Monday, August 3, 2015

Sea Level Fall: The Forgotten Aspect of Sea Level Rise?

Fig. 1 Climate Change and Sea Level
I. Background

Regular readers know that I have been putting a lot of research and writing into the subject of sea level rise (SLR) this year.

That is not to imply that I haven't written anything at all about SLR in years past (e.g. Will This Float Your Boat?, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11; May 2011 -  May 2015).

What I have not focused on is sea level fall (SLF).

While researching the issue, while developing software to calculate future SLR, and while urging more attention to SLR, I just had an epiphany today.

I seems to be science fiction at first blush, but the epiphany is this: regarding the Greenland and Antarctic ice sheets, unless we have had an SLF, we cannot yet have had an SLR.

That is, unless the science team that I wrote about on Friday has presented an invalid hypothesis (Is A New Age Of Pressure Upon Us? - 7).

II. The Issue of Gravity Loss @ Greenland & Antarctica

Take a careful look at Fig. 1 and Fig. 2, as well as the posts they link to, because they show that both SLF and SLR are one of the results of melting ice sheets.
Fig. 2 Axis Upheaval

That is, Fig. 1 and Fig. 2 show a fall in sea level around both Greenland and Antarctica as a result of the loss of gravity caused by the loss of ice mass on those two ice sheets.

And of all things, like I wrote about in Friday's post, quoting the science team that works on this physics oriented aspect of SLR / SLF, when the ice sheet of West Antarctica (WAIS) melts, the resulting SLR of 4 ft. will manifest at, of all places, the coasts of the United States!

Not only that, the same thing happens to the U.S. when the ice sheet at Greenland melts (Greenland & Antarctica Invade The United States, 2, 3).

Double whammy!

III. The Gravamen of the Situation

We must with all dispatch determine if the science in the hypothesis of Professor Jerry X. Mitrovica et al. is correct (see video below).

We must determine if the SLF around Greenland and Antarctica can be detected, and if not, why not.

Fig. 3 Alaska SLF
GRACE, the satellite, has already shown that there is detectable gravity loss in the WAIS.

There is SLF around Alaska where glaciers along with their gravity have vanished into history (Southern Alaskan Sea Level Fall).

The ice shelf floating on the ocean around Antarctica may be a deterrent to detecting SLF there, but there are open water areas around Greenland where that is not the case (e.g. Baffin Bay).

Check it out dear scientists and/or readers.

IV. The Potential Consequence of Not Knowing

There would be no loss of gravity if all the meltwater was going into the huge canyons and river systems beneath both Greenland and Antarctica (The Surge: A Forgotten Aspect of Sea Level Rise).

Which means that at any time whatever is damming the meltwater, whatever is preventing it from reaching the sea, is keeping the gravity there above the land (water has mass, ergo gravity).

Which could set up a "pulse 1C" type of event.

A surge (or "pulse") in this case is a sudden release of meltwater when an obstruction gives way letting all the gravity and water flow into the sea away from the land:
However, meltwater pulse 1C (8,200-7,600 years ago) left traces at numerous locations in the United States, northwestern Europe, and China. It occurred soon after the 8200 year cold event, which resulted from the final catastrophic drainage of glacial Lakes Agassiz and Ojibway around 8400 years ago. The torrent of around 100,000 cubic kilometers unleashed within a few years or less amounted to barely a meter rise in global sea level, if evenly spread across the world's oceans (note 1). Yet the stratigraphic record preserves vestiges of this relatively minor pulse.
(The Surge: A Forgotten Aspect of Sea Level Rise, cf. Weekend Rebel Science Excursion - 45). SLF is the hidden gorilla in the SLR room, and it should be studied forthwith.

V. Conclusion

Somebody has to do it.

In the next few days or so I am upgrading my SLR calculation software to also deal, in some way, with the concept of gravity induced SLF (unless comments by regular readers have valid contra information).

Professor Jerry X. Mitrovica on the gravity / axis bulge SLR issues we don't hear about often enough:

05:00 ... an ice sheet has mass, so it has a gravity effect on the sea water around it.

18:15 ... if glaciers melt in Alaska, sea level around it will drop (see Fig. 3 above).

14:20 ... the scientific literature points out that sea level does not rise nor fall the same all around the globe (it is called "the European problem"). 

19:15 ... unevenness of SLR / SLF informs which ice sheet is melting (e.g. in Greenland or in Antarctica).


  1. "World's Glaciers Melting At Fastest Rate Since Record-Keeping Began" (link)

  2. good find Randy:

    [linked from seemorerocks today]


    “Today we present observational evidence that a large section of the West Antarctic Ice Sheet has gone into irreversible retreat,” an author of one of the papers, Eric Rignot, a glaciologist at NASA’s Jet Propulsion Laboratory, said at a news conference recently. “It has passed the point of no return.”


  3. I am looking for links to any information about SLF being detected near the coasts of Greenland and/or Antarctica.

    I found one indicating an SLF in S.E. Alaska where glaciers are melting.

    I put it in the post (Fig. 3).

  4. I put that comment up after viewing the video, which corroborates that the WAIS is indeed heading seaward, so the rest of the physics knock-on effects Jerry describes (like SLF) will be taking place - and will be measurable at some point. This kind of news will "trickle" in as it becomes known.


    1. Tom,


      Let's keep an eye out for them so other readers, as well as ourselves, can keep up to date on the matter.

      This SLF/SLR contrast exacerbates the ports problem exponentially.

      Some port authorities are going to have to deal with SLF of varying degrees, while others are going to have to deal with SLR of varying degrees.

      All at the same time.

      This is big news I think.