are from syria and that nation has lost a huge portion of the population since the uprising against the assad government began four years ago. in 2011 the population was estimated at 22.4 million. since then at least 7.6 million have been internally displaced meaning they fled their homes but stayed in the country. >> another 4 million have fled syria altogether, most going to lebanon, turkey, or jordan. more than 250,000 syrians have been killed in the continuing war. that leaves about 10.6 million syrians remaining where they were four years ago. strong words and warnings from u.s. president barack obama during an international conference in alaska on the effects of climate change. >> this is the start of a three-day visit to highlight the impact of climate change which mr. obama called the defining threat of the century and