Reuters: North America’s coastlines would be hit especially hard by rising sea levels if the huge West Antarctic Ice Sheet collapses and melts in a warming world as some experts fear, scientists said on Thursday. The loss of that ice sheet alone would inundate some coastal areas, swamping New York, Washington D.C., south Florida, Los Angeles, San Francisco and Seattle, with sea levels in some places higher by 21 feet or more than today, the researchers wrote in the journal …