Comments 1 to 26:

1. Dr. Jay Cadbury, phd. at 03:41 AM on 18 May, 2011
   I've said this before, I don't think anyone can make a statement on glaciers. I think we need a world index of all glaciers. The problems we have with glaciers are numerous. Firstly, I don't know if melting starting points are accurately documented. Furthermore, if a melting glacier resumes growing, could we say this a sign of global cooling? So in summary, more information is needed, I say.
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   Response:

   [DB] Glacial mass-balance is a function of deposition in the glacier's accumulation zone (where it "packs on weight"), and its losses in the ablation zone (everywhere else).  Additionally, slope and terrain play a role as well. 

   If the glacier is getting substantially more deposition through enhanced snowfall in its accumulation zone, it may begin to advance further downslope (that gravity naughtiness).  However, increased meltwater pulses due to a warmer environment downslope may actually cause even greater acceleration and calving at the output end of the glacier due to basal lubrication and subsequent retreat upslope of the glacier.

   Measurements of glacier thickness, accumulation and ablation worldwide are reflected in the enclosed graphic.  In addition to the graphic I provide, see Jimbo's comment at #2 and glaciologist Mauri Pelto's site here:

   

   [Source]

   The reality is that hard-working glaciologists have been all over this for many decades.  And this is all very well-documented in the literature.  And at Skeptical Science (that Search function thingy).

2. Jim Powell at 03:47 AM on 18 May, 2011
   Dr. Jay: World Glacier Monitoring Service
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3. Dr. Jay Cadbury, phd. at 03:58 AM on 18 May, 2011
   That is helpful but I cannot tell from the graphic the total number of glaciers. I am still sorting through the link Jimbo provided.
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   Response:

   [DB] Then go to Mauri's page I linked to.  Or better yet, the primary literature in addition to the WGMS site Jimbo gave you.

4. Dr. Jay Cadbury, phd. at 04:01 AM on 18 May, 2011
   And before anybody goes after me for the question of the empirical evidence for the melting ice caps, I'm just trying to figure out if anyone knows how much the sea level will rise because that is the danger to humans, correct? So I just don't want people to think I'm sounding like a snob, obviously I wouldn't be asking for empirical evidence assessing the risk of the sun if it moved much closer to the earth. I know a fully melted ice cap is probably bad.
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   Response:

   [DB] You are far, far off-topic here.  Many posts exist at SkS (Search thingy will find them).  SLR about 7 meters from Greenland & Canadian Archipelago, 7 meters or so from WAIS, another 60-65 meters from the EAIS.  Even a partially melted ice cap is a very bad thing for people.

   No human civilization we are aware of was around the last time sea levels were at that level.

   Please focus on the topic of this thread from this point on.

5. Manwichstick at 04:02 AM on 18 May, 2011
   RE: 1. Dr. Jay, The experts I consult with have a lot to say about the glaciers melting. What they are much more cautious about is how to model future melt rates. They point to a lack of good on-the-ground data from the glaciers themselves. This uncertainty in how to model, does not make one blind to the already observed rate of glacial melt. Perhaps you are confusing the two.
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6. KR at 04:11 AM on 18 May, 2011
   Fully melted Antarctic and Greenland ice caps would raise sea levels by 80 meters, according to the USGS. That would be, um, bad. Melt of all glaciers besides those would only add an additional half meter. West Antarctic shelf and Greenland melt as per previous interglacials (with temperatures 2°C above present values, well within possible nthropogenic change levels) ~would be 10 meters or more, flooding ~25% of the US population, primarily on the East and Gulf Coasts.
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7. Dr. Jay Cadbury, phd. at 04:25 AM on 18 May, 2011
   @KR This is a good answer. KR, what is the global average sea level, in meters please, if you could.
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   Response:

   [DB]  Google is your friend.  You can look this stuff up yourself, you know, rather than asking.

8. les at 05:51 AM on 18 May, 2011
   7 - Jay "what is the global average sea level, in meters please, if you could." I'm scoring that as the oddest question ever asked on SkS.
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   Moderator Response: (DB) My initial thought was it was a snipe hunt; regardless of units, sea level is normally a base referent and is set as zero.
9. KR at 05:55 AM on 18 May, 2011
   les - It's a bit surprising. I started to get the answer to that halfway through typing "average ocean depth" into Google. Jay - The information about sea rise versus ice melt is also a Google answer. Lots data is out there, you just have to look a bit.
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10. KR at 05:56 AM on 18 May, 2011
    Gah - *lots of data* in the previous post
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11. mspelto at 07:07 AM on 18 May, 2011
    Dr Jay: We have three lines of measurement for glaciers. The WGMS reports glaciers where people with boots on the ground actually make measurements of glacier change annually. Typically this is mass balance of about 100 glaciers and terminus change on 400-500 glaciers. I measure 10 glaciers for mass balance and report all of these. This does not include glaciers where retreat is measured periodically, I measure terminus change on 60 glaciers, but only report about 10 that I examine annually. Most like Ptarmigan Ridge Glacier I do not as I visit them less frequently. Today we can also map the changes in area and hence terminus change using satellite imagery as well as thickness, these are not reported to the WGMS yet. The number that are tracked in this way is in the many thousands and these, take a look at the Colonia Glacier or Hariot Glacier for example, with the detailed terminus maps from satellite images. As we have done this it has confirmed that the WGMS sample is quite representative.
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12. arch stanton at 07:49 AM on 18 May, 2011
    Les (8), I agree with you. I hope the doctor returns to inform us of its relevance.
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13. adelady at 10:00 AM on 18 May, 2011
    arch, I like a little irrelevant mystery occasionally. We can stand a bit of delicious suspense for a while. Anyhoo. It's good to see people not just using the materials here but developing them as teaching and presentation tools. I reckon in another 6-12 months the combination of the visual tools with the phone apps will make a handy package for any community, church or school wanting to DIY a discussion or learning group.
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14. SouthWing at 10:40 AM on 18 May, 2011
    Dear folks, Dr. Jay is rather obviously a "seeker after truth" troll. Back to the topic, please.
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15. scaddenp at 11:08 AM on 18 May, 2011
    See similar pattern in posts from Jay (aka Dr "Dr. Shooshmon) on Realclimate and Blackboard. Assuming the same person of course (only RC noticed that he was using same posting name), then this comment and followings is quite funny.
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16. Bern at 13:48 PM on 18 May, 2011
    scaddenp: I presume the folks at Realclimate had some evidence that those IDs were one and the same, in which case it does seem some sock puppetry is going on. It's a harsh accusation to make against a commenter, so I'd prefer if there were some evidence (I think that it'd need IP logs or some such, at the very least). If they *are* the same, then that Blackboard thread is quite amusing... There does seem to be an increased incidence, lately, of "say it loud, say it often" posts early in threads on here, repeating arguments that have already been debunked so many times it's not funny. I presume John & the moderators here have their work cut out for them dealing with this kind of stuff... for example, at a quick glance I didn't see a single comment for this article that was on-topic! (and they can feel free to delete this post, too, as it's thoroughly off-topic!)
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17. scaddenp at 14:45 PM on 18 May, 2011
    Bern, see the first link at RealClimate (Moderators comment) and then this one where the commentator "Jay Cadbury" explains why he changed name from "Dr Shooshmon". Whether this is the same "jay Cadbury" and "Dr Shooshmon" as at Realclimate and Blackboard cannot of course be verified. However the "concern troll" type posts are pretty similar.
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18. Paul D at 17:20 PM on 18 May, 2011
    Dr Jay: "And before anybody goes after me for the question of the empirical evidence for the melting ice caps, I'm just trying to figure out if anyone knows how much the sea level will rise because that is the danger to humans, correct?" Not exactly. Reducing the area covered by glaciers has a number of impacts. 1. Changes to fresh water and hydro-electric schemes. 2. Increased ice loss further in land (Greenland, Antarctica), which reduces albedo, increasing the warming etc. 3. Probably changes in weather patterns, possibly water circulation to. 4. Sea level increases due to land based ice dumping into the seas. 5. Changes in wildlife and migration, impacts on food chain etc.
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19. JMurphy at 20:02 PM on 18 May, 2011
    Southwing wrote : "Dear folks, Dr. Jay is rather obviously a "seeker after truth" troll. Back to the topic, please." I'm not convinced, especially after this comment from a Dr. Jay Cadbury, phd over on the DeepClimate thread about Wegman's current difficulties : Whatever at least this Wegman guy didn’t try to make a fake graph...
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20. Dr. Jay Cadbury, phd. at 00:23 AM on 19 May, 2011
    I've just checked some of these links people have posted and it appears somebody else is using my same name. I have never heard of a Dr. Shooshmon. The reason I was asking about average global sea level in meters is because I wanted to compare estimated sea level rise rates based on average global sea level and also based on percentage of water glaciers in question of melting hold.
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    Response:

    [DB] This is off-topic for this thread.

21. arch stanton at 01:05 AM on 19 May, 2011
    Adelady (13), I like suspense too, but the question was ambiguous, and no matter how I interpret it, the answer is irrelevant when judging the (human) impact of sea level rise. The doctor has dug himself into a hole (average depth = deep).
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22. Byron Smith at 01:09 AM on 19 May, 2011
    Warming Indicators: The Motion Picture Yes please. That would be excellent.
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23. arch stanton at 01:12 AM on 19 May, 2011
    I missed a response… Doctor - what would be the usefulness of calculating the sea level rise as a percentage of average sea depth?
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24. Dr. Jay Cadbury, phd. at 01:25 AM on 19 May, 2011
    Okay Arch, somebody earlier said "Fully melted Antarctic and Greenland ice caps would raise sea levels by 80 meters, according to the USGS. " That number seems to be way too high to me so I want to know the global average sea level depth and calculate what percentage average sea level would rise. Somebody also said this number is easy to come by, I've been googling and don't see it. There is also no hard numbers for total number of glaciers, globally.
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    Response:

    [DB] KR earlier gave you the link to the USGS site, which itself detailed the sources for the 80 meters quoted.  You are welcome to reinvent the wheel all you like, but not on this thread.  This is now off-topic and further comments on this will be deleted.

25. KR at 01:47 AM on 19 May, 2011
    Jay - I have replied on the far more appropriate How much is sea level rising thread.
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26. arch stanton at 01:52 AM on 19 May, 2011
    Doctor, I don’t see how the depth of the sea is relevant to your question unless of course you were going to include the effect of thermal expansion of sea water. A more relevant question would be the total volume of global land based ice (km^3) / (the total sea surface area (km^2) + whatever new sea surface area would be incorporated by the rising sea level)….I hated calculus.
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