Via the AGU weekly highlights:
In recent decades, the combined forces of climate warming and short-term variability have forced the massive glaciers that blanket Greenland into retreat, with some scientists worrying that deglaciation could become irreversible. The short history of detailed glacier observations, however, makes pinning the ice loss to either short-term dynamics or long-term change difficult. Research by Young et al. detailing the effects of two bouts of sudden and temporary cooling during an otherwise warm phase in Greenland’s climate history could help answer that question by showing just how heavy a hand short-term variability can have in dictating glacier dynamics.
Along the western edge of Greenland, the massive Jakobshavn Isbræ glacier reaches out to the coast, its outflow dropping icebergs into Baffin Bay during the summer months. Flanking the glacier’s tongue are the Tasiussaq and Marrait moraines-piles of rock marking the glacier’s former extent. Researchers suspected the moraines were tied to two periods of abrupt cooling that hit Greenland 9,300 and 8,200 years ago, and the association was reinforced by the authors’ radiocarbon and beryllium isotope analyses of the area surrounding the moraines. Beryllium-10 forms when cosmic radiation travels through the atmosphere and strikes the Earth’s surface, with surface rock concentrations indicating how long it has been ice-free.
The authors’ analyses show that the moraines were laid down 9,200 and 8,200 years ago, corresponding with periods of sudden cooling. They suggest that the Jakobshavn glacier, which had been retreating prior to the sudden temperature changes, started to grow. At the end of each cold phase, the glacier deposited a moraine before it resumed its retreat. In detailing the sensitivity of the Jakobshavn glacier to short-term temperature change, the study suggests that while the Greenland glaciers’ current retreat is not necessarily irreversible, their extent is tightly bound to the variability of our warming world.
Source: Geophysical Research Letters, doi:10.1029/2011GL049639, 2011
http://dx.doi.org/10.1029/2011GL049639
Title: Response of a marine-terminating Greenland outlet glacier to abrupt cooling 8200 and 9300 years ago
Authors: Nicolas E. Young, Jason P. Briner, Beata Csatho and Greg S. Babonis: Department of Geology, University at Buffalo, Buffalo, New York, USA;
Yarrow Axford: Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois, USA;
Dylan H. Rood: Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California, USA, and Earth Research Institute, University of California, Santa Barbara, California, USA, and Scottish Universities Environmental Research Centre (SUERC), East Kilbride, UK;
Robert C. Finkel: Department of Earth and Planetary Sciences, University of California, Berkeley, California, USA.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Why do people lament the loss of glaciers? Do people complain when winter is over and all the snow and ice melts and all the flowers and gardens start to bloom? So a lot of ice melts in some remote location. Who cares?
It’s not clear to me why it has to be revered.
From looking at the photo, about half of the retreat occurred between 1851 and 1950.
Does the glacial melt mirror the decline of the British Empire???
MAKES YOU WONDER !!
/sarc
These scientists claim that Be^10 is formed when cosmic rays strike the surface. I was always taught that it was cosmic rays strike nitrogen atoms in the upper troposphere. Be^10 analysis can indicate past cosmic ray intensity and variability over time.
How many Greenland glaciers are actually monitored? To claim that all are retreating could be wildly wrong. Also glacial retreat can also be a measure of precipitation since all glaciers need this to continue to flow. To claim that glacial calving is a temperature measure can also be wrong. When a glacier ends up as an ice shelf, floating, a good storm will aid calving, nothing to do with temperature.
Interesting, however these massive glaciers scour all evidence of earlier warm periods away, each time they advance. Of more interest are the less mighty glaciers, or simple snow fields, that don’t scour so much, and in some areas press stuff down as they advance, and then reveal the stuff they pressed down, as they retreat.
These lighter glaciers and snow fields give ample evidence of earlier warm periods, where the glaciers retreated even farther than they have retreated today. Off the top of my head I recall reading of A.) dead brush being revealed in East Greenland, where no brush or shrubs grow today, that dated from the MWP. B.) A fairly large log being revealed in Alaska where not a twig grows today, also dating from the MWP. C.) A Roman road, dating from the Roman Climate Optimum, being revealed; the road apparently, according to very old written documents, led to a Roman lead mine, which is still covered with ice.
I always get the feeling this evidence is hushed up. When I do read about it, it always is amidst an article which attempts to prove the evidence shows that recent glacial retreat is “unprecedented,” when in fact it shows exactly the opposite.
irreversible = not to be reversed, unable to change direction. Nothing to do with being revered (from “reverence”).
The Reykjavik long term temperature forecast for both winter and annual temperatures forecast shows (with a good degree of certainty) that Arctic cooling is on the way http://www.vukcevic.talktalk.net/RF.htm
This is based on my Arctic/North Atlantic research.
BTW: Does anyone know where the GISS temperatures database
http://data.giss.nasa.gov/work/gistemp/STATIONS//tmp. (station.number)/station.txt
has moved to?
Seems that Richard Black thinks plants caused the Ice age.
http://twitter.com/#!/BBCRBlack/status/164697423762034688
There are already a couple of comments along the lines of “who cares about ice melt in some utterly remote location?” Add me to the list. So what if glaciers shrink a bit? I mean, it’s mildly interesting, but so what?
Nice map of Greenland:
http://commons.wikimedia.org/wiki/File:F1_large2.JPG
I mean these questions sincerely – does anyone care to elaborate on why ice melt/sublimation in Greenland makes any difference at all outside of:
A proxy for CAGW and we know that ice status is tons of fun arguing about even though from a purely logical viewpoint it isn’t anything more than a proxy for, well, ice. Ice and glaciers form or melt for any number of reasons we simply do not fully understand, but we all like to cheer for the ice every year and for gosh sakes, I don’t want to spoil the fun.
Sea-level rise. Ahem, that doesn’t seem to be working as predicted by CAGW doom sayers but I suppose if enough land-based iced did manage to get itself melted and find its way to sea, the sea-level would go up a bit faster. Here’s an interesting exercise. Google a couple of busy seaports, like Boston Harbor. See if you can find anything on their sites about CAGW sea-level rise. You won’t find much. Lesson: They are commercial enterprises making plenty of money – they will deal with it as they have for hundreds of years. But a direct link from CAGW to sea-level rise is sadly lacking in empirical evidence – CO2 goes up compared to recent history , sea-level not so much.
Ecology/wildlife/etc. Somebody will have to help me here. Not my field at all – I recycle, drive a small car, use non-polluting stuff – but to be honest, I just don’t even think about wild animals, plants, ecology and stuff like that. I am open to being schooled as to why melting ice is so bad for Gaia and her creatures – note: the polar bear thing hasn’t worked out too well for the CAGW crowd either.
Sorry for the longish post, but I am serious – who cares if some ice melts other than earth scientists? (And I don’t mean to slight you guys and gals out there that are into this stuff…I’m glad you are interested in it so you can watch out for all of our best interests.) In the mean time I’m back to work at my profession, building machinery.
How did Richard Black get here? He is well known for producing all sorts of rubbish to prove CAGW. He is the one who did a series of in-house lectures as to how best to promote climate change and the best ways to ignore climate skeptics who complain to the BBC about some preaching about CO2 etc..
Also he is a journalist not a scientist.
Zac says:
February 1, 2012 at 5:18 am
//////////////////////////////////////////////////
The Daily Mail is carrying this story.
http://www.dailymail.co.uk/sciencetech/article-2094775/The-arrival-plants-cooled-planet-triggered-series-ice-ages.html
Of course it is simply based upon model projections which in turn are based upon the underlying assumptions (including forcings their strength and effectivenss) held by the person who wrote the model. As such, models prove nothing and are a complete waste of time.
Climate science will not mature until it gets away from its dependence upon model projections.
Fewer glaciers hogging all the water on the planet, more water in the atmosphere, more rain in TX… In a drought, we aren’t missing these glaciers.
It is mind-boggling that they think they know what is going to happen hundreds of years from now, and state that they know exactly what happened thousands of years ago.
John Marshall says:
February 1, 2012 at 5:52 am
” Also he is a journalist not a scientist.”
I think if there are any true journalists left out there, they may dispute the first part of that statement.
richard verney says:
February 1, 2012 at 5:56 am
Zac says:
February 1, 2012 at 5:18 am
So to prevent another ice-age we have to get rid of the tropical rainforests as a starting point. Who’s going to tell Prince Charles?
Pardon me for asking, but it seems to me that the whole thing about ages of rock piles–not only this report but also, frex, the crater in California (Ubehebe??) rest upon the assumption that beryllium isotopes are a clock. Yet on looking at the discussion, it’s never that the steady drumbeat of radioactive decay is measured. It’s always that the “rain” of beryllium isotopes down from the sky is measured. The *assumption* here seems to be that the beryllium rains down steadily, year after year, at the same exact pace and nothing else can add to or dilute it after it has fallen and the rate of accumulation never changes. Has anyone ever actually studied whether this assumption of clocklike steadiness is true? Because if the rate of beryllium accumulation changes, or if small creatures like ants can knock it off or pile it up…not to mention the scrubbings of floods…
You see what I mean? I begin to wonder if much of the “knowledge” gained from rockpile dating is essentially the proverbial house built on sand, and one day the storm tide will roll in and wash out the foundations from under it altogether. (I live near a barrier island. Can you tell?)
–just an interested reader!
So, glaciers have been retreating since the end of the LIA, who knew? We had snow yesterday and then it melted. Two examples of snow/ice melting after forming. I didn’t shed a tear for yesterday’s snow and I won’t for the melting glaciers.
The Sun is burning up it’s fuel, shouldn’t we worry about that? Maybe, if we start now, we will be prepared for it’s inevitable exhaustion. Why be proactive about eradicating climate cycles while being oblivious to the certain doom of a zero-degree-Kelvin future?
A thought: How about more CO2 to keep us warm post-sol.
BDTP
Yes I did make a mistake Black acts like a yob not journalist. I do hate to revert to name calling.(sarc. off).
Glaciers come and go.
The great Aletsch Glacier has been going since 1860. Before that time it was coming, and eating up precious pastureland. The Catholic church held ceremonies to stop its advance.
http://3.bp.blogspot.com/-M_qAas_Ctoc/Tnz2VWOdfcI/AAAAAAAAABM/nU5MKRG6Fho/s400/Image3.jpg
UNPRECEDENTED COOLING
in the South Atlantic SST 60 year record
http://www.vukcevic.talktalk.net/SA-SST.htm
data: link
I really hate this “irreversible” language (I was going to use an expletive but decided against). It is generally accepted that the Earth was once ice-free from pole to pole, so how did the glacier get there in the first place? It obviously isn’t “irreversible” as evidence indicates that it “reverses” all the time on geological time scales! WHAT UTTER RUBBISH!
Hey what’s with the Obama 2012 ad showing up on this post? Really?
The myth of the cursed glaciers:
http://blogs.scientificamerican.com/history-of-geology/2011/12/26/cursed-glaciers/
“The details differ but the general structure of the myth is very similar: A long time ago there existed a rich city surrounded by fertile pastures where today is the glacier. Unfortunately the wealth corrupted the inhabitants and they wasted the fortune, one day they decided to use milk and bread to clean the streets of the city. When a beggar asked for a piece of bread the presumptuous inhabitants denied him this humble request. So he cursed the city, dark clouds covered the sky and heavy and persistent snow started falling in the mountains. When the sun reappeared, the city and pastures were gone, lost forever under the glacier.
Some historians suggest that this myth is based on observations of advancing glaciers during the period of the “Little Ice Age“, a period of cooling extending in the Alps from the 16th to the 19th centuries.”
Kathy: Funny thing about ads, if you click on them they have to pay a small amount to keep Anthony’s site running. Isn’t it wonderful to force the Obama campaign to keep this fine establishment going?
Imagine that today would be 11,500 years ago, how would the IPCC react to the “irreversible” glacier retreat and sea rise flooding coastal towns because of global warming ?
http://www.iceagenow.com/Ice-Age_Maps.htm
http://iceagenow.info/wp-content/uploads/2011/06/Easterbrook-Natural_global_warming.jpg
We already know that according to map makers Greenland glaciers can shrink and then grow back in just a few years.