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Green Alps?
June 18, 2005 7:49 AM   Subscribe

A New Alpine Melt Theory: "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." Fascinating report from Der Spiegal about the "Green Alps" theory. This page has a small graphic showing the Alps today and how they might have looked in a warmer period. Another article here. Maybe Otzi forgot to pack his sunscreen?
posted by LarryC (9 comments total)

 
Ooops--via Arts & Letters Daily. Both articles describe the theory as controversial, but I could not find a good link showing the other side of the debate. Anyone?
posted by LarryC at 7:51 AM on June 18, 2005


Wasn't there a story last year about how the arctic glaciers were growing?
posted by jikel_morten at 8:11 AM on June 18, 2005


This Green Alps theory is improbable. These and other alpine glaciers are remnants of the last continental Wisonsinan glaciation. They have gradually been retreating for about 18,000 yrs. don't tend to advance or retreat rapidly, but they do fluctuate. Some think that we're in a "super interglacial" period that is being prolonged by man-made climatic change. At any rate there are relatively regular periods of glaciation, in terms of geologic time. The triggers for the beginning and end of the glacial periods are theorized to be caused largely by Milankovitch Cycles, including changes in the angle of Earth's axis, obliquity of orbit, and precession of equinoxes.
posted by philmas at 11:06 AM on June 18, 2005


These articles deal with alpine glaciers, which account for 5% of the glacial ice mass on Earth. The other 95% is found in the massive continental glaciers--- the Arctic and Antarctic ice sheets. So, when using the behavior of these glaciers to debate the effects or even occurrence of global warming, it is important to realize that alpine glaciers have a small overall contribution, and these particular glaciers even less.

It seems likely that a climate change debate will spring up in this thread, so here are my two cents: Geological evidence (old wave cut platforms at elevations well above current sea levels, etc.) indicates that there is a regular cycle of the continental glaciers melting and reforming along with the attendant sea level changes, so whether or not humans are having a major effect, a process is occurring and we should be aware of it.

jikel_morton: According to satellite imagery, the arctic glaciers are definitely shrinking.

On Preview: Yeah, what philmas said.
posted by Derive the Hamiltonian of... at 11:27 AM on June 18, 2005


LarryC. HOW DARE YOU challenge the dogma that the alpine glaciers have existed for eternity and that they are now disappearing solely due to mankind's profligate use of fossil fuels?

Fix your facts to the policy and don't attempt to interject any form of scientific inquiry into the debate.
posted by three blind mice at 11:44 AM on June 18, 2005


Mmm... alpine melt. with avocado.
posted by dreamsign at 11:49 AM on June 18, 2005


I don't have a dog in this fight, truly, I just thought the idea was interesting. But as one of the articles points out, how is it that the glaciers contain so much woody debris, include whole logs, if there was not a forest up above them at one point?
posted by LarryC at 11:51 AM on June 18, 2005


I think the reason why you can't find the other side to this "controversial" issue is that it isn't all that controversial. I think most people believe that the climate has fluctuated quite a bit even over the last 2,000 years. Try checking out the "medieval warm period".

The controversial part is: How much of the recent climate change is due to anthropogenic influence? Because if we are changing the climate, then maybe we are in control (i.e. we can do something to stop it). If it isn't us, then we should figure out what it is and try to stop it...right? And if it really is us-- what happens if we don't stop it?

Check out Real Climate .ORG; This article talks about glacier retreat.
posted by spaceviking at 1:05 PM on June 18, 2005


Check out this graph of temperature change over last ~15,000 years. Looks like a lot of spaghetti, but it seems that it was much warmer ~6,000 years ago.

Also remember this is a graph trying to reconstruct global temperatures, and local temperature variations could be more extreme due to changes in weather patterns and ocean currents.
posted by spaceviking at 1:17 PM on June 18, 2005


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