Glaciers like this are bucking the global trend and growing despite a warming planet (Source: Andrew Mackintosh)
Posted on 05/02/2009 12:14:16 PM PDT by neverdem
Glaciers like this are bucking the global trend and growing despite a warming planet (Source: Andrew Mackintosh)
Southern hemisphere glaciers evolve quite differently to those in the north, according to a new study.
Glaciologist Dr Andrew Mackintosh of Victoria University in Wellington, New Zealand and colleagues report their findings in today's issue of the journal Science.
"Don't assume that warming will be uniform over the earth," he says.
Mackintosh says the advance and retreat of glaciers are a good indication of climate change.
But, he says, there has been some concern that studies of glaciers to date have not been representative of global trends.
"A lot of this work has been led by northern hemisphere researchers who come to New Zealand or Patagonia or wherever, and look for some of the features they've seen in the north," says Mackintosh.
"But the more we're learning about the southern hemisphere we understand that it has its own climate system that's somewhat different."
Mackintosh and colleagues plotted the retreat and advance of glaciers in New Zealand over the past 11,500 years and compared it to data gathered from the northern hemisphere.
They gathered their data by dating the age of the moraines, which are piles of rocks left, like tide marks, as glaciers retreat.
The method, which analyses beryllium-10 isotopes that accumulate as cosmic rays bombard quartz minerals, is the most reliable method available, says Mackintosh.
"It's certainly the most complete chronology of events that has so far been worked out," he says.
The researchers found no real correlation between data from the northern and southern hemispheres.
As reported in recent years, Mackintosh and colleagues found some New Zealand glaciers, including Fox and Franz Joseph Glaciers, are growing, despite global warming.
"Even though over the past 100 years or so there's been overall retreat … there can be changes in atmospheric circulation locally which make the glaciers in New Zealand buck that trend," says Mackintosh."
He says glaciers are growing in response to changes such as El Niño which brings cool, wet conditions to New Zealand, and changes in the position of westerly winds.
He says other New Zealand glaciers would also be advancing if it was not for other factors stopping them from responding to that local climate.
Mackintosh says such regional climate could also explain why predictions for New Zealand show less warming than the rest of the world over the next 100 years.
Mackintosh and colleagues found that overall, northern hemisphere glaciers grew until the end of what is known as the Little Ice Age in the 1800s, when they began to retreat.
By contrast, southern hemisphere glaciers have on the whole been shrinking throughout the Holocene.
Mackintosh says long term orbital differences, known as Milankovitch cycles, may explain this but he says more work is required to determine if this is the case.
He says the latest data will be useful in better understanding of how climate works. It will also improve climate models so they better predict how specific regions of the world will respond to global warming.
High-Frequency Holocene Glacier Fluctuations in New Zealand Differ from the Northern Signature
Climate model X.0 needs some fixing. BTW, where's the warming?
I love statements like this. The planet has cooled over the last ten years of "warming". Why would it surprise anyone that the glaciers have also grown during this cooling trend?
Your glaciers haven’t followed the program!
Just another in a growing list of “Don’t believe your lying eyes” type of article designed to confound the issue.
“Planet Warming Despite Falling Temperatures.”
Do not assume that by "warming" we mean "getting warmer". In fact, it may be that global warming will lead to a decrease in average temperatures around the globe. However at nearly any time some part of the earth will be warmer than it was before (where we get to say what "before" means) and so we will still get to try to ruin your lives and your economy.
Uh glaciers are like a tank of water. Put more in (snow) and it gets deeper/longer, drain more out and it gets shallower/shorter. A glacier is not a thermometer nor something more permanent like rock.
I suspect that the Obama administration is going to adopt a similar strategy when they soon postulate that increasing unemployment numbers are really a sign of a growing and robust economy.
Yet I have read numerous articles on how global warming is melting our glaciers. If warming would melt them, it's odd that their growth is not evidence against global warming. That said, I agree with your post, in terms of the science. The point is that science has as little to do with global warming as it has with astrology ... so we make fun of the True Believers whenever the evidence makes them look particularly absurd (and that's pretty often).
When will the glaciers be forced to melt for denying global warming?
“But the more we’re learning about the southern hemisphere we understand that it has its own climate system that’s somewhat different.”
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Gollleeee! Who’da thunk sech as that? I’sa beginnin’ tuh thank I knows mo’ ‘bout da climb eight then them thare fellers.
Is it just me or does Gore look more and more like a madman every time I see a picture of him?
It’s because the glaciers in the south are upside down.
It's now Semi-Globull Warming Theory.
B.S.P.H.D. ,,,,,,,,,B.O.H.I.C.A.
And pet the polar bears as you go, says ManBearPig Gore.
Slightly warmer temperatures can result in more moisture producing more snow especially in areas where temperatures are so cold as to be have near-desert amounts of precipitation (less than 10 inches per year). More snow can change the glacier’s balance to growth even though the temperature rises a bit.
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