Changes in Arctic sea ice coverage from 1978 to 2008 developed by Ignatius Rigor at the University of Washington, Seattle Applied Physics Lab. Pulses depict the annual expansion and contraction of the sea ice from winter to summer. Red dots represent the buoys that measure the ice
Arctic sea ice has declined slightly less dramatically this year than in the past couple of years. But the seasonal minimum, reached this week, is still the third-lowest on record since satellite radar measurements began.
This summer, a group of scientists and students set out from Resolute Bay, Canada, on the icebreaker Louis S. St-Laurent. They were headed through the Northwest Passage, and combined satellites and submarines datas to piece together a history of ice thickness during the last 50 years.