Earlier this week, the University of Washington’s Polar Science Center released its latest Arctic sea ice measurements to make them current as of September 15, 2010. The Polar Science Center uses a satellite to measure the three-dimensional volume of the Arctic sea ice (a approach different than that of the National Snow and Ice Data Center, which measures the two-dimensional extent of Arctic sea ice).
As usual, Polar Science Center data is presented in the form of two graphs which should be interpreted jointly. The first graph is a description of the 1979-2009 average volume of the Arctic sea ice at the midpoint of each month of the year. Units are in thousands of cubic kilometers.
The 1979-2009 average Arctic sea ice volume in the middle of September is about 13,500 cubic kilometers. The graph below shows the deviation from each month’s average volume over time, with the last reading to the right being the deviation from average measured on September 15, 2010. As you can see, on September the volume of sea ice in the Arctic was about 9,500 cubic kilometers below the average.
From this point, it’s a simple exercise in math: 13,500 cubic kilometers minus 9,500 cubic kilometers is 4,000 cubic kilometers. According to Polar Science Center measurements, there are only 4,000 cubic kilometers of Arctic sea ice left. The Arctic sea ice has shrunk 70% from its recent average, a stunning climate change.
Units are 1000s of cubic kilometers. For example, looking at the far left-hand side of the graph, we can see that on the first day of measurement in 1979 the volume of sea ice stood at a point 5,000 cubic kilometers greater than the average for that day of the year, averaged from 1979-2009.