Skip to comments.The Coming and Going of Glaciers: A New Alpine Melt Theory
Posted on 06/18/2005 5:06:43 AM PDT by aculeus
The Alpine glaciers are shrinking, that much we know. But new research suggests that in the time of the Roman Empire, they were smaller than today. And 7,000 years ago they probably weren't around at all. A group of climatologists have come up with a controversial new theory on how the Alps must have looked over the ages.
The Morteratsch glacier in Switzerland has retreated by 1.5 km since 1900. Some scientists believe that glacial fluctuation could be a more normal development than previously thought.
He may not look like a revolutionary, but Ulrich Joerin, a wiry Swiss scientist in his late twenties, is part of a small group of climatologists who are in the process of radically changing the image of the Swiss mountain world. He and a colleague are standing in front of the Tschierva Glacier in Engadin, Switzerland at 2,200 meters (7,217 feet). "A few thousand years ago, there were no glaciers here at all," he says. "Back then we would have been standing in the middle of a forest." He digs into the ground with his mountain boot until something dark appears: an old tree trunk, covered in ice, polished by water and almost black with humidity. "And here is the proof," says Joerin.
Radical new theory
The tree trunk in the ice is part of a huge climatic puzzle that Joerin is analyzing for his doctoral thesis for the Institute for Geological Science at the University of Bern. And he is coming to an astonishing conclusion. The fact that the Alpine glaciers are melting right now appears to be part of regular cycle in which snow and ice have been coming and going for thousands of years.
The glaciers, according to the new hypothesis, have shrunk down to almost nothing at least ten times since the last ice age 10,000 years ago. "At the time of the Roman Empire, for example, the glacier tongue was about 300 meters higher than today," says Joerin. Indeed, Hannibal probably never saw a single big chunk of ice when he was crossing the Alps with his army.
The most dramatic change in the landscape occurred some 7,000 years ago. At the time, the entire mountain range was practically glacier-free -- and probably not due to a lack of snow, but because the sun melted the ice. The timber line was higher then as well.
The scientists' conclusion puts the vanishing glaciers of the past 150 years into an entirely new context: "Over of the past 10,000 years, fifty percent of the time, the glaciers were smaller than today," Joerin states in an essay written together with his doctoral advisor Christian Schluechter. They call it the "Green Alps" theory.
Joerin admits his theory goes against conventional wisdom. "It is hard to imagine that the glaciers, as we know them, were not the norm in past millennia, but rather an exception," he says while he and his companions dig out the tree trunk with shovels, axes and bare hands.
Indeed, critics accuse him and his colleagues of relying on a thin and ambivalent layer of facts. The Green Alpinists respond to the argument their own way: with a large orange chain saw. Kurt Nicolussi, a slender man in his late 40s, slices a slab of wood as large as a wiener schnitzel out of the trunk and analyzes it. "At least 400 annual rings, well preserved, perhaps the best sample we have ever had," he declares proudly.
Dead wood tells a lively story
Nicolussi, professor for Alpine Research at the University of Innsbruck, Nicolussi is a dendrochronologist, something of a tree historian. He records the exact location of the find, carefully packs up the slab and labels it with a new name: "TSC-160" -- find number 160 of the Tschierva Glacier. Under the microscope, the thickness and the shape of the annual rings reveal a considerable amount of detail about the location and the climate conditions under which the tree grew. To date, he has collected and analyzed more than 400 chunks of wood.
Nicolussi's assessment of TSC-160: It comes from a stone pine (Pinus cembra) that lived at least 538 years. "This is not unusual, pines grow extremely slowly, but become quite old," the scientist explains. TSC-160 died approximately 6880 years ago, during the Neolithic Age, somewhere at the foot of Piz Bernina which is today covered with an impenetrable ice shield.
Somewhere along the line, the tree was buried by masses of ice and dragged into the valley where it remained until the glacier set it free again last summer -- a secret message from the Stone Age at a place thought to be covered in "eternal ice."
Although glacier experts like Hanspeter Holzhauser have been collecting remains of plants in the vicinity of glaciers for years, they only began systematically analyzing the finds about 13 years ago.
At first, he and his students collected over a thousand little chunks of wood and shreds of turf on their excursions along the glaciers, from the Engadin in the east to the Unterwallis in the west, from the Forno and Stei Glacier to the du Mont Mine Glacier. Finds include the remains of birch trees, willows, Norway spruce, pines, larch and a lot of the resilient Swiss stone pine.
There is a simple deduction that lends support to the Green Alp theory: The bits of trees that have been washed out of the glaciers must come from further up the mountain. And if trees grew up there, then the mountains could not have been covered by glaciers.
Schluechter sent over a hundred of the old bits of wood to a special laboratory for carbon dating. They discovered that the trees didn't grow up there continually, but rather within ten periods of time since the end of the last ice age.
The dynamic history of glaciers
"The history of the glacial cover apparently is more dynamic than had been assumed until now," says Schleuchter. According to this model, the glaciers were smallest about 7,000 years ago, largest during the "mini ice age" of 1650 to 1850. Since this last cold spell, the tongues of ice have been receding quickly -- for a paleo-climatologist 150 years are just a wink in time.
Schluechter knew that his theory would be a hard sell in professional circles, and he needed more samples to back it up. He came up with a trick to get help: He and doctoral candidate Joerin published an article in the the Swiss Alpine Association's members magazine. At the end they included a plea to "mountain guides, mountaineering schools and hut keepers, to register wood and turf finds. They promised that "Finders would get the next summit drink for free." The feedback was amazing: some 50 envelopes with tips and samples landed in the Institute's mailbox.
Some experts have greeted the Green Alp theory with great interest. They include Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research, who studied Schluechter's results. He too considers it possible that the Alpine glaciers used to be smaller than they are today.
But there are critics. Like Oetzi, the 5,300 year old Stone Age man whose body was found in the Oetz Valley Alps. After all, how could his corpse have remained intact if the ice receded again and again? The Green Alpinists argue that the fluctuation in the glacier level was subject to local influences and did not hold true for the entire Alps region.
Wilfried Haeberli of the Department of Geography at the University of Zurich is a more vocal critic. The extreme warm phases suggested by Schluechter's theory are not compatible with findings derived from ocean sediments, pollen analysis and ice cores. In fact, most climate data proves that since the Ice Age, it has never been warmer than it is today. How, one might ask, could the Alps have been free of glaciers in the Stone Age?
Negating the effect of climate change?
Joerin is quick to explain that he is not trying to explain away the effects of man-made warming of the past few years: "Our findings so far could also be seen as giving the exact opposite of a climatic all-clear," he says. "If we can prove that there were ancient forests where the glaciers are today, it means one thing in particular: that the climate can change more suddenly than we thought."
Up on the Tschierva Glacier the two scientists are especially keen on finding the answers to the most pressing questions of the day: How quickly did the climate change? How quickly did the balance of ice slip from a plus into a minus and back again? The carbon dating method they've been using is far too imprecise for this, which is why the scientists plan to compare their results to the analysis of the carbon rings. For that they need more samples like TSC-160.
Joerin spots the ideal specimen. "Up there, that is a prime example," he says, pointing to a tree trunk in the ice, deep and unreachable. The scientists will have to return at another time, but they have already set a date. By October the glacier will have receded another 50 meters, freeing the tree trunk for the chainsaw and the microscope.
© DER SPIEGEL 21/2005 All Rights Reserved Reproduction only allowed with the permission of SPIEGELnet GmbH
I am assured by a local global warming enthusiast (supposedly has a degree in climatology) that Southern Ohio's drastically higher temperatures are due to automobile exhaust.
Current temp here in Southern Ohio is 62 degrees Fahrenheit on June 18th 2005.
Me thinks someone is full of B.S.!!!
This lends to the theory that the Earth works in cycles, probably not the case since nothing BC (before Clinton/s) matters. We'll need to have someone in Congress call for an investigation into these startling new revalations...
Everything - the energy of the sun, earth's climate, earthquake and volcanic activity, human civilization - moves in cycles. The ancients did not develop the zodiac to tell your fortune or decide when to plant crops.
Reading a lot of Roman History, if the ice was there, as it is today, the movement of Roman merchants and Roman military would have been greatly curtailed. Armies were moved back and forth with a speed that would indicate that the ice as we know it today was not there.
We know so little about solar cycles and the sun in general. It seems pointlessly arrogant to assume that we are the cause of the climate change (if there is any). It reminds me of the rooster who thinks his crowing is what brings on the dawn.
Ya mean Hannibal's elephants didn't have to use snow shovels?
I think it is exactly that --(the rooster that brings on the dawn)-- to assume that such a huge (earth)system could be negatively impacted by something so insignificant to geological events (cow farts, humans, bbq's). Do the data (global warming/ cars) correlate? Yes, perhaps. Is car exhaust causative? It is so highly unlikely. This is an interesting study, in the Alps. Always good when existing theories are challenged.
The Medieval Warm Period (MWP) or Medieval Climate Optimum was an unusually warm period during the European Medieval period, lasting from about the 10th century to about the 14th century. It has been argued a better name would be the Medieval Climatic Anomaly.
Initial research on the MWP and LIA was largely done in Europe, where the phenomenon was most obvious and clearly documented.
It was initially believed that the temperature changes were global. However, this view has been questioned by some scientists, amongst them Bradley and Jones, 1993; Hughes and Diaz, 1994; Crowley and Lowery, 2000. The 2001 IPCC report summarises this research, saying: " current evidence does not support globally synchronous periods of anomalous cold or warmth over this timeframe, and the conventional terms of 'Little Ice Age' and 'Medieval Warm Period' appear to have limited utility in describing trends in hemispheric or global mean temperature changes in past centuries"
During this time wine grapes were grown in Europe and southern Britain (however, factors other than climate strongly influence the commercial success of vineyards; and the time of greatest extent of mediaeval vineyards falls outside the MWP). The Vikings took advantage of ice-free seas to colonize Greenland and other outlying lands of the far north. The period was followed by the Little Ice Age (LIA), a period of cooling that lasted until the 19th century when the current period of global warming began.
An interesting question, since Ariana Huffington blames SUV's for global warming--and there weren't a lot of those around in the thirteenth and fourteenth centuries.
In 1976, scientists at Lamont-Doherty Earth Observatory spearheaded a project called CLIMAP (Clint: Long-range Investigation Mapping and Prediction) to map the history of the oceans and climate. They discovered that ice ages begin or end, almost like clockwork, every 11,500 years. It's a dependable, predictable, natural cycle. Pacemaker of the Ice Ages, they called it.
I often read that the earth is warmer now than it has been since 1500 or 1300 or some other far away date. My question is what made it so warm then? I know cattle contribute a bit but there could not have been as many cattle then as now and there certainly wasn't anywhere near as much industry.
It's that &*^&*^&*^&*^( leftover dinosaur poop.
Since there is still year around ice in Antarctica and Greenland we are, by definition, still in an ice age and have been for over 1,000,000 years.
During this time there are periodic advances and withdrawals of continental glaciers to which the 11,500 year cycle refers. And we are now past due.
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This is ridiculous. There are no "cycles", global warming is caused by Republicans, and George Bush in particular.
Thanks for that link Kabar. That "pacemaker" isn't a pacemaker at all; for one thing, it isn't like clockwork, not in the least, and that was known from data gathered before and after that study; for another, it merely looked at (selective) data in order to (erroneously) model glaciations in a way that would make them nice a regular and predictable.
It would be nice to think that they are nice and regular and predictable. And it would be nice to attribute them to Maunder Minimums (solar activity). The world does cool down when the sun dims a bit (which it does, but the "cycle" isn't regular) and warms up when the sun brightens a bit (which it has been doing). But there's no way to get massive glaciation with gradualist processes and long term trends.