From the University of Innsbruck, another modeling study.
This news release is available in German.
The ongoing global glacier retreat causes rising sea-levels, changing seasonal water availability and increasing geo-hazards. While melting glaciers have become emblematic of anthropogenic climate change, glacier extent responds very slowly to climate changes. “Typically, it takes glaciers decades or centuries to adjust to climate changes,” says climate researcher Ben Marzeion from the Institute of Meteorology and Geophysics of the University of Innsbruck.
The global retreat of glaciers observed today started around the middle of the 19th century at the end of the Little Ice Age. Glaciers respond both to naturally caused climate change of past centuries, for example solar variability, and to anthropogenic changes. The real extent of human contribution to glacier mass loss has been unclear until now.
Anthropogenic Causes
By using computer simulations of the climate, Ben Marzeion’s team of researchers simulated glacier changes during the period of 1851 and 2010 in a model of glacier evolution. “The results of our models are consistent with observed glacier mass balances,” says Marzeion. All glaciers in the world outside Antarctica were included in the study. The recently established Randolph Glacier Inventory (RGI), a complete inventory of all glaciers worldwide, enabled the scientists to run their model. “The RGI provides data of nearly all glaciers on the Earth in machine-readable format,” explains Graham Cogley from Trent University in Canada, one of the coordinators of the RGI and co-author of the current study.
Caption: This image shows the Artesonraju Glacier in Cordillera Blanca, Peru.
Credit: Ben Marzeion
Since the climate researchers are able to include different factors contributing to climate change in their model, they can differentiate between natural and anthropogenic influences on glacier mass loss. “While we keep factors such as solar variability and volcanic eruptions unchanged, we are able to modify land use changes and greenhouse gas emissions in our models,” says Ben Marzeion, who sums up the study: “In our data we find unambiguous evidence of anthropogenic contribution to glacier mass loss.”
Significant Increase in Recent Decades
The scientists show that only about one quarter (25 +/-35 %) of the global glacier mass loss during the period of 1851 to 2010 is attributable to anthropogenic causes. However, during the last two decades between 1991 and 2010 the fraction increased to about two thirds (69+/-24%). “In the 19th and first half of 20th century we observed that glacier mass loss attributable to human activity is hardly noticeable but since then has steadily increased,” says Ben Marzeion. The authors of the study also looked at model results on regional scales. However, the current observation data is insufficient in general to derive any clear results for specific regions, even though anthropogenic influence is detectable in a few regions such as North America and the Alps. In these regions, glaciers changes are particularly well documented.
The study is supported, among others, by the Austrian Science Fund (FWF) and the research area Scientific Computing at the University of Innsbruck.
Can someone explain the melting percentages listed (25% +/- 35%)???
I have seen persentages listed as say 25% +/- 5% indicating a range of 20% – 30%
But this would give the warming percentage a range of -10% to +60%
What exactly is stated by 25% +/- 35%???
Ignore Dr. Christian Schlüchter and his findings. He is not a Team member and therefore must be considered unreliable. Even worse, his work is not supported by a computer simulation.
During the Little Ice Age (~1300 to ~1915 AD), alpine glaciers reached their maximum extent since the last big Ice Age ended ~12,000 years ago. Little Ice Age glaciers oscillated back and forth over multiple periods of warming and cooling, mostly lasting about 25-35 years. At the end of the last significant cool period (1880-1915), many alpine glacier termini were not far from their maximum Little Age positions. Most of the glacier recession this century took place during the 1915-1945 warm period, before human CO2 emissions began to increase significantly (after 1945). With this in mind, how does their model account for these pre-CO2 recessions? Their paper claims “during the last two decades between 1991 and 2010 the fraction (of anthropogenic-caused ice loss) increased to about two thirds (69+/-24%).” But wait a minute–there has been no global warming for 15-18 years while CO2 has continued to increase. Global climate has actually been cooling for more than a decade and glaciers in Scandinavia, Alaska, and South America have stopped retreating and have begun to advance, so how can ‘human-caused CO2 warming’ be to blame? The disparity between their model results and reality is astounding.
And it gets even worse the farther back in time we look. There have been 40 periods of warming and cooling since 1500 AD, none of which involved CO2. The Medieval Warm Period was significantly warmer than present, and almost all of the past 10,000 years have been several degrees warmer than now without anthropogenic CO2.
Computer models are not evidence of anything–they are incapable of ‘proving’ anything because they are all based on assumed numbers, not real-life data. Computer models have totally failed to correctly predict temperatures over even the past few decades. Whoever said ‘garbage in, garbage out’ certainly had it right!
Nylo says:
August 15, 2014 at 12:23 pm
In the unlikely event that CO2 works in the atmosphere as it does in a lab, then the effect of increasing its concentration from three molecules per 10,000 in dry air to four molecules should not even be measurable. The increase will be entirely swamped by the GHG effect of about 400 molecules of water vapor (whose absorption bands largely overlap CO2’s) in the moist tropics & perhaps 300 on average in temperate zones, but might register in dry polar regions, but not enough for a meaningful climatic effect.
If a doubling of CO2 from 280 to 560 ppm produces in nature the ~1.2 degrees C increase derived in lab experiments, then the majority of that putative rise has already occurred (given enough time for equilibrium), due to the logarithmic nature of the effect. However during the past 150 years, global temperature has risen while CO2 levels were falling, as during the Depression years, & fallen while CO2 was increasing, as from the late 1940s to ’70s. Only for a brief accidental interval from about 1977 to 1996 did average global T (poorly measured) rise while CO2 was also rising.
Besides which, there are most likely powerful negative feedbacks to whatever scarcely measurable (at best) effect “our” presumed additional molecule per hundreds of GHG molecules in dry air might actually have. The climate system is homeostatic. The positive feedback from water vapor assumed in climate models is simply not in evidence, indeed has been shown false.
The net effect of human activity might be cooling because our other potential influences, such as aerosols & CCN creation, could cancel out whatever small effect our GHGs might have, if any. Thus, I have seen no evidence of a net human contribution to “climate change” on a global scale, although clearly we have heated up some localities.
So I’m still waiting for conclusive, convincing evidence of a global effect of human activity on the climate system.
reposted from another thread;
I have done a lot of research on glaciers aided by such books as Laduries ‘Tines of Feast times of Famine’ from which we are able to reconstruct the generalities (but not the nuances) of Glacial advances and retreats in the Northern Hemisphere over the last few thousand years. I have also visited several glaciers and examined their records in the local museums
Here are these retreats and advances against which has been set the Hockey Stick and CET
http://wattsupwiththat.files.wordpress.com/2013/08/clip_image010.jpg
“Fig 5-3000 year Glacier movements with CET decadal/50 year steps and Mann et al 1998
A closed blue horizontal line at the top of the graph equates to a period of glacial retreat (warmth) and a closed blue line at foot of graph demonstrates glacier advance (cold)
That glacial movements can be surprisingly short lived can be seen in the century long glacier advance around 1200 to 1300 AD, and to a lesser extent the 30 year retreat around 1730. Such short changes as noted in this latter period may be relatively common, but the records are unlikely to exist to be able to trace them in earlier times.
The small temperature deviations from the ‘norm’ shown in paleo proxy reconstructions- including that of Mann et al 1998-seem most unlikely to be of a scale that can precipitate glacier movements of any consequence. Several consecutive warm cold decades that can be noted in the instrumental records will however likely start such movements which will be accentuated if the prevailing characteristic of warmth or cold lasts for some time. In the case of the MWP this period of warmth lasted around 450 years . (Clearly however brief Warm periods can occur during a general glacial retreat and brief cold periods during glacial advance.) ”
Glaciers have been retreating in part since 1750. They have been rather volatile items in their retreats and advances over the ages and the idea that we have impacted on them via co2 over the last 20 years is fanciful.
They are currently generally retreating from a considerable high point of glacial action during the LIA . Eventually history tells us they will generally advance.
tonyb
Nylo:
At August 15, 2014 at 12:23 pm you say
You have seen different things from me.
I’ve seen our CO2 emissions continue unabated, I’ve seen atmospheric concentration of CO2 unabated, I’ve seen the CO2 absorption bands and I have seen the Earth’s infrared radiation spectrum. I know that at present atmospheric CO2 concentration more CO2 means trivially narrower radiation spectrum for Earth, which means that, incoming energy being equal, the remaining frequencies need to adjust a little, and for that to happen, the compounds (e.g. water vapour) responsible for the emissions in those frequencies have to be warmer or to change concentration. Given that I have seen no evidence of reduced incoming energy and the world has not warmed for nearly two decades, everything indicates that the CO2 changes are not relevant to global temperature change.
Richard
There is a plenty of similar “research” reported… Today’s university is what used to be called a high school a century ago
There is no credible experiment that proves that the greenhouse gas effect exist. There are many experiments that show that the greenhouse gas effect does not exist.
Here is something for the supposed scientists to ponder.
The 1.5 to 2.0 million scientists that are “skeptics” are accused of ignoring two hundred years of science when they claim that the Hypotheses of the greenhouse gas effect (GHGE) does not exist. This is a falsehood ,just the opposite is true. To prove this we must start with a definition and procedure of science. Science is never settled!
A scientist looks at some event in nature and asks why?
The scientists start to gather data that will help explain the event.
To organize the data a hypotheses is proposed.
The data is rearranged to see if it correlates to the hypotheses.
If the data and the hypotheses seem to agree, more data is obtained and an experiment most be developed to prove the hypotheses.
The experiment is performed with variations of the perimeters.
The results are compared to the hypotheses.
Does results agree with the hypotheses and the original “nature event “
If the original “nature event” , hypotheses and experimental results agree a paper would be prepared to present to the scientists with the most knowledge of the subject to review and attempt to duplicate the results.
If the results do not agree with either the” nature event” and /or the hypotheses then back to the drawing board. Many hypotheses fail. Some succeed and go on to further testing and evaluation.
Progress in science is made from both successful and failed hypotheses. Failed hypotheses can only help if they are analyzed honestly why they failed.
With this outline as a basis, lets look at the Hypotheses of the Greenhouse effect and then the modified Hypotheses of the greenhouse gas effect. These are often confused by the public and especially the nitwits in the media. They really don’t understand that a few wrong words make a difference especially in science.
During the 1800’s it was thought that The greenhouse effect was do to resonance of IR within the glass wall of the structure. IR and visible light passed through the glass, heated the contents, which radiated IR of a different wavelength that did not go through the glass but reflected back to build up the heat within the greenhouse.
In 1909 Robert W. Wood an expert in both IR and UV radiation did a very simple experiment that proved that the original Hypotheses was wrong. His experiment which can be found on the internet and is listed in the list of references proved that what happens in the “greenhouse or any other similar hot box is “ confined space heating”. This concept is address in many papers and other experiments including The paper “Falsification of the Atmospheric CO2 greenhouse effect within the frame of physics” by Gerhard Gerlich and Ralf D. Tscheuschner and Wood is correct: There is no Greenhouse Effect
Posted on July 19, 2011 by Dr. Ed (Berry @ur momisugly www. ClimateClash.com)
Repeatability of Professor Robert W. Wood’s 1909 experiment on the Theory of the Greenhouse (Summary by Ed Berry. Full report here or here. & PolyMontana.)
by Nasif S. Nahle, June 12, 2011
University Professor, Scientific Research Director at Biology Cabinet® San Nicolas de los Garza, N. L., Mexico.
End part 1
Part 2.
Although the concept of back radiation (back forcing) is still believed to exist and is covered in the papers of G&T but it can not be proven by experiment.
Now lets look at the other Hypotheses of greenhouse gas effect.
The original Hypotheses was proposed by Fourier in 1824. Fourier is a very credible mathematician and physicists but I have not found any indication that he actually attempted to prove the Hypotheses that gases could cause the back forcing of radiation or heating of the gases in the atmosphere.
In the 1850-60 period John Tyndall a scientists and physicists carried out experiments that proved that certain gases will absorb IR; there is no question about this,every IR spectrophotometer uses this as an analytical tool millions of times a day. A question I ask myself is would the spectrophotometer work if back-forcing exists.
When I first learned about IR absorption I was told that that only three or more atom molecule would absorb IR. Since doing more research it is shown that both O2 and N2 absorb IR, this has a significant impact on what are “greenhouse gases”.
When reading the papers of Tyndall he stated that the most significant “GHG is water vapor” This is questionable see the following experiment http://www1.lsbu.ac.uk/water/vibrat.htmlWater Absorption Spectrum by Martin Chaplin. What phase we are looking at is very important which will be discussed later. Tyndall himself stated that there was not enough “traces gases in the atmosphere “ (including CO2 )to cause measurable temperature change.
His experiments did not prove that when a gas absorbs IR that it caused gas molecules around it to heat.
In 1896 Arrhenius gave a paper that “speculated” that increasing the CO2 concentration would cause the atmosphere to heat. Quoting a foot note by the IPCC Fouth Addition-In the 1860s, physicist John Tyndall recognized the Earth’s natural greenhouse effect and suggested that slight changes in the atmospheric composition could bring about climatic variations. In 1896, a seminal paper by Swedish scientist Svante Arrhenius first speculated that changes in the levels of carbon dioxide in the atmosphere could substantially alter the surface temperature through the greenhouse effect.”
Now Arrhenius was a very accomplished Biological physicists having been recognized with a Noble prize for his work. To him more CO2 and higher temperatures were beneficial to growing plants. However in 1903 Knut Angstrom pointed out significant flaws in Arrhenius’s work. Later I ‘ve been told that Niels Bohr told Arrhenius that he was all wrong. Niels Bohr knew something that Arrhenius did not know.( now called quantum physics)
When Arrhenius did his paper , he did a series of experiments however he was not able to prove that the effect existed. Another failed hypotheses.
After the turn of the century many significant developments in physics, quantum physics , and thermodynamics changed how we look at the world. The works of R.W.Wood, Niels Bohr, Albert Einstein, Max Plank, etc. etc. etc. etc. During this period between 1900 and 1970 there were many paper claiming that based on observations of atmospheric conditions that showed the “greenhouse gas effect” existed. The problem is that observation could not be repeated, because there are to many variable that can not be controlled. These observations are subject to subjective interpretation. Because the researchers had an ax to grind they blamed CO2 and other “GHG’s” for the effect.(They have ignored the fact that O2 and N2 which compose 96% of the atmosphere also absorb some IR thus should be called GHG’s) They never bothered to actually prove that the Hypotheses existed. Experiment after experiment( really only observations) were performed by people that had no business attempting to do scientific experiments, they called themselves “climatologist” most did not have any training in the field that really should be studying “ atmospheric physics “ – physicists, meteorologists, radiation scientists, and mechanical engineers trained in thermodynamics and HVAC. IF any of these observation were meaningful why can’t they decide what the atmosphere sensitivity of CO2 is supposed to be? There is absolutely no reason to spend billions of dollars to control CO2 when there is not one experiment that shows what effect reducing the CO2 will cause. Everything is “speculation” and bad speculation at that.
End part 2
Part 3
n the list of references are experiments that show that mixtures of Water/liquid/ solid and CO2 cause the atmosphere to cool not heat. Again there are experiments that prove that the greenhouse gas effect does not exist. These are experiments not speculation.
The reference http://www1.lsbu.ac.uk/water/vibrat.html Water Absorption Spectrum by Martin Chaplin. Which is based on experimenters; it is shown that ice absorb significantly more IR that liquid and vapor. This has to be understood when we evaluate the melting of glaciers. Air temperature is insignificant when observing the melting of ice. When it is sunny,snow and ice melts at significant rates even when the air temperature is below 32 degrees F. A simple observation proves this. For those of us that get ice dams and icicle go out on a below 32 degree F but sunny day, look at snow and ice in the shade, not a sign of melting. Then go to a part of your house that is in bright sunshine the snow and ice will be melting and flowing like you’re under Niagara Falls.
It is claimed by the cult of AGW that when the north pole is white it reflects significant visible light thus it does not cause the glaciers to melt and that small changes in average atmospheric temperature is responsible for the loss of the glaciers. They are wrong which is proved by the above. Ice absorb significant IR even when the visible light is reflected. IR melts ice far faster that air temperature. The world is in an inter-glacier period the glaciers are supposed to be receding. The fear -mongers are at it again. If the glaciers had not melted much of the northern and southern hemisphere would be under 2 miles of ice.
The Greenhouse Effect Explored
Written by Carl Brehmer | 26 May 2012
Is “Water Vapor Feedback” Positive or Negative?
Exploiting the medium of Youtube Carl Brehmer is drawing wider attention to a fascinating experiment
Your right : what John Tyndall said in 1850-60 was based on the misconception that the Greenhouse effect was caused by resonating IR within the container. This was proved false in 1909 by Robert w. Wood a professor of Optics at John Hopkins University. His experiment proved that the “greenhouse effect ” is really “confined space heating” a totally different concept. R.W.Woods was a recognized expert in IR and UV radiation, Many of his finding are referenced today in the world of optics ,IR ,and UV radiation.
The Wood experiment was verified in 2009 referenced below.
Greenhouse Gas Hypothesis Violates Fundamentals of Physics” by Dipl-Ing Heinz Thieme Many link are included that support the truth that the greenhouse gas effect is a hoax.
R.W.Wood
from the London, Edinborough and Dublin Philosophical Magazine , 1909, vol 17, p319-320. Cambridge UL shelf mark p340.1.c.95, i
The Hidden Flaw in Greenhouse Theory
By Alan Siddons
from:http://www.americanthinker.com/2010/02/the_hidden_flaw_in_greenhouse.html at March 01, 2010 – 09:10:34 AM CST
Wood is correct: There is no Greenhouse Effect
Repeatability of Professor Robert W. Wood’s 1909 experiment on the Theory of the Greenhouse (Summary by Ed Berry. Full report here or here. & PolyMontana.)
by Nasif S. Nahle, JunPosted on July 19, 2011 by Dr. Ed
e 12, 2011
University Professor, Scientific Research Director at Biology Cabinet® San Nicolas de los Garza, N. L., Mexico
Science is never settled. When the Cult of AGW goes back 200 years and claims that a Hypotheses or similar reference is valid but does not look at the developments that have occurred since that disprove the old hypotheses then we know they don’t know a thing about science. Science is built on failed and correct hypotheses.
New information trumps old unprovable data.
Ah, more console games…
Albert Einstein once said, “No amount of experimentation can ever prove me right; a single experiment can prove me wrong.” Einstein’s words express a foundational principle of science intoned by the logician, Karl Popper: Falsifiability. In order to verify a hypothesis there must be a test by which it can be proved false. A thousand observations may appear to verify a hypothesis, but one critical failure could result in its demise. The history of science is littered with such examples.
The Experiment that Failed which can save the World Trillions:
Proving the “greenhouse gas effect” does not exist!
By Berthold Klein P.E (January 15, 2012)
Edited by John O’Sullivan, incorporating comments by Dr. Pierre Latour, Professor Nasif Nahle, Edward J. Haddad Jr. P.E, Ganesh Krish, and others.
Dedication
To Professor Robert W. Wood (1909), the first scientist to demonstrate that the Hypothesis of the “Greenhouse effect in the atmosphere” was unscientific. To all other scientists since Professor Wood who have added sound technical and scientific knowledge in many related fields to strengthen the case against the greenhouse gas effect hoax.
To protect my grandsons JJ and BA plus their generation and all the generations that follow – because we finally got it right. For the generations that would otherwise suffer extreme economic harm if the Hoax of (Michael) Mann-made global warming – AKA the “greenhouse gas effect” (GHGE) is not stopped now and forever.
Nylo says:
I’ve seen our CO2 emissions rocket, I’ve seen atmospheric concentration of CO2 rocket, I’ve seen the CO2 absorption bands and I have seen the Earth’s infrared radiation spectrum. I know that more CO2 means slightly narrower radiation spectrum for Earth, which means that, incoming energy being equal, the remaining frecuencies need to carry more energy, and for that to happen, the elements responsible for the emissions in those frequencies have to be warmer. Given that I have seen no evidence of reduced incoming energy and I have seen the world warm, everything adds up.
You think everything adds up to anthropogenic global warming? OK then…
Please post testable scientific evidence showing the fraction of a degree of global warming caused by human emissions. Please quantify that with measurements, because simply throwing out various observations is not proof that human-emitted CO2 is the cause of AGW. It may be. But we need verifiable evidence, not random obsevations.
See, it could be that the change in CO2 is the result of past global warming. We know there is a lag time involved in ocean outgassing. Could it not be that the rise in CO2 is due to recent global warming? Or even due to global warming during the MWP, ≈800 years ago?
There is a wealth of empirical evidence showing that ∆T causes ∆CO2. But there is no comparable evidence showing that the rise in temperature is caused by rising CO2. That is only an evidence-free conjecture.
You have to be careful to not make evidence-free assumptions. As Richard Feynman pointed out, the person it is most easily to fool is yourself.
Q: How many computer modelers does it take to change a light-bulb?
A: None; the model says it’s still working.
dbstealey says:
August 15, 2014 at 1:40 pm
” showing that ∆T causes ∆CO2.”
…
All your link shows is that the 6-month variation is due to summer-winter changes in CO2 absorption due to the uptake of CO2 in the Northern Hemisphere in summer.
If only their models were reality-based instead of fantasy-based they’d be somewhere.
“The real extent of human contribution to glacier mass loss has been unclear until now.”
——————————————————————————
We knew man was destroying the glaciers all along, though cause that was settled science.
Isn’t it amazing how this settled climate science just keeps getting settleder and settleder.
(Odd, my computer doesn’t recognize settleder.)
I suppose this is more better perfect science since everything is finally clear now.
cn
richard verney (August 15, 2014 at 12:02 pm) challenges the statement: “However, during the last two decades between 1991 and 2010 the fraction [of the global glacier mass loss during the period of 1851 to 2010 attributable to anthropogenic causes] increased to about two thirds (69+/-24%).”.
rv, it’s actually very straightforward. The model calculates a rising AGW effect and subtracts it from a constant overall effect in order to estimate a negative natural effect.
In the world of climate models, there aren’t any turtles. It’s circular logic all the way down.
The retreat of the glaciers has provided a very insightful tidbit of data that proves the MWP was not warmer than today. All one needs to do is visit Glacier National Park, and obtain samples from tree stumps exposed by the melting glaciers. When dated by radiocarbon technices, the stumps are not 1000+/- years old as would be expected if the MWP was warmer than today. If the MWP was warmer than today, these glaciers would have melted, and trees would have grown up in the exposed surface. Re-glaciation during the LIA would have covered them up again.
The tree stumps data at 3000 years…..so obviously the MWP was NOT warmer than today.
http://www.geog.uvic.ca/dept/uvtrl/2000-02.pdf
http://alaskaresearch.voices.wooster.edu/files/2010/07/AppletonIS.pdf
Edward Richardson says:
August 15, 2014 at 2:49 pm
This blog has exploded & exposed this bogus argument at great length already. Please see comments in this post. Search for “stumps”:
http://wattsupwiththat.com/2014/08/08/receding-swiss-glaciers-incoveniently-reveal-4000-year-old-forests-and-make-it-clear-that-glacier-retreat-is-nothing-new/
You aren’t by any chance “H Grouse” are you?
The evidence from all over the world that the MWP was warmer than now is overwhelming. Same for the Roman & Minoan WPs (even warmer) & the Holocene Climatic Optimum (warmer still), plus the previous interglacial, the Eemian, & earlier interglacials. Current warmth is nothing special. Indeed far from it.
The Null Hypothesis of natural climate variation has not been shown false.
milodonharlani says:
August 15, 2014 at 3:07 pm
“Null Hypothesis ”
If the MWP was warmer than today, the tree stumps exposed at Glacier National Park would not date as 3000 years BP, they would date at 1000 years. Only takes one data point to prove that the MWP was not warmer than today.
All the data you can find doesn’t prove anything about the MWP, but one data point proving it wrong falsifies your hypothesis that the MWP was warmer than today.
Your “null hypotheisis” of the MWP was warmer than today is falsified by the radiocarbon dating of tree stumps at Glacier National Park.
..
Edward Richardson says:
August 15, 2014 at 3:15 pm
I’m not going to rehash the whole long discussion in the comments to which I linked. Please read it & get back to me.
The alleged age of the alleged stumps falsifies nothing. Even if it did, which it doesn’t, glaciers are affected by local conditions, so those in one small area are hardly dispositive for the entire globe. Besides which, they could have been exposed during the MWP, too, but didn’t rot away due to a high & cold environment.
You’ve got nothing.
milodonharlani says:
August 15, 2014 at 3:07 pm
BTW….
…
Your link also shows that the MWP and the Roman warm period was not warmer than today. IF they were, the remains at the edge of the Swiss glaciers would date younger than 4000 years BP.
Just for laughs
http://www.treehugger.com/clean-technology/melting-glacier-in-italy-gets-a-giant-thermal-blanket.html
http://photoblog.nbcnews.com/_news/2013/06/27/19170081-glacier-covered-with-blankets-to-reduce-summer-ice-melt
http://www.popsci.com/scitech/article/2007-06/duct-tape-methods-save-earth-insulate-glaciers.
Edward Richardson says:
August 15, 2014 at 3:24 pm
Don’t know to which link you refer.
The Swiss glaciers which are retreating have confirmed that the Holocene Optimum, Minoan, Roman & Medieval WPs were warmer than now. Artifacts found in their exposed valleys date from these intervals. How do you know that more such finds aren’t still buried under remaining ice?
From the geology of the valleys, it’s clear that glaciers had generally retreated more during the previous warm cycles. But again, local conditions mean that different glaciers behave differently, not all in unison. The same is true today, when some glaciers are advancing & some retreating.
milodonharlani says:
August 15, 2014 at 3:41 pm
“Roman & Medieval WPs were warmer than now”
If the MWP were warmer than now, the artifacts would date at 1000 BP not at 3 or 4000 years BP.