The number of refugees crossing borders to escape conflict and persecution increased last year, and threatens to continue to grow because of factors like climate change and scarce resources, the United Nations refugee agency warned Tuesday. The Office of the United Nations High Commissioner for Refugees oversaw the care of 11.4 million refugees in 2007, including about 400,000 people who were enduring conflict in their own countries, the agency said. The total was 9.9 million people in 2006. The numbers were modest compared with the 17.8 million refugees during the Balkan wars in 1992, but after a steady drop from 2001 to 2005 they represent a worrisome trend, the agency said. "We are now faced with a complex mix of global challenges that could threaten even more forced displacement in the future,' Ant