Antarctica

[Gray-Wolf]

Seems we lost our 'Antarctic' thread so best start another.

Along with the changes to the wind patterns/oceanic mixing that is driving change down there it would seem the the 'healing' of the Ozone is set to reverse the central continental cooling in line with rest of the general planetary 'warm up'.

http://www.sciencedaily.com/releases/2008/...80424113454.htm

[J07]

Goodness me, a scientific article that uses Miles and Fahrenheit. It's like stepping back into the 18th century.

The scientists found that as ozone levels recover, the lower stratosphere over the polar region will absorb more harmful ultraviolet radiation from the sun. This could cause air temperatures roughly 6 to 12 miles above Earth's surface to rise by as much as 16 degrees Fahrenheit, reducing the strong north-south temperature gradient that currently favors the positive phase of SAM, said the research team. The supercomputer modeling effort also indicated that ozone hole recovery would weaken the intense westerly winds that currently whip around Antarctica and block air masses from crossing into the continent's interior. As a result, Antarctica would no longer be isolated from the warming patterns affecting the rest of the world.

That is quite a claim. I understand that they're saying with less of a thermal gradient between the pole and the equator, the westerlies would weaken, which makes sense, and this would possible be a positive feedback situation. However, with no significant land mass between 60S and 50S, they are always going to be very strong winds regardless.

My gut feeling doesn't trump a supercomputer though.

[millennia]

Seems we lost our 'Antarctic' thread so best start another.

Along with the changes to the wind patterns/oceanic mixing that is driving change down there it would seem the the 'healing' of the Ozone is set to reverse the central continental cooling in line with rest of the general planetary 'warm up'.

http://www.sciencedaily.com/releases/2008/...80424113454.htm

So what do we do, take an axe to lots of fridges? When you get articles basically stating that the effects of trying to clear up a previous mess will invigorate another one it's enough to make you give up entirely. The ozone hole was quite a rapid development that will take a lot of time to be reversed, and was also a great example of a human screw up that can have very wide ranging if not totally planetary consequences. However should this latest theory hold any water any effect will be the far side of the latest solar minima so there are more pressing things to concentrate on - and there's sod all we can do about it anyway except open up the ozone hole again.

Great to see an article that didn't blame CO2 for a change though.

[beng]

The thing is though that according to the climatic data that's out there, most of the warming has occured in the Northern Hemisphere - so even if we did see a reduction in the polar westerlies down there - why shoud this then expose Antartica to the effects of the warming trend - given it's been primarily focused in the Northern half of our globe.

Based on the current trend, yes it would likely warm somewhat, but not to any alarming level - not unless the IPCC is correct with its most extreme possibility of a 5c+ rise in the next century - in which case I suspect the polar westerlies probably wouldn't save it anyway

[BLAST FROM THE PAST]

But what was it like before the Ozone depletion? There hasn't always been a big hole in the ozone and antarctica didn't melt into the sea then.

BFTP

[Gray-Wolf]

But what was it like before the Ozone depletion? There hasn't always been a big hole in the ozone and Antarctica didn't melt into the sea then.

BFTP

Neither has there been 6 Billion of us screwing over the planet before............

[ghrud]

Southern sea ice building rapidly again now and still well above average.

[BLAST FROM THE PAST]

Neither has there been 6 Billion of us screwing over the planet before............

GW

What the hell has that got to do with my question and why does having more people affect what happens in the antarctic as regards to Ozone and no Ozone?

BFTP

[johnholmes]

had there not been umpteen billion of us around BFTP then the ozone problem would not have occurred. It was a direct result of us all wanting to use fridges, hair sprays etc etc that caused the ozone hole, hence the Montreal protocol, or whatever ts title banning aerosols of that type?

link to BAS (British Antarctic Survey site), their scientists discovered it in spite of NASA/NOAA trying to discredit their findings initially.

http://search.antarctica.ac.uk/search?q=oz...ault_collection

Edited April 25, 2008 by johnholmes

[davehsug]

had there not been umpteen billion of us around BFTP then the ozone problem would not have occurred. It was a direct result of us all wanting to use fridges, hair sprays etc etc that caused the ozone hole, hence the Montreal protocol, or whatever ts title banning aerosols of that type?

link to BAS (British Antarctic Survey site), their scientists discovered it in spite of NASA/NOAA trying to discredit their findings initially.

http://search.antarctica.ac.uk/search?q=oz...ault_collection

But how do we know this? A question I've still never had answered. The hole in the ozone layer was "discovered". As far as I'm aware, we have no knowledge of any history. Is it a natural event, added to by man's activity? Was it there in some form 100 years ago, 1,000 years ago?

Answers anyone?

Dave

[Optimus Prime]

There's also an active volcano in the Antarctic that emits a load of sulphur and other gases into the Antarctic's atmosphere. That plays a big part in Ozone reduction from what I can gather.

Edited April 25, 2008 by Optimus Prime

[BLAST FROM THE PAST]

had there not been umpteen billion of us around BFTP then the ozone problem would not have occurred. It was a direct result of us all wanting to use fridges, hair sprays etc etc that caused the ozone hole, hence the Montreal protocol, or whatever ts title banning aerosols of that type?

John

Guilty re fridges but not with hairspray

So the antarctic would have been on a continued warming trend would it if the ozone had not been depleted. I am referring to the initial post whereby us 'healing' the ozone is going to reverse the cooling, change the climate etc etc. Indeed as some have mentioned has this all happened before, if it didn't why is the antarctic going to melt this time when ozone is back to completion? Assuming man made the hole and ozone has always been complete why didn't this alleged scenario happen in the past?

According to that report man's damaging ways stopped the antarctic from being at a very warm/melting state...which quite frankly I think is a little way off the mark.

BFTP

Edited April 26, 2008 by BLAST FROM THE PAST

[beng]

Seeing as the topic of ozone layer depletion has come up - apparently there maybe new data suggesting the cause is natural

http://www.nature.com/news/2007/070924/full/449382a.html

I don't have access to the article so I'd be interested in knowing whether anyone's read it?

Edited April 26, 2008 by beng

[Devonian]

There's also an active volcano in the Antarctic that emits a load of sulphur and other gases into the Antarctic's atmosphere. That plays a big part in Ozone reduction from what I can gather.

Can you explain the mechanism proposed and show a correlation between the activity of the volcano and ozone loss?

Seeing as the topic of ozone layer depletion has come up - apparently there maybe new data suggesting the cause is natural

http://www.nature.com/news/2007/070924/full/449382a.html

I don't have access to the article so I'd be interested in knowing whether anyone's read it?

A quick google of the article title reveal quite a few hits, mostly they are sites which actively oppose what we might call 'green' issues.

I think this paper is, as you say, just suggesting. It's one paper, and not so far full results. Lets see if other scientists back it up. But, as I say, expect those with a conviction to latch onto it.

Edited April 26, 2008 by Devonian

[Admiral_Bobski]

Can you explain the mechanism proposed and show a correlation between the activity of the volcano and ozone loss?

Hi Dev,

I don't know specifics about Antarctic volcanoes, but it is well-established that volcanic eruptions cause localised ozone depletion - sulphates and chlorine churned into the atmosphere by eruptions cause the ozone to break down by exactly the same mechanism that CFCs cause ozone depletion (basically by preferential bonding).

Interestingly, there is a known link between increased UV and ozone depletion. The theory goes that during "normal" sunspot phases the rate of ozone break-up and ozone bonding pretty much cancel each other out, leading to a zero net effect. During periods of heightened sunspot activity there is more incoming UV which causes active depletion of stratospheric ozone (ozone doesn't form as quickly as it is destroyed). Since the last couple of sunspot cycles have been higher than the historic average, perhaps the ozone hole has somewhat more to do with increased incoming UV than has been assumed.

CB

[johnholmes]

But how do we know this? A question I've still never had answered. The hole in the ozone layer was "discovered". As far as I'm aware, we have no knowledge of any history. Is it a natural event, added to by man's activity? Was it there in some form 100 years ago, 1,000 years ago?

Answers anyone?

Dave

they knew it was there because over previous decades BAS who monitored events in Antarctica, never reported it before, or that is how I understand what happened but best to read all the literature there is on their web site.

correction

The hole was there, it came and went but had never been the size it showed up as when NASA tried to say it had not got larger.

Since the Montreal Protocol it has slowly decreased in size as far as I am aware, but again read the BAS information on this.

Edited April 26, 2008 by johnholmes

[Optimus Prime]

Can you explain the mechanism proposed and show a correlation between the activity of the volcano and ozone loss?

I would if I could, be bothered to do some research online but I can't. It's common knowledge Volcanos make a huge impact on the atmosphere above them due to the gases released. It's bound to have some negative freeback on the Ozone if these same natural gases we release cause this apparent effect.

[Gray-Wolf]

I would if I could, be bothered to do some research on line but I can't. It's common knowledge Volcano's make a huge impact on the atmosphere above them due to the gases released. It's bound to have some negative free back on the Ozone if these same natural gases we release cause this apparent effect.

If you couple the volcanic output with the isolation, due to the circumpolar winds, of the polar air down there then you may find a mechanism that allows moderate volcanic events to have a very localised 'major' impact. The southernmost 'active volcano (mount terror?) is one of the few volcanoes to have a permanent lava pool in it's crater so it must be in a permanent state of 'out gassing' into the polar air masses.

In the same way as we seek to mimic nature with 'man made' inventions I'm sure, somewhere in nature there exists a 'natural version' be it CF C's or aspirin and it has it's 'natural impacts. It doesn't mean that we did not contribute to the Ozone hole with our activities because we find a 'natural' way of producing the same effect, if anything it helps confirm our impact.

In so far as our changing climate man plus nature seems a very bad combination.

If we look at CO2 then we know from records that temp rises induce natural CO2 surges. We have warmed the world by releasing CO2 but now nature will have her own 'dose' to add (by sink failures, biomass decay, tundra melting,cathrate releases).

Maybe when nature 'kicks in 'with her tuppenny worth the nay sayers will reveal themselves by their eagerness to blame a 'cycle' (it wasn't me guv.')

Ten metres of sea level rise from moderate Antarctic melt and Greenland meltdown will not be out of the question in the lifetime of some of us or some of our kids.

[Admiral_Bobski]

If we look at CO2 then we know from records that temp rises induce natural CO2 surges. We have warmed the world by releasing CO2 but now nature will have her own 'dose' to add (by sink failures, biomass decay, tundra melting,cathrate releases).

Agreed that temperature rises induce CO2 rises, which is shown by the historic record. But then you take it as read that our CO2 emissions have warmed the world, which will lead to natural release of CO2 which will warm the world further. There was a debate on these boards several months back about this very issue - if CO2 follows temperature, but then temperature starts to follow CO2 at some point, why does the historic record fail to show some kind of "swapover" point?

If temperatures rise all by themselves (as has happened historically), leading to CO2 being released, then the released CO2 forces temperatures higher then there should, by all rights, be a step-change in warming at that point (because the CO2-induced warming would be in addition to the already-present natural warming). There is no such point in the historic record, which suggests either that natural temp increases just happen to coincidentally stop or slow down at the point of CO2 taking over - which would take a coincidence of "Warming Just Happened To Begin With The Industrial Revolution" proportions - or else the forcing effect of CO2 is negligible or non-existant.

I remember that I raised this point with P3, and he asked the question of a climatologist with whom he was in contact. The climatologist was unable to offer an explanation.

CB

[BLAST FROM THE PAST]

Ten metres of sea level rise from moderate Antarctic melt and Greenland meltdown will not be out of the question in the lifetime of some of us or some of our kids.

GW

It is whilst record ice levels are being recorded

BFTP

Edited April 27, 2008 by BLAST FROM THE PAST

[Gray-Wolf]

GW

It is whilst record ice levels are being recorded

BFTP

As you know the degradation of the ice sheets in Antarctica is not dependant on sea ice levels, in fact more sea ice exerts greater leverage on shelf edges when sea swells are icreased (due to a faster circumpolar wind) leading to an increase in shelf failure. We all know from the Peninsula what happens to the glaciers behind when you take away the fringing coastal shelf ice and just how busy things are below both East and West Antarctic ice sheets.

[ghrud]

As you know the degradation of the ice sheets in Antarctica is not dependant on sea ice levels, in fact more sea ice exerts greater leverage on shelf edges when sea swells are icreased (due to a faster circumpolar wind) leading to an increase in shelf failure. We all know from the Peninsula what happens to the glaciers behind when you take away the fringing coastal shelf ice and just how busy things are below both East and West Antarctic ice sheets.

Too much ice, too little ice; you can't have your cake and eat it!

[Gray-Wolf]

Too much ice, too little ice; you can't have your cake and eat it!

Without wanting to sound too British Rail you need be mindful of the type of ice you are talking about.

Which would you rather be facing ,ghrud , if it were flowing towards you 1m of sea ice or 3km of glacial ice in the form of an ice sheet????

You see they may be frozen water but they are oh such different beasties.

Which do you imagine has more to fear from gravity? 1m of ice or 3km of ice? Which ice type would keep supercooled water fluid and under immense pressures ? 1m of ice or 3km of ice? Which type of ice poses the biggest threat to mankind on it's ablation? 1m sea ice or 3km of continental ice sheet.......

Be careful of words that only wish to illuminate our facile sides ghrud.....

Ho Hum.

[Iceberg]

I missed this article from March.Sorry if it's already been posted.

http://nsidc.org/news/press/20080325_Wilkins.html

Antarctic Ice Shelf Disintegration caused by melting trigger.

And this in a season which was described as very good for sea ice. Hope we don't get a bad one.

[Gray-Wolf]

Though I'm struggling to find the article research into glacier movement have recently recently declared that they move in a different way to what we once thought. Seismometers on the ice (in both Greenland and Antarctica) have been showing many 'glacier Quakes' since the study started in 03'. Initially this was put down to calving at the snout but recent triangulation work has shown that the focus of the quakes is from within the glacier itself. It would appear that instead of a steady 'creep' the whole glacier has snaps where it moves a distance in one catastrophic failure and then 'freezes back to the base (the source of the quakes.....some which dwarf most 'normal ' earthquakes giving a 7 on the Richter scale and easily measurable from stations in Australia).

The acceleration of glaciers would seem to involve more and greater 'steps' with each jolt and obviously, if the momentum is great enough, has the ability to drain huge quantities of glacial ice in a very short 'event'.

With the upland melt noted on the EAIS lubricating the glaciers feeding Ross Embayment the fear now is that the glacial movement itself could push/fracture the embayment itself releasing the upland ice into the arctic ocean and is not reliant upon the shelf ablating prior to any draining of the upland ice.

The Wilkins breakup may have been this type of event with the shelf still trapped in winter sea ice when it failed.