Giving the warning about the world situation, he said on Tuesday that he will use the landmark anniversary to listen to what people want the UN to be.
"I want the UN, in this anniversary, essentially to listen - so we are marking our anniversary based on conversations in every corner of the world about the future we want and the UN we need," he said at a news conference.
He said: "The disquiet in streets and squares across the world is proof that people want to be heard. They want world leaders to answer their anxieties with effective action."
His bleak prognosis was based on the lack of action on climate change, the retreat from deescalation of the high levels of tensions seen last year, faltering economies and terrorism.
"There is a feeling of growing instability and hair-trigger tensions, which makes everything far more unpredictable and uncontrollable, with a heightened risk of miscalculation," he said.
He said: "He saw problems feeding on each other and escalating: As economies falter, poverty remains entrenched; As future prospects look bleak, populist and ethnic nationalist narratives gain appeal; As instability rises, investment dries up, and development cycles down. When armed conflicts persist, societies reach perilous tipping points. And as governance grows weak, terrorists get stronger."
"In the year ahead I will press to break the vicious circles of suffering and conflict and to push for a strong surge of diplomacy for peace," he pledged.
Replying to a reporter's question on climate change, he said that India and the other big emitters of greenhouse gases have to keep their commitment to become carbon neutral by 2050 because that is the only way to keep global warming down.
(Arul Louis can be contacted at arul.l@.in and Nikhila Natarajan can be contacted at @byniknat)
( With inputs from IANS )