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Post by icefisher on Dec 28, 2014 22:19:44 GMT
The current literature recognizes that the MWP and the LIA were both global events. Only the folks who couldn't model them tried to make them regional. Mr. Lamb was more correct in his analysis than those that followed till a few years ago again, when the regional idea was overcome by the proxy data all over the world in regards to both LIA and MWP. Only those in denial still cling to the short lived belief that the MWP and LIA were regional. The same group that clings to the idea that regional arctic ice losses is being caused by global-wide warming. . . .its only regional when convenient.
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Post by sigurdur on Jan 3, 2015 6:27:20 GMT
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Post by douglavers on Jan 3, 2015 8:40:37 GMT
I've long known I am simple minded, but I can't understand how a paper can suggest the Antarctic [or rather its ice sheet] is unstable, when sea ice levels keep breaking new extent records. This is for the period over which serious [accurate] measurement was possible.
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Post by graywolf on Jan 3, 2015 12:16:20 GMT
C'mon Doug! there are plenty of papers outlining why AGW aumented winds and freshening of surface water by melt allows us to regain some of the sea ice levels we used to enjoy.
The sad thing is that we now know that such conditions are what were present the last great land ice melt ( cool fresh surface, warm bottom waters)as the shelfs fall easier when attacked by warm water below than they do from warm air above.
The current switch from deep water warming to surface water warming across the world oceans signals a return to the conditions we saw in the 80's/90's so we can expect Thwaites/P.I.G. to resume their massive loss rates, sadly Thwaites is just about clear of the choke point as it migrates inland and will soon enter a wide basin massivel increasing its potential to calve bergs.
My concern is that this past 7 years has seen the warm water not only arrive at the base of ross but also to begin its work there. Ross holds metres of sea level rise in its mass and rests on the sea bed well below sea level. Ross disappeared the last time we had atmospheric CO2 at these levels and so it appears we are waiting for its demise but how fast will such a collapse take?
Do the huge 'rucks' under the surface of the shelf, from the over run of ice behind when the front stalled and cemented to the bed the last time it formed, mean that the shelf is 'spring loaded' and once enough of the basal contact melts the shelf will float forwards for break up and float off from Ross Sea? That process would take less than a decade and raise ocean levels by over 4m. Are we ready to mitigate such or do we see cities abandoned?
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Post by Ratty on Jan 3, 2015 12:40:31 GMT
GW, regarding warm water, have you seen this? Could it be a factor in some ice melting, or is it outside the alarmist meme?
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Post by graywolf on Jan 3, 2015 16:43:32 GMT
There will be an input under some sectors of the W.A.I.S from geothermal but has this suddenly 'peaked' over the past 30 years? The geologists have not been alerted to the tell tale signs of magma migration and the ice sheet itself shows none of the tell tale signs of such ( as we see in Iceland after active phases of sub glacial activity).
This , of course, is no guarantee that the impacts on that current stability of shedding gigatonnes of ice overburden will not cause issues? Both earthquake activity and increases in volcanic activity are part of isostatic rebound and so I guess that we may need to examine just what an eruption ( fissure type) would mean for both flow rates of the ocean terminating glaciers and the dropping in height of the ice sheet to warmer lower levels?
Personally I think the current warm bottom waters impacts on grounding lines ( and the upstream glacial retreat that they are driving) are far more cause for concern than isolated magma intrusions beneath a limited area of the W.a.I.S. pose as the scales of impact are, excuse the pun, poles apart?
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Post by icefisher on Jan 3, 2015 17:08:24 GMT
There will be an input under some sectors of the W.A.I.S from geothermal but has this suddenly 'peaked' over the past 30 years? The geologists have not been alerted to the tell tale signs of magma migration and the ice sheet itself shows none of the tell tale signs of such ( as we see in Iceland after active phases of sub glacial activity). This , of course, is no guarantee that the impacts on that current stability of shedding gigatonnes of ice overburden will not cause issues? Both earthquake activity and increases in volcanic activity are part of isostatic rebound and so I guess that we may need to examine just what an eruption ( fissure type) would mean for both flow rates of the ocean terminating glaciers and the dropping in height of the ice sheet to warmer lower levels? Personally I think the current warm bottom waters impacts on grounding lines ( and the upstream glacial retreat that they are driving) are far more cause for concern than isolated magma intrusions beneath a limited area of the W.a.I.S. pose as the scales of impact are, excuse the pun, poles apart? We should have been more concerned about the piling up of all those gigatonnes of ice overburden since the Holocene temperature optimum. After all according to the Al Gore sandpile theory, you pile the sand too high and its eventually going to cause a landslide.
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Post by sigurdur on Jan 3, 2015 18:07:58 GMT
Graywolf: The Western P of Antarctica has melted during past interglacials. What would make the Holocene period so special that we wouldn't expect the WP to melt again? Isn't this to be expected as a long term consequence of 1,000's of years of warmth? Isn't it somewhat silly to try and tie CO2 to a known happening? In the past it was called natural, and now it is called? ??
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Post by duwayne on Jan 3, 2015 18:31:38 GMT
The January 1 Antarctic sea ice area is 37% greater than the 1980's average for that date? Why is the ice increasing so much?
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Post by douglavers on Jan 3, 2015 18:55:07 GMT
GW, you comment "AGW augmented winds and freshening of surface water by melt".
I would have thought more wind would help break up and disperse sea ice.
On the other hand, I can quite see that freshening the surface water would assist in freezing. Having said that, I suspect that winds coming off the central core of Antarctica at perhaps -20degC to -30degC would freeze seawater pretty quickly irrespective of salt concentration. There would be plenty of water available already at -2degC.
Your two effects would seem to work in opposite directions.
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Post by nautonnier on Jan 3, 2015 19:34:51 GMT
The January 1 Antarctic sea ice area is 37% greater than the 1980's average for that date? Why is the ice increasing so much? Duwayne get with the program - - The ice is increasing so much in the Antarctic because of the warming
- The ice was decreasing so much in the Arctic because of the warming
- There is more ice now in the Arctic because of the warming
It is called an unfalsifyable hypothesis
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Post by sigurdur on Jan 3, 2015 19:49:00 GMT
The January 1 Antarctic sea ice area is 37% greater than the 1980's average for that date? Why is the ice increasing so much? Because it is damned cold around Antarctica. Setting new record lows, as we know them by measurement. Last I checked, cold produces ice. At least it does in ND, and somehow I don't think North Dakota has its own physics laws.
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Post by douglavers on Jan 4, 2015 4:56:25 GMT
nsidc.org/data/seaice_index/images/daily_images/S_stddev_timeseries.pngThe Antarctic Ice anomaly is becoming very large again. The Emperor Penguins are in for a bad year. They depend on the ice melting enough during the Summer for the [relatively] open sea to be close enough for their chicks to reach at the end of Summer. Not to mention the increased journeys their parents are going to have to make to feed them. Perhaps the World Wildlife Fund should put in a protest to all those people who want a less warm climate.
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Post by sigurdur on Jan 4, 2015 5:16:45 GMT
Guess they will have to learn to fly.
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Post by duwayne on Jan 4, 2015 14:54:18 GMT
The January 1 Antarctic sea ice area is 37% greater than the 1980's average for that date? Why is the ice increasing so much? Duwayne get with the program - - The ice is increasing so much in the Antarctic because of the warming
- The ice was decreasing so much in the Arctic because of the warming
- There is more ice now in the Arctic because of the warming
It is called an unfalsifyable hypothesis So there is some truth to the notion that things are upside down in the southern hemisphere.
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