The data are not really the same and the methods used are not either. There are many people that live in or near the sea ice region in the Arctic, lots of observation points, more aircraft, the shipping industry is always watching, etc. For example, pretty much every southward bound ice berg that forms in the North Atlantic is identified, numbered, and tracked. In the southern ocean, there are very few living people most of the year, and nowhere near the data on the ground. It is absolutely possible for some buoys or or sat data to be off in the southern ocean with very little ground truthing, and the data density is very different.

Filip, I think that is a very interesting and pertinent question. I think I might know the answer to it too, but I’m very busy this morning. I will try to get back to this later. The question brings up a lot of interesting aspects of the research.

Btw, I am not a climate change science denialist!