Pseudoscientists cherry pick data that suits them, and ignore wider contexts.
This is the kind of thing that 9-11 twoofers have to do in order to maintain their inaccurate worldviews. Find the ONE bit of data to cling to, ignore anything else that contradicts it, and claim that anyone who puts forth data that contradicts this world view is part of the conspiracy.
Missing bits of context:
What about the land ice?
What is happening at the other pole?
How thick is the sea ice? (volume has three dimensions, length, width and depth, so it is possible for something to be longer and wider, but still have less volume).
http://www.skepticalscience.com/arct...ic-sea-ice.htm