The arctic ice cap has existed for at least 5 million years, not decades. It has diminished with summer melt, but it has never come close to melting to the point of a blue ocean event (essentially gone) in the time that humans have been on earth in any form.

"Parts of the Arctic have been covered by the polar ice cap for at least the last five million years, with estimates ranging up to 15 million." http://science.jrank.org/pages/5371/Polar-Ice-Caps-Polar-ice-caps-geologic-history.html

You could not be more incorrect.