The cause of this cold lurch was seemingly settled some time ago when Wallace Broecker, a Columbia University geochemist, suggested that a North American ice sheet collapsed, flooding the Atlantic with fresh water, which interrupted the normal circulation of the Gulf Stream.
Warm conditions in the Atlantic and cooler conditions than normal in the Pacific Ocean also have forced the jet stream farther north and created a corridor for newly born hurricanes to move unimpeded from the ocean waters up the Atlantic coast, Liu said.