As icebergs drifted by his Antarctica-bound ship, David Holland spoke this week of how the melting glacier he's cruising towards may contain warning signals for the coasts of far-off Canada. The atmospheric and ocean scientist from Newfoundland is part of an expedition to one of the world's most frigid and remote spots -- the Thwaites glacier in the western portion of the continent -- where he'll measure water temperatures in an undersea channel the size of Manhattan.