Maybe you have read about this; an expedition being undertaken by three people to measure the thickness of the ice around the North Pole. To do this they will have to walk 2,000km (1,200 miles) from Point Barrow, Alaska, to the geographic North Pole; a journey that will take approximately 100 days. The three people are Ann Daniels, a member of the first all-women teams to trek to both the North and South Poles; Pen Hadow, the first explorer to trek solo and unsupported from Canada to the North Pole and Martin Hartley, a specialist polar photographer. They started on February 28th and details of their progress can be found on the BBC website, here.
What I am confused about is why in all the reports that I have read it says something to the effect that they are doing this in order to discover how quickly the sea-ice is melting and how long it might take for the ocean to become ice-free in summers. Since nobody has done this before how can they discover how quickly the sea-ice is melting? Surely all they can do is determine a baseline for future comparison. However, I am then confused because I know that the ice at the North Pole is floating and it moves. So when somebody in a few years time measures the thickness of the ice at 81°55’N, 129°52’W will they be able to compare their measurement of the thickness of the ice at that point with the one taken on this expedition and be able to come up with a meaningful conclusion?