Every month I post here a graph showing the sea ice extent in the Arctic ocean, contrasting the amount of sea covered by ice with previous months back to the beginning of the era of satellite monitoring (1979).
But ice extent is an area measure, it does not take into account the thickness of sea ice, which normally is in the range of several meters.
This video examines that parameter.
https://www.youtube.com/watch?v=JYNDT2kProU
Data is from the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center.
It must be pointed out that the ice area can be measured unambiguously and with great accuracy and precision by IR radiometers on spacecraft, while ice thickness must be modeled using a variety of different types of data. That is, this is not primary observational data, but involves interpretation and certain algorithmic assumptions. For more links and information on this process, as well as additional data and interpretation, please consult the Neven Ice Blog.
http://neven1.typepad.com/
It may too late to do anything about this, but we still have some time left to reflect on it.