United Nations secretary general Ban Ki-moon with actor Leonardo DiCaprio during his designation ceremony as the UN Messenger of Peace. Photograph: EPA
Julian Borger - New York The Guardian
21 Sep 2014 16.55 BST
More than 140 heads of state and government fly in to New York this week for the United Nations general assembly amid apprehension that international order is unraveling at an accelerating pace, while the world's leaders seem ever less willing or able to deal with the proliferating threats.
The UN's humanitarian agencies are in danger of being completely overwhelmed by the multiple crises. Ebola is spreading rapidly across West Africa, swamping rickety national health systems and a thus-far underfunded UN effort to stop its advance. The spread of Islamic State (Isis) extremists in the Middle East, feeding on the destruction of the Syrian civil war and exposing the weakness of the Iraqi state, has similarly outpaced patchy international efforts at containment.