The image on the right shows a NASA Worldview satellite image of a blue Beaufort Sea (with Barrow, Alaska, at the top left, on September 7, 2022). The image shows that there is a lot of open water between the coast of Alaska and the sea ice. Such a satellite image provides a visual way to determine how much sea ice is present. It can be hard to determine where there is open water and where the sea ice starts; the sea ice is often covered by clouds; furthermore, even when there are no clouds, the question remains what is to be regarded as sea ice and what is to be regarded as water. Another way to measure how much sea ice is there is to look at sea ice concentration. Sea ice concentration in the Central Arctic region has been very low for some time. The image on the right, from an earlier post , shows that on August 12, 2022, sea ice concentration in a large area close to the North Pole was as low as 0%. In the two images below, Nico Sun calculates the ...