Increasing Antarctic Albedo?

[Jim Hunt]

I have recently found myself in conversation on Twitter with a somewhat sceptical enquirer. We've agreed to meet up here for a hopefully sensible discussion:

https://twitter.com/jim_hunt/status/559410838080356353

The main query in brief, if I've understood it correctly:

Aren't you concerned about increased albedo at present due to increasing Antarctic sea ice?

I pointed out that personally I am more concerned about melt ponds in the Beaufort Sea in the Arctic summer, but this is the Antarctic section so let's try and keep on topic!

[Lennart van der Linde]

personally I am more concerned about melt ponds in the Beaufort Sea in the Arctic summer

Looking at this graph from the ASI-blog I would be more concerned about declining Arctic albedo too:
https://d3800158-a-62cb3a1a-s-sites.googlegroups.com/site/arcticseaicegraphs/longterm/2014_sea_ice_CT_min.png?attachauth=ANoY7crz7Xre0VmKvWQVvkXCyM0amPpNaCfK9-qdEiQFspCzWVY2_xT_aT4KLumNk6VGMRnz5PRGYS0wD1TYlGAQRlMpaHz3vMy892TnqZxSH4ADfZ-70Wc_NSYKX1sUMHVbTcRmLS_JeiCBPIt9BLNnU2OhnzbH_CTw9PRSbHbQs0Pf587rQyaS2c5FSnRyhyEGure8p2afIpNpcCLHksQyMMsH0L79cc2FafcvYvjfK6oYEuNuBBWJE3JnyAHN-q-yVi22SvOe&attredirects=0

Average minimum Antarctic sea ice area, as a rough indicator for albedo, has gone up maybe 20% from about 1.7 million km2 to around 2 million km2 from 1979-2014, while average minimum Arctic sea ice area has gone down over 40% from a little over 5 million km2 to around 3 million km2 over this period.

So over the past 35 years, we lost maybe about 1.7 million km2 of sea ice at minimum, as a rough indicator for global albedo loss from global sea ice. And then we haven't looked yet at declining snow cover and albedo in the Northern Hemisphere, and at warmer ocean water reaching Antarctic glaciers from below.

[crandles]

http://www.realclimate.org/index.php/archives/2014/12/clarity-on-antarctic-sea-ice/

As it turns out, comparing observations with the results of model experiments like those of Bitz and Polvani (2012) is misleading. Most such experiments are equilibrium experiments: What’s done is to run a model under “preindustrial” conditions, and then to run it again with reduced ozone and increased CO2, and to look at the difference. This provide a measure of what will eventually happen (at least in the model) after many decades or centuries. But when you look at the transient response to changes in the circumpolar winds, as Marshall et al (2014) have done, it turns out that two important things happen. The winds tend to push the sea ice boundary northward, as we would have expected. But the winds push the surface ocean northward too, and cause a slow rise in the isopycnal surfaces (surfaces of constant density). This brings relatively warm deep water closer to the surface, eventually melting sea ice after a period of a few decades, countering the initial increase in sea ice. These results explain why equilibrium model calculations find sea ice decreasing in response to ozone forced changes in the circumpolar winds, and also why observations show the opposite. Not enough time has passed for the equilibrium response to be manifested. These results suggest that some time in the next few decades, there will reverse, and average sea ice will begin to decline.

Furthermore, there’s a whole lot more going on with the winds than just “increased westerlies”. In the areas where the big sea ice losses have occurred, the concept of “circumpolar westerlies” isn’t very relevant. A far more important measure of wind variability in the Amundsen and Bellingshausen Seas is the Amundsen Sea Low (ASL).5

...

So, do we get the right answer if we take into account all of the wind changes that have occurred over the last few decades? The answer is yes. This is nicely illustrated in a study by Holland and Kwok (2012), who showed that wind, ice motion, and ice concentration changes match each other remarkably well. Where the wind has been increasingly northward, concentrations are increasing; where wind and ice motion changes are toward the continent, ice concentrations are decreasing. And this year, Holland et al. (2014), showed that when they drive an ocean and sea ice model with observed winds — not just increased westerlies, but the full range of wind changes, as calculated by the ECMWF (European Center for Medium Range Weather Forecasting) –- they correctly simulate the overall expansion of sea ice, and they also get the pattern of changes pretty much spot-on. To be sure, the authors note that not all the details are explained, and they highlight the possibly greater importance of thermodynamic consideration (i.e. ocean temperature/stratification) in some areas than in others.  Also, the period they study (1992-2010 only) is pretty short.  The results are nevertheless pretty compelling. Just like the observations, the calculations show large decreases in the Amundsen and Bellinghausen seas, but increases nearly everywhere else.7

In short, the models are getting it right and increases in Antarctic sea ice area will turn towards decreases in area in future.

[Shared Humanity]

I also think it is wrong to only consider changes in SIE in the Antarctic (both min and max) when trying to understand the potential changes in albedo. You need to consider the entire southern pole cryosphere. What is the area of the ice covered Antarctic land mass? Include this to get a sense of the percentage increase that a 330K km2 increase in minimum means. I would imagine it is pretty damn small.

[crandles]

What is the area of the ice covered Antarctic land mass? Include this to get a sense of the percentage increase that a 330K km2 increase in minimum means. I would imagine it is pretty damn small.

Area of the ice covered Antarctic land mass doesn't change much so at least the noise in this number doesn't mask the sea ice area increase.

If it is 'pretty damn small' to the point of insignificance(?) then the change in Arctic sea ice area is also pretty damn small to the point of insignificance? Hmm., that might not be the way to argue it. Though, there is a lot of ocean in southern hemisphere with lots of heat capacity so I suppose you could argue the albedo effect in Southern hemisphere is more diluted by lots of ocean with high heat capacity.

However I think that argument is practically conceding that Antarctic sea ice will continue increasing while the science may have other ideas. If SH oceans are warming then the ice area increase is not going to continue indefinitely.

[S.Pansa]

Tamino posted about this a couple of years ago https://tamino.wordpress.com/2012/10/01/sea-ice-insolation/. Interesting read as usual, even If I just understand .

For the differences in insolation see the image below from the post. It shows:

Since 2012 is incomplete, this doesn’t include this year’s ever-so-slightly record high Antarctic sea ice or way-astounding record low Arctic sea ice. But you can see the trends. Clearly. The trend has shown an increase in Antarctic sea ice insolation of about 53 TW, and a decrease in Arctic sea ice insolation of about 329 TW. That’s over 6 times as great.

As fare as I can see, this is without the changes in snow cover, changes that are, too,  much more pronounced in the Arctic. And as the real climate article notes: The growth in Antarctic Sea Ice extent is most certainly temporary.

The Arctic Sea Ice on the other hand ...

So at least I am much more concerned with the albedo changes in the Arctic (I seem to recall a recent paper that estimates the forcing for a complete loss of Arctic Sea Ice in the range of 3 watts per meter [Caldeira 2014??]). Of course the Antarctic provides a lot of other interesting features worth to be concerned about, as Lennart and AbruptSRL have shown.

[AbruptSLR]

I certainly concur that for many decades to come Arctic Amplification will be greater than Antarctic Amplification (on average), and I also concur that the Southern Ocean is not in equilibrium and that within 2 or more decades the Antarctic Sea Ice extent should start decreasing.  However, with a longer-term prospective (say after 2050) one should remember that:

(a) The Antarctic Sea Ice extent actually accelerates ice mass loss from Antarctic marine glaciers by protecting advected warm Circumpolar Deep Water from cooling as it crosses continental shelves on its way to melt ice from the bottom of ice shelves and from the grounding lines of marine glaciers.  Thus until sometime around 2050 the presence of the sea ice is likely accelerating ice mass loss from the Amundsen-Bellingshausen Seas Sector and from key marine glaciers like Totten in East Antarctica.
(b) After 2050 when the Antarctic Sea Ice extent will almost certainly decrease, the combined decrease in albedo and the increase in local atmospheric humidity, will both serve to accelerate the cliff failure and hydrofracting collapse mechanisms described by Pollard et al 2015; which will likely lead to a significant partial collapse of the WAIS by 2100, which will accelerate Arctic Amplification by pushing warm Pacific Ocean water into the Arctic Ocean via the Bering Strait.
(c) The partial collapse of the WAIS will further decrease Antarctic albedo by opening new seaways by 2100; which will carry in more warm ocean water to melt more East Antarctic marine glaciers, which will contribute to more Antarctic Amplification.
(d) If things get bad enough (ie we stay on a BAU to say 2100) then we are at risk of seeing a shift in atmospheric circulation patterns into an equitable pattern that will carry tropic heat directly to one or both poles.

[Jim Hunt]

All of which reminds me that part of my recent long winded Twitter conversation included:

http://climatesight.org/2015/01/16/the-most-terrifying-papers-i-read-last-year/

[AbruptSLR]

Jim,

If you need more talking points (Twitter points) as to why the current trend for increasing Antarctic Sea Ice extent is temporary, you can scroll through the posts in the following thread:

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

[Jim Hunt]

With the Antarctic sea ice extent minimum rapidly approaching, and particularly for any Badgers that may be lurking, here is the preliminary report following the Arctische Pinguin's recent journey to his ancestral home:

[LRC1962]

In the Antarctic the usual deflecting argument is always the increasing sea ice area and therefore the albedo. The overwhelming problem in the Antarctic as AbruptSLR keeps pointing out is the melt of the ice sheets. Once they really start affecting sea level (as in cm rather mm) it won't matter how much the albedo has risen or not anyone on the coastline will have to move minus any equity you used to have.

[Jim Hunt]

The overwhelming problem in the Antarctic as AbruptSLR keeps pointing out is the melt of the ice sheets.

Here's the first regional area graph. It's currently being advertised on Twitter, where a certain "TallBloke" admits he doesn't have a clue!

https://twitter.com/jim_hunt/status/563332927443173376

Wipneus is busy automating the process of producing regional graphs, as he has done for the Arctic. In the mean time here's a few manually created ones from yours truly:

http://GreatWhiteCon.info/resources/antarctic-sea-ice-graphs/

[Jim Hunt]

Tom Woods (of Weather Underground fame) is commenting on the Twitter thread above:

It's called Antarctic Circumpolar Waves + topography = regional SIE. Antarctica seaice extent will take a downward trend over next 20yrs. It has to do with ACWs. Due to wave axises (sic) 20yrs hence. Bellingshausen Sea will no longer be posted, but Weddell and Ross will.

Any thoughts on the ACW from the Antarctic experts in here?

[AbruptSLR]

As the linked reference indicates, the ACW is a complex phenomenon with input from different ocean basins and atmospheric conditions, but which is dominated by subtropical input from the South Pacific associated with the ENSO.  As large ENSO events (El Ninos/La Ninas) happen on a 15 to 20 year cycle, it is reasonable to believe that some mode of the ACW would have a period on this time-scale, which would affect the SSTA and PrWat in the Southern Ocean, which would in-turn affect a change in the Antarctic Sea Ice extent.  However, I am not familiar with any particular phase relationship at the moment, but the 1997-98 Super El Nino was about 17 years ago so possibly there could be a natural mode period involved.

Peterson, R. G., and W. B. White (1998), Slow oceanic teleconnections linking the Antarctic Circumpolar Wave with the tropical El Niño-Southern Oscillation, J. Geophys. Res., 103(C11), 24573–24583, doi:10.1029/98JC01947.

http://onlinelibrary.wiley.com/doi/10.1029/98JC01947/abstract

Abstract: "A case study for the period 1982–1994 shows that a major source for the Antarctic Circumpolar Wave is in the western subtropical South Pacific, where interannual anomalies in sea surface temperature (SST) and precipitable water (PrWat) form. Once established, these interannual anomalies, in tandem with anomalies in sea level pressure (SLP), move south toward the Southern Ocean. The system then migrates east around the globe through a combination of oceanic advection with the Antarctic Circumpolar Current and ocean-atmosphere coupling. The coincidence of interannual anomalies in SST, SLP, and PrWat indicates the extratropical ocean and atmosphere are tightly linked on these timescales. Large portions of the interannual SST anomalies branch advectively northward into the South Atlantic and Indian Oceans, ultimately reaching the tropics in each basin some 6–8 years after appearing in the low-latitude Pacific. This constitutes a slow, oceanic teleconnection that is unique in climate dynamics, made possible by the continuity of Earth's oceans via the Southern Ocean. In the tropical Indian Ocean these interannual anomalies move east and arrive at the Indo-Pacific transition in advance of the trans-Pacific propagation of the respective El Niño-Southern Oscillation (ENSO) phases. The interannual SST and PrWat anomalies that appear in the subtropical South Pacific are directly linked with the ENSO cycle on the equator through anomalous vertical convection and a regional overturning cell in the troposphere, the same cell that initiates fast planetary waves in the atmosphere that carry ENSO signals around the southern hemisphere on much shorter timescales."

[AbruptSLR]

Also see the following threads on similar topics:

http://forum.arctic-sea-ice.net/index.php/topic,904.50.html

http://forum.arctic-sea-ice.net/index.php/topic,724.0.html

[SCYetti]

The biggest difference may be that the Antarctic's increased albedo occurs in the dark of winter. The Arctic's lessened albedo occurs in the light of summer.