

Your paper brings nothing new to the discussion, it is a recycling of the IPCC values. 

Quote

The paper models earth system carbon cycle feedbacks.  A major criticism of the IPCC in this thread is that the IPCC did not model carbon cycle feedbacks.

They model sea ice remaining through 2065, and negligible land-use responses while we are observing crushing droughts in the amazon, the south west and a massive increase in boreal forest fires, including boreal peat fires. 

Drought in the Amazon and the southwest, and peat fires are not land use changes, they are carbon cycle feedbacks.  The paper clearly states that the model shows higher carbon cycle feedbacks today than are actually being observed.

As I said before, and you still refuse to acknowledge, these events are being observed TODAY.

The amazon is drying out, California is in major drought .  Peat is burning.  The total rate of carbon emitted into the atmosphere by these and all other sources is currently slower than the CMIP models project as the paper I linked to points out.  Which is no guarantee that these feedbacks will be slower than model for the future but is a good start.  Arctic is certainly melting faster than model predictions.

I've acknowledged your points.  Now how about you try acknowledging some of my points.  Like the fact that Antarctic sea ice is not melting as fast as the models predict.  Both factors that may cause accelerated warming and those that may cause reduced warming need to be considered together.  If you point to the Antarctic and ignore the rest of the globe you are a denier.  If you point at the Arctic and ignore the rest of the globe you are just as ignorant.  And how about acknowledging the fact that models that include carbon cycle feedbacks show only 0.2 degrees more warming than the IPCC projections, and also show more carbon cycle feedbacks currently occuring than are measured, instead of saying that the paper 'adds nothing new to the discussion'
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Neven

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Re: Conservative Scientists & its Consequences
« Reply #458 on: January 29, 2015, 10:48:46 PM »
Like the fact that Antarctic sea ice is not melting as fast as the models predict.

Pray tell, which 'the' models? Not the 1992 one from Manabe et al, I presume.
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Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #459 on: January 29, 2015, 11:59:54 PM »
Like the fact that Antarctic sea ice is not melting as fast as the models predict.

Pray tell, which 'the' models? Not the 1992 one from Manabe et al, I presume.

I was sure I had posted the link, but I can't find where I did so maybe I accidently deleted it or something.  Here it is again.  The CMIP 5 models show negative trends for Antarctic for all models, and most of them are statistically significant.

I am not arguing any significance to the Antarctic sea ice beyond pointing out that the whole picture needs to be looked at.  The fact that some components of the climate system are reacting faster than modelled can be balanced by other components reacting slower than modelled.  Overall the global temperature has recently been just below model - close enough to comfortably call the models accurate, but I want to emphasise the fact that global temperatures are lower than modelled for anyone who is arguing that thing are happening faster than expected.
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Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #460 on: January 30, 2015, 12:03:25 AM »
I also retract my agreement that Arctic ice is melting significantly faster than models predict.  While this was true 5 or so years ago it looks like the latest CMIP projections are a bit more aggressive with 2007 within the 1 standard deviation range, 2012 just below the range, and the higher years of 13 and 14, while not shown would be comfortably within the range and closer to the model mean than the bottom of the range.
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Neven

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Re: Conservative Scientists & its Consequences
« Reply #461 on: January 30, 2015, 01:06:50 AM »
I am not arguing any significance to the Antarctic sea ice beyond pointing out that the whole picture needs to be looked at.  The fact that some components of the climate system are reacting faster than modelled can be balanced by other components reacting slower than modelled.

Hold on, this is like saying that world hunger is balanced by obesity. We've got two pretty extreme events going on at both poles, but somehow this is reassuring because they're not going in the same direction?

To tell the truth, I'd be reassured if Antarctic sea ice would remain stable, while Arctic sea ice declines. Of course, I'd be extremely worried if Antarctic sea ice were declining as well, but that wouldn't make sense, as the Antarctic is a harder nut to crack, as it is the most dominant factor in its region (continent surrounded by sea, etc). It's not warm enough for that yet.

But the fact that Antarctic sea ice is growing so significantly (especially at the maximum), to me could be a sign that things are already changing there as well. Besides the stuff happening to the land ice, of course.

And second: Perhaps Antarctic sea ice is reacting faster as well, just not in the direction that models anticipated, because of their imperfections? Why does growing sea ice around the Antarctic mean AGW-induced climate change can't have anything to do with it?
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #462 on: January 30, 2015, 02:00:14 AM »
For what it is worth, Tamino posted about this a couple of years ago comparing the change in Arctic and Antarctic sea ice insolation, indicating that the change in the Arctic is about six times the change in the Antarctic (see the attached Tamino plot):

https://tamino.wordpress.com/2012/10/01/sea-ice-insolation/.
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Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #463 on: January 30, 2015, 03:36:25 AM »

Hold on, this is like saying that world hunger is balanced by obesity. We've got two pretty extreme events going on at both poles, but somehow this is reassuring because they're not going in the same direction?


I have been arguing about global temperature changes, and that you can't just look at one part of the globe that is experiencing faster than modelled changes and automatically conclude the global temperature change will be faster than modelled. 

More ice in Antarctica will certainly partially balance out less ice in the Arctic as far as global warming is concerned, even if there are other potential issues (eg the SH polar vortex tightening up around Antarctica and contributing to drought in Southern Australia).
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Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #464 on: January 30, 2015, 03:50:20 AM »
For what it is worth, Tamino posted about this a couple of years ago comparing the change in Arctic and Antarctic sea ice insolation, indicating that the change in the Arctic is about six times the change in the Antarctic (see the attached Tamino plot):

https://tamino.wordpress.com/2012/10/01/sea-ice-insolation/.

Back in 2012 when this was written the global sea ice totals were clearly down.  Since then Antarctica has gone up a lot - so a very short term event that can hardly be called a long term trend and could quite easily reverse just as quickly.  At the same time the Arctic has had two years of less melt.  But the upshot is that global sea ice totals have been very near long term averages in the last two years since that chart was produced (and I'd guess will be on the way down again shortly).  And to get a total global picture of albedo effects the big drop in NH snow cover needs to then be added.  The drop in snow cover in June has been greater than the loss of Arctic sea ice.

(technically SH snow and ice sheet areas also need to be added, but the area of ice sheet lost so far, and total SH snow cover is tiny)
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wili

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Re: Conservative Scientists & its Consequences
« Reply #465 on: January 30, 2015, 05:02:24 AM »
(Straight out of denialists tired hand hackneyed playbook--"My brain tumor is twice the size of my head, but then at the same time my legs have shriveled up and nearly fallen away, so my total body flesh totals have been very near my long term averages...so I guess I'm just fine!" Rather disgusting, really.)

I any case, Antarctic sea ice is down to 3,298,000 km^2 which is lower than 2003, 2013 and 2014 for this date and will still be falling for around two more weeks.


http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.antarctic.png




« Last Edit: January 30, 2015, 05:07:46 AM by wili »
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Neven

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Re: Conservative Scientists & its Consequences
« Reply #466 on: January 30, 2015, 07:28:23 AM »
More ice in Antarctica will certainly partially balance out less ice in the Arctic as far as global warming is concerned,

More obese people balances out world hunger, but that doesn't mean mortality rates will decrease.

Again, I would be more assured if Antarctic sea ice would be more stable.
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Lennart van der Linde

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Re: Conservative Scientists & its Consequences
« Reply #467 on: January 30, 2015, 07:58:28 AM »
I have been arguing about global temperature changes, and that you can't just look at one part of the globe that is experiencing faster than modelled changes and automatically conclude the global temperature change will be faster than modelled. 

Ok, but then shouldn't we also look at ocean heat content, melting land ice and permafrost, to get a picture of the total energy balance? My concern is not that changes will certainly be faster than modelled, but that they could be faster, and that both IPCC and the public are not taking this risk seriously enough. Brysse et al 2013 and Anderegg et al 2014 give some strong arguments for that concern, among others. You seem less concerned, but why is not clear to me.

Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #468 on: January 30, 2015, 10:32:27 AM »
I am arguing that the IPCC is the best source of climate change information, and that their projections are the most accurate thing we have.

I get accused of stating that things are fine and making plays straight from the denialists handbook.

I think someone is missing the point.
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Lennart van der Linde

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Re: Conservative Scientists & its Consequences
« Reply #469 on: January 30, 2015, 10:39:03 AM »
Ok, but what do you think of Brysse et al 2013 ('erring on side of least drama') and Anderegg et al 2014 ('risk of type 2 errors')? And about IPCC itself stating that it's SLR-projections beyond 2100 are probably under-estimates and that carbon feedbacks are not (fully) included in their models?

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Re: Conservative Scientists & its Consequences
« Reply #470 on: January 30, 2015, 04:09:52 PM »
Michael Hauber,

You think someone is missing the point?

Then i have to say that.......
"More ice in Antarctica will certainly partially balance out less ice in the Arctic as far as global warming is concerned, even if there are other potential issues (eg the SH polar vortex tightening up around Antarctica and contributing to drought in Southern Australia).".......
you have to think twice before you make such statements, because they give exactly the impression that you are citing out of denialists handbook.

Not only is it a phrase often used in the denialosphere, but it is almost certainly wrong.
There are many threads just about why antarctic sea ice is growing and there is plenty of research going on since years which clearly gives us the first answers why antarctic sea ice is growing, that it is growing despite melting, and we get information that it probably has been like today during former deglaciations, with melting deep down and a lock of insulating ice on top.

You have to concider that the albedo effect of antarctic ice growth is much less than in the arctic, because the growth in summer in the antarctic is much less than the loss of snow and ice in the north.

"arguing that the IPCC is the best source of climate change information,"
Here you are of course right, provided that you take your time to read the many papers too which are basis of the reports, but....
"that their projections are the most accurate thing we have."?
Let me eppress my doubts about this part of your statement.
In regard to IPCC´s mandate to provide a synthesis between research and policy there must be a tendency to be on the conservative side of the picture and this is obvious at least when you only read the summarys for policymakers.





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Re: Conservative Scientists & its Consequences
« Reply #471 on: January 30, 2015, 05:41:09 PM »
For what it is worth, Tamino posted about this a couple of years ago comparing the change in Arctic and Antarctic sea ice insolation, indicating that the change in the Arctic is about six times the change in the Antarctic (see the attached Tamino plot):

https://tamino.wordpress.com/2012/10/01/sea-ice-insolation/.

Back in 2012 when this was written the global sea ice totals were clearly down.  Since then Antarctica has gone up a lot - so a very short term event that can hardly be called a long term trend and could quite easily reverse just as quickly.  At the same time the Arctic has had two years of less melt.  But the upshot is that global sea ice totals have been very near long term averages in the last two years since that chart was produced (and I'd guess will be on the way down again shortly).  And to get a total global picture of albedo effects the big drop in NH snow cover needs to then be added.  The drop in snow cover in June has been greater than the loss of Arctic sea ice.

(technically SH snow and ice sheet areas also need to be added, but the area of ice sheet lost so far, and total SH snow cover is tiny)

You seem to both be mixing-up: (a) long-term trends in sea ice extent with short-term fluctuations (a common denialist tactic); and (b) ice extent with insolation.  Regarding insolation, as you can see from wili's plot in Reply #465 that most of the recent increase in Antarctic sea ice extent occurs during the austral Fall and Winter when there is little solar insolation; while there is relatively little increase in Antarctic sea ice extent in the austral Spring and Summer.

In no way is it reasonable to postulate that the GCM modeling done for AR5 is sufficient to safeguard society from future climate change risks, and it is essential that new state-of-the-art ESM projections be developed such as the US DOE is doing in the ACME project.
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Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #472 on: January 31, 2015, 12:00:13 AM »

Not only is it a phrase often used in the denialosphere, but it is almost certainly wrong.
There are many threads just about why antarctic sea ice is growing and there is plenty of research going on since years which clearly gives us the first answers why antarctic sea ice is growing, that it is growing despite melting, and we get information that it probably has been like today during former deglaciations, with melting deep down and a lock of insulating ice on top.


The fact that we know why the sea ice is growing does not mean that it is not growing, and does not mean that it is not relfecting sunlight and reducing the amount of warming that we have been experiencing.

(of course if growth in Antarctic ice has been causing a cooling over the last 30 years then when it inevitably starts melting sometime in the future this will result in an increase in the warming rate)
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Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #473 on: January 31, 2015, 12:07:31 AM »



You seem to both be mixing-up: (a) long-term trends in sea ice extent with short-term fluctuations (a common denialist tactic);
The trend for Antarctcic sea ice for the complete satellite record is statistically significant growth.  The trend for all CMIP models over the same period is decline, and mostly statistically significant.
and (b) ice extent with insolation.  Regarding insolation, as you can see from wili's plot in Reply #465 that most of the recent increase in Antarctic sea ice extent occurs during the austral Fall and Winter when there is little solar insolation; while there is relatively little increase in Antarctic sea ice extent in the austral Spring and Summer.

So I'm looking at short term graphs when I look at 30 + year trends, but you are not when you look at a 2 year chart.

Look at the chart again and in particular the anomaly line.  Peak insolation is December - which is just before the markers for 2014 and 2015.  Both Decembers show quite high peaks (although not quite as high as the peak in 2014).  Perhaps if you definition of 'most' is >50% you might just scrape in by a whisker.
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Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #474 on: January 31, 2015, 12:22:31 AM »
Ok, but what do you think of Brysse et al 2013 ('erring on side of least drama') and Anderegg et al 2014 ('risk of type 2 errors')? And about IPCC itself stating that it's SLR-projections beyond 2100 are probably under-estimates and that carbon feedbacks are not (fully) included in their models?

If the IPCC is doing a good job then they will overestimate some things and underestimate others.  Studies that pick a small handful of things that they are underestimating and claim a systematic bias are about as convincing as Denial Depot's claim that the world is cooling. (this denier wouldn't be caught dead reading WUWT, but loves DD and is very sad it ended).

On SLR-projections I went and had a look at the first assessment report on sea level rise.  In 1990 they predicted a 18.3cm sea level rise by 2030.  This is 4.6mm/year.  The trend from 1990 to 2015 is currently 3.2mm/year.  While the possibility of acceleration in the near future is certainly there, I don't think that the next 15 years won't be enough to make up the difference and it will turn out that the IPCC first assessment report made at least one overestimation of one aspect of climate change.

Of course sea level rise to date has been dominated by thermal expansion so this overestimation is no guarantee that dynamic component won't push actual trends over the projection in the future.
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Re: Conservative Scientists & its Consequences
« Reply #475 on: January 31, 2015, 01:16:07 AM »
For those that are interested I provide the following link to a Real Climate article entitled: "Clarity on Antarctic sea ice":

http://www.realclimate.org/index.php/archives/2014/12/clarity-on-antarctic-sea-ice/
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Re: Conservative Scientists & its Consequences
« Reply #476 on: January 31, 2015, 05:19:18 AM »
Southern sea ice increase is in winter where there is no sun to reflect and ice insulates OHC against heat loss to winter atmosphere, while the pronounced arctic sea ice loss in summer decreases albedo exactly when the sun never sets.

Is this so hard to understand or are people being intentionally obtuse on this matter ? Especially when one considers that part of SH winter sea ice increase is from freshening of surface water from Antarctic land ice melt, effectively an export of heat from lower latitudes into the AIS.

This is not difficult. Follow the heat.

sidd

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Re: Conservative Scientists & its Consequences
« Reply #477 on: January 31, 2015, 08:46:05 AM »
If the IPCC is doing a good job then they will overestimate some things and underestimate others.  Studies that pick a small handful of things that they are underestimating and claim a systematic bias are about as convincing as Denial Depot's claim that the world is cooling. (this denier wouldn't be caught dead reading WUWT, but loves DD and is very sad it ended).

On SLR-projections I went and had a look at the first assessment report on sea level rise.  In 1990 they predicted a 18.3cm sea level rise by 2030.  This is 4.6mm/year.  The trend from 1990 to 2015 is currently 3.2mm/year.  While the possibility of acceleration in the near future is certainly there, I don't think that the next 15 years won't be enough to make up the difference and it will turn out that the IPCC first assessment report made at least one overestimation of one aspect of climate change.

But Brysse et al find more systematic under-estimation by IPCC:
https://www.wageningenur.nl/upload_mm/2/0/b/f2601035-3fa4-41cb-b0f5-77de713695fc_erring.pdf

You think they're cherry picking, but you only give one example of potential over-estimation from 1990. Is that enough for you to dismiss Brysse et al? Their paper seems much more convincing than your (potential) counter-example.

Steven

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Re: Conservative Scientists & its Consequences
« Reply #478 on: January 31, 2015, 01:07:00 PM »
Tamino posted about this a couple of years ago comparing the change in Arctic and Antarctic sea ice insolation, indicating that the change in the Arctic is about six times the change in the Antarctic (see the attached Tamino plot):

https://tamino.wordpress.com/2012/10/01/sea-ice-insolation/.

For what it's worth, I played around with a simplified version of Tamino's calculation.

For each year from 1979 to 2014, I calculated a (weighted) average of the daily CT sea ice area data from January to December.  For the weights, I used insolation values from here.  So the weights are maximal at summer solstice, i.e., 21 June in the Northern Hemisphere and 21 December in the Southern Hem.  For simplicity, for these weights I used the daily insolation values for latitudes 75 or 80°N (for the NH), and 65 or 70°S (for the SH).

Here is the resulting graph that I calculated for the sea ice insolation for the Arctic (red) and Antarctic (blue):




Note that the values in this graph are very similar to those in Tamino's graph.

Tamino's graph has data for 1979-2011, whereas the above graph uses data up to 2014.

For what it's worth, the 1979-2014 linear trendlines in the above graph show an increase in Antarctic sea ice insolation of about 101 TeraWatt, and a decrease in Arctic sea ice insolation of about 352 TW.
« Last Edit: January 31, 2015, 04:28:43 PM by Steven »

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #479 on: January 31, 2015, 04:45:41 PM »
As far as I can tell, no one in this discussion is denying that the Antarctic sea ice extent has been trending upward since anthropogenic chlorofluorocarbons created an ozone hole over Antarctica just before 1979; which:
(a) Among other things increased the circumpolar westerly wind velocities over the Southern Ocean; which,
(b) Drove warm Circumpolar Deep Water over the continental shelves in most parts of Antarctica; which,
(c) Contributed to an increase in basal ice melting of ice shelves and at the grounding lines of marine glaciers.   

Furthermore (in general terms): (a) the changed wind patterns pushed sea ice made near the shore seaward so that more ice could form, and (b) the freshening of the Southern Ocean surface waters due to all of the ice melt water also makes it easier to form sea ice.  While these points are just part of the Antarctic sea ice story, it clearly indicates that the increases of the trend in Antarctic sea ice extent is driven primarily by anthropogenic causes (e.g. chlorofluorocarbons and their cousins); which as Neven points out implies that the observed increasing trend of Antarctic sea ice extent is a clear sign of anthropogenic climate change; which is bad news.
See other details for the arguments to these points in the linked thread from the Antarctic folder at:

http://forum.arctic-sea-ice.net/index.php?topic=1128.0
&
http://forum.arctic-sea-ice.net/index.php/topic,904.0.html

Certainly, the increase in Antarctic sea ice extend has led to some increase in the associated insolation; which is clearly far less than the decrease in Arctic insolation associated with the trending decrease in Arctic sea ice extent.  But Mike's argument that the observed increase in Antarctic sea isolation somehow means that GCMs used for the AR5 projections are the best that we can do, and are also good enough that we can all just relax and get back to Business-As-Usual, is sadly mistaken for many reasons including:
1) Sherwood, S. C., S. Bony, O. Boucher, C. Bretherton, P. M. Forster, J. M. Gregory and B. Stevens, (2014), "Adjustments in the forcing-feedback framework for understanding climate change", Bull. Amer. Meteorol. Soc., doi: http://dx.doi.org/10.1175/BAMS-D-13-00167.1; argue that the modeling of the forcing feedback mechanisms used in the AR5 GCM projections should at least be modified to account for feedback mechanisms that are not directly related to changes in mean global temperature such as chlorofluorocarbons (which is the primary cause of the observed trend of increases in Antarctic sea ice extent) and anthropogenic aerosols.  Thus even without changing to state-of-the-art Earth System Models, ESMs, we can and should do better analyses with GCMs than we did in AR5.
2) Cowtan & Way, clearly showed that the published mean global temperature rise values do not adequately account for Artic Amplification; which implies that the AR5 hind-casts may be too low (even when corrected for changes in ocean heat content, aerosols and volcanoes).
3) With continued global warming (say RCP 4.5) it is ridiculous to believe that the recently observed trend of increasing Antarctic sea ice extent will continue for more than a few more decades, and thus this negative feedback that Mike is counting on to counter-balance the positive feedback of Arctic Amplification is a fool's dream, as is relying on the negative feedback of anthropogenic aerosols, and the temporary spurt of plant growth driven by increasing atmospheric CO₂ levels.

Thus just as President Obama (yesterday) signed an Executive order forbidding all government agencies from using linear projections of historical SLR trends, but instead required them to use non-linear projections of SLR, for their coastal design work; we all need to think non-linear climate sensitivity risks rather than to play games of linearly extending recent (non-equilibrium) trends of increasing Antarctic sea ice insolation trends in to the future and to dream that such a relatively small negative feedback mechanism will offset other more numerous and more forceful non-linearly increasing positive feedback mechanisms.
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #480 on: January 31, 2015, 10:53:29 PM »
The linked op-ed from Livescience entitled: "Fear, Ridicule, Danger: Is It Safe to Be a Climate Scientist?" discusses some of the pressures put on climate scientists (and associated teachers) by society.  Not only does the public (particularly in the USA) ignore their conservative warnings of climate risks; but the societal pressures described in the article make these scientists think twice before presenting any controversial finding.  If our entire generation is not going to be vilified by generations for centuries to come; we had all better grow-up and open our societal eyes to the reality in front of our faces.

http://www.livescience.com/49641-fear-permeates-climate-science.html

Extract: "In fact, the harassment of climate scientists has become so prevalent that a nonprofit group, the Climate Science Legal Defense Fund, has popped up for the sole purpose of providing legal counsel to climate scientists."
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Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #481 on: February 01, 2015, 10:34:17 PM »


For what it's worth, I played around with a simplified version of Tamino's calculation.

For each year from 1979 to 2014, I calculated a (weighted) average of the daily CT sea ice area data from January to December.  For the weights, I used insolation values from here.  So the weights are maximal at summer solstice, i.e., 21 June in the Northern Hemisphere and 21 December in the Southern Hem.  For simplicity, for these weights I used the daily insolation values for latitudes 75 or 80°N (for the NH), and 65 or 70°S (for the SH).

Here is the resulting graph that I calculated for the sea ice insolation for the Arctic (red) and Antarctic (blue):




Note that the values in this graph are very similar to those in Tamino's graph.

Tamino's graph has data for 1979-2011, whereas the above graph uses data up to 2014.

For what it's worth, the 1979-2014 linear trendlines in the above graph show an increase in Antarctic sea ice insolation of about 101 TeraWatt, and a decrease in Arctic sea ice insolation of about 352 TW.

And then on top of this consider what the CMIP5  models used in the latest IPCC report.  They show decreases in both Arctic and Antarctic sea.  For Arctic I guess by eyeball that the CMIP models project roughly 75% of the recent trend in ice loss.  So that would make the current increase in Arctic insolation due to loss of sea ice roughly 75 TW greater than IPCC estimates.  As the CMIP models show a loss of Antarctic sea ice the reduction in Antarctic insolation due to gain of sea ice is going to be greater than 101 TW.  So I'd guess that the gain in Antarctic sea ice more than balances out the loss of Arctic sea ice if we are asking 'are things worse than the IPCC CMIP 5 models'.  Of course if we are asking 'is the world warming up at all' then the raw amounts of 352 vs 105 show that Antarctic is nowhere near balancing the Arctic. 

Also remember that the NH snow cover reduction has to be considered as well.  The reduction in snow cover at peak insolation has been even greater than the reduction in sea ice, and there has been if anything an increase in NH snow cover near minimum insolation.  I'd expect a substantial increase in insolation due to loss of NH snow cover of similar size to the Arctic, which when compared to no warming skews things even further out of balance.  How it effects comparisons with CMIP models I have no idea.
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Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #482 on: February 01, 2015, 10:38:45 PM »

You think they're cherry picking, but you only give one example of potential over-estimation from 1990. Is that enough for you to dismiss Brysse et al? Their paper seems much more convincing than your (potential) counter-example.

- methane emissions
- Australian rainfall reductions (as a whole Australian rainfall has increased - however reductions have been in the more heavily populated and farmed southern areas)
- US temperature increases (regional effect - but then so really is Arctic sea ice reduction)
Climate change:  Prepare for the worst, hope for the best, expect the middle.

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #483 on: February 02, 2015, 02:05:45 AM »
The linked article emphasizes the importance/dominance of the Southern Ocean w.r.t. anthropogenic carbon and heat uptake; and as the following extract states this area is the region models differ the most.  Therefore, it is un-imaginable to me that anyone could think that such models do not need further improvement in order to provide projections that are sufficiently accurate (particularly in this Antarctic region) to match the serious risks associated with climate change.

Extract: "The results highlight the significance of the Southern Ocean for the global climate and as the region where models differ the most in representation of anthropogenic CO2 and, in particular, heat uptake."

Thomas L. Frölicher, Jorge L. Sarmiento, David J. Paynter, John P. Dunne, John P. Krasting, and Michael Winton, (2015) "Dominance of the Southern Ocean in Anthropogenic Carbon and Heat Uptake in CMIP5 Models", J. Climate, 28, 862–886, doi: http://dx.doi.org/10.1175/JCLI-D-14-00117.1

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-14-00117.1

Abstract: "The authors assess the uptake, transport, and storage of oceanic anthropogenic carbon and heat over the period 1861–2005 in a new set of coupled carbon–climate Earth system models conducted for the fifth phase of the Coupled Model Intercomparison Project (CMIP5), with a particular focus on the Southern Ocean. Simulations show that the Southern Ocean south of 30°S, occupying 30% of global surface ocean area, accounts for 43% ± 3% (42 ± 5 Pg C) of anthropogenic CO2 and 75% ± 22% (23 ± 9 × 1022 J) of heat uptake by the ocean over the historical period. Northward transport out of the Southern Ocean is vigorous, reducing the storage to 33 ± 6 Pg anthropogenic carbon and 12 ± 7 × 1022 J heat in the region. The CMIP5 models, as a class, tend to underestimate the observation-based global anthropogenic carbon storage but simulate trends in global ocean heat storage over the last 50 years within uncertainties of observation-based estimates. CMIP5 models suggest global and Southern Ocean CO2 uptake have been largely unaffected by recent climate variability and change. Anthropogenic carbon and heat storage show a common broad-scale pattern of change, but ocean heat storage is more structured than ocean carbon storage. The results highlight the significance of the Southern Ocean for the global climate and as the region where models differ the most in representation of anthropogenic CO2 and, in particular, heat uptake."
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #484 on: February 02, 2015, 05:09:34 PM »
As a follow-up to my last post (Reply #483), it is important to note that trends in insolation related Antarctic sea ice (and it is not clear to me that Steven's extension of Tamino's work correctly captures the timing differences between when the sea ice is present and when the solar irradiance is occurring) is only one transient consideration.  Other considerations include: (a) the influence of polar amplification on climate sensitivity (ie what ever difference in Arctic vs Antarctic sea ice insolation trends that there is, polar amplification will make this difference about three times more important to mean global warming); (b) the influence of CO₂ venting on the net amount of CO₂ absorbed by the Southern Ocean and (c) the recent, and likely to continue, slow-down of Antarctic Bottom Water, AABW, production which will likely slow the future rate of heat absorption by the ocean.

In this regards, the first linked reference (with a free pdf by Armour et al 2014), indicates that heat input directly into the high latitudes, is about three times more effective at promoting mean global temperature rise, than an equal heat input into the tropics.  This polar amplification emphasizes the importance of the Southern Ocean venting (see the second linked reference by Quere et al 2007) CO₂ directly into the high latitude Southern Atmosphere, as well as the reduce OHU in the Southern Ocean due to the slow-down in the AABW production rate:

Rose, B. E. J., K. C. Armour, D. S., Battisti, N. Feldl, and D. D. B. Koll, (2014)," The dependence of transient climate sensitivity and radiative feedbacks on the spatial pattern of ocean heat uptake", Geophys. Res. Lett., 41, doi:10.1002/2013GL058955.

http://web.mit.edu/karmour/www/Rose_etal_GRL2014.pdf

Abstract: "The effect of ocean heat uptake (OHU) on transient global warming is studied in a multimodel framework. Simple heat sinks are prescribed in shallow aquaplanet ocean mixed layers underlying atmospheric general circulation models independently and combined with CO2 forcing. Sinks are localized to either tropical or high latitudes, representing distinct modes of OHU found in coupled simulations. Tropical OHU produces modest cooling at all latitudes, offsetting only a fraction of CO2 warming. High latitude OHU produces three times more global mean cooling in a strongly polar-amplified pattern. Global sensitivities in each scenario are set primarily by large differences in local shortwave cloud feedbacks, robust across models. Differences in atmospheric energy transport set the pattern of temperature change.  Results imply that global and regional warming rates depend sensitively on regional ocean processes setting the OHU pattern, and that equilibrium climate sensitivity cannot be reliably estimated from transient observations."

The first attached image by Le Quere shows her original field data compared to the previously expected CO₂ absorption projections for the Southern Ocean (see the caption below).  The second image shows the increase in the wind velocities, primary due to the ozone hole.

Corinne Le Quéré, Christian Rödenbeck, Erik T. Buitenhuis, Thomas J. Conway, Ray Langenfelds, Antony Gomez, Casper Labuschagne, Michel Ramonet, Takakiyo Nakazawa, Nicolas Metzl, Nathan Gillett, Martin Heimann, (2007),"Saturation of the Southern Ocean CO₂ Sink Due to Recent Climate Change", Science, Vol. 316, no. 5832  pp. 1735-1738, DOI: 10.1126/science.1136188

http://www.cccma.ec.gc.ca/papers/ngillett/PDFS/1735.pdf

http://www.sciencemag.org/content/316/5832/1735

Abstract: "Based on observed atmospheric carbon dioxide (CO2) concentration and an inverse method, we estimate that the Southern Ocean sink of CO2 has weakened between 1981 and 2004 by 0.08 petagrams of carbon per year per decade relative to the trend expected from the large increase in atmospheric CO2. We attribute this weakening to the observed increase in Southern Ocean winds resulting from human activities, which is projected to continue in the future. Consequences include a reduction of the efficiency of the Southern Ocean sink of CO2 in the short term (about 25 years) and possibly a higher level of stabilization of atmospheric CO2 on a multicentury time scale."

Caption for the first image: " Le Quéré expected to see a steady increase in the amount of carbon dioxide absorbed by the Southern Ocean between 1981 and 2004 (blue line). Instead, weather station measurements (red line) suggested year-to-year variability, but no long-term increase over time. (Graph by Corrine Le Quéré, University of East Anglia.)"

See also the "Southern Ocean Venting of CO₂" thread:

http://forum.arctic-sea-ice.net/index.php/topic,888.0.html

Edit: The devil is in the detail and it is essential that models be improved to capture all such key Antarctic and global feedback mechanisms.
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Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #485 on: February 02, 2015, 09:51:40 PM »
The linked article emphasizes the importance/dominance of the Southern Ocean w.r.t. anthropogenic carbon and heat uptake; and as the following extract states this area is the region models differ the most.  Therefore, it is un-imaginable to me that anyone could think that such models do not need further improvement in order to provide projections that are sufficiently accurate (particularly in this Antarctic region) to match the serious risks associated with climate change.

Extract: "The results highlight the significance of the Southern Ocean for the global climate and as the region where models differ the most in representation of anthropogenic CO2 and, in particular, heat uptake."

Thomas L. Frölicher, Jorge L. Sarmiento, David J. Paynter, John P. Dunne, John P. Krasting, and Michael Winton, (2015) "Dominance of the Southern Ocean in Anthropogenic Carbon and Heat Uptake in CMIP5 Models", J. Climate, 28, 862–886, doi: http://dx.doi.org/10.1175/JCLI-D-14-00117.1

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-14-00117.1

Abstract: "The authors assess the uptake, transport, and storage of oceanic anthropogenic carbon and heat over the period 1861–2005 in a new set of coupled carbon–climate Earth system models conducted for the fifth phase of the Coupled Model Intercomparison Project (CMIP5), with a particular focus on the Southern Ocean. Simulations show that the Southern Ocean south of 30°S, occupying 30% of global surface ocean area, accounts for 43% ± 3% (42 ± 5 Pg C) of anthropogenic CO2 and 75% ± 22% (23 ± 9 × 1022 J) of heat uptake by the ocean over the historical period. Northward transport out of the Southern Ocean is vigorous, reducing the storage to 33 ± 6 Pg anthropogenic carbon and 12 ± 7 × 1022 J heat in the region. The CMIP5 models, as a class, tend to underestimate the observation-based global anthropogenic carbon storage but simulate trends in global ocean heat storage over the last 50 years within uncertainties of observation-based estimates. CMIP5 models suggest global and Southern Ocean CO2 uptake have been largely unaffected by recent climate variability and change. Anthropogenic carbon and heat storage show a common broad-scale pattern of change, but ocean heat storage is more structured than ocean carbon storage. The results highlight the significance of the Southern Ocean for the global climate and as the region where models differ the most in representation of anthropogenic CO2 and, in particular, heat uptake."

CMIP models underestiamte carbon uptake in the southern ocean, and estimates of heat content are found to be within range of observations (which seems to be at odds with Durack et al).  More Co2 in the oceans means less in the atmosphere so this study is good news for us, and bad news for the sea life in the southern ocean.
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Neven

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Re: Conservative Scientists & its Consequences
« Reply #486 on: February 02, 2015, 10:29:35 PM »
More Co2 in the oceans means less in the atmosphere so this study is good news for us, and bad news for the sea life in the southern ocean.

Which means bad news for us.
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #487 on: February 02, 2015, 10:40:11 PM »
CMIP models underestiamte carbon uptake in the southern ocean, and estimates of heat content are found to be within range of observations (which seems to be at odds with Durack et al).  More Co2 in the oceans means less in the atmosphere so this study is good news for us, and bad news for the sea life in the southern ocean.

There is an old joke that goes like: "A man comes across a group of scientists looking around on the ground beneath a street lamp on a dark night, and he asks what are you doing; can I help?  They reply that they lost their car keys and they are looking for them.  After a few minutes of helping them look around he asks where they lost the keys, and they point off in the distance away from the lamp.  So the man asks: "If you lost your keys over there, why are you looking over here?"  To which the scientists replied that they are looking here because the light is so much better beneath the lamp."

Saying that society is safer because: (a) Antarctic sea ice extent is temporarily trending upwards; and/or (b) the Southern Ocean is temporarily absorbing more CO2 and heat content; is pure and simply poor risk management, just as when Faust bargained with the Devil to live in paradise for a day in exchange for living in hell for the rest of eternity.  If higher CO2 absorption in the Southern Ocean now leads to an earlier loss of plankton in the future, we are trading a lower transient climate sensitivity today for a higher equilibrium climate sensitivity, ECS, in a few more decades (and the same said about warmer AABW taking some heat out of the atmosphere today but slowing down the ocean currents so that less heat is taken out of the atmosphere in a few decades time).

With a hat-tip to deep octopus, in the linked article (and associated image) at Skeptical Science Cowtan explains that there is a high degree of uncertainty about what is the actual temperature in the high latitudes of the Southern Hemisphere.  While some denialist would say that such uncertainty means that society should take no action and should just continue on an BAU pathway because it is the easiest path forward, much as the group of scientists under the lamp would prefer to continue looking under the lamp because it is convenient.  In reality we need to be looking into the darker future conditions in the Antarctic region rather than the partially lighted past (note we do not even know the true current temperatures in Antarctica), in order to find our lost keys to a safe future free from accelerating ECS values.

http://www.skepticalscience.com/cowtan_way_2014_roundup.html#.VM-dcnpKWwI.twitter
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Steven

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Re: Conservative Scientists & its Consequences
« Reply #488 on: February 02, 2015, 11:52:27 PM »
... it is not clear to me that Steven's extension of Tamino's work correctly captures the timing differences between when the sea ice is present and when the solar irradiance is occurring

The method does this correctly.  In my calculation, the daily sea ice area data are weighted in such a way that their weight (i.e., their relative importance) has a peak at the summer solstice (21 December in the SH), and gradually decreases away from that date.  The data for the dark winter months play a negligible role.

Here is an image showing my graph (left) next to Tamino's graph (right).  Note that the blue curves in these two graphs, and the locations of their peaks and troughs, are almost identical.  (Tamino's blue curve ends in 2011 and mine in 2014).  My values are systematically slightly higher than Tamino's, but that doesn't matter much, because only the trends are important.

For the period 1979-2011 (ignoring the 2012-2014 data), my calculated linear trends show a decrease in sea ice insolation of 331 TW for the Arctic, and an increase of 47 TW for the Antarctic, over these 32 years.  This is in good agreement with Tamino's values for that period, which are 329 TW and 53 TW for the Arctic and Antarctic respectively.
« Last Edit: February 03, 2015, 11:50:15 PM by Steven »

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #489 on: February 03, 2015, 12:10:55 AM »
Steven,

Thanks for the clarification.

Best,
ASLR
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #490 on: February 03, 2015, 02:21:40 AM »
I would like to note that a significant amount of effort is currently being put into up-grading Earth System Models, ESMs, including the following work using the CESM to disentangle the signal between model error and internal climate variability:

Title: "The Community Earth System Model (CESM) Large Ensemble Project: A Community
Resource for Studying Climate Change in the Presence of Internal Climate Variability"

http://cires.colorado.edu/science/groups/kay/Publications/papers/BAMS-D-13-00255_submit.pdf

Extract: "While internal climate variability is known to affect climate projections, its influence is often underappreciated and confused with model error. Why? In general, modeling centers  contribute a small number of realizations to international climate model assessments (e.g.,
Coupled Model Intercomparison Project 5 (CMIP5)).  As a result, model error and internal   climate variability are difficult, and at times impossible, to disentangle.

…..

 Internal climate variability alone can produce projection spread comparable to that in
CMIP5.  Scientists and stakeholders can use CESMWLE outputs to help interpret the observational record, to understand projection spread, and to plan for a range of possible futures influenced by both internal climate variability and forced climate change."


Edit: The following provides a more complete citation:

J. E. Kay, C. Deser, A. Phillips, A. Mai, C. Hannay, G. Strand, J. M. Arblaster, S. C. Bates, G. Danabasoglu, J. Edwards, M. Holland, P. Kushner, J.-F. Lamarque, D. Lawrence, K. Lindsay, A. Middleton, E. Munoz, R. Neale, K. Oleson, L. Polvani, M. Vertenstein, (2014), "The Community Earth System Model (CESM) Large Ensemble Project: A Community Resource for Studying Climate Change in the Presence of Internal Climate Variability", Bulletin of the American Meteorological Society; doi: http://dx.doi.org/10.1175/BAMS-D-13-00255.1


http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-13-00255.1

Abstract: "While internal climate variability is known to affect climate projections, its influence is often underappreciated and confused with model error. Why? In general, modeling centers contribute a small number of realizations to international climate model assessments (e.g., Coupled Model Intercomparison Project 5 (CMIP5)). As a result, model error and internal climate variability are difficult, and at times impossible, to disentangle. In response, the Community Earth System Model (CESM) community designed the CESM Large Ensemble (CESM-LE) with the explicit goal of enabling assessment of climate change in the presence of internal climate variability. All CESM-LE simulations use a single CMIP5 model (CESM with the Community Atmosphere Model version 5). The core simulations replay the 20–21st century (1920–2100) 30 times under historical and Representative Concentration Pathway 8.5 external forcing with small initial condition differences. Two companion 1000+-year long pre-industrial control simulations (fully coupled, prognostic atmosphere and land only) allow assessment of internal climate variability in the absence of climate change. Comprehensive outputs, including many daily fields, are available as single-variable time series on the Earth System Grid for anyone to use. Early results demonstrate the substantial influence of internal climate variability on 20th–21st century climate trajectories. Global warming hiatus decades occur, similar to those recently observed. Internal climate variability alone can produce projection spread comparable to that in CMIP5. Scientists and stakeholders can use CESM-LE outputs to help interpret the observational record, to understand projection spread, and to plan for a range of possible futures influenced by both internal climate variability and forced climate change."
« Last Edit: February 03, 2015, 11:51:34 PM by AbruptSLR »
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sidd

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Re: Conservative Scientists & its Consequences
« Reply #491 on: February 03, 2015, 04:18:07 AM »
"the daily sea ice area data are weighted in such a way that their weight (i.e., their relative importance) has a peak at the summer solstice (21 December in the SH), and gradually decreases away from that date."

Is there latitude dependence in the weighting ? ie, a patch of sea ine at 50 S is not illuminated the same as one at 67S

sidd

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #492 on: February 03, 2015, 04:41:30 PM »
While I know less about sea ice than many of the experts on this forum, and while I think that focusing on Antarctic sea ice extend trends is a distraction from more important issues, nevertheless, as sidd raised the question of correcting isolation data for latitude, I will point-out that there are a lot of other potential corrections for the influence of Antarctic sea ice extent on mean global surface temperature warming (or alternately error bars should be added to the plots reflecting the lack of adjustments), including:

1. Corrections for sea ice concentration vs sea ice extent
2. Corrections for the albedo of melt ponds and wave inundation of the sea ice (not to mention the difference in albedo of ice vs snow covered ice).
3. Corrections for the influence of clouds on both insolation and on outgoing longwave radiation, OLR, including: (a) variable cloud cover, (b) variable cloud height and type, (c) variable cloud density and ice content, etc.
4. Corrections to the data to account for natural multi-decadal oscillations in Antarctic sea ice extent.
5.  Corrections for variations in atmospheric specific humidity.

Furthermore, if the Cowtan & Way regional surface temperature data for the high latitudes of the Southern Hemisphere cited in Reply #487 are correct then the Antarctic surface temperatures were significantly higher in 2010, 2013 and 2014 than official agencies reported measuring.  Thus if someone wants to discuss how important the increase in insolation due to the recent (short-term) transient trend in Antarctic sea ice to offsetting all of the other deficiencies of the AR5 GCM projections, then they should also parse out the differences of surface heating from teleconnection of energy from other regions (like the tropical Pacific/Indian/Atlantic Oceans) in order to provide a meaningful discussion.

To paraphrase an old say: "A broken clock (or AR5 model) is right twice a day", and while some may say that the use of such incomplete AR5 model projections should be good enough for the masses, I believe that we should focus on trying to create new state-of-the-art Earth Systems Models linked to Big Data modules in order to get a much more accurate idea of the climate change risks that society is facing.
« Last Edit: February 04, 2015, 12:24:12 AM by AbruptSLR »
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #493 on: February 03, 2015, 06:27:56 PM »
The linked reference indicates that when evaluating the range of plausible warming rates (ie plausible ranges of climate sensitivity) it is critical to include a proper evaluation of the nonlinear regional warming distributions.  That is to say that if strong regional superlinear warming drives nonlinear positive feedback mechanisms, consideration of this phenomena will result in higher estimates of climate sensitivity than currently estimated by AR5:

Peter Good, Jason A. Lowe, Timothy Andrews, Andrew Wiltshire, Robin Chadwick, Jeff K. Ridley, Matthew B. Menary, Nathaelle Bouttes, Jean Louis Dufresne, Jonathan M. Gregory, Nathalie Schaller & Hideo Shiogama (2015), "Nonlinear regional warming with increasing CO2 concentrations", Nature Climate Change, Volume: 5, Pages: 138–142, doi:10.1038/nclimate2498

http://www.nature.com/nclimate/journal/v5/n2/full/nclimate2498.html

Abstract: "When considering adaptation measures and global climate mitigation goals, stakeholders need regional-scale climate projections, including the range of plausible warming rates. To assist these stakeholders, it is important to understand whether some locations may see disproportionately high or low warming from additional forcing above targets such as 2 K. There is a need to narrow uncertainty in this nonlinear warming, which requires understanding how climate changes as forcings increase from medium to high levels. However, quantifying and understanding regional nonlinear processes is challenging. Here we show that regional-scale warming can be strongly superlinear to successive CO2 doublings, using five different climate models. Ensemble-mean warming is superlinear over most land locations. Further, the inter-model spread tends to be amplified at higher forcing levels, as nonlinearities grow—especially when considering changes per kelvin of global warming. Regional nonlinearities in surface warming arise from nonlinearities in global-mean radiative balance, the Atlantic meridional overturning circulation, surface snow/ice cover and evapotranspiration. For robust adaptation and mitigation advice, therefore, potentially avoidable climate change (the difference between business-as-usual and mitigation scenarios) and unavoidable climate change (change under strong mitigation scenarios) may need different analysis methods."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #494 on: February 03, 2015, 11:59:03 PM »
The linked research indicates that thermodynamics (warming and near-surface stability) control 21st century Southern Ocean shortwave climate feedbacks.  Besides illustrating how challenging it is to correctly model the Antarctic region, this research indicates to me that if the telecommunication of Pacific Tropical energy to the West Antarctic occurs (as many models project), then the West Antarctic could be subject to more positive feedback (warming) in the 21st century than previous assumed in the AR5 models.

Kay, J. E., B. Medeiros, Y.-T. Hwang, A. Gettelman, J. Perket, and M. G. Flanner (2014), Processes controlling Southern Ocean shortwave climate feedbacks in CESM, Geophys. Res. Lett., 41, 616–622, doi:10.1002/2013GL058315.

http://onlinelibrary.wiley.com/doi/10.1002/2013GL058315/abstract

Abstract: "A climate model (Community Earth System Model with the Community Atmosphere Model version 5 (CESM-CAM5)) is used to identify processes controlling Southern Ocean (30–70°S) absorbed shortwave radiation (ASR). In response to 21st century Representative Concentration Pathway 8.5 forcing, both sea ice loss (2.6 W m−2) and cloud changes (1.2 W m−2) enhance ASR, but their relative importance depends on location and season. Poleward of ~55°S, surface albedo reductions and increased cloud liquid water content (LWC) have competing effects on ASR changes. Equatorward of ~55°S, decreased LWC enhances ASR. The 21st century cloud LWC changes result from warming and near-surface stability changes but appear unrelated to a small (1°) poleward shift in the eddy-driven jet. In fact, the 21st century ASR changes are 5 times greater than ASR changes resulting from large (5°) naturally occurring jet latitude variability. More broadly, these results suggest that thermodynamics (warming and near-surface stability), not poleward jet shifts, control 21st century Southern Ocean shortwave climate feedbacks."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #495 on: February 04, 2015, 12:19:06 AM »
More Co2 in the oceans means less in the atmosphere so this study is good news for us, and bad news for the sea life in the southern ocean.

Which means bad news for us.

So do you think the bad news for fish = bad news for us factor is going to outweigh the less Co2 in atmosphere = good news for us?
Climate change:  Prepare for the worst, hope for the best, expect the middle.

Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #496 on: February 04, 2015, 12:22:25 AM »
To paraphrase an old say: "A broken clock (or AR5 model) is right twice a day", and while some may say that the use of such incomplete AR5 model projections should be good enough for the masses, I believe that we should focus on trying to create new state-of-the-art Earth Systems Models linked to Big Data modules in order to get a much more accurate idea of the climate change risks that society is facing.

Deniers have told me exactly the same thing as  an excuse to ignore what the model projections show.  We do of course want to improve the models as much as we can.  Model projections that were made on frightfully primitive basis compared to what we had in the early 80s have proved reasonably accurate - if not perfect.  All the advances we have made in modelling from this time to now have not made any significant change to climate projections.  Perhaps the next factor that they add in will make a big difference where all the other factors added to date have not.  Perhaps that will make things worse, or perhaps it will make things better.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

Neven

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Re: Conservative Scientists & its Consequences
« Reply #497 on: February 04, 2015, 12:26:44 AM »
So do you think the bad news for fish = bad news for us factor is going to outweigh the less Co2 in atmosphere = good news for us?

I agree that dying from gangrene takes longer than dying directly from a fatal wound.  ;D

In other words, in the short term the bad news will not outweigh the good news, but in the end the effect will be the same. Because, you see, everything is connected. If something is bad for sea life, it will eventually be bad for us (human civilisation) too.
Il faut comparer, comparer, comparer, et cultiver notre jardin

Michael Hauber

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Re: Conservative Scientists & its Consequences
« Reply #498 on: February 04, 2015, 12:36:38 AM »
The linked research indicates that thermodynamics (warming and near-surface stability) control 21st century Southern Ocean shortwave climate feedbacks.  Besides illustrating how challenging it is to correctly model the Antarctic region, this research indicates to me that if the telecommunication of Pacific Tropical energy to the West Antarctic occurs (as many models project), then the West Antarctic could be subject to more positive feedback (warming) in the 21st century than previous assumed in the AR5 models.


Many models are projecting something to occur which would mean more feedbacks than the models used in AR5.  Do you realise that the model used in the research you refer to is one of the models used in CMIP5?
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AbruptSLR

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Re: Conservative Scientists & its Consequences
« Reply #499 on: February 04, 2015, 01:21:17 AM »
There are many different versions/generations of Earth Systems Models.  Thus saying that an earlier version of the Community Earth System Model, was included in CMIP5 does not mean that we have the final answer in hand from AR5.  Indeed, the ACME project lead by the DOE (and which will not be complete for another 10 years) is based on (started from) the Community Earth System Model, but will be further developed for the DOE mission and computers.

I am hoping that ACME will provide sufficient guidance to allow decision makers to make reasonably well informed decisions.  Until then (& even after then) we will need to make the best decisions that we can with the information that we have; understanding that decision makers with a high tolerance for risk will push the envelope perhaps further than what is good for the global community/environment.
« Last Edit: February 04, 2015, 01:26:37 AM by AbruptSLR »
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson