[GLIMS] NSIDC write-up on "extinct glaciers" tracking in GLIMS

[Bruce Raup]

Hello Andrea,

Thanks for the questions.  I meant to say that in this context, we're
interested in glaciers that have disappeared, or been de-listed as
"glaciers", within the last 50-100 years or so.  Obviously, many glaciers
have gone away since the last ice age, but we're interested in those that
are victims of more recent changes.

Some glaciers have completely melted away -- those are the easy cases.
Some have become small ice patches that would no longer be considered
glaciers.  Dead debris-covered ice is usually not called "a glacier"
anymore, even if we might say that it is "glacial ice".  So, there is some
subjectivity to this, but if you, expert as you are in your geographic
area, would say that an ice body is no longer a glacier, then we will call
it "extinct" on your authority.

In my view, if a glacier has become "invisible", it may still be a glacier,
or it may be considered a rock glacier.  Invisible glaciers in Colorado are
called rock glaciers, but large expanses of debris-covered ice in the
Karakorum (for example) are still considered glaciers.  Here again, I would
defer to the people who have the deepest knowledge of the area.

I point out that this tracking in GLIMS is recent, and I will likely add
a field to each "extinct" record to note the source of the pronouncement of
extinction.

Best regards,
Bruce


2023-11-09, 10:29:  Fischer, Andrea wrote:

> hi Bruce,
> i actually thought about a Compilation of glacier extinced in 2023, is
> there any Definition you use? What about dead ice still present under
> debris or something like that? Would it be ok also to hab’s a compilation
> of glacier which are „invisible“ or do you also include glaciers Where we
> could see small remnants of dead ice? We might habe lost about 5 percent
> this year… cheers, andrea
>
> PD Dr. Andrea Fischer
> Institute for Interdisciplinary Mountain Research
> Austrian Academy of Sciences
> Innrain 25/3, 6020 Innsbruck
> Austria
>
>
>> Am 09.11.2023 um 17:07 schrieb Bruce Raup <braup at colorado.edu>:
>>
>> Hi all,
>>
>> Our media person (Audrey Payne) recently posted this story on the recently added tracking of extinct glaciers in GLIMS:
>>
>> nsidc.org/news-analyses/news-stories/showcasing-death-worlds-glaciers
>>
>> We've just begun to add extinct glaciers to the GLIMS Glacier Database, so if you can add more such data, I would appreciate it!
>>
>> As the fundamental entity in the GLIMS Glacier Database is the glacier outline, data on extinct glaciers need to be tied to outlines.  A list of
>> GLIMS glacier IDs, together with estimated date (or year) of disappearance
>> and uncertainty in that estimate, would be the easiest to handle.
>>
>> I hope everyone is having a pleasant Autumn, or Spring.
>>
>> Bruce
>>
>> --
>> Bruce H. RAUP
>> National Snow and Ice Data Center
>> University of Colorado
>> cires.colorado.edu/~braup/
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>

-- 
Bruce H. RAUP
National Snow and Ice Data Center
University of Colorado
cires.colorado.edu/~braup/