Reader Chris71 has discovered the smoking gun on the NSIDC web site. Read on.

A few weeks ago, NSIDC put out this press release, claiming that 5+ year old ice is at its smallest level on record.

ice at least 5 years or older, is at its smallest level in the satellite record, representing only 3 percent of the total ice cover

The press release included the map below. This is a new style map which they just started in week 39 2015. The map below is for week 41 2015. All of their previous 1984-2015 maps have been deleted from their archive.

March ends a most interesting winter | Arctic Sea Ice News and Analysis

The good news is that Chris found one of their old style maps which had not been scrubbed from their website, and is annotated with the following text.

This graph is reloaded from ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age${year}_${month}.gif every day and is available here as http://www.arctic-charts.net/ccar.colorado.edu/pub/tschudi/iceage/gifs/latest.gif

www.arctic-charts.net/ccar.colorado.edu/pub/tschudi/iceage/gifs/

NSIDC has deleted the original graphs, but seem to have forgotten to get rid of the copy.

Here is where they get in trouble. Besides deleting data, NSIDC also deleted a lot of older ice when they switched maps. Note inside the circle how the red five year old ice has disappeared in their new maps.

The alterations are huge, and shown in the graph below. NSIDC deleted almost half of the five year old ice when they switched to the new maps. They also deleted about a third of the four year old ice, and some of the three year old ice.

Referring back to the top graph again, it becomes clear what they are up to. Had they used the same map set for the 2016 data as they did for all the other data in the graph below, 2016 would have had the most 4+ ice since about 2009. The graph below is junk science, useful only for propaganda.

It is bad enough that they switched data without telling anyone and used it to generate meaningless propaganda, but they also deleted all of the 1984 to week 36 2015 data from the disk. Fortunately they missed one map, which is the smoking gun. If the old data was that bad and needed to be deleted, then any comparisons made between the old and new data are extremely misleading- which is exactly what NSIDC was doing. They tracked that region of five year old ice for several years, and then suddenly decided it didn’t exist. Unbelievable.

They are busted, big time.