Sea Ice Extent

Arctic Sea Ice Extent 1979-2017 (aka "The Ice Extent Death Spiral")
This graph divides each calendar year into 12 "slices", one for each month. Arctic sea ice extent is plotted for each day of the year,
moving clockwise around the graph and taking one full year to complete a circuit. The extent of sea covered by ice on a particular
day is represented by that plot's distance from the center of the graph; as shown by the vertical axis, greater ice extent places the plot
farther from the center of the graph, while lesser ice extent places the plot closer to the center. Past years are represented by thin gray
lines, while decadal averages and the current year are thicker and color-coded as detailed in the legend.