Antarctica

[Chris Knight]

I would say probably a bit of political "correction".

It can't grow outwards indefinitely in the southern ocean current, it has to thicken as well as grow in extent. So the ice edge wobbles to and fro. It's still growing, as the animation below shows.

if it ain't linear, it's probably due to "weather" :lol:

Edited July 3, 2008 by Chris Knight

[Gray-Wolf]

Thank you Chris, and so to the point. Is the circumpolar wind becoming a 'limiting' factor as well as a causal factor for ice growth? if the ice is favouring growing in the lee of features that 'protect' that bit of open water from the worst of the circumpolar wind/current then any step beyond could end in disaster as the 'belt' of wind/currents erodes the ice.

[Filski]

I'm doing some work with the AAO for an aussie LRF this winter. The is an indicator of the strength of the polar low and position of the highs/lows. Lately the AAO has indicated a strong polar low and winds but you can see occasions that roughly coorelate - end of April, etc - with a drop in the AAO. It might be something...

[Gray-Wolf]

For 15 yrs or so years folk have been noting the changes in 'regimes' down there.

Be it the increase in circumpolar winds or increase in snowfall over the peninsula. Maybe there is a 'core change' taking place in the normal weather patterns as the global changes impose upon it. If anything were to interrupt the Katabatic winds from the centre of Antarctica over the southern summer (allowing warmer waters into the coasts) then there would be trouble!

[Gray-Wolf]

[millennia]

Har Har! I see your graph GW and I raise you this!

http://arctic.atmos.uiuc.edu/cryosphere/IM...t.365.south.jpg

How come the anomoly doesn't read zero here?

[Gray-Wolf]

Har Har! I see your graph GW and I raise you this!

http://arctic.atmos.uiuc.edu/cryosphere/IM...t.365.south.jpg

How come the anomoly doesn't read zero here?

cos. IMHO, they can't tell their rectum from their funnybone

Edited July 11, 2008 by Gray-Wolf

[Gray-Wolf]

http://www.sciencedaily.com/releases/2008/...80710115142.htm

Wilkins continues to disintegrate. Now hanging by it's last little ice bridge before the final collapse. Apparently the 'thin' sea ice and warm water under the shelf isn't helping.

[Gray-Wolf]

http://nsidc.org/data/seaice_index/images/..._timeseries.png

Guy's, guy's. You stopped updating me on how far above 'normal ' ice levels were down there so I had to look myself and .....well you can see for yourself (above). Seeing as Antarctica is having one of the coldest winters since '88 I'd have expected more.

Sooooo, what gives? (apart from Wilkins that is ).

[Mondy]

[Gray-Wolf]

Thanks Delta!As Delta's graph above shows quite well the ice anom seems to have peaked early in the season and now, in the middle of one of the coldest winters for many years, seems to have fallen back somewhat.

[bluecon]

Thanks Delta!As Delta's graph above shows quite well the ice anom seems to have peaked early in the season and now, in the middle of one of the coldest winters for many years, seems to have fallen back somewhat.

Why so cold during this period of unstoppable AGW?

[Mondy]

Thanks Delta!As Delta's graph above shows quite well the ice anom seems to have peaked early in the season and now, in the middle of one of the coldest winters for many years, seems to have fallen back somewhat.

Considering the peak appears to be the highest in 20-odd years, I guess a little "fallback" is nothing to worry about.

[Roger J Smith]

Bluecon, it has been pretty widely observed here on Net-weather if not in the weather community in general, that the southern hemisphere has seen some cold episodes in recent winters linked to a colder Antarctica and the larger expanse of sea-ice which is definitely at a maximum for the recent past at least. I can think of half a dozen people who have commented on this, certainly the temperatures this past week over the Antarctic continent have been very cold, it was even into the -30s in the most temperate part south of South America, and well below -60 C over the high plateau near the South Pole.

The IPCC seems to downplay this fact in their reports, and the media in general still obsess about one or two details they can glean about ice shelves breaking off (a natural occurrence in all climatic episodes) and any mild weather records they happen to discover from the peninsula that points to South America (one place where it sometimes does get a bit milder).

However, southern hemisphere perceptions are more influenced by temperate zone weather events and here the recent menu is somewhat mixed as it has been in the northern hemisphere. Droughts, heat waves, wet spells, cooler than average episodes, all mixed in together, probably the southern hemisphere is also seeing a slight overall downturn after a peak of warmth in the 1990s.

I'll just say for the record that as an AGW skeptic I do not choose to cherry pick events because this can easily turn around to bite you, however, the overall impression I have is that the Antarctic is getting slightly colder this decade. On the other hand, I could entertain a global warming theory that included an expanded southern polar region, not all hemispheric warmings are in phase with the other one, although that does seem to be the predominant mode during the last complex glacial era. The small part of the AGW theory that I do accept, let's say one third of the observed warming since 1980, might be unevenly distributed by climatic region. The biggest impacts could be in climate zones that are already warm and unstable by nature, and negative feedback is conceivable in a cut off stagnant polar climate such as they have over Antarctica. Perhaps it's not a coincidence, but some very cold temperatures (relatively speaking) have recently been noted over central Greenland. This could be an extension of the general principle in meteorology, when you shunt warm, stable air over a cold surface, it tends to stagnate as a massive dome of high pressure. The large domes of ice mask the true extent of the high pressure, as the weather watchers among us know only too well, a Greenland high is not necessarily a very stable or long-lived feature like a true arctic high.

I can really recommend a book called "Climate Change in Prehistory: An End to the Age of Chaos" by William Burroughs. This presents the latest research on the complex climate and related human and natural history throughout the Wisconsin or Wurm glacial era that was in full swing up until about 12,000 years ago and has only reached its post-glacial stage since about 6000 BC. This will really give anyone a complete picture of all the complex changes in the northern hemisphere climate in particular, and provide a really good foundation for anyone, whether an AGW proponent or skeptic, or just somebody looking for answers, to assess what recent facts or theories really mean in a larger context. I'm not saying it will answer every question, it may raise more, but it does provide a very sobering perspective for the current phrase du jour, climate change. It does not attempt to discuss the validity of climate change theories today.

I've been doing a lot of other reading this summer (yes, we have those in Canada) on the subject of "the ice age" which I've come to understand is a layman's term for the last major glaciation, when geologists speak of "the ice age" they are more likely to be talking about the period of the recent four major glaciations, or four ice ages to us. I may start a thread to discuss some of this, but the most salient fact that emerges is that we live in a relatively unusual warm climatic period by recent standards, and these warm periods are also lower variability periods -- when the climate gets colder, it also gets more variable. Now living in North America and trying to imagine a climate with twice the current variability is no easy exercise, we have about as much variability now as we really need. The glacial climate must have been quite different from anything we've seen in our lifetimes, even the really cold episodes one could mention would probably seem like the warmest parts of a glacial epoch.

Edited July 15, 2008 by Roger J Smith

[Iceberg]

Roger out of interest what's your view on the Ozone depleation and upper atmosphere changes effecting the temperature below and possibly the South poles polar jet getting stronger retaining the colder inner core, allowing for warming up of the extremities and subsequent ice sheet/shelf melt.?

[BLAST FROM THE PAST]

Thanks Delta!As Delta's graph above shows quite well the ice anom seems to have peaked early in the season and now, in the middle of one of the coldest winters for many years, seems to have fallen back somewhat.

It did exactly thast last year GW and the ice maxima wasn't reached until Oct/Nov....and this year is way ahead of last year.

BFTP

[Roger J Smith]

Iceberg, I'll look into that subject (again) ... is this a current theory or was it developed 10-20 years ago?

[bluecon]

Thanks Roger

If I get a chance I will read the book. Busy lately with everything in turmoil in the markets and such. I am a lot more worried about an economic imploshion than AGW.

And the Arctic had a cold last winter and the summer temps are not very warm. Something appears to be going on, although it is only one year. Must be the climate changing.

[0000]

Iceberg, I'll look into that subject (again) ... is this a current theory or was it developed 10-20 years ago?

Roger sorry to impose but again i'll ask the significance of a completely ice free Antartic/artic in ley mans terms please

[Gray-Wolf]

http://nsidc.org/data/seaice_index/images/..._timeseries.png

When I start to think I'm lossing the plot I really get concerned.

So what the shell is going on? We start the southern winter with sea ice levels well above the 79-2000 average and then , through the course of the winter (which is one of the coldest for many years) sea ice levels fall back to the 79-2000 average.

Does this not seem to be a bit back to front?

Ta,

[Mondy]

http://nsidc.org/data/seaice_index/images/..._timeseries.png

When I start to think I'm lossing the plot I really get concerned.

So what the shell is going on? We start the southern winter with sea ice levels well above the 79-2000 average and then , through the course of the winter (which is one of the coldest for many years) sea ice levels fall back to the 79-2000 average.

Does this not seem to be a bit back to front?

Ta,

So since the rapid thickening of ice sheets in the majority of Antartica is obvious and temps now much colder down there, will there soon be cause for concern that sea levels will recede??!!

[Gray-Wolf]

So since the rapid thickening of ice sheets in the majority of Antarctica is obvious and temps now much colder down there, will there soon be cause for concern that sea levels will recede??!!

errrm, oft time's when one increases the 'reservoir' behind a failing dam you can expect trouble. I think you'll find gravity is still a constant Delta..........

[Roger J Smith]

Hannegan, I noted your question but could you possibly rephrase it because I am not too sure what you are asking me.

Do you mean free from ice on land as well as in the oceans? And by significance do you mean, what would this mean for global climate, or for the regions themselves?

I could hazard a wild guess if I had a clearer idea what question you were asking there.

[beng]

http://arctic.atmos.uiuc.edu/cryosphere/IM...t.365.south.jpg

Ice increasing once again relative to the average - will it continue or grind to another halt?

[Gray-Wolf]

http://arctic.atmos.uiuc.edu/cryosphere/IM...t.365.south.jpg

Ice increasing once again relative to the average - will it continue or grind to another halt? :lol:

There are generally 2 ice 'tounges' that push out from in front of the wedell sea and the Ross sea. It could be that the presence of the circumpolar belt of high winds does limit the extent that the ice can grow out to. In more settled periods the ice pushes further out from these areas but is then broken and drifts off when the heavy weather returns.

Living in splendid isolation does work both ways (nothing out, nothing in)