BY CHERYL KATZ A conveyor belt of ocean water that loops the planet and regulates global temperatures could be heading for a tipping point. THE HIGH ARCTIC, ABOARD THE R.V. KRONPRINS HAAKON Summer sea ice has been shrinking so dramatically here in the Fram Strait, high in the Arctic between Norway and Greenland, that researchersContinue reading “Why is an ocean current critical to world weather losing steam? Scientists search the Arctic for answers.”