From the University of New South Wales. The logic here seems a bit muddled. If this event where migration of westerly winds towards the south pole happened 15,000 years ago, what makes them think that it happening again now is due to global warming?
Global warming endangers South American water supply
Tuesday, July 29: Chile and Argentina may face critical water storage issues due to rain-bearing westerly winds over South America’s Patagonian Ice-Field to moving south as a result of global warming.
A reconstruction of past changes in the North and Central Patagonian Ice-field, which plays a vital role in the hydrology of the region, has revealed the ice field had suddenly contracted around 15,000 years ago after a southerly migration of westerly winds.
This migration of westerly winds towards the south pole has been observed again in modern times and is expected to continue under a warming climate, likely leading to further ice declines in this area affecting seasonal water storage.
“We found that precipitation brought to this region by Southern Hemisphere westerlies played an important role in the glaciation of the North Patagonian Ice-Fields,” said Dr Chris Fogwill from the Climate Change Research Centre at the University of New South Wales.
“Our research has shown this ice-field significantly reduced in size when those winds moved southwards.”
The North Patagonian Ice-field is vital to maintain seasonal water storage capacity for Argentina and Chile.
“Worryingly, this study suggests the region may well be on a trajectory of irreversible change, which will have profound impacts on agriculture and the increasing dependency on hydroelectric power in Chile and Argentina,” Dr Fogwill said.
The team revealed the importance of the winds on the ice-sheets and consequent water supply by using rare isotopes to uncover changes in the ice-sheet thickness since the last major glaciation. This revealed the decline in the ice-sheet between 15,000 to 19,000 years ago.
Using a separate collection of ocean cores they were then able to determine that this decline coincided with the movement southwards of the westerlies.
The researchers found that a lack of precipitation caused by this movement, coupled with additional warming caused by rapid ice loss saw a sharp decline in glaciers with no seasonal recovery.
Interestingly, the southern part of the ice-field did not appear to be impacted by the movement of these winds. Instead it appeared that ocean currents and temperatures played a more important role in maintaining the ice in this section.
“The ice-field in the Northern and Central region of the Patagonian ice-field are highly sensitive to precipitation and need this to remain healthy,” said Dr Fogwill.
Paper: Rapid thinning of the late Pleistocene Patagonian Ice Sheet followed migration of the Southern Westerlies (DOI: 10.1038/srep02118)
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I forgot the link
http://www.nature.com/nature/journal/v369/n6481/abs/369546a0.html
“This revealed the decline in the ice-sheet between 15,000 to 19,000 years ago.”
The coldest part of the last glacial period was roughly between 15.000 and 25,000 years ago(the last glacial maximum)
http://www.climate4you.com/images/VostokTemp0-420000%20BP.gif
Given that this could have happened 19.000 years ago??????
Why do we believe that the world is static and unchanging except for those changes brought about by humans?
Most of the ‘global warming’ positive anomaly is to be found in the high latitudes of the Northern Hemisphere
http://www.vukcevic.talktalk.net/AGT.htm
Southern Hemisphere appear to be more a stabilising rather than perturbing factor.
They are clueless that 15,000 years ago the planet started moving out of a glaciation period and warming up into an Interglacial? It would appear that they do not have much knowledge of the Holocene.
Margaret Hardman says:
July 30, 2013 at 9:40 am
Anthony, I don’t see the logic is faulty. An event caused by changing wind patterns 15,000 years ago could be repeated in the near future as wind patterns change as climate changes. No real logic failure there.
Maybe you should try reading a bit more closely:
“This migration of westerly winds towards the south pole has been observed again in modern times and is expected to continue under a warming climate, likely leading to further ice declines in this area affecting seasonal water storage.”
Note that “the warming climate” is simply assumed. It plays very neatly into the whole alarmist tone of the paper. If the paper was simply about a repeat of the event 15,000 years ago, why mention the “warming climate”? Logic fail.
Reading is fundamental.
Meanwhile, in the real world, South America has been getting more rain, and snow up to the tropics…
iceagenow.info
I haven’t bothered reading the original yet. But the excerpts surely make no sense at all. There is no such thing as a North Patagonia (let alone Central Patagonia) ice-field. Both ice-fields are located in the south of Patagonia. And their importance for the water supply of Chile or Argentina is absolutely negligible. On the Chilean side they discharge mainly to the ocean and in Argentina only a tiny percentage of the country and even tinier of its population depend on those ice-fields for their water supply. Some of their outlet glaciers are actually advancing and Punta Arenas, the southernmost town with a 100+ years temperature record has not experienced any warming in the last century.
Margaret Hardman says at July 30, 2013 at 9:40 am
Yes, so far so good.
But 15,000 years ago the climate changes were certainly not caused by man. The Hyperboreans, Atlantens and Lemurians lacked fossil fuel power stations. They probably lacked existence even.
It wasn’t catastrophic Anthropogenic Global Warming (cAGW).
So the logical fail is suggesting that this is either:
1) Evidence of what cAGW will do.
or
2) That a repeat event will be evidence for cAGW (or even AGW for that matter).
The alarmists probably would have tried to blame the 15,000 year old event on modern AGW, if they could think of a way to do it.
“what makes them think that it happening again now is due to global warming?”
I assume that is a rhetorical question.
John Tillman, Gary Pearse–
Kong:
Primary target, the ICBM complex at Laputa. Target reference Yankee Golf Tango Three Six Zero. Thirty megaton nuclear device fused for airburst at ten thousand feet. Twenty megaton nuclear device will be used if first malfunctions. Otherwise proceed to secondary target, missile complex seven miles east of Barshaw. Target reference November Bravo X-Ray One Zero Eight. Fused airburst at ten, check, twelve thousand feet.
Pat Michaels,
I always wondered why the airburst altimeter was dialed down to zero altitude.
Also, I don’t think we had a 30 MT nuke in our arsenal.
I read an event 15,000 years ago is today blamed on Global Warming – it may seem very subtle but this paper seems to suggest some other forces at work other than Global Warming if it happened 15,000 years ago. That is the big picture I took from this article.
Interesting, Perito Moreno, the largest of the glaciers in the ice field is actually growing. Water levels in Argentino and Viedma lake are steady and overall there is a great amount of water between the lakes and the glaciers, more than they will use in thousands of years. And if there is a water crisis, they have one of the world’s largest aquifers nearby in eastern Patagonia. This is just another study that observes a current trend then extrapolates that trend into the future indefinitely. Didn’t these people learn their lesson in the 90s when they extrapolated the 1975-98 warming trend indefinitely into the future?
and need this to remain healthy…….
ROTFL……a glacier vet
Margaret Hardman says:
July 30, 2013 at 9:40 am
… An event caused by changing wind patterns 15,000 years ago could be repeated in the near future as wind patterns change as climate changes. No real logic failure there.
The statement below is the logic fail; something that reversed all by itself 15 kya will now be ‘irreversible’.
… Worryingly, this study suggests the region may well be on a trajectory of irreversible change …
Whatever…..is good for a publication.
Billy
Did you spot the conditional tense being used – irreversible is not inevitable according to your quote. Still don’t see any logic fail and I did read it carefully. To busy watching parking meters.
The irreversible change has clearly reversed in recent years. There has been a large increase in sea ice around the tip of the Antarctic Peninsula where Antarctica is most influenced by westerly winds. Clearly it’s getting colder there.
http://nsidc.org/data/seaice_index/images/daily_images/S_bm_extent_hires.png
When I read the article, weones came to mind. This article is probably obliquely related to HidroAisen.
http://en.mercopress.com/2013/07/26/polar-blast-covers-80-towns-of-southern-sunny-brazil-with-snow
Definitley getting warmer!
“the southern part of the ice-field did not appear to be impacted by the movement of these winds.”
But was it affected by the movement of these winds?
If the contraction of the ice sheet 15,000 yr ago was irreversible, how can it be happening again? Now? ??????
Margaret Hardman says:
July 30, 2013 at 2:02 pm
“Billy
Did you spot the conditional tense being used – irreversible is not inevitable according to your quote. Still don’t see any logic fail and I did read it carefully. To busy watching parking meters.”
Margaret, what would the world say if they hadn’t used (a weak) conditional! (Caleb says:
July 30, 2013 at 10:10 am: “Likely an interesting study, under the bright pink tutu it is necessary to prance about in, to gain grant money.”
This CAGW-speak we refer to as woulda-coulda-shoulda here. It is designed for mass consumption by folks that don’t make the distinction. What could possibly suggest that it would be irreversible. There isn’t even enough to say it will even happen let alone plot its course to remain so forever. I find it particularly illogical to me because they are comparing this to an ice age scenario with low CO2 in the atmosphere- not a CO2-glutted global warming scenario. If I were to say to you “suggests that the sun won’t come up tomorrow” would that make it alright for you? Science should not be a semantic exercise, although it is clear that the post-normal science of CAGW proponents works this aspect to the bone. If they were presenting to a skeptical scientific community (the usual type before all this NGO science got started – let’s pray this is reversible), they would highlight first off how they determined which way the wind was blowing and where the jet stream was, before they got any further. That’s just it, they don’t have to anymore.