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.
Just one more day of growth in the Arctic this year, baby. Give us one more day. . . actually, three more days would be neat (get the winter max into April). But I’ll take one more day of more than 12k increase.
Steve Goddard (08:19:59) :
Phil.
A negative AO is typified by high pressure or clockwise circulation. The older ice is located north of Canada and Greenland and is circulating away from the Fram Strait.
You’ll find thie figure below more illuminating, the ice going out the Fram is 2yo and my also the my ice from the Beaufort and Canadian coastline is being swept into the strong transpolar flow towards the Fram. That coupled with the early opening of the North water referred to above leads me to be pessimistic about the my ice this year.
Summer extent will very likely increase again this year.
I don’t share your optimism, it’s setting up more like 2007 so far.
http://i302.photobucket.com/albums/nn107/Sprintstar400/Drift20100317-20100323.jpg
I’m optimistic: click
Phil,
Your map is interesting but only shows six day vectors. The actual 60 day drift map shows minimal movement from the Siberian side.
http://iabp.apl.washington.edu/maps_daily_track-map.html
And all of the 3+ year old ice is on the Canadian side and is moving away from the Fram Strait.
Steve Goddard (08:19:59) :
Summer extent will very likely increase again this year.
Richard Sharpe (08:26:17) :
Something seems to be up in the Arctic:
Or perhaps there is a problem with their algorithms …
geo (08:51:06) :
Just one more day of growth in the Arctic this year, baby. Give us one more day. . .
——————
This sounds a lot like sports fans rooting for their team.
There must be a good website for placing bets somewhere, better than Intrade…
I’d be willing to bet the September minimum ice extent falls between 2005 and 2007:
http://nsidc.org/images/arcticseaicenews/20091005_Figure2.png
This March stuff is like Spring Training, it won’t carry into the post-season. This recent ice will be the first to melt. With the start of the next sunspot cycle, the warming caused by ENSO, and the underlying warming trend, we’ll be seeing Arctic sea surface temperatures more like 2007 and 2008:
http://nsidc.org/images/arcticseaicenews/20091005_Figure4.png
melting the diminished thick ice:
http://nsidc.org/images/arcticseaicenews/20091005_Figure5.png
The East Siberian league is sure to take a pounding this season, anc Chukchi did not have a good off-season to prepare for Summer 2010:
http://nsidc.org/images/arcticseaicenews/20090908_Figure4.png
Probably not a championship season, but I expect a strong push for the Pennant.
I had said:
Steve Goddard (07:27:44) replied
Steve, you should know by now that I don’t just pull numbers out of my fundamental orifice. Because of that, it’s much better tactics to say “cite?”, rather than claim I’m blowing smoke and guess at the number. All that does is make you look foolish.
In this case the citation is the US Geological Service report entitled “Polar Bear Population Status in Southern Hudson Bay, Canada“. In Table 2 they give the number of Hudson Bay ice-free days for each year from 1983 to 2005. These averaged 4.4 months, with a standard deviation of 0.6 months. I rounded to the nearest month and reported this as “4-5 months”, which was the average ± one standard deviation. The longest ice-free period was 5.5 months, and the shortest was 3.4 months.
Note that your guess of “only three months a year” was shorter than the shortest actual ice-free period in that 23 year record …
Maybe the increase in sea ice extent is a bad thing, as if you would look at Cryosphere today and see where the ice area is increasing.
It is going up in the Greenland, Baffin, and Newfoundland seas.
Someone mentioned the Greenland Ice sheet loosing mass of 385 cubic miles in the last 7 years and that is enough to add some 100,000 square kilometers of sea ice to this polar region each year.
After all, all that ice on Greenland is going to keep some ice in the arctic ocean for quite a few years.
Steve Goddard (11:02:50) :
Phil,
Your map is interesting but only shows six day vectors. The actual 60 day drift map shows minimal movement from the Siberian side.
http://iabp.apl.washington.edu/maps_daily_track-map.html
That’s because there are no buoys there! You can go take a look at the last 60 days of vector plots if you like. It’s far from minimal movement, take a look at the ice concentration on the Siberian coast on CT, you’ll notice it’s dropping, wonder where it’s going?
And all of the 3+ year old ice is on the Canadian side and is moving away from the Fram Strait.
And as I said before it’s off into the Beaufort gyre, once there it’s only a matter of time before it’s in the Atlantic. As you’d expect from the strong drift this year the ice there is more broken up than last year. The circulation of the gyre was also clockwise in 2007.
Willis,
The UIUC Hudson Bay link I provided you is a measurement, not a “guess.”
Here it is again.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.13.html
Hudson Bay is ice free for three months a year.
Steve Goddard (05:44:03)
Please tell me you didn’t just cite wikipedia on a controversial subject. Wikipedia doesn’t change reality any more than your belief system does. I just gave you a very interesting citation on the feeding habits of polar bears. It says inter alia:
In other words, about half of the ringed seals that the polar bears catch are not caught in the manner you describe. They are caught in the seal’s lairs, which are generally on shore. Note also that the bears don’t just eat the ice-obligate ringed seals, they also eat harp, hooded, and bearded seals. These flourish where there is less ice. From the same source:
And unlike the simplistic Wikipedia claim you quoted above about how they only hunt by laying in wait, they hunt different seals in different manners. Ringed seals are hunted in that manner, but instead of laying in wait the bears usually stalk and then charge bearded seals. Yes, they hunt mainly in the way that you have described, but my previous citation also says:
Marx Hugoson (20:11:12) :
Bit of a fuddy-duddy myself but I thought I’d do a rough translation to SI.
82°F ~ 28°C Enthalpy @ur momisugly 63%RH = 66.12KJ/Kg
105°F ~ 40.5°C. Enthalpy @ur momisugly 10%RH = 52.72KJ/Kg
Figures approximate but I think close enough.
DaveE.
Steve Goddard (12:47:17) :
Hudson Bay is ice free for three months a year.
Hey, guys.
This is becoming silly. Without an agreed upon definition of ice-free there is nothing to discuss. From Steve’s graph it looks like only one month is ice-free [meaning NO ice, and perhaps zero months if one magnified the graph].
Willis,
Most Wikipedia articles are well cited, and the Polar Bear article is no exception. The feeding information was taken directly from a USGS study.
http://www.usgs.gov/newsroom/special/polar_bears/docs/USGS_PolarBear_Amstrup_Forecast_lowres.pdf
There is no question that Polar Bears experience severe stress from long ice free periods, and it does little for credibility to argue otherwise.
Willis Eschenbach (13:04:13) :
Willis, just a thought relating to the following pargh. in the study you mentioned:
“Abundance in the Southern Hudson Bay population was unchanged between two intensive capture-recapture periods, which were separated by almost 20 years (1984–86 vs. 2003–05). This was so despite the evidence for a decline of 22% in abundance for the neighboring Western Hudson Bay population over roughly the same period (i.e., 1987-2004; Regehr et al. 2007). Forested areas come close to the coast in the north-western section of the study area making sighting and capture of bears difficult.”
WHAT? They couldn’t see the bears for the forest??
And note the phrase – “… a decline of 22% in abundance…”?? In other words, they have no clue if those “missing” bears died or migrated. They just couldn’t find them. If you were a smart P.bear like the kind that went to DC, wouldn’t you move north if the ice was breaking up to early?
BTW, I remember a factoid from 20-30 years ago – maybe Pop Sci mag – that more people have been killed by polar bears on land than on ice. It stuck in my head being so odd, but not sure it’s true.
Re: Polar bear hunting methods
“The steady enemy of the seal is the polar bear. How this awkward animal catches the watchful seal I could not imagine. The Esquimaux say he prowls about examining the ice holes of the seals and, finding one close to high broken ice, there hides himself. When the seals are basking in the sun and half asleep, he springs upon them, seizes one, which he hugs to death, and, as fast as possible with his teeth, cuts the back sinews of the neck. The seal is then powerless and the bruin feasts on him at his leisure.” David Thompson, Churchill, c.1785
“On the sixth day we had a deep brook to cross, and on the opposite side of the ford was a large polar bear feasting on a beluga. We boldly took the ford thinking the bear would go away, but when about half way across, he lifted his head, placed his forepaws on the beluga, and uttering a low growl, showed to us such a set of teeth as made us turn up the stream and for 50 yards wade up to our middle before we could cross. During this time the bear eyed us, growling like a Mastiff dog.” David Thompson, York Factory September 1785
On 29 March 2007 the arctic ice area was 1 million square kilometers less than today (and already shrinking), so while I cannot know what will happen in Summer 2010, it seems probable that we will end up with more ice than 2007.
Sean Peake – Nice Thompson reference. While I’m sure it is largely accurate, there are two problems with these excerpts.
The description of how polar bears kill seals is heresay from Inuit – and he could not speak their language. He was never in the Arctic.
The parts of his Narrative that early were written entirely from memory, starting 60 years later (1845). He did not start keeping his own journals until 1789.
Steve Goddard – The usgs is not a reliable source of information about polar bears as they are full tilt AGW proponent staffed mostly be True Green Believers. They were co-conspirators in getting them listed as Endangered in AK.
And wiki is not a reliable source on anything remotely connected to AGW.
http://network.nationalpost.com/np/blogs/fullcomment/archive/2009/12/19/lawrence-solomon-wikipedia-s-climate-doctor.aspx
http://network.nationalpost.com/np/blogs/fullcomment/archive/2009/12/23/lawrence-solomon-wikipedia-s-hockey-stick-wars.aspx
As for the severe stress they experience, that is an annual event, worse some years than others.
About Hudson Bay ice.
Overgeneralizing is always THE problem. What does “ice free” mean? The whole Bay? That does not matter. What does matter is whether there is ice near where the bears are. For example, what is the relevant “ice free” period for the famous AGW poster population down by Churchill on the SW side?
Willis and Milwaukee Bob,
About that decline in the “western’ Hudson Bay population. Most of that work is done around Churchill, which is near an area where bears from a large area came onshore for as long as we know (see that David Thompson excerpt above) and probably much longer. (The reasons why they used that area historically are interesting but that’s another story.) A very significant event impacted that population. They closed off access to the Churchill dump, where large numbers of bears used to feed. As happened with grizzly bears in Yellowstone (and some other parks), when you suddenly cut off that super-rich food source, it has major impacts on the individuals, their reproduction rates, the size of the bears, and state of the whole population. You effectively reduce its carrying capacity with predictable results.
Funny that nobody from the AGW crowd mentions that.
And funny how they constantly use that SW Hudson Bay population, the most southerly in the world, as their poster child for ‘Arctic’ impacts.
When they closed dumps in Yellowstone in about 1970, the greenies used what was an absolutely predictable decline and increase in bear mortality as the excuse to list the grizzly as a Threatened species in the Lower 48. And that had all sorts of implications, not to mention creating what is now a very robust ‘save the grizzly’ research-industrial complex.
There is at least as much BS about bears and ‘endangered species’ as there is about AGW, thanks to the new politicized pseudoscience called ‘Conservation Biology.’ Their grand plan is called ‘Rewilding.’ Google and gasp!
The USGS is a great source of information, as is Wikipedia which is a much better reference than what I grew up with – (World Book and Encyclopedia Britannica.)
If the Arctic warms 16C as the Met Office predicts, there will be drastic changes. Not much evidence of that so far though.
There’s an update today from IARC-JAXA which shows Arctic sea ice has hit a new peak of 14.390m km².
This exceeds the peak of 14.375m km² reached March 8, and is also the latest date for a peak level since they started their records in 2002.
It should also be noted that this is not, however, the highest peak they’ve recorded.
Catlin will probably find that it’s all rotten ice…
Here’s the scary trend in the number of ice-free days on the Hudson Bay, data from the citation above.
Photo is of a Hudson Bay polar bear.
For more on how wikipedia works, read Orwell’s 1984.
The USGS is a good source of information on some things, but not when it comes to ‘endangered’ species or those that could be labeled as such.
Willis – Great photo. Looks like he/she is just sitting there watching the ice melt, or perhaps the sea level rise.
Arctic ice area has “death spiraled” above the 30 year mean.
http://arctic-roos.org/observations/satellite-data/sea-ice/observation_images/ssmi1_ice_area.png