2011-01-14 23:25:42Monckton Myth #6: Global Sea Ice
James Wight

jameswight@southernphone.com...
112.213.154.212

This is the original version. See below for the current revision.

[I will add an opening paragraph depending on the framing of the preceding “Monckton Myths” posts.]

Monckton claims:

“[T]he global sea ice record shows virtually no change throughout the past 30 years, because the quite rapid loss of Arctic sea ice since the satellites were watching has been matched by a near-equally rapid gain of Antarctic sea ice.”

Have Arctic ice losses truly been balanced by Antarctic gains? The first point to clarify is that we are talking about floating sea ice, not to be confused with land ice. Land ice at both poles and in glaciers around the world is sliding into the ocean at an accelerating rate. This net loss of land ice is contributing to sea level rise.

However, Monckton is clearly referring to sea ice. The rapid decline of Arctic sea ice has indeed coincided with an increase in Antarctic sea ice. But do these two opposite trends cancel out as Monckton suggests? In reality, the upward Antarctic trend is only slight compared to the plummeting Arctic trend:

 

Figure 1: Sea ice extent anomalies and trends since 1979 in the Arctic and Antarctic. (Source: US National Snow and Ice Data Center.)

Monckton continues:

“Indeed, when the summer extent of Arctic sea ice reached its lowest point in the 30-year record in mid-September 2007, just three weeks later the Antarctic sea [sic] extent reached a 30-year record high. The record low was widely reported; the corresponding record high was almost entirely unreported.”

Here Monckton is comparing the Arctic summer to the Antarctic winter, not the most appropriate comparison because summer is the most important time of year for sea ice. Sea ice grows and shrinks seasonally, with an Arctic minimum in September and an Antarctic minimum in February. When ice melts, it makes the surface less reflective and amplifies the warming (as is currently occurring in the Arctic). Such changes in reflectivity make the greatest difference in summer because that is when the surface receives the most heat from the Sun.

So how does the Antarctic minimum compare? See for yourself:

 

Figure 2: Minimum sea ice extent since 1979 in the Arctic and Antarctic. (Image source: James Hansen. Data is from US National Snow and Ice Data Center.)

While the summer Arctic has lost an extent equivalent to the area of Western Australia, the summer Antarctic growth is only about the size of Victoria. Even that slight upward trend is less than the year-to-year variability. Although 2003 and 2008 tied for the highest February extent, 2006 was third lowest. Again, the real world contradicts Monckton’s assertion that changes in the Arctic are being balanced out by the Antarctic.

Furthermore, Monckton fails to mention that Arctic sea ice is not only shrinking in extent but also has been thinning rapidly. Although its lowest extent was in 2007, its volume has continued declining since then, hitting another record low in 2010:

 

Figure 3: Arctic sea ice volume anomalies since 1979. (Source: University of Washington Polar Science Center.)

As thinner ice is easier to melt, the rapid Arctic melt is set to continue; ice-free summers are now probably inevitable. In contrast, the Antarctic increase is occurring despite the warming of the Southern Ocean and is expected to reverse as the warming continues. Antarctic sea ice is just a distraction from the looming specter of an ice-free Arctic.
2011-01-14 23:35:33Notes
James Wight

jameswight@southernphone.com...
112.213.154.212

I’ve just thrown the above rebuttal together this evening. I hope it will suffice.

I haven’t bothered with the graph of global sea ice area as Monckton is clearly talking about extent and I think the Arctic vs Antarctic graphs are visually better anyway.

Also, I’ve found an alternative graph of Arctic sea ice volume, by somebody on Wikipedia, combining the numbers from the two Polar Science Center graphs. Do we have a problem with referencing Wikipedia? If not I suggest we use this one because it is more graphic:


2011-01-15 03:01:52
MarkR
Mark Richardson
m.t.richardson2@gmail...
192.171.166.144

Umm... your first graph is standardised anomalies. If Antarctica has larger standard deviation, then he can claim to be correct. Total sea ice area might have no trend. When you say;

"Again, the real world contradicts Monckton’s assertion that changes in the Arctic are being balanced out by the Antarctic."

you're painting an easy target for Monckton in this case. The reality is more nuanced.

You go in the right direction by saying that summer ice is the most important, but I think you could do with more explanation of this. Bring in the importance of polar amplification in Arctic sea decline and how summer extent is the most important because it actually has light shining on it.

 

Maybe bring up how Antarctic change isn't statistically significant, but Arctic is. And we have some good pages on Antarctic sea ice already...

2011-01-15 03:23:41standardized anomalies
dana1981
Dana Nuccitelli
dana1981@yahoo...
38.223.231.252

Hmm good point by Mark, that's an unfortunate choice of plotting convention by NSIDC.  This site shows extent in both hemispheres on the same graph in terms of millions of square km.  We may have to make a similar plot ourselves.

Good write-up though, James.  Good suggestions from Mark, and I'd also add that you should include the areas (in square km) when you mention Western Australia and Victoria.  Personally I have no idea how big Victoria is.

2011-01-15 05:32:46
Riccardo

riccardoreitano@tiscali...
93.147.82.111
I'd drop the discussion on volume. Alternatively you need to compare the two volumes; add that Antarctic sea ice is seasonal and hence thin.
2011-01-15 07:42:06Comment
Robert Way

robert_way19@hotmail...
134.153.163.105
tamino addressed this topic on his blog directly today or yesterday.
2011-01-15 09:57:14Tamino
dana1981
Dana Nuccitelli
dana1981@yahoo...
38.223.231.252

Yes, Tamino has a nice plot of global sea ice extent.  I asked if we could borrow it for this rebuttal.

I like the discussion about volume, but Riccardo has a point that without Antarctic ice volume, it's rather unbalanced.

2011-01-15 18:58:45Version 2
James Wight

jameswight@southernphone.com...
112.213.154.212

Mark and Dana, good point about the standardised anomalies. I’ve substituted Tamino’s graph of global sea ice and linked to his post.

Mark, I have tried to clarify the part about polar daylight etc.

Dana, I have quantified the minimum extent trends as you suggested.

Riccardo, I looked for info on Antarctic sea ice volume, but the only thing I could find was Zhang 2007. That paper only went up to 2004 and found an increase of 5,000 km3 (from about 18,000 to 23,000 km3) – pretty insubstantial compared to the Arctic. However it’s not clear to me whether this volume is for summer or winter (admittedly I didn’t read the whole paper). Can anyone explain this to me? And if anyone knows of updated Antarctic volume data can you please point me in the right direction?


[I will add an opening paragraph depending on the framing of the preceding “Monckton Myths” posts.]

Monckton claims:

“[T]he global sea ice record shows virtually no change throughout the past 30 years, because the quite rapid loss of Arctic sea ice since the satellites were watching has been matched by a near-equally rapid gain of Antarctic sea ice.”

Have Arctic ice losses truly been balanced by Antarctic gains? The first point to clarify is that we are talking about floating sea ice, not to be confused with land ice. Land ice at both poles and in glaciers around the world is sliding into the ocean at an accelerating rate. This net loss of land ice is contributing to sea level rise.

However, Monckton is clearly referring to sea ice. The rapid decline of Arctic sea ice has indeed coincided with an increase in Antarctic sea ice. But do these two opposite trends cancel out as Monckton suggests? In reality, the upward Antarctic trend is only slight compared to the plummeting Arctic trend. Tamino has crunched the numbers and found the Arctic trend is in fact more than three times faster than the Antarctic one. The net result is a global decrease in sea ice:

 

Figure 1: Global sea ice extent since 1979. (Image source: Tamino. Data is from US National Snow and Ice Data Center.)

Monckton continues:

“Indeed, when the summer extent of Arctic sea ice reached its lowest point in the 30-year record in mid-September 2007, just three weeks later the Antarctic sea [sic] extent reached a 30-year record high. The record low was widely reported; the corresponding record high was almost entirely unreported.”

Here Monckton is comparing the Arctic summer to the Antarctic winter, not the most appropriate comparison. Sea ice grows and shrinks seasonally because polar latitudes have vastly more daylight hours in summer than in winter. When ice melts, it makes the surface less reflective and amplifies the warming (as is currently occurring in the Arctic), but this effect can only make a difference when the Sun is up. Thus the most important time of year for sea ice is its annual minimum which occurs at the end of the summer: September in the Arctic but February in the Antarctic.

So how do the two compare?

 

Figure 2: Minimum sea ice extent since 1979 in the Arctic and Antarctic. (Image source: James Hansen. Data is from US National Snow and Ice Data Center.)

While the summer Arctic has lost an extent of about 2.5 million km2 (equivalent to the area of Western Australia), the summer Antarctic growth is only 0.3 million km2 (about the size of Victoria). Even that slight upward trend is less than the year-to-year variability; although 2003 and 2008 tied for the highest February extent, 2006 was third lowest. Again, the real world contradicts Monckton’s assertion that changes in the Arctic are being balanced out by the Antarctic.

Furthermore, Monckton fails to mention that Arctic sea ice is not only shrinking in extent but also has been thinning rapidly. Although its lowest extent was in 2007, its volume has continued declining since then, hitting another record low in 2010:

 

Figure 3: Arctic sea ice volume anomalies since 1979. (Source: University of Washington Polar Science Center.)

As thinner ice is easier to melt, the rapid Arctic melt is set to continue; ice-free summers are now probably inevitable. In contrast, the Antarctic increase is occurring despite the warming of the Southern Ocean and is expected to reverse as the warming continues. Antarctic sea ice is just a distraction from the looming specter of an ice-free Arctic.

2011-01-15 19:03:00
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.84.43
"The net result is a global increase in sea ice:" - should be "decrease"
2011-01-15 19:06:00Whoops!
James Wight

jameswight@southernphone.com...
112.213.154.212
Glad you noticed that! I've corrected it now.
2011-01-15 19:13:12
Rob Painting
Rob
paintingskeri@vodafone.co...
118.92.84.43
Being a Kiwi I have a fair idea how big the state of Victoria is, but it won't be immediately obvious to most readers. Can't help with the Antarctic sea ice volume, but even if you can't locate figures, still think the volume discussion should be included, unbalanced or not. Looks good to me.
2011-01-15 23:52:45
Riccardo

riccardoreitano@tiscali...
93.147.82.81
I don't know about recent data on Antarctic sea ice volume but, for your purpose, Zhang 2007 will suffice. At least you may say that Antarctic sea ice is thinner than its Arctic counterpart and then an increase in extent has a smaller impact on total volume.
2011-01-16 01:10:58How do I get useable graphs from a PDF?
James Wight

jameswight@southernphone.com...
112.213.154.212
John, how did you get the Zhang 2007 figures for the "southern sea ice" rebuttal?
2011-01-16 03:55:12nice update
dana1981
Dana Nuccitelli
dana1981@yahoo...
71.140.0.210
This is looking good.  I would also add after "The net result is a global decrease in sea ice:" that the net decrease is approximately 1 million square km, plus adding a brief discussion of Zhang '07.
2011-01-16 04:58:58Response to James
Robert Way

robert_way19@hotmail...
142.162.207.106
There's a snapshot feature in adobe. right click on the grey bar to get a tool bar and find it.
2011-01-16 05:16:55PDFs
dana1981
Dana Nuccitelli
dana1981@yahoo...
71.140.0.210
Yes, if you want to take a figure from a PDF, you can use the snapshot tool, but it's difficult to get that into a useful format like jpeg (I used to use the snapshot tool, the copy into Word, then save the image as jpeg).   There's some good software that can accomplish this by taking screenshots though, both easier and better quality.  I recently started using Jing, which works great.
2011-01-16 13:48:28How is this?
James Wight

jameswight@southernphone.com...
112.213.154.212
2011-01-16 13:50:56Hmmm, that didn't work
James Wight

jameswight@southernphone.com...
112.213.154.212
I tried using the snapshot tool and saved it as a JPEG, but for some reason I couldn't get it to upload to SkS. Then I tried saving it as an Enhanced Windows Metafile and uploaded that to SkS, but for some reason it's displaying as above.
2011-01-16 13:53:24Okay, here is the JPEG version
James Wight

jameswight@southernphone.com...
112.213.154.212

I renamed the file and this time it uploaded properly.

2011-01-19 10:05:18#6
dana1981
Dana Nuccitelli
dana1981@yahoo...
38.223.231.252

So James, I think this will be "Monckton Myth #6: Global Sea Ice", or some similar sub-title.  John just went live with #4, I'll probably do #5 tomorrow, and maybe the next day we can do this one as #6?

The other question is whether we should look at the snow cover myth, or just skip over that one.

2011-01-19 17:24:17Something to consider
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

NSIDC

Caption:  These images show the change in ice age from spring 2010 to fall 2010. The negative phase of the Arctic Oscillation this winter slowed the export of older ice out of the Arctic in the winter, but a large amount of older ice melted out during the summer.  [Source is: http://nsidc.org/arcticseaicenews/2010/100410.html]

The above image might help reinforce the point about the loss of ice volume.  Some might balk at the PIOMAS data because it is from model output (I disagree) but the above figure covers that.

You should also mention that the increase in Antarctic sea ice area in August and September is not statistically significant, whereas the decrease in Arctic sea ice for those months is.  Please see my post for details:

 http://skepticalscience.com/news.php?p=2&t=103&&n=473#32519 

 

A poster SRJ also posted some valuable stats, and found that the increase in SH sea ice for all months is stat. sig.:

 http://skepticalscience.com/news.php?p=1&t=103&&n=473#32340

 

SRJ also found that the decrease in global sea ice is stat. sig.:

 http://skepticalscience.com/news.php?p=3&t=103&&n=473#33336

 [the second value (-0.0367) is for extent not area]

2011-01-19 17:35:12SRJ
John Cook

john@skepticalscience...
121.222.100.112
That's some great comments posted by SRJ. I've just sent him an email, inviting him to join us on the forum if he's interested.
2011-01-20 01:19:09Hopefully final version
James Wight

jameswight@southernphone.com...
112.213.154.212

I have changed Figure 3 to the Wikipedia graph of Arctic sea ice volume because I think it is more visual than the Polar Science Center one I used in the original draft. John, if you don’t want to reference Wikipedia then just substitute the Polar Science Center graph.

I have also added the Antarctic sea ice volume graph from Zhang 2007 and the multiyear ice graph suggested by Albatross, added section titles, and made some other minor changes.

I haven't included Albatross's info about area trends because Monckton was talking about sea ice extent, not area.


Monckton Myth #6: Global Sea Ice

As part of an ongoing series looking at Christopher Monckton’s response to Mike Steketee, this post examines Monckton’s arguments about global sea ice. Monckton claims:

“[T]he global sea ice record shows virtually no change throughout the past 30 years, because the quite rapid loss of Arctic sea ice since the satellites were watching has been matched by a near-equally rapid gain of Antarctic sea ice.”

Global Sea Ice Is Decreasing

Have Arctic ice losses truly been balanced by Antarctic gains? The first point to clarify is that we are talking about floating sea ice, not to be confused with land ice. Land ice at both poles and in glaciers around the world is sliding into the ocean at an accelerating rate. This net loss of land ice is contributing to sea level rise.

However, Monckton is clearly referring to sea ice. The rapid decline of Arctic sea ice has indeed coincided with an increase in Antarctic sea ice. But do these two opposite trends cancel out as Monckton suggests? In reality, the upward Antarctic trend is only slight compared to the plummeting Arctic trend. Tamino has crunched the numbers and found the Arctic trend is in fact more than three times faster than the Antarctic one. The net result is a global sea ice decrease of more than a million km2 – would you agree with Monckton that this is “virtually no change”?

 

Figure 1: Global sea ice extent since 1979. (Image source: Tamino. Data is from US National Snow and Ice Data Center.)

Summer and Winter, Apples and Oranges

Monckton continues:

“Indeed, when the summer extent of Arctic sea ice reached its lowest point in the 30-year record in mid-September 2007, just three weeks later the Antarctic sea [sic] extent reached a 30-year record high. The record low was widely reported; the corresponding record high was almost entirely unreported.”

Here Monckton is comparing the Arctic summer to the Antarctic winter, not the most appropriate comparison. Sea ice grows and shrinks seasonally because polar latitudes have vastly more daylight hours in summer than in winter. When ice melts, it makes the surface less reflective and amplifies the warming (as is currently occurring in the Arctic), but this effect can only make a difference when the Sun is up. Thus the most important time of year for sea ice is its annual minimum which occurs at the end of the summer: September in the Arctic but February in the Antarctic.

So how do the two compare?

 

Figure 2: Minimum sea ice extent since 1979 in the Arctic and Antarctic. (Image source: James Hansen. Data is from US National Snow and Ice Data Center.)

While the summer Arctic has lost an extent of about 2.5 million km2 (equivalent to the area of Western Australia), the summer Antarctic growth is only 0.3 million km2 (about the size of Victoria). Even that slight upward trend is less than the year-to-year variability; although 2003 and 2008 tied for the highest February extent, 2006 was third lowest. Again, the real world contradicts Monckton’s assertion that changes in the Arctic are being balanced out by the Antarctic.

The Third Dimension

Furthermore, Monckton fails to mention that Arctic sea ice is not only shrinking in extent but also has been thinning rapidly. Although its lowest extent was in 2007, its volume has continued declining since then, hitting another record low in 2010:

Figure 3: Arctic sea ice volume since 1979. (Image source: Wikipedia. Based on data from University of Washington Polar Science Center.)

The volume data is supported by a sharp decline in thick multiyear ice in recent years:

 

Figure 4: September Arctic sea ice age since 1981. (Source: US National Snow and Ice Data Center.)

Meanwhile there has been an upward trend in Antarctic sea ice volume, but it’s not nearly as impressive:

 

Figure 5: Antarctic sea ice volume from 1979 to 2004. (Source: Zhang 2007.)

The Polar Prognosis

As thinner and younger ice is easier to melt, the rapid Arctic melt is set to continue; ice-free summers are now probably inevitable. In contrast, the Antarctic increase is occurring despite the warming of the Southern Ocean and is expected to reverse as the warming continues. Antarctic sea ice is just a distraction from the looming specter of an ice-free Arctic.

2011-01-20 03:40:44Antarctic volume notes
dana1981
Dana Nuccitelli
dana1981@yahoo...
38.223.231.252
It's probably worth adding that essentially all of the increase in Antarctic sea ice volume came during a spike in 1983-1987, and it didn't increase in the following 17 years.  I'd also specify that the increase is about 5,000 km2, which is about half of the ice volume loss in the Arctic.  "Not as impressive" is rather vague.
2011-01-20 04:40:40More comments
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

Hi James,

The post is looking good.  Just remembered that my post from last night did not have a salutation-- sorry, it was late and my brain stops working after 10 pm ;)

SRJ did calculate some  stats for the trends in both area and extent (http://skepticalscience.com/news.php?p=3&t=103&&n=473#33336).  The results for extent are similar to those for area. 

I have just looked at the numbers for S. Hemisphere extent in September.  The increase in September Antarctic sea-ice extent is  statistically significant at the 95% confidence level (p=0.037)--  S. Hemi. sea ice area trend for September is marginally statistically significant at the 90% level (p =0.117). More importantly, in terms of the albedo effect, is that the trend in S. Hemisphere sea-ice extent in February is not statistically significant, not even close (p= 0.173).  Additionally, the best fit for the N. Hemi. September sea-ice extent is a quadratic (Adjusted R2 = 0.744, p = 0.000), although linear is close (Adjusted R2 = 0.675, p = 0.000)

That all said, the decrease in global sea-ice extent (using all the data it seems) is statistically significant as shown by Tamino and by SRJ.  Sorry to harp on this, but that fact is, IMHO, very important and really nails Monckton.  Otherwise Monckton and his supporters could weasel and say “So what, maybe global ice extent is declining, but the data are noisy and the trend is not of statistical significance”, i.e.,  they could used the same “trick” with the rate of warming in the HadCRUT data. So it would be prudent to nip that one beforehand.

Regarding your excellent last sentence--which is key.  Might I offer a suggestion?  How about...

 "Antarctic sea ice is just a distraction from the looming specter of an ice-free Arctic, and the worrying (significant?) loss of ice from the west Antarctic and Greenland ice sheets."

Or something along those lines.  It is this ice loss that is probably going to be an important contributor to global sea-level in the coming decades and centuries.  As was stated by Robert Way a while ago here on SS:

"All the sea ice talk aside, it is quite clear that really when it comes to Antarctic ice, sea ice is not the most important thing to measure. In Antarctica, the most important ice mass is the land ice sitting on the West Antarctic Ice Sheet and the East Antarctic Ice Sheet. Estimates of recent changes in Antarctic land ice (Figure 2) range from losing 100 Gt/year to over 300 Gt/year. Because 360 Gt/year represents an annual sea level rise of 1 mm/year, recent estimates indicate a contribution of between 0.27 mm/year and 0.83 mm/year coming from Antarctica. There is of course uncertainty in the estimations methods but multiple different types of measurement techniques (explained here) all show the same thing, Antarctica is losing land ice as a whole, and these losses are accelerating quickly."

 

Regarding this statement (speaking to the Arctic multi-year ice):

"The volume data is supported by a sharp decline in thick multiyear ice in recent years"

Maybe best to quantify this.  For example, "Whereas over 60% of the Arctic basin was covered in thick, multi-year ice in the early eighties, that has now declined to less than 20% in recent years".  That is a huge decrease.

 A final note, sorry James (!). The Zhang 2007 figure has no x-axis label (should be 1979-2004).  I do not really like that graph (the post already has figures in may different formats, with some data having the seasonal signal removed and others not, and this is in a different format still)-- but agree that the message is important.  Also, are these modelled data or from observations?  I know that they can follow the link, but maybe briefly speak to the fact that they are modelled data.

All the best.

2011-01-21 00:54:28Hopefully finally final version
James Wight

jameswight@southernphone.com...
112.213.158.135

Albatross, I have tweaked the text to say the global sea ice trend is statistically significant, and quantified the multiyear ice decline as you suggested. I have also added a mention of the ice sheets in the final sentence but it still finishes with “the looming specter of a sea-ice-free Arctic” because I think that is a stronger ending.

The reason the Zhang 2007 graph has no x-axis is because it is part of a larger figure. I didn’t think of that problem. So here’s a compromise: I’ve taken out the graph (now you see it, now you don’t!) and instead I just link to Zhang 2007. I have tried to work in Dana’s point as well.

 


Monckton Myth #6: Global Sea Ice

As part of an ongoing series looking at Christopher Monckton’s response to Mike Steketee, this post examines Monckton’s arguments about global sea ice. Monckton claims:

“[T]he global sea ice record shows virtually no change throughout the past 30 years, because the quite rapid loss of Arctic sea ice since the satellites were watching has been matched by a near-equally rapid gain of Antarctic sea ice.”

Global Sea Ice Is Decreasing

Have Arctic ice losses truly been balanced by Antarctic gains? The first point to clarify is that we are talking about floating sea ice, not to be confused with land ice. Land ice at both poles and in glaciers around the world is sliding into the ocean at an accelerating rate. This net loss of land ice is contributing to sea level rise.

However, Monckton is clearly referring to sea ice. The rapid decline of Arctic sea ice has indeed coincided with an increase in Antarctic sea ice. But do these two opposite trends cancel out as Monckton suggests? In reality, the upward Antarctic trend is only slight compared to the plummeting Arctic trend. Tamino has crunched the numbers and found the Arctic trend is in fact more than three times faster than the Antarctic one. The net result is a statistically significant global decrease of more than a million km2 – would you agree with Monckton that this is “virtually no change”?

 

Figure 1: Global sea ice extent since 1979. (Image source: Tamino. Data is from US National Snow and Ice Data Center.)

Summer and Winter, Apples and Oranges

Monckton continues:

“Indeed, when the summer extent of Arctic sea ice reached its lowest point in the 30-year record in mid-September 2007, just three weeks later the Antarctic sea [sic] extent reached a 30-year record high. The record low was widely reported; the corresponding record high was almost entirely unreported.”

Here Monckton is comparing the Arctic summer to the Antarctic winter, not the most appropriate comparison. Sea ice grows and shrinks seasonally because polar latitudes have vastly more daylight hours in summer than in winter. When ice melts, it makes the surface less reflective and amplifies the warming (as is currently occurring in the Arctic), but this effect can only make a difference when the Sun is up. Thus the most important time of year for sea ice is its annual minimum which occurs at the end of the summer: September in the Arctic but February in the Antarctic.

So how do the two compare?

 

Figure 2: Minimum sea ice extent since 1979 in the Arctic and Antarctic. (Image source: James Hansen. Data is from US National Snow and Ice Data Center.)

While the summer Arctic has lost an extent of about 2.5 million km2 (equivalent to the area of Western Australia), the summer Antarctic growth is only 0.3 million km2 (about the size of Victoria). Even that slight upward trend is less than the year-to-year variability; although 2003 and 2008 tied for the highest February extent, 2006 was third lowest. Again, the real world contradicts Monckton’s assertion that changes in the Arctic are being balanced out by the Antarctic.

The Third Dimension

Furthermore, Monckton fails to mention that Arctic sea ice is not only shrinking in extent but also has been thinning rapidly. Although its lowest extent was in 2007, its volume has continued declining since then, hitting another record low in 2010:

 

Figure 3: Arctic sea ice volume since 1979. (Image source: Wikipedia. Based on data from University of Washington Polar Science Center.)

The volume data is supported by a sharp decline in thick multiyear ice, from around 60% of ice cover in the 1980s to just 15% in 2010:

 

Figure 4: September Arctic sea ice age since 1981. (Source: US National Snow and Ice Data Center.)

Meanwhile there has been a slight increase in Antarctic sea ice volume, but only by about 5,000 km3 and most of it in a few years at the start of the record.

The Polar Prognosis

As thinner and younger ice is easier to melt, the rapid Arctic melt is set to continue; ice-free summers are now probably inevitable. In contrast, the Antarctic increase is occurring despite the warming of the Southern Ocean and is expected to reverse as the warming continues. Antarctic sea ice is just a distraction from the accelerating losses from ice sheets and the looming specter of a sea-ice-free Arctic.

2011-01-21 03:35:24
Albatross
Julian Brimelow
stomatalaperture@gmail...
199.126.232.206

Hi James,

Looking good-- thanks for incorporating my suggestions. 

 

So now I'm assuming that all that needs to be done is for John to sign off on it?

2011-01-21 03:42:04yeah
dana1981
Dana Nuccitelli
dana1981@yahoo...
38.223.231.252
I just went live with Myth #5, so we'll probably go live with this one tomorrow.  I'm guessing John will handle that.
2011-01-22 15:05:33
James Wight

jameswight@southernphone.com...
112.213.158.135
Okay, the final version is here. I've set it to "published" but I think only John can go live with it.
2011-01-22 15:36:34published
dana1981
Dana Nuccitelli
dana1981@yahoo...
71.140.0.210
Actually setting it to 'published' makes it go live.