Sea Ice South (3): The Logical Song

By: Dr. Ricky Rood , 11:21 PM GMT on May 25, 2011

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This may be the most complex blog I have ever written. I will try to put together the material from the previous three blogs to expose the basics of sea ice in the Southern Hemisphere. The first in the series examined the Northern Hemisphere, and the amount of accumulated heat that is needed to explain the melting of sea ice in the north. The second in the series looked at the geography of the planet and the characteristics that distinguish the Arctic from the Antarctic. The third in the series looked at some of the basics principles of the Earth’s climate. All of these set the foundation that there is little reason for the behavior of sea ice in the southern hemisphere to mimic the sea ice in the northern hemisphere. And following that, there is no reason that the response of sea ice to a warming planet will be the same in the northern and southern hemispheres.

First some summary facts: Remember that sea ice is made by the sea freezing. Such freezing occurs at high latitudes, where even as the planet warms up, it will still get cold in the winter because the Sun will still go down for a long time. Sea water is salty, and snow and rain and melting ice sheets on the land are fresh water. Salt water freezes at colder temperatures than fresh water – that’s why we salt icy highways. Finally, much of the heat that gets to the poles is by transport of heat from warmer, lower latitudes.

Let’s start with a figure, which is an annotated version of the map from the second blog in the series.



Figure 1: An annotated map of the South Polar Regions.

I drew a little arrow with a “1” in it at the southern tip of Africa. This is to show how the Agulhas Current comes south on the west African coast as a compact current. It then gets swept away towards the west. Therefore, this current does not directly warm the highest latitudes of the ocean. Therefore, this current does not send a concentrated stream of warm water to the pole that can melt ice. (Contrast this with the Gulf Stream in the Northern Hemisphere, which famously warms the North Atlantic and Arctic regions.)

An understanding of the cause of the spread of the Agulhas Current starts with the big green, dashed arrows on the map. These arrows represent atmospheric storms, which start in middle latitudes, propagate south and turn to the east with the Earth’s rotation. Because of the belt of open water that surrounds Antarctica and the high terrain of Antarctica these storms form a belt of high winds. These winds put stress on the ocean and start the surface of the water moving from west to east. As this water moves from west to east it is diverted northwards, again, due to the rotation of the Earth. (For those who do atmospheric and ocean motion, this is the Coriolis force.) The net result of the atmospheric storms in the Antarctic Ocean is a broad surface current from west to east with a northward deflection. Therefore, at its coast, Antarctica is somewhat isolated from the direct effects of warming. (Look at the map closely and you will see that the 1894 cartographer drew it all in.)

What about under the surface? Under the surface of the southern ocean it is warming, and that warm water is propagating towards Antarctica. It is bringing heat to the edge of the continent and to the bottom of the sea ice. Therefore there is the real possibility of the sea ice melting from below, or if not melting, freezing more slowly.

But sea ice is complicated – if nothing else, that is a message from all of my sea ice blogs. If you look at sea ice in the Southern hemisphere it is increasing on average. But it bounces around a lot and in some places it is systematically increasing and other places it is decreasing. Here’s a picture to remind you of what sea ice was doing back in April.




Figure 2: Areal extent of April sea ice in the Southern Hemisphere from 1979 – 2011. (figure from National Snow and Ice Data Center)

This simultaneous occurrence of growth and melting, cooling and warming, should always be suggestive of the oceans and atmosphere mixing hot and cold. That is what weather is always doing - mixing, trying to even it all out. Whenever there is mixing by fluids, and air and water are both fluids in regard to the way they move – whenever there is mixing by fluids, it gets complicated. Slowly drip heavy cream into gently stirred coffee and watch it stretch and mix.

To make it more complex sea ice is made by freezing water with various levels of salt in it. There is snow and rain, fresh water, falling on the sea ice. There is fresh water coming from melting glaciers pouring into the ocean. Fresh water is heavier that salt water, so if fresh water is on top of salt water, it’s happy. But if saltier water is on top of fresher water it sinks, and causes mixing as fresher water comes up to take its place. Of course, it does not stop there, snow is an insulator and if it is on top of ice, it insulates it from both warm and cold extremes of air temperature. And, remember, when it is cold enough to snow, it snows more in a warmer climate. Hence, there is the possibility of growing protective insulation from the warming air. Salt water, fresh water, insulation – what would happen if it got warm enough that it started to rain more instead of snow. What happens when rain falls on snow and ice? It accelerates melting.

Finally, but perhaps not completely, in Antarctica we have the the ozone hole. And ozone is a greenhouse gas, and in the ozone hole there is a huge decrease of ozone. If there is a large decrease of a greenhouse gas, then that would allow the Earth to more easily emit radiation to space, and it would contribute to cooling.

I want to try two more figures. These figures are, in my best tradition, home-grown schematics to get across some of these ideas.




Figure 3: A historical situation where mixing in the upper layer of the ocean, caused by the density differences between fresh and salt water, brings heat from the warmer sub-surface water and the atmosphere to melt sea ice.




Figure 4: A present or future scenario where mixing in the upper layer of the ocean is suppressed because of the presence of more fresh water at the surface. This reduces heat transport from the warmer sub-surface water and the atmosphere.


In the top of the figure we have what might be called a historic situation. There is warm water under the part of the ocean that is well mixed by the stress of the atmospheric storms. There is some snow. There is a pattern of thawing and freezing of sea ice that yields saltier water on top of fresher water. This causes mixing, and with the warmer and warming ocean below, this brings warm water up, and can melt sea ice more quickly. This can also mix in warming air from the atmosphere.

In the bottom figure there is more snow, maybe rain, because the atmosphere is warming and holds more water and precipitates more strongly. The snow insulates the ice from the atmosphere. That snow changes the balance of fresh and salty water at the surface. It ends up with fresher water on the surface. The mixing is decreased; the warmer and warming ocean below is isolated from the surface from the ice and there is decreased melting.

Given all of this it is not only plausible, but perhaps even expected that there will be times and places with more sea ice. Fresh water is worth a couple of degrees of temperature. I am not an expert on this subject, which is why it has taken me a while to put it together. I got started thinking about this because of a conversation with Cecilia Bitz about the work of her student, Clark Kirkman IV. If you look at this paper you see a more detailed study of the mechanisms described above, but you also see that the predictions of climate models are for a “delay” in Antarctica compared with the Arctic. Also, it is seen that some of the models predict regional cooling in the Antarctic. Their work is available here: Kirkman IV and Bitz, 2010. I provide a larger set of references below.

Finally, there are the crabs and maybe the sharks. In the first blog in the series, about the Arctic, I talked about the significance of accumulating heat in the environment. This accumulation of heat over many years is convincing and compelling evidence of systematic warming. Such evidence is expressed in the onset of spring coming earlier, trees species and animals moving to new regions, large pieces of ice on mountains melting.




Figure 5: The Antarctic Peninsula (map from The Traveling Naturalist)


In that part of Antarctica that reaches out towards the tip of South America, the Antarctic Peninsula, the water has been warming. This has led to migration of king crabs, who now find water warm enough to survive. This, of course, leads to massive shifts of the ecosystem. Looking at warming and possible changes to the surface ocean currents, it is within the realm of possibility that species, such as sharks, will migrate more southward.

Sea ice formation and melting is strongly dependent on how low latitude heat is delivered to poles by motions in the oceans and atmosphere. Local conditions of saltiness impact not only the freezing and thawing, but the mixing of heat in the upper layer of the ocean. The energy exchange between the surface of the ice and the rest of the environment is impacted by rain, snow, clouds, sun, greenhouse gases, soot, algae – the list goes on. Large changes in sea ice formation and extent depend on relatively small, 1 watt per square meter, changes in energy. That is a change of 1 out of 100s. There are many paths that can lead to changes of 1, either positive (warming and melting) or negative ( cooling and freezing). But the fact is that the surface of the Earth and the atmosphere is warming. The ocean is accumulating heat. If there are patches of cooling related to local processes, this cooling is vulnerable to the building heat in the environment. It does not represent either a refutation of the basic tenets of predictions of a warming planet or a measure of global self healing.

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Some primary references:

Kirkman IV and Bitz, 2010 / The Effect of the Sea Ice Freshwater Flux on Southern Ocean Temperatures in CCSM3: Deep Ocean Warming and Delayed Surface Warming

Liu and Curry, 2010 / Accelerated warming of the Southern Ocean and its impacts on the hydrological cycle and sea ice

Turner et al. 2009 / Non-annular atmospheric circulation change induced by stratospheric ozone depletion and its role in the recent increase of Antarctic sea ice extent

Zhang, 2006 / Increasing Antarctic Sea Ice under Warming Atmospheric and Oceanic Conditions

Some popular references:

Resolving the Paradox of the Antarctic Sea Ice
Global Warming Protects Antarctic Sea Ice — But Not For Long
Increasing Antarctic Sea Ice Extent Linked to Ozone Hole
King Crabs Invade Antarctic Waters
Crab, Shark Invasion May Threaten Antarctic Marine Life


(If you want to see cool movies that show how rotation organizes flow go to MIT and look at these movies.)


Useful links
Recent sea ice trends
Sea ice data
Rood’s Blogs on Ice

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Viewing: 320 - 270

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320. fred2265
1:08 PM GMT on July 26, 2011
This was a most interesting blog, plenty to be thinking about.


Member Since: July 24, 2011 Posts: 0 Comments: 0
319. LilyZ
9:11 AM GMT on June 07, 2011
Very interesting! Free counters!Free counters!Free counters!


Free counters!Free counters!Free counters!



Member Since: April 2, 2011 Posts: 0 Comments: 5
318. Snowlover123
10:48 AM GMT on June 06, 2011
Quoting RustyShackleford:
2 years ago today. Looks like we are #winning



I believe that is July 6th, not June 6th.
Member Since: April 1, 2010 Posts: 9 Comments: 2699
316. cyclonebuster
1:18 AM GMT on June 06, 2011
Quoting RMuller:


Who the hell cares? It's a thirty year record, even if its even accurate. We are dealing with a five billion year planet history. How can people even consider that 30 years makes a difference. Every sea ice measurement system has a different total. The Norwegian has a much higher measurement. I'd much more trust them than the NOAA and NASA frauds.


I care that is why I built weather machines to restore the arctic ice.

Member Since: January 2, 2006 Posts: 127 Comments: 20401
314. cyclonebuster
1:11 AM GMT on June 06, 2011
LOL! You think ice is thick where there isn't any ice! LOL!
Member Since: January 2, 2006 Posts: 127 Comments: 20401
312. cyclonebuster
1:09 AM GMT on June 06, 2011
NOT THICK HERE EITHER.


Member Since: January 2, 2006 Posts: 127 Comments: 20401
311. cyclonebuster
1:07 AM GMT on June 06, 2011

NOT THICK HERE EITHER.

Member Since: January 2, 2006 Posts: 127 Comments: 20401
310. cyclonebuster
1:04 AM GMT on June 06, 2011
Quoting RustyShackleford:


Can't see.


Member Since: January 2, 2006 Posts: 127 Comments: 20401
308. cyclonebuster
1:03 AM GMT on June 06, 2011
NOT THICK HERE


Member Since: January 2, 2006 Posts: 127 Comments: 20401
305. cyclonebuster
12:56 AM GMT on June 06, 2011
Quoting RustyShackleford:


Isn't that extremely thick ice there?


NOPE!
Member Since: January 2, 2006 Posts: 127 Comments: 20401
303. cyclonebuster
12:49 AM GMT on June 06, 2011
OUCH!


Member Since: January 2, 2006 Posts: 127 Comments: 20401
301. iceagecoming
7:26 PM GMT on June 05, 2011
Quoting Neapolitan:

Maybe this guy has the answer.

P.S. -- JB is not a "climate expert". In fact, some of his more illogical remarks seem to indicate that he knows as much about climate as Sarah Failin' does about basic American history. ;-)

P.P.S. -- The only thing more preposterous than claiming with certainty that this year's record tornadoes were caused by global warming is claiming with certainty that this year's record tornadoes had nothing to do with global warming.



Here is what your buddy had to say;
March 19, 2009: During a taping of "The Tonight Show with Jay Leno," Obama jokes about his miserable bowling skills, which were on display during his campaign battle with Hillary Clinton when he attempted to win voters in the Midwest by showcasing his skills at a blue-collar bowling alley and famously throwing gutter-ball after gutter-ball. Obama tells Leno he has been working on his form by practicing in the White House's basement bowling alley. Unfortunately, all he says all he can muster is a paltry 129.

"It's like -- it was like Special Olympics or something," Obama says.

April 4, 2009: In response to a question asking what he learned from European leaders, Obama responds, "It was ... interesting to see that political interaction in Europe is not that different from the United States Senate. There's a lot of -- I don't know what the term is in Austrian -- wheeling and dealing ...

I won't even bother to mention his dismal display with
our most secure ally this past month.


This country would be so much better off with the
the ex-POW and the Gov.
Member Since: January 27, 2009 Posts: 23 Comments: 1061
278. Neapolitan
1:47 PM GMT on June 04, 2011
Quoting RMuller:
Rosie O'Donnell says "global warming" is responsible for tornadoes. Not so says a climate expert:

Link

Maybe this guy has the answer.

P.S. -- JB is not a "climate expert". In fact, some of his more illogical remarks seem to indicate that he knows as much about climate as Sarah Failin' does about basic American history. ;-)

P.P.S. -- The only thing more preposterous than claiming with certainty that this year's record tornadoes were caused by global warming is claiming with certainty that this year's record tornadoes had nothing to do with global warming.
Member Since: November 8, 2009 Posts: 4 Comments: 13538
277. Neapolitan
11:35 AM GMT on June 04, 2011
Quoting RMuller:


That's putting it mildly. These warmists are being confronted with true scientific data every day; not manipulated data from the likes of NOAA and NASA. "Dr" Michael Mann's email will soon be seeing the light of day, whether it be through FOIA, subpoena, or grand jury testimony. Then we'll have further proof of how this entire climate fraud is being perpetrated. It's truly amazing that the University of VA would spend millions hiding these emails using the pretext that it would have cost them thousands to release them. I wonder if this is the same Michael Mann who produced the fantasy show, Miami Vice in the '80s. Seems as if his fantastical climate science mirrors his Hollywood imagination. Maybe he does belong in the State Pen instead of Penn State.

When Dr. Mann is exonerated and proven once again to be the credible, honest scientist his record and his peers show and know him to be, I wonder whether he'll receive the apologies due him by those who disparaged his good name and dragged him through the muck in an effort to discredit his science work. One would hope so, though I sincerely doubt it; even after five major "climategate" investigations failed to turn up a single shred of evidence that climate scientists were engaged in any hanky-panky, I never heard anything that could even remotely be construed as an apology for that. About the closest I've heard is the real Dr. Mueller, head of the BEST project, being forced to acknowledge that, with a small percentage of the data being released, the temps that have been reported for years by other entities were really correct after all, and the planet does indeed seem to be warming. Of course, that wasn't really an apology so much as a tacit admission that much of the contrarian haranguing had been unearned, but, still, it was something...
Member Since: November 8, 2009 Posts: 4 Comments: 13538
276. Neapolitan
11:27 AM GMT on June 04, 2011
Quoting RMuller:


What in the hell are you talking about? The chart you posted showed sea level conditions for the last twenty years. The current levels are the lowest in almost a decade and they are falling quickly.

In your comment #260, you posted a link to an Aviso MSL graph on the "Steven Goddard" blog showing sea levels "dropping like a rock". I in turn posted an MSL graph from the Aviso site that clearly shows MSL rising at an overall trend of 3.25mm per year since 1993--and that includes the years from 2004 through current.

I do see that the graph "Steven Goddard" posted is one that doesn't show the GIA adjustment; perhaps "his" error is in misunderstanding the difference between raw and actual data? Not to mention, of course, the fact that climate is about long-term trends, so even if MSL had dropped 1.4 cm in a year, the overall rise in global sea levels is well-established:

MSL

MSL

That's what I'm talking about.
Member Since: November 8, 2009 Posts: 4 Comments: 13538
275. sirmaelstrom
5:47 AM GMT on June 04, 2011
№ 273
Quoting Ossqss:

Say what>?

Is Biodegradability a Desirable Attribute for Discarded Solid Waste?
Perspectives from a National Landfill Greenhouse Gas
Inventory Model


Only glanced at it, but I'm assuming this has something to do with greenhouse gases released from biodegradable products. If that's the case, I would think that the amounts here would be rather small compared to total emissions. I guess I would have to look at it more closely later.

Anyway, I'm out for the night.
Member Since: February 19, 2010 Posts: 0 Comments: 580
274. sirmaelstrom
5:08 AM GMT on June 04, 2011
Concerning global sea levels and quoting from № 271:
Quoting RMuller:
[...]
As an addendum: if the sea ice is at an all-time low, just exactly where did the water go when MSL is decreasing?


Sea ice is already floating and has little effect on sea levels when it melts. Expansion of water due to warmer overall SSTs (Sea Surface Temperatures) and melt of land-base ice are the chief contributors to global sea levels, the latter the most significant I would think (I'm sure someone will correct me if I'm mistaken).

Also I think Mr. Goddard is placing a little too much emphasis on the Envisat data as the overall MSL has still shown an increase over the same period (See graph in № 266). There may be a slight slowdown occurring the last couple of years, but at the present it is too slight and too short temporally to be significant, I would think.

Far more interesting to me is the second graph in Neapolitan's post (again № 266). Notably, there are many areas on the graph that really seem to bring up the overall average quite a bit, values very close to 12 mm/yr. How much of that variation is due to temperatures differences, I wonder? Is the largest area of extremes in seal level rise, the area north of Australia, due to a larger change of SSTs in this area, or due to changes in the land itself? It seems that the sea level in this area cannot continue to increase indefinitely at triple the rate (and higher, although I'm just eyeballing it here) of the majority of the sea area.
Member Since: February 19, 2010 Posts: 0 Comments: 580
273. Ossqss
2:53 AM GMT on June 04, 2011

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About RickyRood

I'm a professor at U Michigan and lead a course on climate change problem solving. These articles often come from and contribute to the course.