re: #270 Pythagoras

The graph in #230 is NSIDC’s plot of the September Arctic Sea Ice Extent. It represents area, not volume (or thickness), but it is a very reliable data set, produced by painstaking analysis of satellite photos. I realize that thickness can be different but when sea ice increases for two years in a row, there’s going to be more 2nd & 3rd year ice than before — thus it should be thicker.

This is From the site you linked to:

In addition, ice extent is only one measure of sea ice. Satellite measurements from NASA show that in 2008, Arctic sea ice was thinner than 2007, and likely reached a record low volume. In the spring of 2009, Arctic sea ice was even thinner than in 2008.

nsidc.org