New York Times: President Obama used a commencement address on Wednesday at the Coast Guard Academy to cast his push for urgent action to combat climate change as a national security imperative, saying that the warming of the planet poses an immediate risk to the United States. The speech was part of an effort by Mr. Obama to make a multipronged case for his ambitious climate-change agenda, which he has identified as a top priority for the remainder of his time in office and as a central element of his legacy....