Huffington Post: The Islamic State may be the most immediate challenge facing the Defense Department, but Secretary Chuck Hagel said Wednesday that one of the biggest long-term security threats to the U.S. isn't a terrorist group. It's climate change. "From my perspective, within the portfolio that I have responsibility for -- security of this country -- climate change presents security issues for us," Hagel said during remarks at the Washington Ideas Forum. "This is critically important that we pay attention to...