United Press International: Global warming is forcing animals to higher elevations, causing them to intrude on established populations, a U.S. scientific journal says. Some mountain animals, left with smaller ranges to forage for food, face extinction while others are competing with animal populations in new habitats, Science reported. “These kinds of changes have been going on forever,” said James Patton, a biologist at the University of California, Berkeley, Museum of Vertebrate Zoology. “The …