Oh just being contrary for the fun of it. I do think the sea ice free date is beyond any of the choices you have given so did not vote.onlooker wrote:thanks for that reply vts , that will clarify it for those who detect ambiguity. Though some already correctly assumed I meant sea ice.
Now if you were passing out money to the winners you would indeed have to have a very clear and measurable definition of what constitutes "Ice free".
Perhaps being able to sail a none ice breaking ocean vessel straight north from any point on the arctic shore line , over the pole and then south to the opposite shore without having to change course to avoid any ice. The usual turns for shallow water and islands excepted of course.
Maybe around 2030 depending on how events play out.