A new paper published in Quaternary Science Reviews finds that alpine glaciers in Glacier National Park, Montana retreated up to 6 times faster during the 1930’s and 1940’s than over the past 40 years.
The “Multi-proxy study of sediment cores retrieved from lakes below modern glaciers supports the first detailed Neoglacial chronology for Glacier National Park (GNP)” and shows “maximum reconstructed retreat rates [in] 1930” of about 125 meters per year, compared to near zero in ~1975 and about 20 meters/year at the end of the record in ~2005. The authors report, “Results indicate that alpine glaciers in Glacier National Park advanced and retreated numerous times during the Holocene after the onset of Neoglaciation 6,500 years before the present” and “Retreat from the Little Ice Age maximum was the most dramatic episode of ice retreat in at least the last 1000 years.”
Abstract:
A lacustrine-based Neoglacial record for Glacier National Park, Montana, USA
15 October 2012
Jeffrey S. Munroe | Thomas A. Crocker | Alena M. Giesche | Lukas E. Rahlson | Logan T. Duran | Matthew F. Bigl | Benjamin J.C. Laabs
Multi-proxy study of sediment cores retrieved from lakes below modern glaciers supports the first detailed Neoglacial chronology for Glacier National Park (GNP), Montana. Analysis focused on sedimentary properties sensitive to the extent and activity of upstream glacier ice, including: water, organic matter, carbonate, and biogenic silica content; bulk density; mass accumulation rate; phosphorus fractionation; magnetic susceptibility; L*a*b* color values; and grain size distribution. Results indicate that alpine glaciers in GNP advanced and retreated numerous times during the Holocene after the onset of Neoglaciation ca 6500 BP.
The two oldest phases of glacier expansion were synchronous with the well-documented Garibaldi (5600–6900 BP) and Tiedemann-Peyto (1900–3700 BP) phases in western Canada. Younger phases correspond with the First Millennium Advance in western Canada, as well as glacier with advances in the Sierra Nevada. The culminating Little Ice Age (LIA) advance was the most recent and extensive of a series of advance/retreat cycles over the past millennium. Retreat from the LIA maximum was the most dramatic episode of ice retreat in at least the last 1000 years.
h/t to The Hockey Schtick
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Here is a link to the paper Anthony.
http://community.middlebury.edu/~jmunroe/Papers/35-Munroe_etal_2012_GNP.pdf
“A new paper published in Quaternary Science Reviews finds […]”
Team members already pondering ways to put the Journal out of business?
Interesting that the same very quick warming also took place in Greenland at about the same time, in the case of Greenland from ~ 1919 to ~ 1933. So this study, and the Greenland “echo” of this record, suggest something was happening for a couple of decades. Most likely due in large part to natural variability, perhaps entirely.
The big question: what drove this variability, which certainly seems pretty dramatic.
Coincides very well with AMO index. The same is valid for European glaciers; cold period in 70ties saw on average stabilization of their lengths, suggesting that that period was cold as average of LIA. Exactly as CET record says.
Interesting but not a surprise. So any present glacier melt not unprecedented.
The alarmists will get an answer regardless of that answer’s sanity.
When I visited GNP a few years ago we went to a Ranger presentation and the ranger had a neat powerpoint. One of the slides showed how many glaciers there were in the late 1800s, and how that number has declined over time.
Amazing. Accelerated rapidly from about 10 mm/year retreat in 1920 to a retreat rate of about 130 mm/year in 1930, then slid back to near zero around 1980, now has gradually crept back up to a retreat of about 20 mm/year. (Fig 8).
This advance-retreat complexity throughout the Holocene should come as no surprise to WUWT readers, as Don Easterbrook has posted on the subject. He also wrote an extensively researched book that describes the advance-retreat cycles of the glaciers on Mt. Baker in Washington State. There have been an unfortunate number of “worst evah!” type pronouncements of recent glacial retreat, when the simple fact is that the glaciers have been receding for 20,000 years despite cooling since the Holocene Thermal Maximum (its not PC to say Holocene Optimum anymore).
It really does say 15 October 2012.
Glacier retreat has slowed because the bulk of the ice is gone and the remnants now obviously occupy the highest parts of their accumulation areas. In 1850 ,there were 150 glaciers in Glacier National Park. Now there are 25. Only seven of these have accumulation zones capable of sustaining them for the next three decades. The Agassiz Glacier,one of those feeding a lake in the study, is now about 20% of its LIA area and has lost over 90% of its LIA volume.
While 6x faster is more a peak year than typical, the general picture of the late 20th century being nothing impressive in warming compared to the 1930s-1940s is unsurprising.
For since 1850 A.D., http://pubs.usgs.gov/of/1998/of98-031/90.jpg illustrates that the Sperry Glacier had more area drop in the 18 years between 1927 and 1945 than in the 48 years between 1945 and 1993.
The general picture of rapid temperature rise in the 1920s-1930s with a relatively cool 1960s (including the arctic quite literally being warmer in the 1930s than in the 1990s in non-fudged data) can be seen within http://earthobservatory.nasa.gov/Features/ArcticIce/Images/arctic_temp_trends_rt.gif
How such strongly relates to the pattern in solar activity meanwhile is illustrated, for example, at http://www.appinsys.com/GlobalWarming/GW_Part6_SolarEvidence_files/image024.gif which as http://www.appinsys.com/GlobalWarming/GW_Part6_SolarEvidence.htm notes is from http://www.agu.org/pubs/crossref/2005/2005GL023429.shtml
(There would be the 60-year ocean cycle on top as well, while that does not mention the GCR aspect of how solar variation is increased in effect — see http://www.sciencebits.com/CosmicRaysClimate plus http://calderup.wordpress.com/2011/10/05/further-attempt-to-falsify-the-svensmark-hypothesis/ addressing cosmic ray versus cloud trends in the most recent years –, but it illustrates the general picture, in contrast to such as the vast lack of correlation of non-fudged temperature data in the location of greatest warming with CO2 trends shown at http://www.appinsys.com/GlobalWarming/GW_Part6_SolarEvidence_files/image024.gif ).
Of course, in recent years of politicized “science,” more CAGW-convenient fudged temperature data and fudged solar data has come out to cover that up, but it is rather apparent in original data.
Why wouldn’t that accelerate the loss because of less thermal mass and a less favourable surface area to volume ratio?
Bob says:
September 27, 2012 at 6:43 am
. One of the slides showed how many glaciers there were in the late 1800s, and how that number has declined over time.
================================
Yep, glaciers tend to do that over time.
This should come as no surprise. We’ve been thawing out from the Little Ice Age (LIA) glacier maximum (about 1500 to 1600 AD) and glaciers have been fluctuating back and forth in a see-saw pattern for the past several hundred years. The general thawing out from the LIA has been periodically interrupted by periods of cooling during which glaciers advanced. Glaciers advanced during notable cool periods—the Maunder Minimum (about 1650-1700 AD), the Dalton Minimum (1790-1820 AD), ~1880-1915, and ~1945-1977. Glaciers retreated during warm periods between each of the cool periods, some faster than others. In many places, glacier margins at the end of the 1880-1915 cool period were not very far from their LIA maxima and retreated rapidly during the ~1915-1945 warm period, especially in the 1930s. All of this means that the notion of glaciers only retreating since the increase in CO2 emissions that began after WWII (1945) is total nonsense—it’s been going on for thousands of years.
The global climate has been warmer than present almost all of the past 10,000 years (not just the Medieval Warm Period) and rates of warming were 10-20 times greater than recent periods as we thawed suddenly from the last Ice Age about 10,000 years ago (well before CO2 increased). The idea that recent rates of warming and glacier retreat are “unprecedented” is refuted by a huge mass of data on glaciers and global climate over periods of thousands of years.
Henry Clark’s comments are right on. The real truth lies in the data.
So these glaciers did not have an ice albedo positive feedback effect, where the loss of the shiny glacier ice caused the exposure of darker mountain surfaces which absorbed more sunlight causing increased warming and the inevitable loss of virtually all the glacier ice?
Henry Clark says:
September 27, 2012 at 7:10 am
“Of course, in recent years of politicized “science,” more CAGW-convenient fudged temperature data and fudged solar data has come out to cover that up, but it is rather apparent in original data.”
It isnt difficult to contemplate that this is one of the reasons certain government agencies is fudging data. Lots of tax money in it.
When I visited Glacier National Park some years ago, the info plaques were all about how global warming was making the glaciers disappear. The brainwashing was rather dismaying.
Earlier time period, but in Glacier Bay, Alaska the main glacier retreated around 48 miles between 1794 and 1879, with no help from CAGW!!
http://en.wikipedia.org/wiki/File:Landsat_GlacierBay_01aug99.jpg
How about a little honesty here? ONE glacier in retreated up to six times faster during the 1930’s and 1940’s than today. This isn’t news. The data on retreat of the Agassiz Glacier was published by Carrara and McGimsey in 1981 and merely re-used in this paper.
What units are used to measure glacier retreat? Meters/year. How do we translate units of meters/year into temperature change or climate change? We can’t. The fact that alarmists publicize misleading information about glacial retreat is not a good excuse for WUWT’s doing the same thing.
All of the glaciers in Glacier National Park HAVE SHRUNK dramatically since the end of the LIA. Warmer LOCAL temperatures are presumably responsible for this change, possibly along with reduced snowfall or cloudiness or more rainfall. During most of this period, the concentration of GHG’s in the atmosphere hadn’t risen high enough to have a significant impact on temperature. (Even the IPCC doesn’t attribute warming prior to 1950 to anthropogenic GHG’s and post-1950 global warming was minimal until the late 1970’s.) The Monroe paper simply adds to the consensus that glacial advances and retreats have been common during the Holocene. They don’t tell us anything of value about anthropogenic climate change.
No surprise. The greatest rate of retreat for glaciers around the world from the Sierra Nevada to European Alps has been around the 30’s and 40’s.
It is obvious that the CO2 levels were much higher during the ’30s and ’40s than previously thought so we will just process them through the GISS Data Masticator and update the data bases to reflect what we now know must have been the true levels of atmospheric CO2. How else could this have occurred? sarc/
“A new paper published in Quaternary Science Reviews finds that alpine glaciers in Glacier National Park, Montana retreated up to 6 times faster during the 1930′s and 1940′s than over the past 40 years.”
Clearly, it’s time to homogenize the data here. It’s worked successfully with the temperature data record; so, why not glacial advance/retreat rates? /sarc
Frank says:
September 27, 2012 at 9:06 am
They don’t tell us anything of value about anthropogenic climate change.
Is there anything of value about AGW? Sounds suspiciously like snark. The thing is, the supporters thereof wield glacier retreat as PROOF of AGW. So retreats out of lock-step with the meme are illustrations of its flawed position.
commieBob says:
September 27, 2012 at 7:34 am
“Why wouldn’t that accelerate the loss . . .?”
I call this the “easy ice notion”, meaning the ice easiest to melt, melted first. For example, the Puget Lobe during the Vashon Stade (Fraser Glaciation) is estimated to be a few thousand feet thick in the area of Seattle, WA. with the ice mass depressing the region well below today’s sea level. Relatively speaking this area is closer to the equator and gets higher sun than places, say, in Alaska, Greenland, or Antarctica. This combination of factors caused rapid melting – when the glacial event ended (for whatever reason). The ice that then remained in the mountains responded to the same physical inputs with each warming and cooling. Today remaining ice, because of high elevation and/or high latitude, will be more difficult to melt. It seems to me that if one is looking for an increase in sea level from melting ice – expect it to be slow and slowing or easily reversed. Other contributions to sea level change are many and complicated.
Frank says:
September 27, 2012 at 9:06 am
“…They don’t tell us anything of value about anthropogenic climate change.”
Heh.
Translation: Don’t believe your lyin’ eyes. We have the consensus of the Club. And, the Goreacle is on our side.
Could it be that catastrophic anthropogenic climate change is simply a myth, Frank?
It has begun.