Following Neven's suggestion* (copied below) I re-enclose here the two links that I originally posted on 27th June to "The 2017 Melt Season" thread. Which better fits this thread:
Once the Blue Ocean event materializes on the North Pole and the Arctic Ocean becomes ice-free in the summertime, this leads almost immediately to:
1) rapid acceleration of land-based snow and ice melting that begin to mop up the heat sea ice no longer takes for its melting. These will lead to the risk of very rapid sea level jump and other effects as per the evidence I gave at the UK Houses of Parliament in April:
https://www.academia.edu/33000316/MPs_to_review_UKs_role_in_Arctic_sustainability_-_24th_April_2017.docx2) massive acceleration of seabed based methane release risk like reported in this recent article which was since then re-posted here by others. This link:
http://envisionation.co.uk/index.php/nick-breeze/203-subsea-permafrost-on-east-siberian-arctic-shelf-now-in-accelerated-decline3) I add a third effect to sea level and other land-based effects to these effects. Once there are no sea ice floes left at the Central Arctic Basin, the sea ice growth no longer advances from the North Pole to the South (towards the ocean's perimeter). Now the re-freeze must progress inversely from the perimeter in the south towards the North Pole at the centre of the ocean. This inversion of the direction in spreading of the sea ice's margin growth leads to 4-8 weeks' delay.
Since sea ice has a tendency to be packed against coastal barriers, it will be two delays:
(A) re-freezing must wait until the coastal margin reaches the freezing point (sea ice leads currently begin to cool down from 25th July onwards at CAB and are the first area to freeze) - for the coastal margins to reach the point, a delay is up to two months (positive methane feedback).
(B) the churning of the ocean keeps waters in the Central Arctic and the North Pole increasingly open even in midwinter due to the open waters there mixing vertically. In addition, the growing temperature gradients between a stubbornly-warm ocean center in winter and the rapidly cooling continental landmasses in wintertime (around its perimeter) cause wind and wave actions. The waves break the ice and the winds then will push broken ice towards the Atlantic Ocean and the shorelines where newly formed ice accumulates along seasides. The center remains open and releases heat and snow storms: the Ewing-Dunne 'Lake Snow Effect' of the Arctic Ocean. (The 1950's idea of Maurice Ewing and William Donn that the Ice Ages were caused by the ice-free Arctic Ocean acts like snow cannon to accumulate so much precipitation that it could not possibly melt away during the subsequent short summers of high latitudes.) Even temporary ice shelves may be produced along the shorelines by intense storms piling up sea ice i.e. along the Ellesmere Island and the Queen Elizabeth Islands, topped up with massive snowfalls.
In other words (B) the Central Arctic winter hole will form that delay the onset of sea ice formation and makes it much thinner and volatile for breaking - hence further lowering of the spatial viscosity of the Arctic Sea ice. The warmer and wetter winters bode badly for methane clathrates and methane which can escape from the ocean unhindered by sea ice layer.
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*Hi Albert, There are various threads to talk about consequences (check the Permafrost category, for instance, there are several threads on methane) or politics. I want to keep the melting season thread as uncluttered as possible, because that's the best-read thread at the moment, and long, off-topic comments are highly off-putting. So, either stay on-topic or keep it short. And if people reply to something off-topic, please invite them to a more appropriate thread and continue the conversation there. It will also make it easier to find at a later time. Thanks, Neven