The criteria for resolving yes is that the Arctic must be fully ice-free at any point in time between now and the start of 2050. The Arctic does not need to be fully gone by the year 2050, it just needs to be ice-free at a moment in time.
Whether the Arctic is fully ice-free will be based on news articles from reputable sources. If there's any controversy, I will discuss about it with Manifold users in the comments.
As a last resort of resolution criteria, this question will resolve Yes when the Arctic ice coverage (at a threshold 15% ice density) falls below 100,000 km squared, as reported in numbers from http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
The Arctic has less ice cover in summer than in winter, so it is plausible that in summer, the Arctic will be fully ice-free, but in winter, it will reappear. This type of scenario will resolve as Yes.
Relevant info:
https://english.elpais.com/science-tech/2023-06-07/the-arctic-is-set-to-completely-melt-for-the-first-time-within-two-decades.html
A study supported by observations from NASA and ESA satellites and a sophisticated climate model predicts that the first ice-free September will arrive between 2030 and 2050.
https://phys.org/news/2019-11-arctic-ocean-ice-free-year.html
According to a new study by UCLA climate scientists, human-caused climate change is on track to make the Arctic Ocean functionally ice-free for part of each year starting sometime between 2044 and 2067.
1,000
3.00You may update the title :)
Added 4k subsidy
It is interesting.
Pretty much all the models seem to show that after a period of rapid decline, the rate of decline then becomes slower and slower. This is exactly what we have seen since a rapid decline circa 2000-2012.
This could well be an indicator that the rapid decline is just easy areas melting out and that from now on it gets harder and harder to melt additional areas. This can also be explained in a few ways:
In terms of ice movements: The areas that have retreated are along the Russian side. These areas generally have ice moving away from the coast due to the general movements of the Beaufort Gyre and the Transarctic drift. Because the ice is moving away from the coast gaps tend to open up and this allows extra solar energy to be absorbed by the darker water which assists melting. Contrast near Greenland and Canadian Arctic Archipelago the movements tend to be toward the coast so any gaps that form from melting and cracking tend to close up again.
Thick multiyear ice. Pre 2000 thick multiyear ice used to survive the trip around the Beaufort Gyre. This is fresher water as salt is removed by melting and freezing processes so it is harder to melt the ice and with more thickness there is also more ice to melt. As retreat worked further in from Chukchi, less of the thick multiyear ice made it round the Beaufort gyre so in subsequent years the multiyear ice became, in general, younger so thinner and saltier and less and less made it around the gyre. This made it easier to melt a bit more of the multiyear ice each year in the Chukchi and East Siberian sea until very little now makes it around the gyre.
So the rapid decline near the Russian coast became a vicious circle of enhancing effects during ~2000-2012. Now the ice melts out every year in these areas these effects have ceased and the remaining ice gets harder and harder to melt out.
When you understand how these different areas have behaved differently it becomes obvious that the rate of decline is likely to slow down as the models show and can be seen since ~2012.
The scientists often refer to less than 1 million km^2 extent as ice free or practically ice free. By 2050 we could well be down to that sort of level. However here you have set the level at 100,000 km^2 so I think there is a good chance that at least that amount will remain at the summer minimum until 2050.
Not sure if you wanted such comments but perhaps this might be helpful. Good luck with your debate.
@bohaska I would change the title to include that then. As written I take the Arctic fully melting to include Greenland.