After being held captive for five years, U.S. Army Sergeant Bowe Bergdahl is headed home. But the story is far from over. It's first up today on CNN STUDENT NEWS.There are a lot of questions surrounding the prisoner exchange that led to Sergeant Bergdahl's release. We covered a couple of them in yesterday's show.There's also a debate going on about how and why Bergdahl went missing in the first place.The Pentagon says it doesn't know why he left his Army base in Afghanistan in June of 2009,but some soldiers in Bergdahl's platoon say he deserted and that at least six U.S. troops were killed while looking for him.One soldier,a sergeant whom Bergdahl served with,criticized the government's decision to secure Bergdahl's release by freeing five Taliban prisoners at the U.S. military base in Guantanamo bay, Cuba.Outgoing White House spokesman Jay Carney says that what matters is that Bergdahl was a prisoner in an armed conflict,and that the U.S. doesn't leave its men and women behind. Bergdahl's recovering in an American military base in Germany.His father says there will be a long process of getting Bowe Bergdahl transitioned back to American life.Yesterday, President Obama announced an executive order.This is a type of law that doesn't need Congressional approval, and this is a big one.It requires power plants to reduce their carbon emissions by 30 percent by the year 2030. Many scientists blame carbon emissions for damaging the environment.