World leaders meeting in New York on September 18 will try to revive key goals meant to improve the lot of humanity by 2030, plans that are in doubt today as hunger, poverty and other crises persist. "In thriving economically in the 21st century, you cannot any longer try to do so at the expense of nature, or at the expense of people who are left behind," the head of the United Nations Development Program, Achim Steiner, tells AFP. IMAGES AND SOUNDBITES