New York Times: Half a century after Pacific walruses began recovering from industrial-scale hunting, marine biologists are growing worried that they face a mounting threat from global warming. Masses of lumbering walruses have been crowding on beaches and rocks along the Russian and American sides of the Bering Strait in the absence of the coastal sea ice that normally serves as a late-summer haven and nursery. While the retreats in sea ice around the Arctic this summer were not as extensive …