You are still cherrypicking by concentrating on these data, which are not conclusive. /so, you show me part of an in-depth paper saying that there were data before 1979 .It appears there might. However, in the paper, it says there was not much variance in sea ice significantly between the 1953 and 1984, but that 1960-80 was significantly colder anomaly period. (pp 224-5). But after that... much decline. None of what you talk about it particularly relevant, given ALL the other data about melting glaciers and sea ice extents since 1990, which you carefully ignore.
Look here, for example https://sites.google.com/site/arcticseaicegraphs/longterm