Voice of America: United States Special Envoy for Climate Change Issues Todd Stern told senior visiting Chinese government officials that under the administration of President Barack Obama, climate change has "risen to the top of the U.S. national security set of priorities." Speaking in a teleconference with U.S. officials July 27, after the first day of the U.S.-China Strategic and Economic Dialogue, Special Envoy Stern said that "this issue is of high importance to the President, the Secretary of …