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Snap contest: rising seas, melting ice -- predictions(contest closes 31 Dec 2021, results 2050)

  • 31-10-2021 8:34pm
    #1
    Registered Users Posts: 13,349 ✭✭✭✭ M.T. Cranium
    Registered User


    Enough talk, let's see some numbers ...

    Two questions in this contest, They are actually related if we assume that in net terms, no (or very little) Antarctic ice melts before 2050. Of course some will melt, it does every year, but it is currently sustained by equal amounts of deposition further inland there. Greenland is currently melting down at a rate of about 0.1 to 0.2 per cent a year on average, some years more than others. Canadian and Russian land ice, about 10% of Greenland's load, melt faster than that as the glaciers are smaller and thinner.

    (1) By what levels will global sea levels rise by 2050? (31 Dec 2050 when contest results will be determined by M.T. Cranium III or sryanbruen)

    (2) What percentage of Greenland's land ice will melt by same date?

    This is a serious contest, not joking here, let our descendants know what you were thinking since Greta keeps asking what are we thinking?

    My entries -- 1 meter and 25% (70% of arctic Canada's and Russia's much smaller ice loads will be gone too)

    I believe this will happen because the AGW signal will combine with a natural variability upswing in temperatures, as solar activity returns to stronger levels after this coming peak.

    If I'm not the only person to enter this, we can review progress each five years or so. I may be around for a bit longer to participate in that but at the age of 72 I will go out on a limb and say this contest will fall into the hands of a much younger person than me eventually. Or I will live to be 101. Not really wanting to do that unless health care improves.

    ========================================

    Interesting facts about Canada and Russia -- the arctic islands in both cases have significant amounts of land ice, Ellesmere Island, about the size of Great Britain, is more than half covered today and Devon Island to its south is 75% covered, Baffin Island about 10% covered. The other more western islands are mostly barren rock with patchy permanent snow cover on higher ground but to the north of Victoria Island there are smaller islands with small ice caps and glaciers (Melville Island in particular). And in the Russian arctic, almost all of those islands have some land ice, except for Wrangel Island in the far east. Then there is also Svalbard, a territory of Norway, with a bit more to add. If all of that non-Greenland ice melted, it would be the equivalent of a 10% Greenland meltdown, and if all mountain glaciers melted, that would add 1-2 per cent more.



Comments

  • Registered Users Posts: 8,210 ✭✭✭ Gaoth Laidir
    Registered User


    According to some, we may not make it to 2050, but on the small chance that we do...

    1) Based on the current satellite rate of +3.4 mm/y, a further rise of 90 mm, so the graph below (source) will read 190 mm. Despite this, O'Connell bridge will already be under water.

    2) Greenland will lose around 2.5% of its current volume. The current rate of loss will slow down over the next 10-15 years as the AMO goes negative, and may pick up again thereafter.



  • Registered Users Posts: 13,349 ✭✭✭✭ M.T. Cranium
    Registered User


    Hope you're closer to being correct than me, just for clarity for other entrants, GL's prediction of 90 mm is also 9 cm or 0.09 m, so 9% of my prediction. His ice loss prediction is one eighth of mine. The two predictions are not necessarily linear because there is ice that can melt in places other than Greenland. But the two predictions should be fairly close to proportionate if there is not much loss from the Antarctic ice cap.

    By the way, melting sea ice will have only marginal effects (directly at least) on sea levels. So if you do enter, be mindful of the distinction between land and sea ice losses being discussed by climate scientists (God rest their souls).



  • Registered Users Posts: 632 ✭✭✭ cheezums
    Registered User


    10 cm.


    I think the sea level rise aspect of global warming is poorly understood by the general public and hugely exaggerated by the media.

    I don't have the figures to hand, but glaciers account for a tiny amount of potential sea level rise. greenland ice sheet has about 6 metres worth of sea rise in it. The vast majority of potential sea rise is in the Antarctic ice sheet with about 60 metres worth and until very recently the ice mass was actually increasing. the climate of the continent is as consistent as you can get and doesn't show the same warming trends of the rest of the planet.

    so greenland would be the only one to worry about, and from what I read you are talking 100s of years for all that ice to melt even in worst case warming scenarios.

    extreme weather, drought, food stability and climate migration are what we should really be worried about wrt climate change.



  • Registered Users Posts: 208 ✭✭ littlema
    Registered User


    I feel a head under x3 duvet event by me to counteract this tread and to reduce heating bills by 90%. 😔



  • Registered Users Posts: 3,000 ✭✭✭ Pa ElGrande
    Registered User


    I have a question what datasets are we using as the arbiter for sea level rise (SLR) and surface mass balance in Greenland or are we going with specific sites?

    Because if I go with the NOAA data its 1.7-1.8 mm per year and other data like Chesapeake bay is 3.4 mm per year and the EPA in Ireland are currently going with 3.5 mm per annum since the 1990s with 1 to 2 mm before that period.

    For the record by 2050 I expect between ~50mm and ~90mm rise by 2050 previous sea level rises have never been linear.



    NASA goes with 279 billion metric tons of ice per year between 2002 and 2020.

    The Greenland surface mass balance (above twitter link) has been above average for three out of the past five years. I'm going with a cooling cycle dominating between 2020 and 2050 I'm not expecting much change overall in Greenland coverage but whose data are we working from?



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  • Posts: 0 ✭✭✭ Beckett Enough Penicillin
    Registered User


    Pretty shocked at MTs predictions. Not sure if serious.


    Anyway for me:

    100mm, and 1.2%



  • Registered Users Posts: 13,349 ✭✭✭✭ M.T. Cranium
    Registered User


    I may reduce my numbers a bit by close of contest as perhaps the trends I foresee will not have fully had their impacts by 2050 but that is certainly what I foresee happening eventually in the general time frame of 2050 to 2070 and if it were accelerating by 2050 then the warning aspect of the prediction would be justified even if maybe validation would have to wait a few years. As to whose data they use in 2050 to assess this contest, I will leave that to whoever seems to be in charge of the contest at that point in time, my input might be ghostly by then. But you never know, I made it through one rather moderate bout of COVID19 and perhaps will also defeat COVID 27 and COVID 44.



  • Registered Users Posts: 5,933 ✭✭✭ pauldry
    Registered User


    I'll go for 70mm sea level but will go out on a limb and say Greenland will lose another 10%



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