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Some reading for the “anti-warmalists” and “climate-change deniers”

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Author Topic: Some reading for the “anti-warmalists” and “climate-change deniers”  (Read 35985 times)
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Kiwithrottlejockey
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« on: May 01, 2009, 10:58:30 pm »


Kiwis unlock glacier secret

The Dominion Post with NZPA | Friday, 01 May 2009

Research by three New Zealand scientists may have solved the mystery of why glaciers behave differently in the northern and southern hemispheres.

New Zealand researchers, geologist David Barrell of GNS Science, Victoria University geomorphologist Andrew Mackintosh, and glaciologist Trevor Chinn, of the Alpine and Polar Processes Consultancy, have helped provide definitive dating for changes in glacier behaviour.

The three were part of a team of nine scientists, led by Joerg Schaefer of Lamont-Doherty Earth Observatory, which used an isotope dating technique to get very precise ages for glacial deposits near Aoraki-Mount Cook.

They measured the build-up of beryllium-10 isotopes in surface rocks bombarded by cosmic rays to pinpoint dates when glaciers in the Southern Alps started to recede. The technology is expected to be widely applied to precisely date other glaciers around the world.

Glaciers are sensitive indicators of climate changes, usually advancing when it cools and retreating when it warms.

The first direct confirmation of differences in glacier behaviour between the northern and southern hemispheres, the new work topples theories based on climate in the northern hemisphere changing in tandem with the climate in the southern hemisphere.

The research argues that at times the climate in both hemispheres evolved "in sync" and at other times it evolved differently in different parts of the world.

Dr Barrell told NZPA their research presents "new data of novel high precision" though the team has so far chosen not to roll out wider interpretations too quickly.

He said much of it reinforced work done 30 years ago by Canterbury University researcher Professor Colin Burrows, who used NZ glacier data to highlight some of the similarities and differences between northern and southern records over the past 12,000 years.

The paper published in Science magazine today showed the Mount Cook glaciers advanced to their maximum length 6500 years ago, and have been smaller ever since — but glaciers in the Swiss Alps advanced to their maximum only in the past 700 years — during the northern hemisphere's "Little Ice Age", which ended about 1860.

During some warm periods in Europe, glaciers were advancing in New Zealand. At other times, glaciers were well advanced in both areas.

In a commentary which accompanied the research, Greg Balco, from the Berkeley Geochronology Center in California, said the conclusion that glacier advances in the northern and southern hemispheres were not synchronised was "unexpected".

Dr Barrell said the paper presented only the first instalment of the dating work, and more will be revealed at an international workshop on past climates to be held at Te Papa on May 15.

"We expect that much progress will result from this new work and the discussions at that meeting," he said.

"The New Zealand findings point to the importance of regional shifts in wind directions and sea surface temperatures," he said.

Regional weather patterns such as the El Nino Southern Oscillation (ENSO) were superimposed on the global climate trends reflected in the behaviour of glaciers.


http://www.stuff.co.nz/dominion-post/news/2378376/Kiwis-unlock-glacier-secret
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