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Glaciers have always grown and receded
(Part of the How to Talk to a Climate Sceptic guide)
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It has also been updated and this page is still here only to preserve the original comment thread. Please visit A Few Things Ill Considered there. You may also like to view Painting With Water, Coby Beck's original fine art photography.Labels: Sceptic Guide
posted by coby @ 1/11/2006 12:51:00 PM
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25 Comments:
At March 14, 2006 6:45 PM,
Anonymous said…
I understand that you are not claiming that glacial retreat is not “proof” of AGW but rather “evidence”.
In any case, you need to explain why most glacial retreat (where records are available) began about 1850, well before C02 could be considered a dominant climate forcing.
See the chart at realclimate:
http://www.realclimate.org/index.php?p=129#more-129
As John Finn points out in comments, there is an attribution problem when the effects are manifest earlier than the supposed cause. The responses by Eric and Gavin, are, IMO, non-answers.
At March 14, 2006 8:20 PM,
coby said…
Not sure I concur with the "most" characterization, looks closer to half. Regardless, this surely is an area for more investigation, but I don't agree that it is critical to the case for GHG warming now. There is no rule that one and only one forcing will govern glacial retreat. Some other process was at work before, CO2 is at work now, I see no contradiction.
I have a totally speculative pet hypothesis: this was the early days of the industrial revolution and much more black soot was being produced by coal fires in the cities. Perhaps this soot found its way onto white ice surfaces and darkened them causes melting.
Just a thought!
At March 15, 2006 4:10 AM,
Anonymous said…
Well, to say that glacial retreat is “not inconsistent” with AGW is hardly evidence at all. And you’ve claimed it is evidence.
You seem to be saying that something else caused pre-20th century glacial retreat, but it’s c02 now. This is a nonsense argument. As I said in the earlier comment, if the effect precedes the cause, attribution is difficult.
You say that the issue is not critical to the case of GHG warming. I agree. However I suggest that you amend the talking point on your site to say that “there is no clear relationship between glacial retreat and AGW”.
And if not, I’d like to know why, as we seem to agree on this point.
At March 15, 2006 8:32 AM,
coby said…
Thanks for the clarifications, Mauri.
Anonymous:
"However I suggest that you amend the talking point on your site to say that “there is no clear relationship between glacial retreat and AGW”."
The current rapid and global glacial retreat is very strong evidence of global warming.
At March 20, 2006 4:12 PM,
Anonymous said…
Here's Bruce Molnia of the US Geological Survey:
"There is no question that on a global basis we're seeing a warming that goes back several centuries. There are 2,000 glaciers that descend to below 1,500 metres in Alaska and about 99 per cent of them are retreating," Dr Molnia said.
The loss of glaciers is probably part of a natural process that began with the ending of the last ice, but man-made climate change could also be playing a role.
"Global warming is one factor, but if humans went extinct, glaciers would still be in retreat," Dr Molnia said. "Should we be worried? If glaciers are the source of your drinking water or if you live in an area that is vulnerable to sea-level rise, then yes, you should be worried. But in the longer term, the advance and retreat of glaciers is part of a natural cycle."
http://news.independent.co.uk/environment/article352365.ece
At March 21, 2006 10:23 AM,
coby said…
Also from that article:
"Michael Zemp and colleagues from the World Glacier Monitoring Service at the University of Zurich in Switzerland believe that warmer air temperatures in Europe in recent decades is behind the rapid loss of Alpine glaciers.
"Glaciers have been shrinking since 1850 but there has been a definite acceleration over the past two decades," Dr Zemp said.
The latest study shows that there has been a 50 per cent decrease in the area of the Alps covered by glaciers over the past 150 years. However, the rate of loss between the 1970s and 2000 was almost three times faster than the rate of loss seen between 1850 and 1970, Dr Zemp said.
In fact, the situation is even more dramatic because much of the loss between 1970 and 2000 occurred after 1985. And since 2000 there have been exceptionally warm years where glaciers have shrunk even faster than in previous years, Dr Zemp said."
http://news.independent.co.uk/environment/article352365.ece
At March 21, 2006 5:41 PM,
Anonymous said…
Yes, but the question we are discussing is the anthropogenic contribution to glacial retreat. Nobody's arguing about whether glaciers are retreating, or whether there is warming since the second half of the 20th century.
Molnia doesn't seem to think any anthro contribution is important.
At March 21, 2006 7:29 PM,
coby said…
Molnia, assuming he is being quoted correctly and in appropriate context, is expressing an opinion in a newspaper. Peer reviewed studies show that the anthropogenic component is very likely the cause of the current retreat and the marked acceleration of retreat. I suggest at this point you reread the article these comments are under.
At March 23, 2006 5:55 PM,
Anonymous said…
OK, I reread the original post, and looked at the links.
The links are not to peer-reviewed papers but are press-releases, magazine articles and websites.
As far as glaciers are concerned they establish that worldwide glacial retreat began about 1850 ad has accelerated since the second half of the 20th century.
Your position is that retreating glaciers are evidence of AGW. So could you provide citations in the literature that attribute glacial retrreat to the anthropogenic component of global warming?
BTW, I'm not exactly a skeptic, I accept that AGW is likely, but I'm not convinced that glacial retreat is good evidence for it.
Also, I support the idea for your website, but if it's going to be promoted as a "guide to dealing with skeptics" it needs to be accurate and honest.
In that respect, the title of the page and the initial response create something of a straw man. Surely no-one (well, maybe Greenpeace) is claiming that glacial retreat is "proof" of AGW.
The position you have to defend is that glacial retreat is evidence of AGW (not "not inconsistent", anyone would concede that in a heartbeat).
At March 24, 2006 3:47 PM,
coby said…
I will reconsider this article based on your comments. My point was to refute the denial of Global Warming based on evidence of glacial retreat much too early to have been due to GHG's. I do hear people use almost exactly the wording I start with above, "glacial retreat doesn't prove anything...etc" hence the emphasis on putting this single line of evidence in context.
As for attribution of 20th century and in particular late 20th century glacial retreat, I think melting ice is a symptom of warming so any attribution of warming to anthropogenic causes extends to melting. Other articles deal with the "it's not our fault" denials.
I don't mind not linking directly to Science and Nature articles, this site is by and for lay people. That is not to say I don't care to be accurate, I absolutely do, but I have no problem linking to scientific institutions' topic overviews and press releases, (good) science journalism, and websites by climate scientists (RealClimate). The actual papers can be followed up when desired through these sources. (I do have links directly to papers in many articles, but this is just to explain why I am not worried if not every point is properly referenced, as long as I am comfortable it is correct.)
In short, I do strive to be accurate and honest but not so scientifically rigorous as to become confusing or intimidating to non-scientific visitors.
Back to this topic: the world is warming, this causes the glaciers to melt, it really is that simple.
At March 25, 2006 3:24 AM,
Anonymous said…
"As for attribution of 20th century and in particular late 20th century glacial retreat, I think melting ice is a symptom of warming so any attribution of warming to anthropogenic causes extends to melting. Other articles deal with the "it's not our fault" denials."
OK, but that does not mean that glacial retreat is evidence of AGW, only that it is evidence of GW. And we don't need glaciers as evidence of GW, we have thermometers for that.
I'm glad that you are considering rewriting this section. In the absence of the peer-reviewed literature that attributes an anthropogenic component to the warming causing glacial retreat, I'd suggest that my earlier statement "no clear relationship" should prevail.
BTW, it would be really helpful in a discussion such as this if you used the terms GW and AGW in a consistent fashion.
At May 27, 2006 3:25 PM,
Anonymous said…
There is nothing to indicate that unnatural processes are at work modifying Natural climate processes. Sea level rises in a non constant manner. Detailing the relative speed of such rises is NOT showing unnatural influences but highlighting that sea level indeed does rise in a non constant manner.
Melting of Ice is not showing unnatural processes, Ice has been melting everywhere since the reversion of the last Glaciation 20,000 years ago. Live with the REALITY, it is neither showing unnatural alterations are present and highlights that the natural warming is still in evidence.
Understand that as the snow and ice is pressed back to its 'start position' that a portion of warmer land will form around the equator. This is NOT an indication of any unnatural processes being 'evidenced' but the continuance of that known Natural processes. The Sahara was only a few thousand years ago a verdant plain little different than the southern plains of Africa at present.
As an aside, I have mentioned I discuss in short essay within around 1000 words. This is the format generally used within SCIENCE as the minimum expected to elucidate concepts, and also to produce reporting documents (précis reports) on 'papers'.
Your's,
Peter K. Anderson a.k.a. Hartlod(tm)
From the PC of Peter K Anderson
E-Mail: Hartlod@bigpond.com
At May 27, 2006 4:38 PM,
Anonymous said…
I don't see how glaciers can be applied as evidence of global warming. Since the peak of the last Ice age 18,000 years ago they've receded about 3000 kilometers or about 166 meters per year. That’s a lot faster than anything occurring now so I don't understand the argument about glaciers. I mean if after an Ice Age you can have large and thick glaciers receding at that rate of natural causes why is it so surprising that smaller glaciers in a warmer climate are receding. I'm not too sure about my facts however so feel free to point out any mistakes in my argument.
At May 27, 2006 5:58 PM,
coby said…
Hi Kyle,
It is not very useful to draw a straight line like that from 18000 years ago to today. The climb out of the last glacial period stopped around 8-10kyr ago and since that time the climate was very stable, cooling very slightly. See here and here. The current glacial retreat has accelerated alot in the last few decades.
You are also comparing ice sheets and glaciers by the way, but it does not much change your argument except for the relevance of rate of retreat comparison.
At May 27, 2006 6:58 PM,
Peter K. Anderson said…
The flaw in logic of 'unnatural effect' global warmists is that there IS notice of 'rate', and in disproportional 'humanistic' time frames. There is no validity garnered from these 'humanistic time frames' due to the irregular periodicity in natural climate processes of 'rates' in a 'climate time frame'. It is a Human foible to consider a few decades as at all relevant to Climate processes.
The 'last' Glaciation reverted as Natural warming processes again 'accelerated'. That process has not stopped; simply the glaciation is still retreating. Glaciers, especially those still at altitude (the lowest already having melted) alter 'melt rate' however as the Permanent Ice level rises through the Atmosphere. This altitude was around 1500 metres within the glacial event. NOW it is around 2500 metres and rising still (even if slowly), the 'irregularity' muted by the ability of Gases to exhibit Turbulence to inputs of kinetic energy. This is sometimes reported as a 'temperature' but these are inconsistent due to Turbulence.
To rephrase, the muting of effect, and observed lag, is due to the production of Turbulence in reaction to of Kinetic Energy, but is not measurable as Temperature until the processes with Turbulence produce an input that can be measured as Temperature. Kinetic Energy in use within a process of Turbulence is NOT in itself measurable as Temperature, such energy can only be regarded ONCE, a basic concept of SCIENCE. Mass that is being so transported can have an intrinsic 'temperature' and so 'warm' OR 'cool' air can be in motion, for example.
So Glaciers at altitude can still be melting as Polar Ice reforms, the OBSERVATIONS showing only LAG of effect from processes possible already have been in effect previously.
It is the misinterpretations of what IS kinetic energy that over produces attention of 'current rate' and 'argument' over 'future rises'. Most of the 'future' effect is already 'dialed in', it is the observation of delayed effect that is being given 'regard' as a 'greenhouse issue', even as the 'greenhouse effect' is seen as not possible, or that 'greenhouse warming amplification' is not evidenced within possible surface incident energy (as Photons).
Your's,
Peter K. Anderson a.k.a. Hartlod(tm)
From the PC of Peter K Anderson
E-Mail: Hartlod@bigpond.com
At August 19, 2006 8:19 PM,
Anonymous said…
The argument that glacial retreat started in 1850, therefore it doesn't support ACW is false. The human influence on atmospheric CO2 levels started well before automobiles became popular.
This link shows the level generated in Australia from coal:
http://www.geos.ed.ac.uk/ccs/
This link shows Atmospheric CO2 levels increasing in the early 19th century.
http://cdiac.esd.ornl.gov/trends/co2/siple-gr.htm
The agricultural revolution (converting forests and rangelands into farms) started almost 9,000 years ago. This caused a reduction in standing biomass and reduced the uptake of CO2, contributing indirectly to global warming.
Ken
At January 31, 2007 7:28 AM,
Anonymous said…
Sea ice reaches new record declines: http://nsidc.org/news/press/20050928_trendscontinue.html
Glaciers in Greenland are receding and calving at record rates:
http://www.nasa.gov/vision/earth/lookingatearth/grace-20051220.html
http://cires.colorado.edu/science/groups/steffen/greenland/melt2005/
http://news.bbc.co.uk/2/hi/science/nature/4508964.stm
http://www.eurekalert.org/pub_releases/2005-11/uoc--rag111405.php
This is a global phenomenon:
http://www.realclimate.org/index.php?p=129
http://nsidc.org/sotc/glacier_balance.html
http://www.worldviewofglobalwarming.org/pages/glaciers.html
Ancient permafrost is also thawing:
http://www.newscientist.com/channel/earth/mg18725124.500
http://www.gi.alaska.edu/ScienceForum/ASF15/1523.html
http://www.commondreams.org/views04/1215-24.htm
^^^Spamming me with self-fulfilling prophecy, circular logic links is not going to convince me, especially when you don't provide any counter-evidence when you asserted in the original arguement that, "GLacers have been receeding for a long time." That is fascinating because even I havent seen that yet, thanks for the heads up. I will now look for studies on how glaciers have been receeding for a long long time.
At January 31, 2007 7:30 AM,
Anonymous said…
http://en.wikipedia.org/wiki/Image:Grinnell_Glacier2.jpg
^^Wow cool, this glacier has been receeding since 1850, and it looks like the biggest retreat was around 1850.
*must be all that carbon dioxide from those evil automobiles in 1850*
At January 31, 2007 12:08 PM,
coby said…
Ok, so all these scientific institutions and there data don't convinc you. What evidence would you find convincing? (Not that I particularily care, it's just I ask this of everyone in denial as deep as yours. Maybe you will be the first to actually answer)
At January 31, 2007 8:43 PM,
Anonymous said…
Some anonymous guy said:
"Wow cool, this glacier has been receeding since 1850, and it looks like the biggest retreat was around 1850.
must be all that carbon dioxide from those evil automobiles in 1850"
---------------------------
OK, first of all, the image on wiki that you were looking at is not indicating that the "biggest retreat was around 1850". It is showing the approximate former locations of the glacier margin (aka 'the toe'; aka where the edge of the glacier used to be) measured at different points in time. So, where it says 1850 - that's where it was in 1850. Where it says 1937, that is how far it had retreated by 1937... and so on. (I can't believe I'm explaining this.)
Here is a much better image
Second, regarding your comment about "all that carbon dioxide from those evil automobiles in 1850"
Take a look at the post two posts before yours. (It might be helpful if you READ the discussion before joining it).
I'll reprint it for you... and you should follow the links and look at the graphs. It looks to me like it addresses the issue of CO2 emissions prior to petroleum.
No, it is not PROOF of AGW, but it does provide scientific analytical evidence to respond to your post and the posts of others who claim that there is only circular logic without any counter evidence being presented here.
Here is that other post:
------
The argument that glacial retreat started in 1850, therefore it doesn't support ACW is false. The human influence on atmospheric CO2 levels started well before automobiles became popular.
This link shows the level generated in the UK from coal
(UK CO2 emissions since before the industrial revolution. From National Energy Foundation, data from Carbon Dioxide Information Analysis Center. Data compiled by G. Marland, T. A. Boden and R. J. Andres of ORNL)
This link shows Atmospheric CO2 levels increasing in the early 19th century
The agricultural revolution (converting forests and rangelands into farms) started almost 9,000 years ago. This caused a reduction in standing biomass and reduced the uptake of CO2, contributing indirectly to global warming.
At February 20, 2007 2:42 AM,
Anonymous said…
Sorry, I don't deal in circular logic (unless I can get away with it.)
Show an image of "estimated" glacier levels, I says 1850 evil automobiles, and you give me circular logic arguements that have nothing to do with glaciers. GOOD JOB!
gee wiz.
At November 26, 2007 6:57 PM,
Anonymous said…
I'm sorry, but you have totally shown your ignorance in this post. Science is NOT about a "balance of evidence." Science is about valid, repeatable results. Stick to politics. leave the science to people who know what the heck science actually is. Thanks.
At December 13, 2007 2:03 AM,
Will Nitschke said…
This is a poor post that begs the question. No single fact necessarily proves or disproves global warming, as it is the "balance of the evidence" that decides. Then you provide no evidence in this article. Perhaps you can review this post and either remove it or improve it, as it demonstrates the original objection is stronger than your reply. It won't convince a critical thinker, so it serves no purpose in its present form.
At January 14, 2008 5:26 PM,
Anonymous said…
I second that, however I'm bluntly refering to YOUR post... You claim to be a critical thinker? I didn;t have time for this, but at least I read the whole thing through... The argument that glacial retreat started in 1850, therefore it doesn't support ACW is false. The human influence on atmospheric CO2 levels started well before automobiles became popular.
This link shows the level generated in the UK from coal
(UK CO2 emissions since before the industrial revolution. From National Energy Foundation, data from Carbon Dioxide Information Analysis Center. Data compiled by G. Marland, T. A. Boden and R. J. Andres of ORNL)
This link shows Atmospheric CO2 levels increasing in the early 19th century
The agricultural revolution (converting forests and rangelands into farms) started almost 9,000 years ago. This caused a reduction in standing biomass and reduced the uptake of CO2, contributing indirectly to global warming.""
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