The United Nations on Tuesday enlisted a high-profile roster of royalty, entertainers and business leaders to promote its global goals tackling climate change, poverty and conflict that were approved last fall but have slipped from the headlines. Their task is to boost awareness and discussion of the 17 Sustainable Development Goals , which the 193 U.N. member nations approved in September to great fanfare and aim to achieve by 2030 at a cost estimated at US$3 trillion a year.