Report: NSIDC ‘deleted a lot of older Arctic ice when they switched maps’
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.
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.