The Northwest Passage–the legendary shipping route through ice-choked Canadian waters at the top of the world–melted free of ice last week, and is now open for navigation, according to satellite mosaics available from the National Snow and Ice Data Center and The University of Illinois Cryosphere Today. This summThe Northwest Passage–the legendary shipping route through ice-choked Canadian waters at the top of the world–melted free of ice last week, and is now open for navigation, according to satellite mosaics available from the National Snow and Ice Data Center and The University of Illinois Cryosphere Today. This summer marks the fourth consecutive year–and fourth time in recorded history–that the fabled passage has opened for navigation.er marks the fourth consecutive year–and fourth time in recorded history–that the fabled passage has opened for navigation.

(Reposted from Climate Progress)