There are no very long term data sets that are consistent due to a range of factors including standards, methodologies, and technology. In the case of sea ice, the 30 year average referred to in my earlier post provides, for the first time for this data series, reliable, consistent and accurate information.Sneak'n,
Which comes back to one of my original points, that there is no clean data set, that has not been adjusted, that shows climate change of any significance, in a world where the climate does change all the time. This is even before we get to any discussion on weatherit is man made, or if it is possibly a good thing (like keeping us from having an ice age).
brty
Trends are identifiable through the time series, and are typically self-evident.