Guest Post by Willis Eschenbach
Inspired by this thread over at Bishop Hill’s excellent blog, I thought I’d write about sea ice. Among the many catastrophic things claimed to be the result of “global warming”, declining sea ice is one of the most popular. We see scary graphics of this all the time, things that look like this:
FIgure 1. Terrifying computer projections showing that we may not have any Arctic sea ice before the end of this century. Clearly, the implication is that we should be very concerned … SOURCE
Now, what’s wrong with this picture?
The problem with the picture is that the earth has two poles. And for reasons which are not well understood, when one pole warms, the other pole cools.
Looking at just the Arctic sea ice is like looking at someone who is pouring water from one glass to another and back again. If we want to see how much water there is, it is useless to observe just one of the person’s hands. We need to look at both hands to see what is happening with the water.
Similarly, to see what is happening in the frozen parts of the ocean, we need to look at global sea ice. There are several records of the area of sea ice. One is the Reynolds Optimally Interpolated dataset (Reynolds OI V2). A second is the National Snow and Ice Data Center (NSIDC) record. Finally, we have the Hadcrut Ice and Sea Surface Temperature dataset (HadISST1). All of them are available from that most marvellous resource, the KNMI data portal .
It turns out that the NSIDC and the HadISST1 records are nearly identical. The correlation between the two in the Arctic is 0.995 (1.0 is perfect agreement), and in the Antarctic it is 0.999. So in Fig. 2, I have not shown the NSIDC dataset, but you can imagine that there is a third record almost identical to the HadISST1 dataset. Here is what has happened to the global sea ice area from 1982 to the present:
FIgure 2. Global Sea Ice Area 1982-present. Data from satellite observations.
As you can see, while it is certainly true that the Arctic has been losing ice, the Antarctic has been gaining ice. And the total global sea ice has barely changed at all over the period of the record. It goes up a little, it goes down a little, it goes nowhere …
Why should the Antarctic warm when the Arctic cools? The short answer is that we don’t know, although it happens at both short and long time scales. A recent article in Science Magazine Online (subscription required) says:
Eddies and the Seesaw
A series of warm episodes, each lasting several thousand years, occurred in Antarctica between 90,000 and 30,000 years ago. These events correlated with rapid climate oscillations in the Arctic, with Antarctica warming while the Arctic was cooling or already cold. This bipolar seesaw is thought to have been driven by changes in the strength of the deep overturning circulation in the North Atlantic Ocean, but some have questioned how completely that process can account for the fine details of Antarctic warming events.
Keeling and Visbeck offer an explanation that builds upon earlier suggestions that include the effects of shallow-water processes as well as deep ones. They suggest that changes in the surface salinity gradient across the Antarctic Circumpolar Current were caused by the melting of icebergs discharged from the Arctic, which allowed increased heat transport to Antarctica by ocean eddies. This mechanism produces Antarctic warming of the magnitude observed in ice core records.
However, not everyone agrees that this is the full explanation. Henrik Svensmark adds another factor to what may be happening:
The cosmic-ray and cloud-forcing hypothesis therefore predicts that temperature changes in Antarctica should be opposite in sign to changes in temperature in the rest of the world. This is exactly what is observed, in a well-known phenomenon that some geophysicists have called the polar see-saw, but for which “the Antarctic climate anomaly” seems a better name (Svensmark 2007).
To account for evidence spanning many thousands of years from drilling sites in Antarctica and Greenland, which show many episodes of climate change going in opposite directions, ad hoc hypotheses on offer involve major reorganization of ocean currents. While they might be possible explanations for low-resolution climate records, with error-bars of centuries, they cannot begin to explain the rapid operation of the Antarctic climate anomaly from decade to decade as seen in the 20th century (figure 6). Cloud forcing is by far the most economical explanation of the anomaly on all timescales.
Regardless of why the polar see-saw is happening, it is a real phenomenon. Ignoring it by looking just at the Arctic leads to unwarranted conclusions about what is happening to sea ice on our most amazing planet. We have to look at both hands, we have to include the other side of the ice, to see the full situation. The real answer to what is happening to global sea ice is …
Nothing.
John Egan (19:25:04) :
Two words – wind & currents
Another ad hoc theory –
North pole has polar bears. South pole has penguins.
or maybe –
North pole is sea surrounded by land. South pole is land surrounded by sea.
I can’t see the problem, what with the huge lack of temperature data points in both places, and the relatively small temperature variations to begin with.
The recent lack of ice in the north is largely a
problemsituation due to flushing the old ice out into the Atlantic.Bottom line, so what, assuming you aren’t a seal forced to haul out on shore instead of the safety of ice.
Anthony,
We see a few comments wondering about GISS anomoly in the arctic compared to the lack of anomoly on the DMI actric temperature graphic linked on your page. But, I haven’t run across an answer to any of them. Seems like a comment on this would be a good post. Forgive me if I missed the answer in a comment somewhere.
The WARMERS claim we should be concerned about Arctic sea ice declines (conveniently ignoring Antarctic ice growth) because of alleged atmospheric temperature increases. Students of WUWT know that the instrumental temp record (HadCRU, NASA-GISS, and similar data compilations) is fraught with problems and unreliable, especially in the high latitudes.
But more to the point. Why should we think that air temp has ANY significant influence on melting of sea ice? One of the Caitlin fiasco discussions above links to a Univ Alaska-Fairbanks site that shows a temperature profile through Arctic sea ice. What it shows (real-time data) should be self-evident.
http://www.gi.alaska.edu/snowice/sea-lake-ice/Brw10/
The temperature probes show that sea ice is in contact with liquid sea water on the bottom at about -2C and in contact with air at about -20C on the top. In between, sea ice shows a linear gradient from bottom to top.
So, if sea ice is going to melt due to rising temperatures, will it melt first at the top (ambient temp -20C) or at the bottom (ambient temp -2C)?
Those of you who didn’t sleep through elementary physics or P-chem will know – ice will melt first/most at the bottom as a result of changes in sea-water temperature. Sea-water temperatures at both poles are primarily governed by ocean currents that transport warmer water to colder environments. That is, most polar ice loss is likely due to the transfer of heat that was added to the ocean SOMEWHERE ELSE and conveyed to the polar seas.
Air temp is (mostly well below freezing and) mostly irrelevant.
Dear Mr. Tinsdale:
Although I think your work is quite fine, I must protest the USE OF AVERAGE TEMPERATURES as though they have ANY MEANING at all.
I will note: I’m on a CRUSADE ON THIS!
Consider the following situation – Air temp, 82 F. RH 63%, ENTHALPY of the air, 36 BTU/lbm of air.
Air temp 105 F, 10% RH (Typical AZ, where my Mother lives). ENTHALPY of the air, 30 BTU/lbm.
Which atmosphere is “hotter”? TEMPERATURES ARE MEANINGLESS without the knowledge of the local humidities. In point of fact, because WE DON’T KNOW THE HUMIDITY PROFILES in areas, the significance of “temperature changes” over ANY time period (decades, centuries, millenia) are MEANINGLESS.
The ONLY data we can work with involves systems were we HAVE complete RH and Temperatures, which…of course, are particularily few and far between.
Now with regard to using, “English Units”, sorry..I’m an old fuddy duddy.
Max
John Egan (19:25:04) :
“one must acknowledge that the Arctic sea ice drop in 2007 was dramatic.”
Acknowledged, dramatic based on the 30 year satellite record we have on our 4,500,000,000 year old planet, but it appears that the decrease was primarily related to wind and currents versus a warming Arctic:
http://wattsupwiththat.com/2010/03/22/the-guardian-sees-the-light-on-wind-driven-arctic-ice-loss/
Bob, you write, regarding the Arctic and Antarctic seeming to warm and cool like a teeter-totter: “I believe the myth was based solely on the trends for the TLT anomalies.”
But Willis has quoted Svensmark in the piece above in re changes over thousands of years. I know that to some extent Svensmark relies on research by Dorthe Dahl-Jensen of the Niels Bohr Institute who compared borehole records from Greenland and Antarctica and wrote the following: “Antarctica has a tendency to warm up when Greenland is ‘cold’ and to cool off when Greenland is ‘warm.’ “
Between the UN IPCC and the real world lies a gigantic pile of very expensive propaganda based on flawed models, cherry picked and massaged data and a political enforced consensus that isn’t.
Thank you Willis.
Has anyone seen this interesting paper?
How Fast is Arctic Sea Ice Declining?
http://homepage.ntlworld.com/jdrake/Questioning_Climate/userfiles/How_Fast_is_Arctic_Sea_Ice_Declining_v2.pdf
In it he suggests the possibility of satellite drift,that would create a steep decline in ice cover area.
Someone over on Bishop Hill’s blog is arguing that your graph shows area, and that sea ice volume is what’s important. I’m assuming that volume shows something different. However, the antarctic ice volume is reportedly going up as well. So, maybe it’s about the same story as the sea ice area. Or maybe that doesn’t count in the sea ice volume?
I went looking for global sea ice volume but could only find the sea ice index. Could you add a link? What about polar ice volume or extent? That would make more sense due to the fact that most antarctic ice isn’t floating. Would your constant trend hold up using this definition of polar ice extent?
Kazinksi (18:50:18) :
I woinder why they picked 2007 to end the data series? I think we all know.
Yes we do, the graph is dated 23 Sept 2007!
John Egan (19:25:04), thanks for your thoughts.
That is a tautology, since a permanent loss of multi-year Arctic ice could only happen if there are significant climate changes.
But there is no indication that the northern ice is going away. Everything in nature goes up and down. I’m not going to be concerned until I see something that is outside the natural variations. People are looking at a tiny slice of history and say “OMG, it’s going down (or up as the case may be), everyone panic!!”
As we used to say about these kinds of statements when I was a kid, “Yes, and if my aunt had wheels she’s be a tea-tray.” Of course there would be impacts, just like there would be if the Gulf Stream stopped moving or thunderstorms stopped forming.
However, until we have some reason to believe that any of those are happening, they just like my aunt’s wheels …
But I must say that I don’t think that an ice-free summer in the Arctic would make much difference. Polar bears and Inuit people have seen it before, there’s clear evidence of it happening during the Holocene. And how much difference would it make in New York or Calcutta? … not a whole lot, I’d say.
In fact, except for the ability of our satellites to monitor the ice, we might not even have noticed the changes from say 2004 to 2007 to 2010 … it’s not like the world revolves around the Arctic ice area. It is quite likely that there was little ice during the 1930s, it just didn’t make headlines.
Any change can be portrayed as dramatic, just adjust the scale of the graph and trumpet it in the news media. And nature specializes in what is called the “Noah effect”. This means that in a string of natural occurrences, the biggest one may well be bigger than the sum of all of the rest. So yes, it is dramatic, but nature goes in for drama on what might be called a “planetary scale” …
And what would you say that acting “with prudence” would entail? We know that the Arctic was as warm (or warmer) in the thirties than it is now. The Greenland ice cores show us that the Arctic was warmer a thousand years ago than it is now. There is good evidence that the Arctic has been ice-free during the Holocene (the current interglacial).
And yet here we still are, polar bears and all. In a world where temperatures can vary that much due entirely to natural fluctuations, what does prudent action look like to you?
To me, prudent action means economic development. That’s how we protect ourselves against whatever the climate brings next, hot or cold, wet or dry. We build dikes. We heat or cool our houses. We put lightning rods on our buildings. We construct levees in New Orleans, and rebuild them when they fail. We install irrigation systems for our crops.
And all of that costs money. That’s why I see the fight against carbon as being totally and tragically misguided, not just because it is futile, but mainly because for the foreseeable future at least, carbon = development.
However, YMMV …
Um, it’s kinda well known why one pole gets cooler while the other warms. It’s precession. The Earth isn’t a globe in a stand sitting on God’s desk. It’s a ball of molten star stuff with a thin cool shell. As the North Pole tips towards the Sun, the South Pole sees less direct sunlight. It happens every year as the seasons change, too, but precession is long term. A full cycle is ~24,000 years. In my lifetime, the tilt has changed almost 1°. Polaris is a little further away from true north. (It never was exactly north in my lifetime, but it was closer.)
The alarmists say they have precession coded into their computer models, but we aren’t allowed to check their “proprietary software.” It’s still GIGO to me…
JDN (20:53:54)
As far as I know, nobody has anything resembling a long-term dataset of sea ice volume. I’d be happy to look at one, but I’ve never seen one. I don’t even know how you’d get one … go skating on the other side of the ice and measure the thickness as you went? There’s only a few measurements that I know of, from nuclear submarines. Most scientists don’t have those, though …
Regarding area vs. extent, area is the total amount of the sea surface covered by ice. Extent is what you get when you draw a line around the outermost ice. Since there are often regions of open sea within the ice extent outline, I use area.
Phil. (20:55:24)
Well played, that’s exactly why I try not to speculate on motives.
Bill (19:41:30) :
The earth is in an eccentric orbit around the sun, plus the sun shifts its position relative to the solar system center of gravity as it is pulled by the gas giants.
The latter does not affect distance between the Sun and the Earth. Look at it this way: The center of gravity between the Sun and the Earth also orbits the solar system center of gravity. And the location of the center of gravity [as a fraction of the whole distance] between the Sun and the Earth depends only on the ratio of the masses of the Sun and the Earth.
Harold Ambler (20:27:22) :
But Willis has quoted Svensmark
Perhaps Svensmark works oppositely at the two poles 🙂
You know, when you don’t know how it works, anything is possible…
willis, is it really u saying:
“That’s why I see the fight against carbon as being totally and tragically misguided, not just because it is futile, but mainly because for the foreseeable future at least, carbon = development”
what “development” are u talking about:
this?
28 March: UK Times: Jonathan Leake and Chris Hastings : Wealthy landowners make millions in the wind rush
Among the biggest potential beneficiaries is the Duke of Roxburghe, whose planned 48-turbine scheme on his Scottish estate would generate an estimated £30m a year, shared with developers. About £17m of this would come from subsidies from consumers.
Others seeking to capitalise on the new wind rush include the Duke of Beaufort, Sir Reginald Sheffield, father of Samantha Cameron (wife of Tory leader, David Cameron), and Michael Ancram, the Tory grandee.
The growing interest in wind farms stems from the government’s subsidy system
http://www.timesonline.co.uk/tol/news/environment/article7078856.ece
or this?
29 March: Australian: Sid Maher: World cool on Rudd’s clean coal funding
AUSTRALIAN taxpayers are the only financial backers for Kevin Rudd’s $100 million-a-year global clean coal initiative, as world leaders have failed to match their resounding endorsement of the idea at the G8 meeting last July with a single dollar. …
http://www.theaustralian.com.au/news/nation/world-cool-on-rudds-clean-coal-funding/story-e6frg6nf-1225846623758
u may not mind funding all this, but i can think of plenty of taxpayers who will fight relentlessly to stop the commodifying of CO2.
We are all doomed! Or not. Let me know what the weather will be like 2 weeks from now. Oh wait – weather isn’t climate. Cripes.
pdcant (21:13:42) :
In my lifetime, the tilt has changed almost 1°.
You must be very old. The tilt changes about an 1/8 of a degree in a thousand years….
I made a graph of UAH North Pole minus South Pole temperatures. They are steadily diverging at a rate of .49C/decade.
https://spreadsheets.google.com/oimg?key=0AnKz9p_7fMvBdHRkenhGVjlFanM2WHcxZXFhTGtZMlE&oid=2&v=1269838244765
If they were symmetrical, we would expect to see a slope of zero.
” Kazinksi (18:50:18) :
I woinder why they picked 2007 to end the data series? I think we all know.
Yes we do, the graph is dated 23 Sept 2007! ”
And what date was the report made? If later than the graph you know why they chose the graph they did.
Now here’s a trend I am looking forward to seeing the National Snow and Ice Data Center (NSIDC) try to continue:
December 7, 2002 – Arctic Sea Ice Shrinking, Greenland ice sheet melting, according to study
http://nsidc.org/news/press/20021207_seaice.html
8 December 2003 – Arctic Sea Ice Low, Second Year in a Row
http://nsidc.org/news/press/20031208_minimum.html
4 October 2004 – Arctic Sea Ice Decline Continues
http://nsidc.org/news/press/20041004_decline.html
18 March 2005 – Arctic Ice Decline in Summer and Winter
http://nsidc.org/news/press/20050318_arcdec.html
28 September 2005 – Sea Ice Decline Intensifies
http://nsidc.org/news/press/20050928_trendscontinue.html
5 April 2006 – Winter Sea Ice Fails to Recover, Down to Record Low
http://nsidc.org/news/press/20060404_winterrecovery.html
3 October 2006 – Arctic Sea Ice Shrinks as Temperatures Rise
http://nsidc.org/news/press/2006_seaiceminimum/20061003_pressrelease.html
4 April 2007 – Arctic Sea Ice Narrowly Misses Wintertime Record Low
http://nsidc.org/news/press/20070403_winterrecovery.html
1 October 2007 – Arctic Sea Ice Shatters All Previous Record Lows
http://nsidc.org/news/press/2007_seaiceminimum/20071001_pressrelease.html
April 7, 2008 – Arctic sea ice extent at maximum below average, thin
http://nsidc.org/arcticseaicenews/2008/040708.html
2 October 2008 – Arctic Sea Ice Down to Second-Lowest Extent; Likely Record-Low Volume
http://nsidc.org/news/press/20081002_seaice_pressrelease.html
March 30, 2009 – Annual maximum ice extent confirmed – This year’s maximum was the fifth lowest in the satellite record.
http://nsidc.org/arcticseaicenews/2009/033009.html
6 October 2009 – Arctic sea ice extent remains low; 2009 sees third-lowest mark
http://nsidc.org/news/press/20091005_minimumpr.html
I await NSIDC’s forthcoming 2010 maximum press release with bated breath, wondering how they will to try to spin this:
http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png
into some form of catastrophic decline…
Leif Svalgaard (21:24:11) :
The [Sun’s shifting its position relative to the solar system center of gravity] does not affect [the] distance between the Sun and the Earth.
The question is not if it affects the distance between the Sun and the Earth. Nobody made such an assertion (at least in this thread).
The question is: how it affects the characteristics of solar activity and, therefore, the climate on Earth?
There is no need to quote again some percentages allegedly showing how Earth’s temperature practically doesn’t depend on intensity of the Solar radiation. Earth is not a black body, and numbers calculated without taking into account hundreds of interdependent feedback mechanisms (most of which we still don’t understand or understand very poorly) are utterly meaningless.
Willis Eschenbach (21:08:04) : “…To me, prudent action means economic development. That’s how we protect ourselves against whatever the climate brings next, hot or cold, wet or dry. We build dikes. We heat or cool our houses. We put lightning rods on our buildings. We construct levees in New Orleans, and rebuild them when they fail. We install irrigation systems for our crops….”
And we stop building cities below sea level.